JP2016501044A - Apparatus and method for operating a wide diopter range real-time sequential wavefront sensor - Google Patents

Abstract

A light source (172), a beam deflection element (112), a position sensitive detector (122) configured to output a plurality of output signals, and each coupled to receive one of the detector output signals A sequential wavefront sensor is disclosed that includes a plurality of combined transimpedance amplifiers (see FIG. 11). The output of each composite transimpedance amplifier is phase-locked to the light source drive signal and the beam deflection element drive signal.

Description

This application is a priority from US Provisional Patent Application No. 61 / 723,531, filed Nov. 7, 2012, entitled `` Apparatus and Method for Operating a Real Time Large Diopter Range Sequential Wavefront Sensor. '' Asserts rights.

TECHNICAL FIELD OF THE INVENTION One or more aspects of the present invention generally relate to wavefront sensors for use in vision correction procedures. In particular, the present invention relates to electronics and algorithms for driving, controlling and processing real-time sequential wavefront sensors and other subassembly data associated with the wavefront sensors.

BACKGROUND OF THE INVENTION Conventional wavefront sensors for characterization of the human eye wavefront generally take one snapshot or several snapshots of the patient's eyefront with the room illumination diminished or turned off. Designed. These wavefront sensors generally require the use of a CCD or CMOS image sensor to capture wavefront data and the use of relatively complex data processing algorithms to resolve wavefront aberrations. Due to the fact that CCD or CMOS image sensors generally have a limited number of gray scales and cannot be operated at frame rates well above the 1 / f noise range, these wavefront sensors are The lock-in detection scheme cannot be fully utilized to provide a higher signal-to-noise ratio. They cannot quickly derive wavefront aberrations using a simple algorithm. As a result, when these wavefront sensors are integrated with an ophthalmic device such as a surgical microscope, they generally turn on accurate / reproducible real-time wavefront aberration measurements, especially the illumination light of the microscope In state, can not be provided.

  There is a need in the art for an apparatus and method that not only achieves real-time wavefront measurement and display, but also addresses a variety of problems, including those described above.

  One or more embodiments meet one or more of the needs identified above in the art. In particular, one aspect is an electronic control and drive circuit with associated algorithms and software for driving, controlling, and processing real-time sequential wavefront sensor data to achieve various functions. .

  Circuits include optoelectronic position sensitive detector / device (PSD) such as quadrant photodiode / detector / cell / sensor or lateral effect position sensitive detector, transimpedance amplifier, analog-to-digital (A / D) converter, programmable Digital amplifier with gain control, super luminescent diode (SLD or SLED) and its drive circuit, wavefront scanning / shifting device and its drive circuit, and front-end data processing unit (eg processor, microcontroller, PGA, programmable device) )including. In addition, a camera is used to provide a live video image of the eye whose wavefront is being measured. In addition, a back-end data processing unit is used to convert sequential wavefront data from the front-end processing unit to display clinical ophthalmic information superimposed or side-by-side with a live image of the patient's eye. Circuits (front end and / or back end) include, for example, lateral eye position measurement devices, eye distance measurement devices, adjustable eye fixations, data storage devices, laser-based surgical ablation devices, and display devices It can be electronically connected to one or more various devices in some way for coordinated operation of each device.

  One aspect of the present disclosure uses a variable gain amplifier between a transimpedance amplifier and an A / D converter in the above circuit to achieve a wide range of signal strength measurements over a wider signal strength dynamic range. It is. The need for such a wide signal strength measurement dynamic range is various, such as dense cataract eyes vs. aphakic eyes, or long eyes vs. short eyes, or long distances from the eyes or bright external lighting. Because of eye conditions or environmental conditions arises from the need to measure both weak and strong wavefront signals.

  Another aspect of the present disclosure provides a high impedance as part of a transimpedance amplifier to maximize signal to noise ratio, reduce electronic noise, and maintain amplifier stability without reducing gain bandwidth product. Using a composite amplifier with a feedback resistor.

  Yet another aspect of the present disclosure is to combine a composite transimpedance amplifier and a lock-in detection circuit to recover a small signal that would otherwise be obscured by a much larger noise source than the signal of interest. .

  Yet another aspect is a light source configured to output a light beam to illuminate a subject's eye; a light source driver coupled to the light source and configured to output a light source drive signal at a first pulse frequency A position sensitive detector having a plurality of detector elements configured to output a plurality of detector output signals indicative of the signal intensity of incident light at each detector element; and the target eye is illuminated by a light source A first beam deflection element configured to block the wavefront beam returned from the subject's eye when directed and to direct a portion of the wavefront from the subject's eye through the aperture to the detector. The portion of the wavefront directed through the aperture forms a spot on the detector, and the magnitude of the centroid deflection of the spot from the reference point at the detector determines the ratio of the signal intensity. A first beam deflection element approximately indicated by a lick combination and the magnitude of the deflection indicating the degree of tilt or convergence or divergence of the portion of the wavefront from the plane wave; coupled to the first beam deflection element; A beam deflector drive circuit 720 configured to output a beam deflector drive signal to scan a portion of the wavefront at a wavefront scanning frequency; coupled to receive one of a plurality of detector output signals; A plurality of composite transimpedance amplifiers each having an input and an output for providing an amplified detector output signal, wherein the output of each transimpedance amplifier is phase locked to the light source drive signal and the beam deflection element drive signal. A wavefront sensor including a plurality of composite transimpedance amplifiers.

  These and other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments in conjunction with the accompanying drawings.

1 illustrates an exemplary embodiment of an optical arrangement of a wide diopter range real-time sequential wavefront sensor integrated with a surgical microscope. FIG. 2 illustrates an exemplary embodiment of an electronic device interfaced with the optical elements of the wavefront sensor in FIG. 1, with those potentially active devices connected to an electronic control circuit. It shows what happens to the wavefront sampling region on the cornea when the eye moves laterally and the corresponding change is not made to the wavefront sampling scheme. Even if the eye moves laterally, how to compensate for the lateral movement of the eye by DC offsetting the wavefront beam scanner, and therefore keep scanning the same annular ring properly centered Show if you can. Figure 3 illustrates what happens to the measured wavefront or refractive error when the eye moves axially from a design position. FIG. 3 shows an overall block diagram of an exemplary embodiment of an electronic system that controls and drives a sequential wavefront sensor and related devices shown in FIGS. 1 and 2. A block diagram of an exemplary embodiment of a front-end electronic processing system, as well as a live imaging camera residing within a sequential wavefront sensor module, and a back-end electronic processing system residing within the host computer and display module shown in FIG. Indicates. FIG. 4 illustrates an exemplary internal calibration target that can be moved into a wavefront relay beam path to create one or more reference wavefronts for internal calibration and / or verification. FIG. 4 illustrates one aspect of an electronics block diagram that accomplishes the tasks of automatic SLD indexing and digital gain control to optimize signal-to-noise ratio. Fig. 4 shows a quadrant detector having an image spot of light that first arrives at the center and then an image spot that arrives slightly away from the center. Displayed as a flat wavefront, many typical situations of defocus and astigmatism, the associated image spot position on the quadrant detector behind the sub-wavefront focusing lens, and a 2D data point pattern on the monitor Shows the sequential movement of the corresponding centroid position. FIG. 3 shows an exemplary process flow block diagram in optimizing the signal to noise ratio by changing the gain and SLD output of a variable gain amplifier. An example of a composite transimpedance amplifier with lock-in detection that can be used to amplify the signal from any one of the four quadrant photodiodes, as used in the position sensitive detector circuit of FIG. A specific embodiment is shown. 1 illustrates one exemplary embodiment of a combination of a conventional transimpedance amplifier with a lock-in detection circuit. Shows the situation where the MEMS scan mirror is oriented so that the entire wavefront is shifted downward when the SLD pulse is fired. In this situation, the aperture samples the upper part of the circular wavefront section. The situation is shown where the wavefront is shifted to the left when the SLD pulse is fired so that the aperture samples the right part of the circular wavefront section. Fig. 4 shows a situation where the wavefront is shifted upward when the SLD pulse is fired so that the aperture samples the bottom part of the circular wavefront section. The situation is shown where the wavefront is shifted to the right when the SLD pulse is fired so that the aperture samples the left part of the circular wavefront section. Depicts that a sequential scanning sequence of 4 pulses per cycle is equivalent to sampling a wavefront section with 4 detectors arranged in a ring. Shows the location of the eight SLD pulse firings relative to the X and Y axes of the MEMS scanner, with four odd or even numbered pulses of the eight pulses aligned with the X and Y axes of the MEMS scanner, etc. The four pulses are arranged in the middle of the ring between the X and Y axes. Initially, the four SLD pulse firing positions aligned with the X and Y axes of the wavefront scanner as shown in Figure 13F are shifted 15 ° away from the X and Y axes by slightly delaying the SLD pulse. An example is shown. FIG. 5 shows the collective effect of sampling the wavefront at offset angles of 0 ° on the first frame, 15 ° on the second frame, and 30 ° on the third frame. FIG. 4 illustrates an example of a theoretically determined relationship between a PSD ratiometric estimate and an actual centroid displacement or position along either the X or Y axis. FIG. 4 shows an exemplary flow diagram illustrating how calibration can be performed to obtain a modified relationship and to provide a more accurate wavefront aberration measurement. Shows a graphical representation of a sequential ellipse using trigonometric formulas (where U (t) = a · cos (t) and V (t) = b · sin (t), a>b> 0) , Resulting in an ellipse that rotates counterclockwise at a point (U (t ₀ ), V (t ₀ )) in the first quadrant of UV Cartesian coordinates. Corresponding to similar sequential ellipses using trigonometric formulas (where U (t) =-a · cos (t), V (t) =-b · sin (t), a>b> 0) Shows a graphical representation, resulting in an ellipse that rotates counterclockwise at a point (U (t ₀ ), V (t ₀ )) in the third quadrant of UV Cartesian coordinates. Corresponding graphical representation of similar sequential ellipses using trigonometric formulas, where U (t) = a · cos (t), V (t) =-b · sin (t), a>b> 0 The representation shows an ellipse that rotates clockwise at a point (U (t ₀ ), V (t ₀ )) in the fourth quadrant of UV Cartesian coordinates. Corresponding graphical representation of similar sequential ellipses using trigonometric formulas (where U (t) =-a · cos (t), V (t) = b · sin (t), a>b> 0) The representation shows an ellipse that rotates clockwise at a point (U (t ₀ ), V (t ₀ )) in the second quadrant of UV Cartesian coordinates. Fig. 4 shows an example of a sequential centroid data point expected from the divergent spherical wavefront and the location and polarity of the resulting data point. Fig. 6 shows another example of a sequential centroid data point expected from the convergent spherical wavefront and the resulting data point position and polarity. Cartesian coordinate translation and rotation of eight sequentially sampled centroid data points fitted to a sequential ellipse, from the original XY coordinates to the translated Xtr-Ytr coordinates and further rotated to UV coordinates Indicates. The result of the coordinate rotation transformation and 8 centroid data points on the UV coordinates are shown, the left side corresponds to a divergent spherical wavefront with a positive major axis and a minor axis, and the right side has a negative major axis and a minor axis. Corresponds to a convergent spherical wavefront with an axis. FIG. 5 shows a process flow diagram of an exemplary embodiment in decoding spherical and cylindrical diopter values and cylindrical axis angles. 2 shows an exemplary process flow diagram of an eye tracking algorithm. FIG. 5 shows an exemplary process flow diagram illustrating the concept of using live eye images to determine the maximum wavefront sampling annular ring diameter and to obtain better diopter resolution for pseudo lens measurements. Detects the presence of unintended objects in the wavefront relay beam path or that the eye has moved away from the desired position range so that SLD can be turned off and erroneous "bright" or "dark" wavefront data can be discarded Thus, an exemplary process flow diagram illustrating the concept of using either live eye images and / or wavefront sensor signals is shown.

DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to various aspects of the invention. Examples of these aspects are illustrated in the accompanying drawings. While the invention will be described in conjunction with these embodiments, it will be understood that they are not intended to limit the invention to any embodiment. On the contrary, it is intended to include alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of various aspects. However, the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention or to limit the present invention. Moreover, each occurrence of the phrase “exemplary aspect” in various places in the specification is not necessarily referring to the same exemplary aspect.

In a typical wavefront sensor used for measuring the wavefront aberrations of the human eye, the wavefront from the eye's pupil or corneal surface is generally one or more times using the well-known 4-F relay principle, Relayed to wavefront sensing or sampling plane (eg, J. Liang, et al. (1994) "Objective measurement of the wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor," J. Opt Soc. Am. A 11, 1949-1957; JJ Widiker, et al. (2006) "High-speed Shack-Hartmann wavefront sensor design with commercial off-the-shelf optics," Applied Optics, 45 (2), 383 -395; see US7654672. Such single or multiple 4-F relay systems preserve the phase information of the incident wavefront while at the same time allowing it to be relayed without detrimental ripple effects. In addition, by configuring an afocal imaging system using two lenses with different focal lengths to implement a 4-F relay, the relay can be reduced or enlarged in relation to the divergence or convergence of the incident wavefront. with, it is possible to allow expansion or contraction of the incident wavefront (e.g., JW Goodman, see ^{Introduction to Fourier Optics, 2 nd ed} . McGraw-Hill, 1996).

  In recent years, real-time wavefront sensors to provide live feedback for various vision correction procedures such as LRI / AK refinement, laser enhancement, and cataract / refractive surgery It is understood that there is a need for. With respect to these procedures, it is understood that any interference with normal surgery is undesirable, especially the turn-off of the surgical microscope illumination light and the waiting period for wavefront data acquisition and processing. The surgeon wants real-time feedback to be provided to them during normal performance of vision correction procedures. In addition, most surgeons also synchronize the continuously displayed real-time wavefront measurement results with the real-time video display / video of the eye and overlay it or display it next to it. It is preferred that the wavefront measurement results superimposed or displayed side by side are presented in a qualitative or quantitative manner or a combined qualitative / quantitative manner. Another major problem is eye movement relative to the wavefront sensor during a vision correction surgical procedure while the wavefront is being measured in real time. Previous wavefront sensors do not provide a means to compensate for eye movement; rather, meaningful wavefront measurements require realignment of the eye with the wavefront sensor.

  In a co-pending patent application (US20120026466) assigned to the same assignee as this patent application, a wide diopter range sequential wavefront sensor is disclosed that is particularly suitable for addressing the problems encountered during vision correction procedures. While many optical design / placement details are disclosed in that co-pending patent application, details of electronics control and data processing for operating such a wide diopter range sequential wavefront sensor include: Not disclosed. Additional measurement capabilities of different subassemblies are not discussed in detail. In this disclosure, various features of electronic device control and drive aspects as well as associated algorithms for achieving various functions are disclosed.

  In accordance with one or more aspects of the present invention, a lock-in detection electronics system associated with an associated algorithm for achieving highly accurate wavefront measurements is disclosed. The electronics system obtains its electronic signal from the optoelectronic position sensing device / detector; it amplifies the analog signal with a composite transimpedance amplifier, converts the analog signal to a digital signal via an A / D converter, The digital signal is amplified via a digital amplifier and the data is processed via a data processing unit. The electronics system is connected to some or all of those electronically active devices of the wavefront sensor module to achieve different functionality. Examples of these active devices are light sources such as super luminescent diodes (SLD), SLD beam focusing and / or steering modules, wavefront scanning / shifting such as MEMS scan mirrors to generate the object wavefront to be measured. , Eye pupil lateral position and distance sensing / measuring device, eye fixation target, various variable focus active lenses, one or more data processing and storage devices, end user usable input devices, and Includes display device.

  FIG. 1 shows an exemplary embodiment of the optical arrangement of a real-time sequential wavefront sensor with a wide diopter range integrated with a surgical microscope, and FIG. 2 shows an electronic connection version of the wavefront sensor arrangement of FIG. Those potentially active devices are connected to the electronics system.

  In the embodiment of FIGS. 1 and 2, the first lens 104/204 of the 8-F wavefront relay is arranged at the very first optical input port of the wavefront sensor module. The first lens 104/204 is used jointly by a surgical microscope and a wavefront sensor module. The advantage of arranging the first lens 104/204 of this 8-F wavefront relay as close as possible to the patient's eye is that the design focal length of this first lens is the shortest according to the requirements of the 8-F wavefront relay. Therefore, the total optical path length of the wavefront sensor can be minimized. By combining this with the folding of the wavefront relay beam path, the wavefront sensor module can be made compact. In addition, a wider diopter measurement range of the wavefront from the eye can be achieved when compared to lenses of the same diameter but arranged further downstream of the light beam path. In addition, since there is always a need for the wavefront sensor to have an optical window at this location, the lens therefore serves the dual purpose of both the window and the first lens for the wavefront relay system and for the microscope Can do. It should be noted that the first lens 104/204 can also be arranged behind a dichroic or short path beam splitter 161/261.

  The dichroic or short path beam splitters 161/261 shown in FIGS. 1 and 2 allow near-infrared wavefront relay beams (superluminescent) while allowing most of the visible light to pass (eg about 85%). Used to reflect / deflect the remaining wavefront sensor module with high efficiency (including at least the optical spectral region of the SLD 172/272). Dichroic or short path beam splitter 161/261 allows visible and / or near infrared light outside the SLD spectral region so that a clear live image of the anterior side of the patient's eye can be acquired by the image sensor 162/262 May be designed to allow a portion of the to be reflected / deflected.

  The compensating lens 102/202 on the dichroic or short path beam splitter 161/261 is used to perform several functions. First, ensure that the surgical field of view provided to the surgeon by the surgical microscope is not affected by the use of the first lens 104/204 of the 8-F wavefront relay This compensation lens 102/202 can be designed to compensate for the influence of the first lens 104/204 on the microscope field of view. Second, the compensating lens 102/202 can serve as an upper optical window that can be required to seal the wavefront sensor module. The third function of the compensator lens 102/202 is that when the illumination beam hits the lens 104/204, the specular reflection from the lens 104/204 is directed back to the two stereoscopic viewing paths of the surgical microscope. To direct the illumination beam from the surgical microscope away from the optical axis so as not to interfere with the scene's surgeon's view. Finally, the compensating lens 102/202 can also be coated so that only the visible spectrum of light is transmitted, allowing the near-infrared and ultraviolet spectra of light to be reflected and / or absorbed. Thus, the near-infrared spectral portion of the light corresponding to the SLD spectrum from the microscope illumination source either enters the wavefront sensor module and saturates the position sensing device / detector or creates background noise. Does not arrive at the patient's eye to produce any near-infrared background light that is returned from the eye. On the other hand, the coating can also block or absorb any UV light from the illumination source of the microscope. However, if the first lens is arranged behind a dichroic or short path beam splitter 161/261, there is no need for a compensation lens and a window with a certain wavelength filtering function is sufficient. It should be noted.

  1 and 2, the wavefront from the eye is relayed to the wavefront sampling image plane downstream of 8-F where the wavefront sampling aperture 118/218 is located. The wavefront relay includes two cascaded 4-F relay stages, or a first lens 104/204, in addition to a second lens 116/216, a third lens 140/240 and a fourth lens 142/242. Including using 8-F wavefront relays. The wavefront relay beam path is folded by polarization beam splitter (PBS) 174/274, mirrors 152/252 and MEMS beam scanning / shifting / deflecting mirror 112/212 to make the wavefront sensor module compact. Along the wavefront relay beam path, bandpass filters 176/276 are used with dichroic or short path beam splitters 161/261 to filter out any light outside the SLD spectrum and reduce background noise. It can be arranged somewhere between the quadrant detectors 122/222. In addition, the aperture 177/277 is placed in the second Fourier transform plane to serve the function of limiting the cone angle of the ray from the eye and hence the diopter measurement range of the wavefront from the eye to the desired range To prevent light from arriving outside the mirror surface area of the MEMS scanner 112/212, it can be arranged in a first Fourier transform plane between the PBS 174/274 and the mirror 152/252.

  MEMS scan mirror 112/212 is an 8-F wavefront to angularly scan the object wave so that the relayed wavefront in the final wavefront image plane can be shifted laterally with respect to the wavefront sampling aperture 118/218. Located on the second Fourier transform plane of the relay. The wavefront sampling aperture 118/218 may be a fixed size or an active variable aperture. Sub-wavefront focusing lenses 120/220 behind apertures 118/218 are sequentially placed on top of position sensing device / detector (PSD) 122/222 (such as quadrant detector / sensor or side effect position sensitive detector) Focus the sampled sub-wavefront. The electronics system is connected at least to SLD 172/272, wavefront shifting MEMS scan mirror 112/212 and PSD 122/222 so that SLD can be pulsed, MEMS mirror scanned and lock-in detection can be realized It should be noted that signals from PSD can be collected synchronously.

  In this regard, it should be noted that in FIGS. 1 and 2, the first lens of the wavefront relay is arranged at the input port location of the wavefront sensor module or enclosure, but this need not be the case. The first lens 104/204 can be arranged behind a dichroic or short path beam splitter 161/261 and a glass window can be arranged at the input port location. Thus, the remaining wavefront relay can be redesigned and the optical function of the compensation lens or window 102/202 can be modified to ensure that a good microscopic image is presented to the surgeon.

  In addition to the folded wavefront relay beam path, three more light beam paths are shown in Figures 1 and 2, one for imaging the eye and one for the fixation target. One is for delivering a superluminescent diode (SLD) beam to the eye for the generation of a wavefront relay beam from the eye carrying the eye wavefront information.

  The imaging beam splitter 160/260 is a 2D pixel array through the lens or lens set 168/268 for at least some imaging light returned from the eye and reflected by the dichroic or short pass beam splitter 161/261 Turn to image sensor 162/262 like CCD / CMOS sensor. Image sensor 162/262 may be a monochrome or color CMOS / CCD image sensor connected to the electronics system. The image sensor 162/262 provides a coplanar video image or still image of the subject's eye and can be focused to image either the front side or the back side of the eye. In addition, the fixation / imaging beam splitter 166/266, along with the first lens 104/204, causes the image of the fixation target 164/264 formed by the lens or lens set 170/270 to be in the reverse path. Along the eye of the patient. The lens 168/268 in front of the image sensor 162/262 works with the first lens 104/204 to live in front of or behind the patient's eye on the display (not shown in FIGS. 1 and 2). Ensure that the image sensor surface can be designed to provide the desired optical magnification for the image and that it is in a conjugate relationship with, for example, the eye pupil surface so that a clear eye pupil image can be obtained Therefore, it can be used to adjust the focus either manually or automatically if necessary. In the case of autofocus, the lens 168/268 needs to be connected to the electronics system.

  The lens 170/270 in front of the fixation target 164/264 may be designed to provide a comfortable fixation target of the correct size and brightness to the patient's eye. It also adjusts the focus to ensure that the fixation target is in a conjugate relationship with the retina of the eye, or to fix the eye at different distances or orientations, or even to fog the eye Can be used. In doing so, the lenses 170/270 need to be activated and connected to the electronics system. The fixation light source 164/264 can be driven or flashed or flashed at a desired rate to be driven by the electronics system to distinguish it from, for example, the illumination light of a surgical microscope. Also, the color of the fixation light source 164/264 may change. The fixation target can be a microdisplay and the displayed pattern or spot is variable depending on the wishes of the surgeon / clinician. In addition, microdisplay-based fixation targets also gaze in different directions so that a 2D array aberration map of the eye can be measured and generated that can be used to assess the peripheral vision of the patient Can be used to guide the patient.

  The fixation target 164/264 can be a red, green or yellow (or any color) light emitting diode (LED) whose output light power is dynamically controlled by the electronics system based on different background lighting conditions Can be controlled. For example, when a relatively strong illumination beam from a surgical microscope is turned on, the brightness of the fixation light source 164/264 is increased so that the patient can easily find the fixation target and stare at it Can be able to. A variable aperture or aperture (not shown in Figure 1 or 2) is arranged in front of the lens 168/268 in front of the image sensor to control the depth of field of the live image in front or back of the eye May be connected to an electronic device system. By dynamically changing the aperture size, it is possible to control the blur of the eye image when the eye moves axially away from the design distance, and the blur of the eye image according to the aperture or aperture size. And the axial position of the eye can be used as a signal to determine the axial distance of the eye. Alternatively, eye distance can also be measured through well-known means such as triangulation based on image spot positions where one or more near-infrared illumination sources are scattered / reflected at the cornea. As disclosed below, ocular distance measurement based on low coherence interferometry may also be used.

  One ring or multiple rings (or arrays) (135/235) of LEDs may be annularly arranged around the input port of the wavefront enclosure to perform multiple functions. One function is simply to provide flood illumination in the wavelength spectral region so that light returned from the eye in this spectrum can reach the image sensor (162/262). Thus, if there is no illumination from the surgical microscope or the illumination light from the surgical microscope is filtered to allow only visible light to reach the eye, the image sensor (162/262 The contrast of the eye image acquired by (1) can be kept within a desired range. As an example, the image sensor is a monochrome UI-1542LE-M, a very compact board level camera with a resolution of 1.3 megapixels (1280 × 1024 pixels). The NIR bandpass filter can be placed along the imaging path so that only the floodlight reaches the image sensor and maintains a relatively constant contrast of the live eye image.

  The second function of the LED (135/235) is to light the cornea and / or eye lens (natural or artificial) so that a Purkinje image of the LED (135/235) can be produced by the image sensor (162/262) Creating a specular image spot returned from the interface. Through image processing of these Purkinje images, the lateral position of the patient's eye can be determined. In addition, the top and / or bottom surface profiles or topographs of the cornea and / or ophthalmic lens (natural or artificial) can be elucidated in the same way that corneal topographers and / or keratometers / keratoscopes do. This obtained information can be used to determine changes in corneal shape or even some other ocular biometric / anatomical parameters. The measured change is then targeted or during or immediately after refractive surgery so that the final refraction of the eye is as desired when the incision or wound made in the cornea of the eye is fully healed Can be used to set the expected refraction.

  The third function of the LED (135/235) is the principle of optical triangulation, which creates a light spot that can be selectively turned on and projected onto the white eye to be acquired by the image sensor (162/262) This means that eye distance measurement can be realized using. Changes in the centroid position of the imaged light spot can be processed to resolve eye distance.

  In addition to providing live eye pupil / iris or corneal images and imaging flood lighting effects, image sensor signals can also be used for other purposes. For example, live images can be used to detect the size, distance from the first lens (104/204) and lateral position of the eye pupil. If the pupil size is found to be small, the wavefront sampling area can be correspondingly reduced. In other words, the pupil size information can be used in a closed loop manner for automatic and / or dynamic adjustment and / or for scaling the wavefront sensing area according to pupil size.

  One aspect of this disclosure is correction of wavefront measurement errors as a result of eye position changes within a particular position range. The correction can be applied to both the lateral position change of the eye and the axial position change of the eye. In one aspect, the side of the eye or pupil relative to the wavefront sensor module is found if the eye or pupil is not centered sufficiently adequately, i.e., not adequately aligned with the optical axis of the wavefront sensor. The amount of directional motion is determined and used to correct for the measurement wavefront error introduced by such lateral movement of the eye or pupil position, or the same region on the cornea is always sampled The driving signal of the wavefront sampling scanner is adjusted.

  The lateral position of the eye or pupil can be determined using live eye images or other means. For example, the limbus can provide a reference for where the eye is present; the boundary between the pupil and the iris can also provide a reference for where the eye is located. In addition, specularly reflected flood light from the anterior surface of the cornea, acquired by a live eye camera as a bright light spot or detected by an additional position sensitive detector, is also information about the lateral position of the eye Can be used to provide In addition, specularly reflected SLD light from the anterior corneal surface is also acquired by the live eye camera as a bright light spot or detected by an additional position sensitive detector to determine the lateral position of the eye be able to. The SLD beam may also be scanned in two dimensions to look for the strongest corneal apex specular reflection and to determine the lateral position of the eye.

  FIG. 3 shows what happens to the wavefront sampling region on the cornea when the eye moves laterally and the corresponding change is not made to the wavefront sampling scheme. The SLD beam is coaxial with the wavefront sensor optical axis and is fixed in a space relative to the optical axis, and the wavefront sensor is radial or rotationally symmetric with respect to the optical axis of the wavefront sensor on the cornea Suppose we are sampling around an annular ring. When the eye is properly aligned, the SLD beam 302 enters the eye through the corneal apex and the center of the pupil and arrives on the retina near the fovea. Thus, the returned wavefront is sampled in a radial or rotationally symmetric annular ring centered with respect to the corneal apex or the center of the eye pupil, as shown by the annular ring 304 in the right corneal plane cross section. The Now imagine that the eye moves laterally downward with respect to the SLD beam and wavefront sensor. The SLD beam 312 now enters the off-center eye but still arrives on the retina near the fovea. Nevertheless, the exact location can vary slightly depending on the aberrations of the eye. Since the wavefront sampling region is fixed with respect to the SLD beam, on the corneal surface, the annular ring being sampled is therefore the corneal apex or the eye pupil, as shown by the annular ring 314 in the right corneal plane view. Is shifted upward with respect to the center of. Therefore, this non-radiating or non-rotationally symmetric wavefront sample causes wavefront measurement errors. In one aspect of the present disclosure, using information about the lateral position of the eye or pupil, wavefront measurement errors are corrected using software and data processing.

  In one aspect of the present disclosure, using information about the lateral position of the eye or pupil, the SLD beam, for example, to prevent specularly reflected SLD beam returned by the cornea from entering the PSD of the wavefront sensor, The SLD beam may always be scanned to follow or track the eye or pupil so that it enters the cornea from the same corneal position as designed (eg, slightly off the apex of the cornea). Live eye images can also be used to determine the presence of the eye and to turn the SLD / wavefront detection system on or off accordingly. That the SLD beam always enters the eye at the desired corneal position and is not partially or completely blocked by the iris as a result of lateral movement of the eye (within a certain range of eye movement) To ensure that the scan mirror 180/280 for scanning the SLD beam shown in FIGS. 1 and 2 can be positioned in the back focal plane of the first wavefront relay lens 104/204. In this case, the angle scan of the scan mirror 180/280 produces a lateral scan of the SLD beam with respect to the corneal surface. Using a live image of the eye acquired by the image sensor or other means for detecting the lateral position of the eye, the lateral position of the center of the eye is solved, a feedback signal is provided to drive the scan mirror 180/280, and the SLD beam Can follow the eye movement or track the eye.

  In another aspect of the present disclosure, the wavefront beam scanner 112/212 is suitable for following the lateral movement of the eye or tracking the eye so that wavefront sampling is always performed over the same region of the eye pupil. Driven with DC offset. For example, sampling can be performed over an annular ring that is radial or rotationally symmetric about the center of the eye pupil. To see how this is possible, recall that the wavefront beam scanner is located in the second Fourier transform plane of the 8-F wavefront relay configuration. As the eye moves laterally, in the 4-F wavefront image plane, the image of the wavefront also moves laterally with proportional optical magnification or reduction depending on the focal length ratio of the first and second lenses. If the wavefront beam scanner does not do any scanning and there is no DC offset, then this laterally moved wavefront in the intermediate wavefront image plane will also relay to the sampling aperture when it is further relayed to the final wavefront sampling image plane. In contrast, it is displaced laterally. As a result, when the wavefront beam scanner performs an angular rotation scan, the effective annular ring region scanned on the corneal surface is decentered as shown by the lower portion of FIG.

  Figure 4 shows how to compensate for the lateral movement of the eye by DC offsetting the wavefront beam scanner, even if the eye moves laterally, and hence the same annular ring properly centered. Indicates whether scanning can continue. As can be seen in FIG. 4, when there is lateral movement of the eye, the SLD beam 448 enters the off-center eye and is at the corneal surface as the object to be relayed by the 8-F relay. The wavefront is also off-axis. The intermediate wavefront image 402 is therefore displaced laterally, and if there is no DC offset of the wavefront beam scanner, the intermediate wavefront image is also displaced laterally without scanning the wavefront beam in the second Fourier transform image plane. The wavefront image 432 is relayed to the final wavefront sampling plane. In this case, if the wavefront beam scanner scans in the form of a circular angular rotation with respect to a zero DC offset angle, the sampled wavefront will be non-radiating or centered on the eye, as indicated by the annular ring 444. It is a non-rotationally symmetric annular ring. However, if the wavefront beam scanner 462 shown on the right side of FIG. 4 has a certain DC offset appropriately determined based on the lateral displacement of the eye, the final wavefront image 482 is in the final wavefront sampling image plane. When relayed, it can be displaced laterally to re-center with respect to the wavefront sampling aperture 458. In this case, the SLD beam 498 still enters the off-center eye and the wavefront at the cornea as the object to be relayed by the 8-F relay passes through the first, second and third lenses. Off-axis, but after the wavefront scanner, the relay has been corrected by the wavefront scanner and is now on-axis. Thus, further angular rotation scanning of the wavefront beam scanner for this DC offset angle results in sampling of an annular ring 494 that is radial or rotationally symmetric with respect to the center of the eye.

  One aspect of the present disclosure is therefore to control the DC offset of the wavefront scanner for lateral eye movement that can be determined by a live eye camera or other means. Due to the fact that along the wavefront relay path, wavefront imaging is done off-axis along some of the imaging paths, not on-axis, therefore other introduced, including, for example, coma and prism tilt There may be optical aberrations. These additional aberrations introduced as a result of off-axis wavefront relays can be addressed through calibration and processed as if there were an optical imaging or relay system's inherent aberrations, thus using calibration and data processing. Can be deducted.

  In another aspect of the present disclosure, if it is found that the eye is not axially positioned at a design distance from the object plane of the wavefront sensor, the amount of eye axial displacement relative to the design axial position. And the information is used to correct for the measurement wavefront error introduced by such axial movement of the eye. FIG. 5 illustrates what happens to the measured wavefront or refractive error when the eye moves axially from the design position.

  The left column of FIG. 5 shows three normal eyes, with the top one 504 moving away from the wavefront sensor and the middle one 506 is the design axis of the wavefront sensor. In the directional position, the bottom one 508 is moving towards the wavefront sensor. As can be seen, the wavefront that emerges from this stereopsis is planar, so in the design objective plane 502 (from which the wavefront is relayed to the final wavefront sampling plane), the wavefronts 514, 516, and 518 are All are flat in three situations. Therefore, when the eye is slightly displaced in the axial direction from the design position, the wavefront measurement result is not affected when the eye is normal.

  However, the eye lens (525, 527, 529) is shown thicker and the eye (524, 526, 528) is also drawn longer, as shown by the middle column of FIG. In some cases, the wavefront emerging from the eye converges to a point (535, 537, 539) and the wavefront dioptric value at the cornea is determined by the distance from the cornea surface of the eye to the convergence point. . In this case, if the eye moves slightly far away from the wavefront sensor, the wavefront at the object plane 522 of the wavefront sensor is at the corneal surface of the eye, as shown by the top example in the middle column. Is not the same as the wavefront. In fact, the convergence radius of the wavefront curvature at the object plane of the wavefront sensor is smaller than that at the corneal surface. Therefore, when this wavefront 534 at the wavefront sensor objective is measured by the wavefront sensor, the measured result is that the wavefront 534 has a smaller radius of curvature than the wavefront 536, so that Is different. On the other hand, if the eye has moved closer towards the wavefront sensor, as shown by the bottom example in the middle column, the wavefront 538 at the object plane 522 of the wavefront sensor will again be It is not the same as the wavefront 536 at the cornea. In fact, here, the radius of curvature of the wavefront 538 at the object plane of the wavefront sensor is larger than the wavefront 536 at the cornea. As a result, the measured wavefront result at the wavefront objective plane is again different from that at the corneal surface of the eye.

  The lens of the eye is removed, and the eye (544, 546, 548) is also hyperopic, as shown by the right column of FIG. 5, which is drawn shorter than normal to simulate a short aphakic eye. At some point, the wavefront appearing from the eye is divergent, and by extending the divergent ray backward, the virtual focal position (555, 557, 559) that is the starting point of the ray can be found. The farsighted light refraction value of the wavefront at the corneal surface is determined by the distance from the corneal surface of the eye to the virtual focal position. In this case, if the eye has moved away from the wavefront sensor, the wavefront 554 at the object plane 542 of the wavefront sensor is again the corneal surface of the eye, as shown by the example at the top of the right column. Not the same as wavefront 556 at. In fact, here, the radius of divergence of the wavefront 554 at the object plane of the wavefront sensor is greater than the radius of divergence of the wavefront 556 at the cornea. Therefore, when this wavefront 554 at the object plane of the wavefront sensor is measured by the wavefront sensor, the measured result is again different from the wavefront 556 at the corneal surface. On the other hand, as shown by the bottom example in the right column, if the eye moves closer to the wavefront sensor, the wavefront 558 of the wavefront sensor's object plane 542 is still at the corneal surface of the eye. Different from wavefront 556. Indeed, the radius of curvature of the diverging wavefront 558 at the object plane of the wavefront sensor is now smaller than the wavefront 556 at the corneal surface. As a result, the measured wavefront result at the wavefront objective plane is again different from that at the corneal surface of the eye.

  In one aspect of the present disclosure, a real-time means for detecting the axial position of the eye under test is incorporated, and information about the amount of axial movement of the eye relative to the object plane of the wavefront sensor module in real time is It is used to correct the measurement wavefront error introduced by the axial movement of the eye. As discussed below, the means for measuring the axial position of the eye includes optical triangulation and low coherence light interferometry as is well known to those skilled in the art. Calibration can be performed to determine the relationship between the axial position of the eye and the true wavefront aberration of the eye relative to the wavefront aberration at the object plane of the wavefront sensor measured by the wavefront sensor. A lookup table can then be established and used in real time to correct wavefront measurement errors. In the case of cataract surgery, the surgical microscope, when fully zoomed out, presents the surgeon with a relatively sharp and focused field of view of the patient's eyes, typically within an axial range of about ± 2.5 mm. can do. Thus, when the surgeon focuses the patient's eye under a surgical microscope, the variation in the axial position of the patient's eye should be in the range of about ± 2.5 mm. Thus, calibration can be performed over such a range and a look-up table can be established over such a range.

  In one exemplary embodiment of the present disclosure, the eye is irrigated with water / solution, or there is an optical bubble, or the eyelid is in the optical path, or the facial skin or surgeon's hand or surgical tool or instrument Is found to be in the field of view of the image sensor and partially or completely blocking the wavefront relay beam path, the wavefront data is discarded / filtered to eliminate “dark” or “bright” data. At the same time, SLD 172/272 can be turned off. In another exemplary embodiment of the present disclosure, the wavefront sensor is used to determine whether the eye is dry and a reminder in the form of a video or audio signal is sent to the surgeon or clinician to / I can make her realize when to irrigate the eyes. In addition, the signal from the image sensor 162/262 can also be used to identify whether the patient's eye is in a phakic state, an aphasic state, or a pseudophakic state, and thus an SLD pulse Can only be turned on for as long as needed. These approaches reduce the patient's total exposure time to the SLD beam, thus possibly allowing the use of higher peak power or longer on-duration SLD pulses, and a wavefront measurement signal-to-noise ratio. Can be increased. In addition, an algorithm can be applied to the resulting eye image to determine the optimal distance to the eye according to the effective blur of the resulting image and / or in conjunction with the triangulation criteria.

  1 and 2, a large size polarizing beam splitter (PBS) 174/274 is used to deliver an SLD beam to the patient's eye. The reason for using a large window size is to ensure that the wavefront relay beam from the eye over the desired wide diopter measurement range is completely blocked rather than partially by PBS 174/274. In an exemplary embodiment, the beam from SLD 172/272 is preferably p-polarized so that the beam is substantially transmitted through PBS 174/274 and delivered to the eye to create an ocular wavefront. The SLD beam is collimated at the corneal surface as it enters the eye at the corneal surface, or is focused or partially defocused (either divergent or convergent) It can be preformed or manipulated to be either. When an SLD beam arrives on the retina as either a relatively small light spot or a somewhat extended light spot, it is scattered over a relatively wide angular range and the beam thus generated and returned is , Both original and orthogonally polarized. As is well known to those skilled in the art, for ophthalmic wavefront sensor applications, only the orthogonal polarization component of the wavefront relay beam is used for ocular wavefront measurements. This is because in the original polarization direction there is a relatively strongly reflected SLD light wave from the cornea and the eye lens that can cause errors in wavefront measurements. Thus, another feature of large PBS 174/274 is that it allows only orthogonally polarized wavefront relay beams to be reflected by PBS 174/274, and is returned polarized in its original direction. To direct the transmitted light wave to be transmitted through and absorbed by PBS 174/274, or for other purposes such as monitoring the presence of specular reflection of the SLD beam by the cornea or ocular lens returning into the wavefront sensor module Is to use.

  1 and 2, bandpass filters 176/276 are arranged in the wavefront relay beam path to block any visible light and / or environmental background light, and the desired wavefront relay beam light generated by the SLD. Only a relatively narrow spectrum of can enter the remaining wavefront sensor module.

  In addition to the fact that the SLD beam can be scanned to follow the lateral movement of the eye, the SLD beam is also small on the retina using controls from an electronics system including a front-end electronic processor and a host computer. It can be scanned to arrive over the scan area. In one exemplary embodiment, the SLD beam always enters the eye at the desired corneal location and is not partially or completely blocked by the iris as a result of eye movement (within a specific range of eye movement). To ensure that, a scan mirror 180/280 for scanning the SLD beam as shown in FIGS. 1 and 2 can be positioned in the back focal plane of the first wavefront relay lens 104/204. In this case, the angular scan of the scan mirror 180/280 results in a lateral scan of the SLD beam relative to the corneal surface, but still allows the SLD beam to arrive on the same retinal position when the eye is normal To. The live image of the eye pupil acquired by the image sensor drives the scan mirror 180/280 to elucidate the lateral position of the eye pupil center and provides a feedback signal, and the SLD beam moves the eye Can be used to follow the eye or track the eye.

  In one exemplary embodiment, another scan mirror 182/282 as shown in FIGS. 1 and 2 is provided with an SLD so that the SLD beam arrives around a small area on the retina and can be scanned. It can be positioned in a conjugate relationship with the corneal surface at the back focal plane of the beam shape manipulation lens 184/284. Another lens 186/286, for example, focuses the SLD beam from the output port of a single mode optical fiber (such as a polarization maintaining (PM) single mode fiber) 188/288 onto the scan mirror 182/282, Or it can be used to collimate or mold. Scanning an SLD beam over a small area on the retina can provide several advantages; one has an SLD beam that always arrives on the same retinal spot area, especially when the spot size is very small Another advantage is to deliver a higher peak power or longer on-duration pulsed SLD beam to the eye to increase the signal-to-noise ratio for optical wavefront measurements. In addition, diverting light energy over a somewhat larger area of the retina; and yet another advantage is that wavefront measurement errors resulting from retinal topographic inhomogeneities can be averaged or detected and / or As can be quantified, the wavefront measurements can be averaged over a somewhat larger area of the retina. Alternatively, to achieve a similar goal, control the SLD beam spot size on the retina by controlling the focusing and defocusing of the SLD beam using lenses 186/286 (or 184/284) Also good.

  It should be noted that scanning of the SLD beam to the cornea and retina may be performed independently and simultaneously and synchronized. In other words, the two SLD beam scanners 180/280 and 182/282 are independent of each other but can be activated simultaneously. In addition, a laser beam as an eye surgery light beam (not shown in FIGS. 1 and 2) is combined with the SLD beam and delivered to the eye through the same optical fiber or another free space light beam combiner, and the SLD beam Can be delivered to the same scanner or other scanners for which an ophthalmic surgical laser beam can be delivered to an eye such as a limbal relaxing incision (LRI) or other corneal sculpting It should be noted that it can be scanned to perform other refractive surgery. SLD and ophthalmic surgery lasers have different wavelengths and can be combined using fiber optic based wavelength division multiple couplers or free space dichroic beam combiners.

  The internal calibration target 199/299 can be moved into the wavefront relay beam path when it is to be calibrated / verified. The SLD beam can be directed coaxially with the wavefront relay light beam path axis when the internal calibration target is moved into place. The calibration target may be made from a material that scatters light in a manner similar to that of the eye retina, possibly with some desired attenuation, generating a reference wavefront for calibration / verification purposes and applying it to a sequential wavefront sensor So that it can be measured by. The generated reference wavefront can be either a substantially planar wavefront or a typical aphasic wavefront, or any other divergence / convergence divergence or convergence wavefront.

  For ocular wavefront measurements, only the returned beam from the retina with orthogonal polarization is used, but this does not use the returned lightwave with the original polarization from the cornea, eye lens and retina. It does not mean that. On the contrary, these returned light waves with the original polarization can provide very useful information. Figures 1 and 2 show that the light wave returned from the eye with the original polarization is the distance of the eye from the wavefront sensor module, the position of the eye lens (either natural or implanted) in the eye (ie the effective lens) Position), anterior chamber depth, eye length, and other anterior and / or posterior eye biometric or anatomical parameters can be used. In FIGS. 1 and 2, the returned light wave passing through PBS 174/274 is a low coherence optical fiber as typically used for low coherence optical interferometry (OLCI) or optical coherence tomography (OCT) measurements. Collected using an interferometer. The SLD output fiber 188/288 can be single mode (SM) (and polarization-maintaining (PM) if desired), with a portion of the SLD light being sent to the wavefront sensor and another portion of the SLD light being the reference It can be connected to a normal single mode (SM) fiber (or polarization maintaining (PM) single mode optical fiber) coupler to be sent to arm 192/292. The optical path length of the reference arm can be roughly matched to that corresponding to the optical path length of the light wave returned from the eye. The light waves returned from different parts of the eye can be recombined with the reference light waves returned through the reference fiber arm 192/292 at the fiber coupler 190/290 to provide optical low coherence interference. This interference signal may be detected by detector 194/294, as shown in FIGS. 1 and 2, the same fiber coupler 190/290 is used for both splitting and recombining light waves in a Michelson-type optical interferometer configuration, but any other known fiber optic interference. A metering configuration may be used, one example is a Mach-Zehnder using two fiber couplers with a fiber circulator in the sample arm to efficiently direct the light wave returned by the sample arm to the recombination fiber coupler Note that the type configuration.

  Various OLCI / OCT configurations and detection schemes may be used including spectral domain, sweep source, time domain and equilibrium detection. Detection module 194/294, reference arm 192/292 (including reference mirror + fiber loop), and SLD 172 / to keep the wavefront sensor module (e.g. attached to a surgical microscope or slit lamp biomicroscope) compact Even 272 and fiber coupler 190/290 may be located outside the wavefront sensor enclosure. The reason for this is that the detection module 194/294 and / or the reference arm 192/292 and / or the SLD source 172/272 may be bulky depending on the scheme used for OLCI / OCT operation It is. The electronics for operating the OLCI / OCT subassembly can be located either inside the wavefront sensor enclosure or outside the wavefront sensor enclosure. For example, when a balanced detection scheme is used as discussed in US7815310, an optical fiber circulator (not shown) may need to be incorporated into the SLD fiber arm. When time domain detection is used, the reference arm 192/292 may need to include an optical path length scanner or a fast scanning optical delay line (not shown), which needs to be controlled by the electronics. When a spectral domain detection scheme is used, the detection module may need to include an optical spectrometer and a line scan camera (not shown), which needs to be controlled by the electronics. When a sweep source detection scheme is used, the light source may need to include a wavelength scanner (not shown), which needs to be controlled by the electronics.

  In one exemplary embodiment, to ensure that a relatively strong OLCI / OCT signal can be collected, scan mirror 180/280 (and / or 182/282) is controlled by the electronics system, specifically, For example, it is possible to return relatively strong specular reflections from the cornea, eye lens (natural or artificial) and retina back to the fiber optic interferometer, and the axial distance of the optical interface of these eye elements to the wavefront sensor module or between them Enable to measure axial distance. In the latter case, specular reflection should probably be avoided, so this operation can be sequentially separated from the ocular wavefront measurement. Alternatively, two different wavelength bands can be used and spectral separation can be utilized. On the other hand, the OLCI / OCT signal strength can be used as an indicator of whether specular reflections are being collected by the wavefront sensor module, in which case the wavefront sensor data can be discarded.

  In another exemplary embodiment, the SLD beam can be scanned over the front of the eye or over a certain amount of the retina, and biometric or anatomical measurements of various parts of the eye can be made. One particularly useful measurement is the corneal surface and thickness profile.

  In one exemplary embodiment, the beam scanner 112/212 used to shift / scan the wavefront and the one used to scan the SLD beam (180/280, 182/282) are also dynamic DC Having an offset can provide additional benefits to the present disclosure. For example, using a scanner 112/212 used to shift / scan the wavefront, such as temperature to ensure that the wavefront sampling is still rotationally symmetric about the center of the eye pupil. Compensation can be provided for potential misalignment of the optical elements as a result of various environmental changes. On the other hand, the reference point on the position sensing device / detector (PSD) can also be adjusted if necessary for each image spot position compensated through calibration. If the sampled image spot has any angular DC offset relative to the PSD reference point, this can be addressed through calibration and data processing. We use the scanner 180/280 used to scan the SLD beam and follow the lateral movement of the eye within a certain range through the feedback signal from the image sensor 162/262. Mentioned that it can be. As the eye moves relative to the wavefront sensor module, the SLD beam can be allowed to enter the eye through the same corneal position at the same angle as when the eye is properly centered with respect to the wavefront sensor module. However, the wavefront beam returned from the eye is displaced laterally with respect to the optical axis of the wavefront sensor module. As a result, the relayed wavefront at the wavefront sampling image plane is also displaced laterally. In this case, the DC offset of the scanner 112/212 used to shift the wavefront is used to compensate for this displacement and the scanned wavefront beam is still rotationally symmetric with respect to the wavefront sampling aperture 118/218. Can be left. In this case, coma or prism tilt or other additional aberrations may be introduced, but these can be addressed through calibration and data processing. In doing so, any wavefront measurement error induced by changes in eye position / location can be compensated or corrected.

  Combine some or all of the information provided by image sensors, wavefront sensors, specular reflection detectors and / or low coherence interferometers to achieve the automatic selection of the correct calibration curve and / or data processing algorithm Is possible. On the other hand, a data integrity indicator or reliability indicator or a cataract turbidity indicator or an indicator about the presence of an optical bubble can be shown to the surgeon or clinician through audio or video or other means or provide feedback It can be connected to other devices. The combined information may also be used for intraocular pressure (IOP) detection, measurement and / or calibration. For example, intraocular pressure changes in the anterior chamber of the eye, caused by the patient's heartbeat or generated by external sound waves, can be synchronized with the oximeter that monitors the patient's heartbeat signal, It can be detected by a coherence interferometer. A syringe equipped with a pressure gauge can be used to inject a viscoelastic gel into the eye to swell the eye and to measure intraocular pressure. The combined information can also be used to detect and / or confirm the centering and / or tilt of an implanted intraocular lens (IOL), such as a multifocal intraocular lens. The combined information can also be used to detect eye conditions including phakic, aphakic and pseudophakic lenses. The wavefront sensor signal can be combined with the OLCI / OCT signal to measure and display optical scatter and / or opacity of the optical lens or visual system optical media. The wavefront sensor signal can also be combined with the OLCI / OCT signal to measure the distribution of the tear film across the cornea of the patient's eye.

  One requirement for a real-time ophthalmic wavefront sensor is the wide diopter measurement dynamic range that can be encountered during cataract surgery, such as when the natural ocular lens is removed and the eye is aphakic. Although the optical wavefront relay configuration is designed to include a wide diopter measurement dynamic range, the sequential nature eliminates the crosstalk problem and the lock-in detection technology filters out DC and low frequency 1 / f noise. The dynamic range can still be limited by the position sensing device / detector (PSD). In one aspect, the optical element is optimally designed so that the image / light spot size on the PSD is always in a certain range over the desired diopter coverage range, and thus its centroid can be sensed by the PSD. . In another embodiment, as shown in FIGS. 1 and 2, the dynamic wavefront / defocus offset device 178/278 is conjugated with an intermediate wavefront image plane, i.e. both corneal and wavefront sampling planes. Placed on the surface. The dynamic wavefront / defocus offset device 178/278 may be a drop-in lens, a variable focus lens, a liquid crystal based transmitted wavefront manipulator, or a variable mirror based wavefront manipulator. If the PSD is a limiting factor for measuring wide diopter values (positive or negative), the electronics system activates the wavefront / defocus offset device 178/278 to offset some or all of the wavefront aberration Can be partially or fully compensated. For example, in the aphakic state, the wavefront from the patient's eye is relatively divergent, and a positive lens is placed in the wavefront relay beam path at the 4-F wavefront image plane to reduce the spherical defocus component of the wavefront. The image / light spot that is offset and thus arrives on the PSD can be brought to a range where the PSD can sense / measure the center of the sub-wavefront sampled sequentially.

  In other cases, such as high myopia, high hyperopia, relatively large astigmatism or spherical aberration, the wavefront / defocus offset device 178/278 can be scanned and the planned offset is 1 It can be applied to one or more specific aberration components. In this way, some lower order aberrations can be offset, information about other specific higher order wavefront aberrations is emphasized, and clinically important features of the remaining wavefront aberrations that need to be further corrected Can be revealed. By doing so, the vision corrector or surgeon can fine tune the vision correction procedure to minimize the remaining wavefront aberration in real time.

  FIG. 6 shows an overall block diagram of an exemplary embodiment of an electronics system 600 that controls and drives the sequential wavefront sensor and other associated active devices shown in FIGS. 1 and 2. In this aspect, the power supply module 605 converts AC power into DC power for the entire electronic device system 600. Wavefront data and eye images / movies can be acquired and / or recorded synchronously in a streaming manner. The host computer and display module 610 is a back-end process that includes synchronizing the live eye image with the wavefront measurement results, and the wavefront that is superimposed or displayed on top of the live image of the patient's eye Provides a visual display to the user with information. The host computer and display module 610 also converts the wavefront data into digital graphics / synchronized and blended computer graphics to form a composite video that is performed in real time during the vision correction procedure. Synthetic video synchronized with activity can be displayed on the display.

  The host computer and display module 610 also provides power and communicates with the sequential wavefront sensor module 615 through a serial or parallel data link 620. The optical elements shown in FIGS. 1 and 2 are in a sequential wavefront sensor module 615 along with some front end electronics. In one aspect of the present disclosure, the host computer and display module 610 and the sequential wavefront sensor module 615 communicate through a USB connection 620. However, any convenient serial, parallel, or wireless data communication protocol will work well. The host computer and display module 610 also includes optional connections 625 such as Ethernet, wavefront, video and other processed or raw other for other purposes such as later data analysis or playback Data can be downloaded to an external network (not shown in FIG. 6).

  It should be noted that the display should not be limited to a single display shown to be combined with the host computer. The display includes a built-in head-up display, a translucent microdisplay in the eyepiece path of the surgical microscope, and a backprojection display that can project information onto an overlay on the live microscope view as seen by the surgeon / clinician Or many monitors interconnected with each other. In addition to superimposing the wavefront measurement data on the patient's eye image, the wavefront measurement results (as well as other measurement results such as those from the image sensor and low coherence interferometer) are also displayed on different display windows on the same screen. Can be displayed next to each other or separately on different displays / monitors.

  Compared to the prior art wavefront sensor electronics system, the electronics system provides the host computer and display module 610 to provide back-end processing that includes synchronizing live eye images with sequential wavefront measurement data. It is different in that the synchronized information is displayed by superimposing the wavefront information on the live eye image or displaying the wavefront information next to the live eye image. In addition, the front-end electronics within the sequential wavefront sensor module 615 (discussed briefly below) operate the sequential real-time ophthalmic wavefront sensor in lock-in mode and should be synchronized with live eye image data. The processed wavefront data is configured to be transmitted to the host computer and display module 610.

  FIG. 7 shows a block diagram of an exemplary embodiment of a front-end electronic processing system 700 within the wavefront sensor module 615 shown in FIG. In this embodiment, a live imaging camera module 705 (such as a CCD or CMOS image sensor / camera) provides a live image of the patient's eye, and the data is superimposed on the live image of the patient's eye. To the host computer and display module 610 shown in FIG. The front-end processing system 710 includes SLD drive and control circuitry 715 (which also performs SLD beam focusing and SLD beam steering as discussed above in connection with FIGS. 1 and 2 in addition to pulsing the SLD. May be electronically coupled to the wavefront scanner drive circuit 720 and to the position sensitive detector circuit 725. Compared to prior art wavefront sensor electronics systems, the front-end electronic processing system of the present disclosure, when combined in any way, changes the situation and favors real-time ophthalmic wavefront measurement and display, especially during eye refractive cataract surgery It also has many features. The light source used to create the wavefront from the eye is operated in pulsed and / or burst mode. The pulse repetition rate or frequency is more than the typical frame rate of a standard two-dimensional CCD / CMOS image sensor (it is typically about 25-30 Hz (generally considered as the number of frames per second)) (Typically within or above the kHz range). In addition, the position sensitive detector is two-dimensional with a sufficiently high time frequency response so that it can be operated in a lock-in detection mode in synchronization with the pulsed light source at frequencies exceeding the 1 / f noise frequency range. The front end processing system 710 is at least electronically coupled to the SLD drive and control circuit 715, the wavefront scanner drive circuit 720, and the position sensitive detector circuit 725. The front end electronics are configured to phase lock the operation of the light source, wavefront scanner and position sensitive detector.

  In addition, the front-end processing system 710 can also be electronically coupled to the internal fixation and LED drive circuit 730 and the internal calibration target positioning circuit 735. In addition to driving internal fixation as discussed above with reference to FIGS. 1 and 2, the LED drive circuit 730 includes a plurality of LED drivers, and an indicator LED, for an eye live imaging camera Can be used to drive other LEDs, including floodlight LEDs, as well as LEDs for triangulation-based eye distance ranging. An internal calibration target positioning circuit 735 can be used to initiate the generation of a reference wavefront to be measured by a sequential wavefront sensor for calibration / verification purposes.

  The front-end and back-end electronic processing systems include one or more digital processors and non-transitory computer readable memory for storing executable program code and data. The various control and drive circuits 715-735 may be implemented as wired circuitry, digital processing systems, or combinations thereof, as is known in the art.

  FIG. 8 illustrates an exemplary internal calibration and / or verification target 802/832/852 that can be moved into the wavefront relay beam path to create one or more reference wavefronts for internal calibration and / or verification. Show. In one aspect, the internal calibration and / or verification target includes a diffusely reflecting or scattering material such as a lens (such as an aspheric lens) 804 and a piece of spectralon 806. Spectralon 806 may be positioned a short distance in front of or behind the back focal plane of the aspheric lens 804. The aspheric lens 804 can be anti-reflection coated to substantially reduce any specular reflection from the lens itself.

  When the internal calibration and / or verification target 802 is moved into the wavefront relay beam path, it is, for example, by a magnetic stopper (not shown) so that the aspheric lens 804 is centered and coaxial with the wavefront relay optical axis. Stopped. The SLD beam is then blocked by an aspheric lens with minimal specular reflection, and the SLD beam is at least partially focused by the aspheric lens and arrives on the Spectralon 806 as a light spot. Since Spectralon is designed to reflect and / or scatter highly diffusely, the returned light from Spectralon is in the form of a diverging cone 812 and back through the aspheric lens After moving, it becomes a slightly diverging or converging beam of light 814.

  The position of the internal calibration target as shown in FIGS. 1 and 2 is somewhere between the first lens 104/204 and the polarizing beam splitter 174/274, and therefore somewhat slightly there propagating backwards. A diverging or converging beam is equivalent to a beam coming from a point source in front of or behind the object plane of the first lens 104/204. In other words, the internal calibration and / or verification target creation reference wavefront is equivalent to the convergent or divergent wavefront coming from the eye under test.

  In one aspect, the actual axial position of the Spectralon relative to the aspheric lens can be designed such that the reference wavefront can be made similar to the wavefront from the aphakic eye. In another aspect, the actual axial position of Spectralon can be designed such that the reference wavefront created in this way can be made to resemble a wavefront from a normal or myopic eye.

  Here we used aspheric lenses, but using any other type of lens, including spherical lenses and also cylindrical + spherical lenses or tilted spherical lenses, calibration and / or It should be noted that a reference wavefront with certain intended wavefront aberrations for verification can be created. In one aspect, the position of the Spectralon relative to the aspherical lens can also be continuously varied so that the internally generated wavefront has a continuously variable diopter value, and the complete wavefront sensor over the design diopter measurement range. Allow calibration to be possible.

  In another embodiment, the internal calibration target may simply be a piece of bare Spectralon 836. In this case, if any part of the flat Spectralon surface is moved into the wavefront relay beam path, the SLD beam will be interrupted, assuming the topographic characteristics of the Spectralon surface are substantially the same. Since the reference wavefront can be substantially generated, the requirements for the stop position of the piece of Spectralon 836 can be reduced. In this case, the beam emitted from a piece of bare Spectralon is a diverging beam 838.

  In yet another aspect, the internal calibration and / or verification target includes both a piece of bare Spectralon 866 and a structure having an aspheric lens 854 and a piece of Spectralon 856, where Spectralon (866 and 856) may be a single piece. The mechanism for moving the internal calibration and / or verification target 852 into the wavefront relay beam path consists of two stops, an intermediate stop that does not need to be very repeatable, and a highly repeatable final magnetic stop position. Can have. An intermediate stop position can be used to allow a piece of bare Spectralon to block the SLD beam, and a highly reproducible stop position is used to center the aspheric lens sufficiently. And the aspherical lens + spectralon structure can be positioned so that they are coaxial with the optical axis of the wavefront relay beam. In this way, two reference wavefronts (864 and 868) can be obtained, thus determining whether the system transfer function moves as designed using an internal calibration target or whether the wavefront relay optics are misaligned. You can check if you need to compensate.

  Due to the difference in the amount of light returned from the real eye vs. the amount of light returned from a piece of Spectralon, light attenuating means, such as neutral density filters and / or polarizers, are present in the internal calibration and / or verification target. It can be included and placed either in front of or behind the aspheric lens to attenuate the light so that it is approximately the same as light from a real eye. Alternatively, the thickness of the Spectralon can be appropriately selected to allow only the desired amount of light to be diffusely scattered and / or reflected so that the transmitted light is a light absorbing material (shown in FIG. 8). Not absorbed).

  One aspect of the present invention is to interface the front-end processing system 710 with the position sensitive detector circuit 725 and the SLD driver and control circuit 715. The position sensor detector is probably a parallel multi-channel detector because it has a sufficiently high time-frequency response, so it is a small parallel of quadrant detector / sensor, lateral effect position sensitive detector, photodiode It can be a 2D sequence, or others. In the case of quadrant detectors / sensors or side effect position sensitive detectors, there are typically four parallel signal channels. The front end processing system calculates ratiometric X and Y values based on the signal amplitude from each of the four channels (A, B, C, and D), as discussed below. In addition to standard techniques, the front-end processing system uses a final amplified output of A, B, C and D values for all sequential sampled sub-wavefront image spots arriving on the position sensitive detector. The SLD output and the gain of the variable gain amplifier can be automatically adjusted, either independently for each channel or together for all channels, to be optimized for the noise ratio (user's At discretion). This can change the optical signal returned from the patient's eye depending on the refractive state (myopia, orthosight and hyperopia), the surgical condition (phakic, aphakic and pseudophakic) and the degree of cataract of the eye There is so needed.

  FIGS. 9A and 9B show aspects of an electronic block diagram that accomplishes the task of automatic SLD indexing and digital gain control through a servo mechanism to optimize the signal-to-noise ratio, and FIG. 10 processes the exemplary aspects. Shown in the form of a flow block diagram.

  Referring to FIG. 9A, the microprocessor 901 is coupled to a memory unit 905 having code and data stored therein. Microprocessor 901 also includes SLD driver and control circuit 915 with digital / analog conversion to SLD 911, MEMS scanner drive circuit 925 with digital / analog conversion to MEMS scanner 921, and composite transimpedance amplifier 933, coupled to PSD 931 via analog / digital converter 935 and variable gain digital amplifier 937.

  The PSD in this example is a quadrant detector with 4 channels leading to 4 final amplified digital outputs A, B, C and D, and accordingly 4 composite transimpedance amplifiers, 4 analog / digital It should be noted that there are converters and four variable gain digital amplifiers, but only one of each is depicted in FIG. 9A.

  To illustrate these points, we briefly repeat what was discussed in US7445335 with reference to FIG. 9B. A sequential wavefront sensor is used for wavefront sampling, and a PSD quadrant detector 931 with four photosensitive areas A, B, C, and D is sampled sub-wavefront image spot position as shown in FIG. 9B. Assume that it exhibits a local tilt with respect to the centroid position. When the sub wavefront is incident at a normal angle to the sub wavefront focusing lens in front of the quadrant detector 931, the image spot 934 on the quadrant detector 931 is in the center and the four photosensitive areas have the same amount of light. Each zone receives and produces a signal of the same strength. On the other hand, if the sub-wavefront deviates from normal incidence at a tilt angle (eg, towards the upper right), the image spot on the quadrant detector is formed away from the center (as indicated by image spot 938). Moved to the upper right quadrant).

式中、A、B、CおよびDは、象限検出器の対応する各感光性区域の信号強度を表し、分母（A+B+C+D）は、測定を正規化するために使用され、そのため、光源強度変動の影響が取り消され得る。式（1）は、セントロイド位置に関する局所チルトを計算するのに完全には正確ではないが、それは適切な近似値であることに留意すべきである。実際には、何らかの数学を使用する式および内蔵アルゴリズムによって誘導される可能性がある像スポット位置誤差をさらに補正する必要があり得る。 The centroid deviation (x, y) from the center (x = 0, y = 0) can be first-order approximated using the following formula:

Where A, B, C and D represent the signal intensity of each corresponding photosensitive area of the quadrant detector, and the denominator (A + B + C + D) is used to normalize the measurement, Therefore, the influence of the light source intensity fluctuation can be canceled. It should be noted that equation (1) is not completely accurate for calculating the local tilt with respect to the centroid position, but it is a good approximation. In practice, it may be necessary to further correct for image spot position errors that may be induced by some mathematical formula and built-in algorithms.

  Referring to FIG. 10, at start step 1002, the front end microprocessor 901 preferably first sets the SLD to a power level as high as allowed by the eye safety document requirements. The gain of the variable gain digital amplifier 937 at this point can be initially set to a value determined in the last session or an intermediate value as normally selected.

  The next step (1004) is to check the variable gain digital amplifier final outputs A, B, C and D. If the amplified final output of A, B, C, and D values is found to be within the desired signal strength range, which may be the same for each channel, the process flow is variable gain digital Proceed to step 1006 where the gain of the amplifier is kept at the set value. If any or all of the final outputs are below the desired signal strength range, the gain can be increased as indicated by step 1008, and then the final output is checked as indicated by step 1010. If the final output is within the desired range, the gain is greater than the current value as shown in step 1012 in order to overcome variable induced signal changes that may cause the final output to go out of the desired range again. Can also be set at a slightly higher value. The process of increasing the gain through step 1008 and checking the final output through step 1010 if the final output is still below the desired signal strength range and the gain has not reached its maximum as indicated by step 1014 Can be repeated until the final output is within range, and the gain is set as shown in step 1012. One possible exceptional scenario is that when the gain is already increased to its maximum as shown by step 1014, the final output is still below the desired range. In this case, the gain is set to its maximum as shown in step 1016 and the data can still be processed, but the statement is presented to the end user and the wavefront signal is too weak as shown in step 1018. He / she can be notified that the data may be invalid.

  On the other hand, if any of the final outputs A, B, C and D is above the desired signal strength range, the gain of the variable gain digital amplifier may be reduced as shown in step 1020, as shown by step 1022 Final output is checked. If all of the final outputs are within the desired range, as shown in step 1024, the gain is adjusted to overcome the variable induced signal changes that may cause the final output to be re-emitted out of the desired range. It can be set at a value slightly lower than the value. If any of the final outputs are still above the desired signal strength range and the gain has not reached its minimum as checked in step 1026, decrease the gain through step 1020 and final output through step 1022 The process of checking can be repeated until all of the final outputs are in range, and the gain is set as indicated by step 1024.

  However, it is possible that the gain has reached its minimum when checked in step 1026 and that one or more of the final outputs A, B, C and D are still above the desired signal strength range. In this case, the gain is held at its minimum as shown in step 1028 and the SLD output can be reduced as shown by step 1030. Final outputs A, B, C and D are checked in step 1032 after the SLD output has been reduced, and if the final A, B, C and D outputs are found to be within the desired range, step As indicated by 1034, the SLD output is set at a slightly lower level than the current level in order to overcome the fluctuating induced signal changes that may cause the final output to be re-emitted out of the desired range. If one or more final outputs A, B, C, and D are still above the desired range and the SLD output has not reached zero through 1036 check steps, decrease the SLD output as indicated by step 1030. The process of checking the final A, B, C and D outputs as indicated by step 1032 may be repeated until they reach the desired range and the SLD outputs are set as indicated by step 1034. The only exception is that the SLD output reaches zero and one or more of the final A, B, C and D outputs are still above the desired range. This means that there is still a strong wavefront signal even without the SLD output. This can only occur if there is either electronic or optical interference or crosstalk. We hold the SLD output at zero as shown by step 1038 and send a message to the end user that the data is invalid because there is a strong interference signal as shown by step 1040. Can do.

  In addition to the above, alternatively, the end user can also manually control the SLD output and the gain of the variable gain digital amplifier until he / she feels that the actual wavefront measurement results are satisfactory.

  Note that the exemplary aspects given in FIGS. 9A and 9B and 10 are only one of many possible ways to achieve the same goal of improving the signal-to-noise ratio. Should be considered to explain the concept. For example, it is not absolutely necessary to set the SLD output at the same level as allowed by the eye safety document requirements at the start step. The SLD output can be initially set at any level and then adjusted along with the amplifier gain until the final outputs A, B, C and D are within the desired range. The advantage of initially setting the SLD output to a relatively high level is that the optical element or photonics domain, the optical signal-to-noise ratio can be maximized before any optoelectronic conversion. However, this does not mean that other options will not work. Indeed, the SLD output may be initially set to zero and gradually increased along with the amplifier gain adjustment until the final A, B, C and D outputs are within the desired range. In this case, it is believed that there is a corresponding change in the sequence and details of the process flow. These changes should be considered within the scope and spirit of the present disclosure.

  Another aspect of the present disclosure is to use a composite transimpedance amplifier to amplify the position signal of a sequential ophthalmic wavefront sensor. FIG. 11 shows an exemplary embodiment of a composite transimpedance amplifier that can be used to amplify signals from any one quadrant (eg, D1) of the quadrant photodiode of the quadrant detector. The circuit is used in a position sensitive detector circuit as shown in FIG. 9A. In this composite transimpedance amplifier, the current-voltage conversion rate is determined by the value of feedback resistor R1 (which can be, for example, 22 megohms), and in order to balance the input of operational amplifier U1A, resistor R2 Is matched by. Shunt capacitors C1 and C2 can be either the parasitic capacitance of resistors R1 and R2, or a small capacitor added to the feedback loop. The stability and high frequency noise reduction of the transimpedance amplifier stems from the low pass filter formed by resistor R3, capacitor C3 and operational amplifier U2A inside feedback loop 1150. In this circuit, + Vref is some positive reference voltage between ground and + Vcc. The output signal (output A) is proportional to R1, but the noise is proportional to the square root of R1, so the signal-to-noise ratio increases proportionally to the square root of R1 (because it is dominated by Johnson noise in R1) ).

  It should be noted that prior art high bandwidth wavefront sensors generally only use standard transimpedance amplifiers rather than composite transimpedance amplifiers (eg, S. Abado, et. Al. "Two-dimensional High-Bandwidth Shack -Hartmann Wavefront Sensor: Design Guidelines and Evaluation Testing ", Optical Engineering, 49 (6), 064403, June 2010). In addition, prior art wavefront sensors are not purely sequential and are somehow parallel. Furthermore, they do not face the same weak but synchronized and pulsed optical signal challenges that the sequential ophthalmic wavefront sensor faces. When combined in any way, from the perspective of application to optical signal amplification in a sequential ophthalmic wavefront sensor, the features uniquely associated with the composite transimpedance amplifier of the present disclosure include: (1) current-voltage conversion To improve accuracy, the selected feedback resistor value of R1 that is substantially matched by resistor R2 is very high; (2) reduces noise contribution from large resistance values of R1 and R2, while at the same time To maintain adequate signal bandwidth, the two shunt capacitors C1 and C2 have very low capacitance values; (3) the low pass filter formed by R3, C3 and U2A inside the feedback loop is Substantially improve stability and substantially reduce the high-frequency noise of the transimpedance amplifier; (4) positive reference to achieve lock-in detection The voltage + Vref is a properly scaled DC signal that is phase locked to the drive signals of the SLD and MEMS scanners, and is between ground and + Vcc. In addition, quadrant sensors with minimum end capacitance are preferably selected to achieve an optimal signal-to-noise ratio; they avoid any shunt conduction between any two of the four quadrants. Good channel separation between quadrants is preferred.

  In addition to the above circuit, the optical signal converted to an analog current signal by the position sensitive detector is also AC coupled to a conventional transimpedance amplifier, amplified and then combined with a standard lock-in detection circuit. It is possible to recover small signals that are otherwise obscured by noise that could be much larger than the signal of interest. FIG. 12 shows one exemplary embodiment of such a combination. The output signal from the transimpedance amplifier 1295 is mixed (ie, multiplied) by the mixer 1296 with the output of the phase lock loop 1297 locked to the reference signal that drives and pulses the SLD. The output of the mixer 1296 passes through the low pass filter 1298 to remove the sum frequency component of the mixed signal, and the time constant of the low pass filter is selected to reduce the equivalent noise bandwidth. The low-pass filtered signal can be amplified by yet another amplifier 1299 for analog / digital (A / D) conversion further downstream in the signal path.

  An alternative to the above lock-in detection circuit is to start A / D conversion just before the SLD is lit to record the “dark” level and immediately after the SLD is lit to record the “bright” level. To start the / D conversion. The difference can then be calculated to remove the effects of interference. Yet another aspect is to start the A / D conversion immediately after the SLD is lit or to record the “bright” level while ignoring the “dark” level if the interference effects are minimal .

  In addition to the optical signal detection circuit, the next essential electronically controlled component is the wavefront scanner / shifter. In one embodiment, the wavefront scanner / shifter is an electromagnetic MEMS (Micro-Electro-Mechanical System) analog steering mirror driven by four D / A converters controlled by a microprocessor. In one example, the two channels of the D / A converter output a sine wave that is 90 degrees apart in phase, and the other two channels output X and Y DC offset voltages for the wavefront sampling annular ring. Guide the center. The amplitude of the sine and cosine electronic waveforms determines the diameter of the wavefront sampling annular ring, which matches one or more of the wavefronts with the desired diameter in the eye pupil region, as well as to match the various eye pupil diameters. It can be varied to intentionally sample around the annular ring. The aspect ratio of the X and Y widths can also be controlled to ensure that circular scanning is performed when the mirror reflects the wavefront beam laterally.

  FIGS. 13A-13F illustrate how MEMS scanner and SLD pulse synchronization produces the same result as when the wavefront is sampled by multiple detectors arranged in a ring.

  In FIG. 13A, the MEMS 1312 is oriented so that the entire wavefront is shifted downward when the SLD pulse is fired. In this case, the aperture 1332 samples the upper part of the circular wavefront section.

  In FIG. 13B, the wavefront is shifted to the left so that the aperture samples the right part of the circular wavefront section, and in FIG. Shifted, in FIG. 13D, the wavefront is shifted to the right so that the aperture samples the left portion of the circular wavefront section.

  FIG. 13E shows that a sequential scanning sequence of 4 pulses per cycle is equivalent to sampling the wavefront section with 4 detectors arranged in a ring.

  In another example, the SLD can be synchronized with a MEMS scanner and the 8 SLD pulses allow 8 sub-wavefronts to be sampled for each MEMS scanning rotation and hence for each wavefront sampling annular ring rotation. Can be fired. In SLD pulse firing, four odd or even out of eight pulses are aligned with the X and Y axes of the MEMS scanner, and the other four pulses are in the middle of the ring between the X and Y axes. It can be timed to be arranged. FIG. 13F shows the resulting pattern of MEMS scanning rotation and relative SLD firing position. The number of SLD pulses need not be limited to 8 and can be any number, SLD pulses need not be equally spaced, and they must be aligned with the X and Y axes of the MEMS scanner It should be noted that there is nothing.

  Alternatively, for example, by changing the relative timing and / or number of SLD firing pulses relative to the MEMS scanner drive signal, we select the portion of the wavefront to be sampled and also sample the wavefront The wavefront sampling position can be shifted along the wavefront sampling ring to achieve higher spatial resolution in terms of FIG. 14 shows an example in which the eight wavefront sampling positions are shifted 15 ° away from the position shown in FIG. 13F by slightly delaying the SLD pulse.

  As another alternative, we sample the wavefront at offset angles of 0 ° on the first frame, 15 ° on the second frame, and 30 ° on the third frame and repeat this pattern In some cases, we can sample the wavefront with increased spatial resolution when data from multiple frames is processed collectively. FIG. 15 shows such a pattern. This incremental increase in SLD initial firing time per frame can be performed with any desired but practical timing accuracy to reach any desired spatial resolution along any annular wavefront sampling ring. Please keep in mind. In addition, by combining the changes in the amplitude of the sine and cosine drive signals of the MEMS scanner, we can sample different annular rings with different diameters. In this way, sequential sampling of the entire wavefront can be achieved with any desired spatial resolution in both the radial and angular dimensions of the polar coordinate system. It should be noted that this is just one example of many possible sequential wavefront scanning / sampling schemes. For example, a similar approach can be applied in the case of raster scanning.

As described above, with reference to FIG. 9B, a well-known standard in terms of interpreting the centroid position of different sequentially sampled sub-wavefront image spots arriving on the position sensing device / detector (PSD). A ratiometric formula may be used. It is preferable that quadrant detectors or side effect position sensitive detectors are used as PSDs, whose XY axes are aligned with the MEMS scanner axis orientation, so that they have the same X and Y axes, Is not absolutely necessary. For example, in the case of a quadrant detector, the ratiometric X and Y values of the sequentially sampled sub-wavefront image spots are represented based on the signal strength from each of the four quadrants A, B, C, and D. obtain:
X = (A + BCD) / (A + B + C + D)
Y = (A + DBC) / (A + B + C + D)

  In general, these ratiometric values of X and Y do not directly give a highly accurate, lateral displacement or position of the centroid, for example, quadrant detector response, sampled gap distance, This is because it is also an effect of the image spot size, which depends on many factors, including the local average tilt and local divergence / convergence of the sub-wavefront, and the shape and size of the sub-wavefront sampling aperture. One aspect of the present invention is to modify the relationship or equation so that the sampled sub-wavefront tilt can be determined more accurately.

  In one aspect, the relationship between ratiometric measurement results and actual centroid displacement is determined theoretically and / or experimentally, and the ratiometric equation is modified to more accurately reflect the centroid position. FIG. 16 shows an example of a theoretically determined relationship between the ratiometric estimate and the actual centroid displacement or position along either the X or Y axis.

Because of this non-linearity, an approximate inverse of the effect is applied to the original equation, resulting in a modified relationship between the ratiometric (X, Y) and the actual centroid position (X ', Y') be able to. The following is just one example of such an inverse correlation.
X '= PrimeA * X / (1-X ² / PrimeB)
Y '= PrimeB * Y / (1-Y ² / PrimeB)
In the formula, PrimeA and PrimeB are constants.

  It should be noted that the relationships or formulas shown above are exemplary and are not intended as limitations on approaches that may be used to achieve the same goal. In fact, the above correction is for the sampled sub-wavefront centroid position of a particular intensity profile when the image spot is displaced only along the X or Y axis. If the image spot is displaced in both X and Y, further correction is required, especially if a higher degree of measurement accuracy is desired. In one exemplary embodiment, experimentally determined in the form of a data matrix between the ratiometric result reported by the quadrant detector for (X, Y) and the actual centroid position (X ′, Y ′). A relationship can be established and an inverse relationship can be established to convert each (X, Y) data point to a new centroid (X ′, Y ′) data point.

  FIG. 17 shows an exemplary flow diagram showing how calibration can be performed to obtain a modified relationship and to provide a more accurate wavefront aberration measurement. In the first step 1705, the wavefront can be generated using various means, for example from an eye model or, for example, a variable mirror with different divergence and convergence or different wavefronts with different wavefront aberrations. Can be produced from a wavefront manipulator such as In a second step 1710, the actual centroid position (X ′, Y ′) of the different sampled sub-wavefronts is compared with the experimentally measured ratiometric value (X, Y) and (X ′ , Y ′) and (X, Y). On the other hand, a calibrated wavefront tilt and hence photorefractive value versus centroid data point position can be obtained. In a third step 1715, real eye measurements can be taken and the resulting relationship can be used to determine the centroid position and thus the sub-wavefront tilt from the real eye sampled. . In a fourth step 1720, the determined centroid position or the sampled sub-wavefront tilt may be used to determine wavefront aberrations or real eye refractive errors.

  The first and second calibration-related steps can be performed once for each constructed wavefront sensor system, and the third and fourth steps can be repeated for real eye measurements as many times as desired. It should be noted that However, this does not mean that the calibration step should be performed only once. In fact, it is beneficial to repeat the calibration step periodically.

  As one aspect of the present disclosure, the calibration step or partial calibration can be repeated as often as the manufacturer or end user prefers using an internal calibration target driven by a microprocessor as shown in FIG. 9A. For example, the internal calibration target is temporarily moved into the optical wavefront relay beam path every time the system is turned on or even before each actual eye measurement, either automatically or manually as desired by the end user. obtain. An internal calibration need not provide every data point, as a more substantially comprehensive calibration is or can be provided. Rather, the internal calibration target only needs to provide a few data points. Use these data points to experiment with whether the optical alignment of the wavefront sensor is intact or whether environmental factors such as temperature changes and / or mechanical shocks are interfering with the optical alignment of the wavefront sensor. Can be confirmed. As a result, this is whether a completely new comprehensive calibration needs to be done, or is a small correction based on some software sufficient to ensure an accurate real eye wavefront measurement Decide if. Alternatively, the reference wavefront aberration measured using an internal calibration target can elucidate the inherent optical system aberrations that the wavefront sensor optics have, and the actual eye wavefront aberration is the total measured wavefront aberration From this, it can be determined by subtracting the wavefront aberration induced in the optical system.

  As another aspect of the present disclosure and using a calibration target (internal or external), an initial time delay between the SLD firing pulse and the MEMS mirror scanning position, or sub-wavefront sampling along a particular wavefront sampling annular ring An offset angle between the position and the MEMS mirror scanning position can be determined. The same calibration step can also be used to determine whether the SLD firing time is sufficiently accurate with respect to the MEMS scan mirror position and whether there is any deviation from a certain desired accuracy. Then, either electronics hardware based correction or pure software based correction can then be performed to fine tune the SLD firing time or MEMS scanning drive signal.

  As yet another aspect of the present disclosure, if calibration (internal or external) detects that the optical alignment is out of alignment, or the eye is not in the best position for real eye measurements, wavefront measurements Is still located within a range that can be made using software corrections, the software-based adjustment is to respond to such misalignment as described with reference to FIG. Can be implemented.

  In another exemplary embodiment, eight sub-wavefronts are sampled around an annular ring of wavefronts generated from either the calibration target or the real eye, e.g., PSD lateral position shift or wavefront from the patient's eye Centroid tracking of eight measured sub-wavefront tilts (X '(i), Y' (i)), where i = 0, 1, 2, ..., 7 as a result of prism wavefront tilt If a center offset is found, the 8 data points are given new Cartesian coordinates (Xtr, Ytr) and a new set of data points (Xtr (i), Ytr (i)) (where , I = 0, 1, 2, ..., 7), a translation of (X ', Y') Cartesian coordinates can be performed, and the cluster centers of centroid data points are now new Located at the origin (Xtr = 0, Ytr = 0). In this way, any effects that result in the appearance of the overall prism wavefront tilt, eg resulting from misalignment between the sub-wavefront sampling aperture and the position sensitive detector / device, can be filtered out of the measured wavefront. As a result, the remaining data processing can be focused on resolving refractive errors and / or wavefront higher order aberrations.

  Sequential wavefront sampling has the inherent advantage that the location we are sampling on the annular ring can be correlated with the displacement of each individually sampled sub-wavefront centroid position. Please keep in mind.

  As described above, the centroid displacement of the sampled wavefront portion is determined using ratiometric X and Y values calculated from the output signal generated by the PSD. The positions of these output values form a geometric pattern that can be analyzed by a front-end or back-end electronic processing system to determine ophthalmic features of the subject's eye. The formation and analysis of these patterns is illustrated in FIG. 9C. In FIG. 9C, the displacements are shown as if they were displayed on the monitor. However, in other exemplary aspects, the displacement is processed by an algorithm executed as software by the front-end processing system and is not necessarily displayed to the user.

  Figure 9C shows the planar wavefront, defocus and astigmatism, the associated image spot position on the quadrant detector behind the sub-wavefront focusing lens, and when displayed as a 2D data point pattern on the monitor A number of representative situations of sequential movement of corresponding centroid positions are shown. We have sampled and described above with reference to FIGS. 13A-E instead of depicting many shifted wavefronts that are sampled and projected onto the same subwavefront focusing lens and quadrant detector as different subwavefronts. With an equivalent representative example, many sub-wavefronts are drawn around the same annular ring, and so many quadrant detectors are drawn around the same annular ring, and the case of scanning different parts of the wavefront is single sub-wavefront focusing Note that the representation is as a lens and a single quadrant detector.

  We assume that scanning around the wavefront annular ring starts from the upper subwavefront and moves clockwise, as indicated by arrow 9009, to the right second subwavefront, and so on. When the wavefront is a plane wave 9001, all sub-wavefronts (eg 9002) form an image spot 9003 at the center of the quadrant detector 9004, and as a result, the centroid trace 9005 on the monitor 9006 is also always in xy coordinates It can be seen from FIG.

  When the input wavefront diverges as indicated by 9011, the center of the image spot 9013 of each sub-wavefront 9012 is an equal shift from the center of the quadrant detector 9014 and is radially outward from the center of the wavefront, resulting in The trace 9015 on the monitor 9016 starts from the upper position 9017 and is a clockwise circle as indicated by the arrow 9018. On the other hand, if the input wavefront converges as indicated by 9021, the center of the image spot 9023 of each sub-wavefront 9022 is radial with respect to the center of the wavefront with an equal shift from the center of the quadrant detector 9024. On the inside. As a result, the centroid trace 9025 on the monitor 9026 is still circular, but starts at the bottom position 9027 and is still clockwise as indicated by arrow 9028. Thus, it is an indication that the input wavefront is changing from a diverging beam to a converging beam or vice versa when sign conversion is detected for both the x-axis centroid position and the y-axis centroid position. Furthermore, the starting point of the centroid trace may also be used as a reference to indicate whether the input wavefront is diverging or converging.

  It can also be seen from FIG. 9C that when the input wavefront is astigmatism, the wavefront can diverge vertically as indicated by 9031a and converge in the horizontal direction as indicated by 9031b. As a result, the centroid position of the vertical sub-wavefront 9033a is positioned radially outward with respect to the center of the input wavefront, and the centroid position of the horizontal sub-wavefront 9033b is positioned radially inward with respect to the center of the input wavefront. . As a result, the centroid trace 9035 on the monitor 9036 starts from the upper position 9037, but moves counterclockwise as indicated by arrow 9038, so the centroid trace rotation is now reversed.

  Using a similar argument, if the input wavefront is astigmatism but all sub-wavefronts are either completely diverging or fully converging, the rotation of the centroid trace is clockwise. Yes (ie not the opposite), however, for the astigmatism case, the subwavefront along one astigmatism axis is more divergent or convergent than the subwavefront along the other axis, so on the monitor It's not difficult to figure out that the centroid traces are elliptical rather than circular.

  For more general astigmatism wavefronts, the centroid trace rotates in the opposite direction with either an elliptical or circular trace, or the centroid trace rotates in the normal clockwise direction Either the trace is oval. The axis of the ellipse can be any radial direction with respect to the center, which indicates the axis of astigmatism. In such cases, the four sub-wavefronts around the annular ring may not be sufficient to accurately determine the axis of astigmatism, and more sub-wavefronts (8, 16, or 4 instead) 32) can be sampled around the annular ring.

  For example, to summarize the divergent spherical wavefront coming from the human eye versus the converging spherical wavefront, the sub-wavefronts sampled sequentially around the annular ring of the eye's pupil are represented by sequential centroid data points arranged around a circle. However, depending on whether the wavefront diverges or converges, each data point arrives at a different opposing location. In other words, for a divergent wavefront, for example, we have a particular position (eg (Xtr (0), Ytr (0)) = (0, 0.5) where there is a particular data point (eg i = 0). We expect the same data points to be at opposite locations (eg (Xtr (0), Ytr (0) ) = (0, -0.5) On the other hand, if the original wavefront has both spherical and cylindrical components, the centroid data point is an ellipse, straight, non-normal or inverted ellipse, which can be a normal ellipse, And non-forward or reverse circles, these scenarios are discussed in detail in co-assigned US7445335 and co-assigned US8100530.

  One aspect of the present disclosure is to use both the major and minor axis positive and negative values to describe a centroid data point as an equivalent ellipse. For example, a total diverging wavefront can be defined as having a positive major axis and a minor axis, and a total converging wavefront can be defined as generating a “negative” major axis and minor axis.

Figure 18 shows a graphical representation of a sequential ellipse using trigonometric formulas (where U (t) = a · cos (t), V (t) = b · sin (t), a is large The radius of the smaller circle, and b is the radius of the smaller circle). As can be seen, a>b> 0, that is, both a and b are positive, and the ellipse rotates counterclockwise. Thus, a point on the ellipse can represent a sequentially calculated centroid displacement of the total diverging wavefront with both spherical and cylindrical refractive anomalies, where the divergence is in the horizontal and vertical directions. Different. When a = b, the ellipse represents the divergent spherical wavefront, and the divergence is the same in the horizontal direction and the vertical direction. Assuming a t ₀ value of 0 <t ₀ <π / 2, the point (U (t ₀ ), V (t ₀ )) is in the first quadrant of UV Cartesian coordinates.

  In this particular example of FIG. 18, and in FIGS. 19, 20 and 21, we assume that the Cartesian coordinate axes U and V are aligned with the quadrant detector axes x and y, and at the same time the present invention Note that they also assumed that the astigmatism axis was also along the x or y axis. Thus, an ellipse as shown in FIGS. 18-21 is oriented horizontally or vertically.

If the major and minor axes are both negative, we can express them as -a and -b. In this case as shown in FIG. 19, the corresponding sequential ellipse is U (t) = − a · cos (t), V (t) = − b · sin (t) (where a>b> 0, both represented by negative -a and -b). This results in an ellipse that still rotates counterclockwise. This can be considered to represent a fully convergent wavefront with both spherical and cylindrical refractive anomalous components with different degrees of convergence in the horizontal and vertical directions. If a = b, it represents a convergent spherical wavefront with the same degree of convergence in the horizontal and vertical directions. With a t ₀ value of 0 <t ₀ <π / 2, the point (U (t ₀ ), V (t ₀ )) is now in the third quadrant of UV Cartesian coordinates, opposite the coordinate origin compared to FIG. On the side.

If the major axis is positive and the minor axis is negative, we can express them as a and -b. In this case as shown in FIG. 20, the corresponding sequential ellipse is U (t) = a · cos (t), V (t) = − b · sin (t) (where a> b > 0, positive a and negative -b). This results in an ellipse that rotates clockwise starting from the fourth quadrant. This can be viewed as representing a horizontally diverging and vertically converging wavefront with both spherical and cylindrical refractive anomalies that differ in horizontal divergence and vertical convergence. If a = b, it represents a cylindrical wavefront that diverges horizontally and converges vertically, with the same horizontal divergence and vertical convergence. With a t ₀ value of 0 <t ₀ <π / 2, the point (U (t ₀ ), V (t ₀ )) is now in the fourth quadrant of UV Cartesian coordinates.

If the major axis is negative and the minor axis is positive, we can express them as -a and b. In this case as shown in FIG. 21, the corresponding sequential ellipse is U (t) = − a · cos (t), V (t) = b · sin (t) (where a>b> Represented by 0, negative -a and positive b). This results in an ellipse that rotates clockwise starting from the second quadrant. This can be viewed as representing a horizontally converging and vertically diverging wavefront with both spherical and cylindrical refractive anomalies differing in horizontal and vertical divergence. When a = b, it represents a cylindrical wavefront that converges horizontally and diverges vertically, with the same degree of horizontal convergence and vertical divergence. With a t ₀ value of 0 <t ₀ <π / 2, the point (U (t ₀ ), V (t ₀ )) is now in the second quadrant of UV Cartesian coordinates, opposite the coordinate origin compared to FIG. On the side.

  Note that the assignment of divergent wavefronts to the “positive” versus “negative” axis is arbitrary and can be reversed as long as we distinguish them. The positive direction of the axis may be switched. For example, the U axis may point upward instead of pointing to the right, and the V axis may point right instead of pointing upward. In this case, as shown in FIG. 22, the sequential centroid data points expected from the divergent spherical wavefront sampled at the plane represented by the interrupt line result, as indicated by the numbers and arrows in FIG. A clockwise circle with the specified data point position and polarity. Note that the sequential direction of rotation has changed compared to FIG. 18 due to the different axial polarity assignments. Similarly, in the same case, as shown in FIG. 23, the sequential centroid data points expected from the convergent spherical wavefront sampled at the plane represented by the interrupted line are as indicated by the numbers and arrows in FIG. A clockwise circle with the resulting data point position and polarity. Note that as the sampling wavefront changes from divergence to convergence, the numbered data points are switched from their original position in FIG. 22 to the opposite position in FIG.

  One aspect of the present disclosure is to use calibration (internal or external) to determine the initial offset angle of the data point vector relative to the Xtr or Ytr axis. Another aspect of the present disclosure is that at least one of the calibration centroid data points, e.g., i = 0 data points (U (0), V (0)) is either the U or V axis of the new Cartesian coordinate UV. The Cartesian coordinates (Xtr, Ytr) are rotated to another Cartesian coordinates (U, V) by the offset angle so that they are aligned above. In this way, the measured sub-wavefront tilt (at least of the data points) expressed as data points (U (i), V (i)), where i = 0, 1, 2, ..., 7 Can be easily correlated to an ellipse and / or the sub-wavefront tilt can be averaged as if it were on the correlated ellipse (Elliptic parameters are correlated with the spherical and cylindrical diopter values of the sampled wavefront and the major and / or minor axis directions are correlated with the cylindrical axis of the sampled wavefront).

  Figure 24 shows Cartesian parallelism of eight sequentially sampled centroid data points fitted to a sequential ellipse, further rotated to UV coordinates, from the original XY coordinates to the translated Xtr-Ytr coordinates Shows movement and rotation. Note that for all divergent wavefronts and the coordinate axis selection shown, the sequential direction of rotation is clockwise. In this example, the center of the eight sequential data points was first determined, and the XY coordinates were translated to the Xtr-Ytr coordinates, where the origin of the Xtr-Ytr coordinates was obtained eight sequential The center of the data point. Next, the major and minor axes of the fitted ellipse (with their corresponding axial polarities as discussed above) are obtained through digital data processing, and the fitted ellipse major or minor axis is Coordinate rotation is performed by aligning with the U or V axis of the UV coordinates having the same origin as the Xtr-Ytr coordinates. Note that in this example, the first data point (point 0) is already aligned with or located on the U axis. In more general situations this may not be the case. However, if aligning the first data point (point 0) with the U axis aids data processing, the firing time of the SLD relative to the MEMS scanner drive signal can be adjusted to allow this alignment, 2 The phase delay between two signals can be used for data processing simplification.

  The wavefront sampling, coordinate transformation, and associated data processing around the annular ring of the present disclosure is expressed analytically as spherical cylinder diopter values are simply a function of (U (i), V (i)) data point values. And thus has the advantage that data processing is substantially simplified and can be performed very quickly. In other words, the data points (U (i), V (i)) are now represented by the expressions U (t) = a · cos (t) and V (t) = b · sin (t) (where a and b Can be easily fitted to an ellipse at the canonical position (center at the origin, long axis along the U axis) using a major axis and a minor axis, respectively, which can have positive or negative values.

  This algorithm enables real-time high-precision measurement of the ocular wavefront over a wide dynamic range. When the U and V axes are rotated to fit the ellipse into the canonical position, the orientation of the ellipse indicates the axis of astigmatism. In addition, the magnitudes of a and b indicate the relative magnitude of the divergent and convergent astigmatism components, and the direction of rotation identifies which components diverge and which components converge. Help. As a result, a real-time titration of the surgical vision correction procedure can be performed. In particular, use real-time wavefront measurement results to indicate corneal limbal incision (LRI) and / or astigmatic keratotomy (AK) surgery and toric IOL (intraocular lens) rotation adjustment And / or can be aligned and / or guided.

  FIG. 25 shows the special case of FIG. 24, the result of coordinate rotation transformation and eight centroid data points on UV coordinates, the left side is a divergent spherical wavefront with equal positive major and minor axes And the right side corresponds to a converging spherical wavefront with equal negative major and minor axes. Again, note that when the sampling wavefront changes from divergence to convergence, the numbered data points are switched from the original position to the opposite position.

  When there is an astigmatism component superimposed on the spherical component, it depends on the astigmatism wavefront tilt compared to the spherical wavefront tilt, as discussed in coassigned US7445335 and coassigned US8100530. Many centroid data point trace scenarios result. With the Cartesian coordinate transformation described above, the centroid data points draw a pattern centered on the origin of the UV coordinates, with at least one of the data points aligned with either the U or V axis, but with a different ellipse shape and orientation. be able to. The shape of the pattern is a normal ellipse having both a positive major axis and a minor minor axis, a straight line having a major positive or negative major axis or having a minor positive or negative axis, a major negative axis and a minor minor axis. Non-forward or inverted ellipse with positive major axis and negative minor axis, and positive major axis and negative minor axis or negative major and positive minor axis Includes any non-forward or reverse circle.

  Since we measure the wavefront sequentially, in the case of a circular trace, we have three different circular trace patterns (divergent spherical circle, converging spherical circle, and reversal of astigmatism). Yen) can be distinguished. This is because the axial polarity is determined by the order in which wavefront samples are collected. In fact, one axis (major axis or minor axis) has a different sign or polarity than the other axis (minor axis or major axis), so the astigmatism inversion circle is effectively correlated to an ellipse. The orientation of the ellipse or straight or reversed circle can be determined from the major or minor axis direction and can be any angle between 0 and 180 degrees, which is also a habit well accepted by optometrists and ophthalmologists is there. It should be noted that the assignment of the major and / or minor axes is arbitrary and therefore the absolute length of the major axis need not be longer than the absolute length of the minor axis. The assignment is only intended to facilitate the calculation of refractive errors associated with the wavefront from the eye.

  It should also be noted that in addition to sampling the wavefront around one annular ring, multiple annular rings of different diameters or concentric annular rings of wavefronts can be sampled. By doing so, a 2D wavefront map can be obtained and provided to the end user. By dynamically changing the annular ring sampling size of the wavefront sensor, the aphasic state of the subject throughout the corneal field can also be ascertained.

  In yet another aspect, a MEMS scanning mirror can be manipulated to sample a sub-wavefront with a spiral pattern or a variable radius concentric ring to allow detection of higher order aberrations. Zernike decomposition can be performed to extract all wavefront aberration coefficients including higher order aberrations such as trefoil, coma, and spherical aberration. For example, the coma can be determined by detecting the lateral shift of the wavefront as the scan radius is increased or decreased. If the number of samples per ring is divisible by 3, trefoil can be detected when the dots form a triangular pattern that reverses when the scan radius is increased or decreased.

  The effective spacing between any two wavefront sampling points can be controlled by controlling the SLD firing time and the drive signal amplitude of the MEMS scan mirror. In addition to reducing the size of the sub-wavefront sampling aperture that can be achieved by the front-end processing system when the aperture is electronically variable, the higher spatial accuracy / resolution sampling of the wavefront also ensures accurate SLD firing time. It can be achieved by controlling, reducing the SLD pulse width, and increasing accuracy in controlling MEMS scan mirror amplitude or position. In this regard, the MEMS scan mirror can be operated in a closed loop servo mode, and the MEMS mirror scan angle monitor signal is fed back to the microprocessor and / or electronics control system to achieve good scan angle control accuracy. Control the scan angle drive signal. On the other hand, further averaging can be achieved by increasing the size of the sub-wavefront sampling aperture or increasing the pulse width of the SLD. Accordingly, another aspect of the present disclosure controls the SLD and wavefront shifter / scanner to achieve either a higher accuracy / resolution in spatial wavefront sampling or further averaging in spatial wavefront sampling. To use electronic equipment to do. Higher precision / resolution spatial wavefront sampling is desired for higher-order aberration measurements, and more averaged spatial wavefront sampling is a wavefront refractive error in terms of spherical and cylindrical light refraction values, as well as cylinder axis. Or it is desirable to measure astigmatism.

  It should be noted that the aforementioned Cartesian coordinate translation and rotation is only one of many possible coordinate system transformations that can be utilized to facilitate the calculation of refractive errors and wavefront aberrations. For example, non-Cartesian coordinates such as polar coordinates or coordinate transformations based on non-vertical axes can be used. Therefore, the conceptual scope using coordinate transformation to facilitate the calculation of wavefront aberrations and refractive errors should not be limited to Cartesian coordinates. The transformation may be between Cartesian coordinates and polar coordinates.

  In practice, the wavefront from the patient's eye may contain higher order aberrations in addition to spherical and cylindrical refractive errors. However, for most vision correction procedures, such as cataract refractive surgery, generally only spherical and cylindrical refractive errors are corrected. Thus, the need for averaging is desirable so that the best spherical and cylinder corrected photorefractive values and cylinder axis angles can be found and prescribed. This disclosure averages centroid traces over one or more annular rings and correlates with one or more ellipses, with the major and minor axis polarities considered when correlating centroid data points with the ellipse The resulting prescription given in terms of spherical and cylindrical photorefractive values and cylindrical axes already includes averaging the effects of higher order aberrations. Yes. On the other hand, algorithms and data processing can also tell the end user how much higher-order aberrations are in the wavefront by calculating how close the correlation between the centroid data point and the ellipse is. .

  FIG. 26 shows an exemplary embodiment process flow diagram in decoding spherical and cylindrical photorefractive values and cylindrical axis angles. Move the internal calibration target into the wavefront relay path to calibrate the system to obtain the offset angle 2605, obtain the relationship between the SLD pulse delay and the offset angle value 2610, and place the internal calibration target in the wavefront relay beam path The calibration step, including step 2615 to move out of, can be performed once for many measurements of the real eye, such as once a day before any measurement, as discussed above, or each It can be performed multiple times, such as once before the eye measurement.

  Once the offset angle information is obtained, there is an optional step 2620 for changing or adjusting the offset angle, which is the initial of the SLD pulse delay or initial sine and cosine drive signals sent to the MEMS scan mirror. It can be achieved by changing the phase. For example, using a spherical reference wavefront, the offset angle can be adjusted so that one of the centroid data points is aligned with the X or Y axis, in which case no further coordinate rotation transformation is required. Thereby, the burden of data processing can be reduced.

  In the next step 2625, the centroid data point position is changed from the A, B, C, D value to the ratiometric value (X, Y) as discussed above, with the modified centroid position value (X ′, Y ′) can be calculated to the translated centroid position values (Xtr, Ytr). If the SLD pulse delay for MEMS mirror scanning can be controlled so that one of the centroid data points is already on the Xtr or Ytr axis, it includes a coordinate rotation transformation from (Xtr, Ytr) to (U, V), The following step 2630 can be optional.

  In the next step 2635, which determines whether the wavefront is spherical, we use centroid data for the origin in a different way (Xtr = 0, Ytr = 0) or (U = 0, V = 0). Some (eg, vertical pairs) or all magnitudes or lengths of point vectors can be compared. For example, if the standard deviation of all vector magnitudes or lengths is less than a predetermined reference value (eg, a value corresponding to less than 0.25D cylinders), we consider the wavefront to be spherical. Can be handled. Alternatively, the inventors can compare the vector magnitudes of some or all data point vectors, the magnitudes are substantially equal, and the difference is less than a predetermined reference value. In some cases, the wavefront can be considered a spherical surface.

  For such a spherical wavefront, in the subsequent step 2640 as shown in FIG. 26, we can still correlate the data points to the ellipse, but the major or minor axis is substantially equivalent. In addition to calculating the length, we can average the major and minor axis lengths, depending on the sign or polarity of the major and minor axes, which can be either positive or negative. Thus, an averaged positive or negative spherical diopter value can be output. Note that the relationship between the photorefractive value and the major or minor axis length could and should have been obtained during the comprehensive calibration phase as discussed above.

  An optional follow-up step 2645 is to display the calculated spherical photorefractive value quantitatively and / or qualitatively as a circle, where the diameter or radius of the circle represents the absolute spherical photorefractive value and the spherical Are indicated using different colors or line patterns for the circles, for example.

  On the other hand, if the wavefront is found not to be spherical, we can assume that there is an astigmatism component. In follow-up step 2650, we correlate the data points with an ellipse and either major and minor axis lengths with polarity as values that can be positive or negative, and either major or minor axis angles. The ellipse angle, which can be By calculating the ellipse angle, major axis length and minor axis length, we calculate the spherical and cylindrical photorefractive values using experimentally obtained calibration relationships or look-up tables. Can do. It is preferred that the diopter values are monotonically related to the lengths of the major and minor axes (including polarity or sign information), so that there is only a unique solution for a particular ellipse. As in the case of spherical wavefronts, the optional follow-up step 2655 displays the calculated spherical and cylindrical photorefractive values and cylindrical axes quantitatively as a set of numbers and / or qualitatively as a circle + line. The diameter of the circle represents the spherical light refraction value, the straight line length represents the cylindrical light refraction value, and the linear orientation angle that can be indicated by a long thin line or interrupted line or arrow represents the cylinder axis angle. Alternatively, the qualitative display can be in the shape of an ellipse, where the length of either the major or minor axis represents the spherical photorefractive value and the difference between the major and minor axis lengths (polarity is considered) Represents the cylindrical light refraction value, and the elliptical angle represents the cylinder axis angle. Again, the sign of the spherical and cylindrical photorefractive values may be indicated using different colors or different line patterns, for example for a circle + straight line representation or for an elliptical representation. One aspect of the present disclosure is to allow user selection of an ellipse or circle + line to represent a refractive error in the patient's eye.

  It should be noted that there can be many other ways to qualitatively indicate refractive errors. The foregoing qualitative indications are merely illustrative rather than comprehensive. For example, the representation may be an ellipse with its major axis proportional to one independent cylindrical diopter value and its minor axis proportional to another independent vertical cylinder diopter value. In addition, the cylinder axis angle can be either a major axis angle or a minor axis angle, depending on whether the end user prefers a positive or negative cylinder prescription, so one cylinder The representing axis angle or the other cylinder angle is the original angle or may be shifted by 90 °. Alternatively, the display may also be two orthogonal straight lines, one linear length proportional to one independent cylindrical light refraction value and the other orthogonal linear length proportional to the other independent vertical cylindrical light refraction value. possible.

  As previously mentioned, one aspect of the present disclosure is an overlay of the wavefront measurement results on a live video image of the patient's eye in a qualitative and / or quantitative manner. The ellipse or linear angle displayed depends on the surgeon / clinician's orientation relative to the patient's eye (top or temporal) or, in the case of the temporal, the patient's eye is being imaged (right or left) It can also be made. For cataract surgery, the cylindrical axis that is presented to the cataract surgeon is more of the cornea so that the surgeon can perform LRI (corneal limbal incision) based on the presented axial direction. It is preferably aligned with a steep axis.

  Live eye images to achieve eye alignment relative to a supine or upright patient position and / or to determine the axis of a toric IOL implanted relative to an iris landmark such as a crypt Alternatively, it can be processed using a pattern recognition algorithm. In addition, specific images (for example, from the wavefront and / or OLCI / OCT measurements) for alignment and / or comparison of optical signals (eg from wavefronts and / or OLCI / OCT measurements) using live images Natural or artificial) alignment can be specified.

  It should also be noted that the transformation from the major and minor axis lengths of the correlated ellipses to diopter values can be done in different ways depending on the end user's preference. There are three ways to represent the same refractive error prescription, as is well known to those skilled in the art. The first draws it as two independent vertical cylinders, the second draws it as a sphere and a positive cylinder, the third draws it as a sphere and a negative cylinder It is drawn as In addition, the indication can be made for either the prescription or the actual wavefront. Our correlation ellipse actually provides the optical refraction values of two independent vertical cylinders directly. One skilled in the art is familiar with the conversion from one method of display to another. It should be emphasized that one aspect of the present disclosure is the use of both positive and negative values to represent the major and minor axes of the correlated ellipse, either positive or negative This is a calibration approach to correlate the obtained long and short axis lengths to two independent vertical cylindrical light refraction values, which can also be positive or negative.

  Note that optometrists, ophthalmologists, and optical technicians can use different methods to represent the same wavefront in the cornea or pupil plane of the patient's eye. For example, optometrists generally prefer a prescription label, which is a lens used to offset wavefront bending and make it flatter or flat; ophthalmologists prefer spherical and cylindrical photorefractive values and cylinders There is a tendency to prefer a direct representation of what the wavefront at the corneal plane is from an axial perspective; on the other hand, optical engineers generally do not use photorefractive values, but are perfectly flat or flat Use a wavefront map that shows the 2D deviation of the actual wavefront from the correct wavefront, or an expression that uses Zernike polynomial coefficients. One aspect of the present disclosure is the interconversion between these different representations that can be performed by the end user, because the algorithm for doing such a transformation is built into the device, and thus the representation The choice of the format is left to the end user.

  From the perspective of further improving the signal-to-noise ratio and hence measurement accuracy and / or accuracy, an ellipse or circle + linear correlation is a single frame (or set) data points, or multiple frame (or multiple sets) data points. Can be done about. Alternatively, the obtained spherical and cylindrical photorefractive values and cylindrical axis angles can be averaged over multiple acquisitions. For example, averaging can be accomplished simply by adding a given number of spherical and cylindrical light refraction values of multiple measurements, respectively, and dividing by a given number. Similarly, the cylinder angle can also be averaged, but can be more complex due to the wraparound problem near 0 °. However, we report angles from 0 ° to 180 °. As one approach, we use trigonometric functions to solve this wraparound problem.

  It should be noted that the front end processing system as shown in FIG. 7 also controls the internal fixation target in addition to other LEDs. However, the internal fixation need not be limited to a single image, such as a single LED or a back-illuminated hot air balloon. Alternatively, the internal fixation target can be a microdisplay combined with an eye-adjustable optical element such as a variable focus lens. The patient's eye can be fixed in different directions by lighting different pixels of the microdisplay so that peripheral field wavefront information such as a 2D array of wavefront maps can be obtained. In addition, the patient's eyes can be fixed at different distances to allow measurement of the adjustment range or adjustment width. In addition, the fixation microdisplay target can be controlled to flash or blink at various speeds or duty cycles, the microdisplay is colored, the fixation target changes color, and illuminates the pattern or spot Can be made possible.

  As described above, one aspect of the present disclosure is to track the eye. FIG. 27 shows an exemplary process flow diagram of the eye tracking algorithm. The steps involved are either live eye pupil or eye pupil position information from the iris, or other means such as detecting specular reflection from the corneal apex by scanning the SLD beam in two dimensions. Use to estimate eye pupil position 2705; Adjust SLD beam scanner to follow eye movement 2710; The same intended portion of the wavefront from the eye is always sampled regardless of eye movement To offset the DC drive component of the wavefront scanner / shifter in proportion to the SLD beam adjustment to compensate for eye pupil movement 2715; and, optionally, correct the wavefront aberration measurement Includes 2720. The live image camera provides a visual estimate of either (a) the center of the iris or (b) the center of the corneal limbus. By correlating the SLD beam (X, Y) position to the field of view, the SLD can be directed to the same position on the cornea. Typically, for wavefront sensing, this position is slightly offset from the axis or corneal apex, and thus the specular reflection of the SLD beam is generally not directly returned to the wavefront sensor position sensitive detector / device. The center of the iris or limbus can be used as a reference point for directing the SLD beam.

  It should be noted that a unique feature of the disclosed algorithm is the step of offsetting the DC drive component of the wavefront scanner / shifter in proportion to the SLD beam adjustment. This is an essential step as it can ensure that the same part of the wavefront from the eye (such as the same annular ring from the eye) is sampled. Without this step, when the eye moves laterally, different parts of the wavefront from the eye are sampled, which can cause significant wavefront measurement errors. The reason for the optional final step of correcting the wavefront aberration measurement is that using compensation that can be provided by the wavefront scanner / shifter in proportion to the SLD beam adjustment has an effect on the wavefront measurement, astigmatism and / or Or because prism tilt and / or other known aberration components are added to all sampled portions of the wavefront that can be predetermined and considered. We have our refractive error decoding algorithm automatically average the aberrations to resolve the damaged spheres and cylinders and to filter out the prism tilt through coordinate translation. Therefore, it was shown that there is no need for additional prism tilt correction for refractive error measurements. Despite the fact that the amount of coordinate translation is already an indication of the prism tilt of the wavefront from the eye, for complete wavefront measurements to include prism tilt, this additional astigmatism caused by eye tracking and / or Or prism tilt and / or other known aberration components should be subtracted, so a final correction step may still be required.

  Another aspect of the present disclosure provides higher measurement sensitivity and / or resolution while wavefront sampling is performed only in the pupil region of the eye and the response curve slope sensitivity is exploited as a function of the annular ring diameter. It is to adaptively select the diameter of the wavefront sampling annular ring so that it can. In general, among all the photorefractive values of different wavefront aberrations such as spherical, cylindrical and trefoil, the spherical photorefractive value removes the natural ocular lens between different eyes and during cataract surgery (ie As the eye is aphasic), it generally requires a maximum coverage range. On the other hand, once cataract surgery is complete, or once IOL (intraocular lens) is implanted into the eye, the pseudophakic eye should generally be closer to the normal eye, so the wavefront from the eye is nearly planar It should be. For typical automatic refraction measurements, the wavefront from a central area of only 3 mm diameter of the eye pupil is generally sampled. Thus, the wavefront sensor provides sufficient diopter measurement resolution (eg 0.1D) as well as sufficient diopter coverage range (eg -30D to + 30D) over an effective wavefront sampling annular ring region including, for example, a diameter range of 1 mm to 3 mm Can be designed to do. On the other hand, in order to confirm the orthographic eye with higher sensitivity and / or wavefront measurement resolution, we have a pupil size that is large enough to more accurately measure the wavefront or refractive error of pseudophakic eyes. If so, near the end of the cataract refractive surgery, the wavefront sample annular ring can be expanded to a diameter of, for example, 5 mm.

  FIG. 28 shows one aspect of an algorithm flow diagram that can implement this concept. The involved step uses the eye pupil information obtained from the live eye image to estimate the eye pupil size, step 2805, the eye pupil size information to determine the maximum diameter of the wavefront sampling ring Step 2810 to use, and Step 2815 to increase the annular ring diameter to the maximum diameter as determined by Step 2810 for pseudo lens measurements to achieve better diopter resolution. This “zoom in” feature may be user selectable or automatic. In addition, we can also use PSD ratiometric output to adaptively adjust the annular ring diameter for optimal diopter resolution and dynamic range coverage.

  One feature of the present disclosure is that live eye images are combined with wavefront measurement data with or without pattern recognition algorithms to produce eyelids / eyelashes, irises, facial skin, surgical instruments, surgeon's hands, irrigation water Detection of the presence of the eye, or the eye moving away from the design range. By doing so, “dark” or “bright” data can be eliminated and the SLD can be intelligently turned on and off to save exposure time, thereby delivering higher SLD power to the eye And an optical or optical communication signal-to-noise ratio can be increased. FIG. 29 shows an exemplary process flow diagram illustrating such a concept. The steps involved are either live eye images and / or wavefront sensor signals to detect the presence of unintended objects in the wavefront relay beam path, or that the eye has moved away from the desired position and / or range. Use step 2905, discard incorrect "bright" or "dark" wavefront data step 2910, turn off SLD when wavefront data is wrong, step 2915, and wavefront data is wrong or invalid Including an optional step 2920 to inform the end user.

  Another aspect of the present disclosure eliminates speckle, averages, and increases optical power within safe limits that can be delivered into the eye (this can increase the optical signal-to-noise ratio). To potentially enable it is to scan and / or control the incident SLD beam over a small area on the retina. In addition, the divergence / convergence of the SLD beam, and hence the size of the SLD beam spot size on the retina, is also more consistent with the wavefront from the eye, eg using an axially movable lens or a variable focus lens or a variable mirror And / or can be dynamically adjusted so that the SLD spot size on the retina can be controlled to allow a fully calibrated measurement. On the other hand, the SLD beam spot size and / or shape on the retina, for example, use the same live eye image sensor by adjusting its focus or monitor the SLD beam spot on the retina of the eye exclusively. You may monitor using a different image sensor. Using such feedback and the incorporation of a closed loop servo electronics system, the static or scan pattern of the SLD spot on the retina can be controlled.

  Yet another aspect of the present disclosure uses the same SLD beam scanner or different scanners to scan a surgical laser beam for performing refractive correction of the eye such as LRI (corneal limbal incision) Including a laser as a surgical light source that can be combined with an SLD beam delivered through the same optical fiber or another free space light beam combiner. The same laser or different lasers can also "mark" the eye or "guide" the surgeon, i.e. "superimpose" on the eye so that the surgeon can see the laser mark through the surgical microscope Can be used for.

  Another aspect of the present disclosure is to measure the eye distance while the eye wavefront is being measured, and to correct the measurement of the wavefront from the eye when the eye distance is changed. When the natural lens of the eye is removed, i.e. when the eye is in an aphasic state, the wavefront from the eye is highly divergent, and as a result, a small axial movement of the eye relative to the wavefront sensor module can cause refractive errors or wavefront aberration measurements. Information about the eye distance from the wavefront sensor module is particularly important for cataract refractive surgery because it can induce relatively large changes. We have discussed how corrections to the wavefront can be made if the eye moves laterally away from the design position. A similar correction should also be made when the eye moves axially away from its design position. In performing axial correction, either a low optical coherence interferometer (LOCI) or an optical coherence tomographer (OCT) can be included in the wavefront sensor module and used to measure the axial distance. Alternatively, simpler techniques such as using optical triangulation to measure eye distance may be utilized. LOCI and OCT are preferred because ocular biometric / anatomical measurements can be made in addition to ocular distance. These measurements can also reveal the effective lens (natural or artificial) position when the lens is tilted, the depth of the anterior chamber, the thickness of the cornea and lens, and the length of the eye. Especially useful for surgery. Using lateral scanning as can be achieved by an OCT system, the refractive power of the cornea and / or ophthalmic lens (natural or artificial) is derived in conjunction or independently, especially for the case of aphakic eyes be able to.

  Yet another aspect is to combine two or more of the measurement results obtained by the wavefront sensor, eye imaging camera and LOCI / OCT for other purposes. In one aspect, the combined information is used, particularly after the natural ocular lens has been ground by a femtosecond laser, optical scattering and / or turbidity within the media of the visual system, such as cataract opacity and intraocular optics. The presence of bubbles can be detected. The combined information is also needed to detect eye aphasic states and to target refraction in real time in the operating room (OR) either on demand or just prior to implanting the IOL. Can be used to calculate and / or to confirm refraction and / or to find the effective lens position immediately after implantation of the IOL. Furthermore, the combined information can also be used to determine the alignment of the patient's head, i.e., whether the patient's eye is perpendicular to the optical axis of the wavefront sensor module. In addition, the combined information can also be used to perform dry eye detection and to inform the surgeon when to irrigate the eye. In addition, the combined information can also be, for example, whether the targeted eye refraction has been reached at the end of the surgery, or whether the multifocal IOL has been properly centered without significant tilt, or a toric IOL implanted Clinician / surgeon only with preferred information, such as pre-operative eye refractive error, aphasic IOL prescription and endpoint indicator, to indicate whether the center has been centered and rotated to the correct axis angle. May be displayed as customized by him / her. The display can also show a data integrity indicator or a reliability indicator.

  The combined information is further used to determine whether the eye is properly aligned and, if not, to determine whether the patient's eye or microscope should be moved for better alignment. Directional guides can be included in the display to communicate to the clinician. Using information, whether the eyelid is closed, or whether there are debris of broken / broken eye lens material inside the optical bubble or slack under the eye that can affect the wavefront measurement results A reliability indicator may also be included in the display to indicate whether or not the wavefront measurement is eligible.

  Referring back to FIG. 2, it can be noted that the sub-wavefront focusing lens 220 can also be controlled by the electronics system. This lens can be a variable focus lens or an axially movable lens, or even a variable mirror. The purpose of activating this lens is to control open-loop or closed so that the image / light spot size formed by the sub-wavefront focusing lens can be controlled based on the local divergence or convergence of the sequentially sampled sub-wavefront The focal length is dynamically adjusted by one of the loop methods. This is especially true when wavefront sampling is performed around an annular ring. For example, to achieve better response tilt sensitivity for better wavefront tilt measurements in accuracy and / or accuracy, the image spot is the PSD (used to determine the lateral movement of the image spot ( Better focusing on quadrant detectors or side effect position sensitive detectors). Alternatively, the sampled sub-wavefront image spot arriving on the PSD (quadrant detector or lateral effect position sensitive detector) can also be controlled to a certain desired size. For example, one option for spot size is the size of a single quadrant of the quadrant detector as is well known to those skilled in the art. Another possible option is a size that produces a compromised high sensitivity and wide dynamic response range. Yet another option is an image spot size that is approximately twice the gap size of the quadrant detector. These different image spot sizes can be varied dynamically depending on the averaged local divergence or convergence of the sequentially sampled sub-wavefront.

  By dynamically compensating the wavefront or DC offsetting the defocus of the wavefront, the image spot can also be made to always arrive at or near the center of the quadrant detector. Using this approach, it should be possible to lock and zero each sampled sub-wavefront image spot at a size and position such that the highest sensitivity can be achieved. The drive signals for the wavefront compensation or defocus offset device, wavefront shifter and subwavefront focusing lens can be used to accurately determine the wavefront tilt of each sampled subwavefront.

  It should be noted that the apparatus of the present disclosure can accomplish a large number of additional tasks depending on the configuration of the host computer that processes wavefront data, eye image data, eye distance data, low coherence interferometer data, etc. It is. For example, the host computer can analyze wavefront data to obtain metrics such as refractive errors, display metric and / or quantitative metrics on the display, and display qualitative and / or quantitative metrics It can be configured to allow the surgeon / clinician to select a method to do. From the perspective of how wavefront measurements should be displayed, end-users choose to display end-point indicators such as wavefront aberration vs. refraction vs. prescription, and / or positive cylinder vs. negative cylinder, and / or sighted eye be able to.

  The host computer may also be configured to allow the surgeon / clinician to flip or rotate the live image / movie of the patient's eye in a preferred orientation. In addition, the surgeon / clinician can also rewind the desired recorded segment of the composite video, which can include eye images, wavefront measurements and even low coherence interferometry measurements, as required during or after surgery. And can play.

  Most importantly, the present disclosure can guide the surgeon to titrate the vision correction procedure in real time and optimize the results of the vision correction procedure. For example, it can guide the surgeon to adjust the IOL position in the eye with respect to centration, tilt and circumferential orientation until the measurement confirms the optimal placement of the IOL. In addition, it can guide the surgeon to rotate the implanted toric intraocular lens (IOL) to correct / neutralize astigmatism. It is performed by a limbus / corneal dilatation or intrastromal lenticule laser (Flexi) to adjust astigmatism and hence eliminate astigmatism. Can be guided.

  The device of the present disclosure can also be used to indicate whether the implanted multifocal IOL has the desired focusing range and in addition whether its positioning has been optimized. It can also be used to determine whether the implanted AIOL (regulatory or regulatory IOL) can provide the desired range of accommodation.

  A real-time guide is provided on how the vision correction procedure should proceed to facilitate the removal of the remaining aberrations, confirm the results, and describe the aberration values and senses on the display obtain. The real-time information that is displayed also automatically or manually digitally “zooms out” or “to warn the surgeon or vision correction practitioner that the correction procedure is in the wrong or right direction "Zoom in". Once a certain level of correction has been achieved, the displayed information will change to a highlighted form, for example with respect to font size, bold, style or color, to achieve the refraction endpoint goal for the patient, such as a normal eye This can be confirmed during surgery.

  In addition to visual feedback, audio feedback can also be used alone or in combination with video feedback. For example, audio information may or may not use video / graphic information, move the IOL in either direction for proper alignment, or use a toric lens to correct / remove astigmatism. Can be provided to indicate whether to rotate in the direction. A real time audio signal may also be generated to indicate the type of refractive error, the magnitude of the error, and the change in error. The pitch, tone, and magnitude of the real-time audio signal can be changed during the vision correction procedure to show the improvement or deterioration of the applied correction. For example, a specific pitch of the real-time audio signal can be created to identify the error as a cylinder, with a tone indicating the magnitude of the cylinder error.

  One very important application of the present disclosure is to help the cataract surgeon determine when the patient's eye is aphasic, whether the IOL frequency selected before surgery is correct or not. is there. Real-time aphasic wavefront measurements (preferably along with ocular biometric measurements such as those provided by a built-in low-coherence interferometer) more accurately determine the required IOL frequency, and thus selected IOLs prior to surgery The frequency can be verified to be correct or not, particularly for patients undergoing post-operative corneal refractive procedures where pre-operative IOL selection prescriptions do not give consistent results.

  Another important application of the present disclosure is to monitor changes in corneal shape and other ocular biometric / anatomical parameters during the entire cataract surgery session while the wavefront from the patient's eye is measured, It is to record. Changes can be measured before, during and after cataract surgery in the OR (operating room), and as a result of various factors that can cause changes in the wavefront from the patient's eye, corneal curvature measurements There can also be changes in corneal topography and corneal thickness, as measured by pachymetry, anterior chamber depth, lens position and thickness. These factors include, for example, local anesthesia, open device, incision / wound made in the cornea, anterior chamber filling material, intraocular pressure, water / solution irrigation over the cornea, wound sealing, and wound healing effects , And the effects of surgeon-induced wavefront changes caused by surgeon-specific cataract surgery practices.

  Data on changes in eye biometric / anatomical parameters can be used to compensate for effects induced by various factors. Thus, wavefront results after incision / wound healing are expected and can be used to set a certain desired target eye refraction for cataract surgery. Pre- and post-operative corneal shape and other ocular biometric / anatomical parameters include a built-in OCT and eye camera, as well as a built-in or external corneal topographer that can be attached to either a surgical microscope or the disclosed device It can be measured using a keratometer. Pre-surgical measurements can be made in the OR when the patient is in the supine position before and after local anesthesia is applied, and before and after the eyelider is engaged to keep the eyelid open . Intraoperative measurements are made after an incision is made in the cornea, the cataract lens is removed, and the anterior chamber is filled with a specific gel (OVD, Ophthalmic Viscosurgical Device), and then an artificial intraocular lens is implanted. Before the IOL is implanted but before the incision wound is sealed. Immediately after surgery, measurements are also taken in the OR immediately after the surgeon seals the incision / wound but before the open device is removed and when the open device is removed and the patient is still in the supine position. obtain.

  The data thus obtained for changes in corneal shape and other ocular biometric / anatomical parameters can be combined with ocular wavefront measurement data and stored in a database. Another round of measurements may be performed after weeks or months of surgery, after the incision / wound has healed completely, and differences or changes in the ocular wavefront and corneal shape, and / or ocular biometric measurement parameters may also occur. Can be collected. Thus, a nominal database can be established and processed to elucidate the target refraction immediately after cataract surgery that needs to be set to provide the final desired vision correction result after the wound has fully healed. In this way, all effects are taken into account, including even aberrations due to the surgeon, such as, for example, astigmatism arising from a particular individual corneal incision.

  The wavefront sensor of the present disclosure can be combined with a variety of other ophthalmic instruments for a wide range of applications. For example, it can be integrated with a femtosecond laser or excimer laser for LASIK or ocular lens fragmentation, or for alignment and / or guidance on “incision”, or for closed-loop excision of ocular tissue. Live eye images, OLCI / OCT data, and wavefront data can be combined to indicate whether an optical bubble is present in the ophthalmic lens or anterior chamber before, during, and after eye surgery. Alternatively, the wavefront sensor can also be integrated with or adapted to a slit lamp biomicroscope.

  The present invention can also be integrated with or combined with an adaptive control optics system. Real-time wavefront manipulation can be used to partially or fully compensate for some or all of the wavefront error using a variable mirror or LC (liquid crystal) based transmission wavefront compensator.

  In addition, the wavefront sensor of the present disclosure can also be combined with any other type of intraocular pressure (IOP) measurement means. In one aspect, it can even be used directly to detect an IOP by measuring an ocular wavefront change in response to the patient's heartbeat. It can also be used directly to calibrate the IOP.

  These aspects may also be deployed to measure optical elements, spectacles and / or glasses, IOL, and / or guide cutting / machining devices that create optical elements . These embodiments can also be adapted for microscopy or other metrology applications for cell and / or molecular analysis. The present invention may also be used for lens production, eyeglass identification, microbiology applications, and the like.

  Although various aspects have been set forth and described in detail herein incorporating the teachings of the present invention, those skilled in the art can readily devise many other modified embodiments that incorporate these teachings. .

Claims (4)

A light source 172 configured to output a light beam to illuminate a subject's eye;
A light source driver circuit 715 coupled to the light source and configured to output a light source drive signal at a first pulse frequency;
A position sensitive detector 122 having a plurality of detector elements configured to output a plurality of detector output signals indicative of the signal intensity of incident light at each detector element;
Configured to block the wavefront beam returned from the target eye when the target eye is illuminated by the light source, and configured to direct a portion of the wavefront from the target eye to the detector through the aperture; A portion of the wavefront directed through the aperture forms a spot on the detector, and the magnitude of the centroid deflection of the spot from the reference point at the detector is the signal intensity A first beam deflection element 112 approximately indicated by a ratiometric combination and the magnitude of deflection indicates the degree of tilt or convergence or divergence of the portion of the wavefront from the plane wave;
A beam deflection element drive circuit 720 coupled to the first beam deflection element and configured to output a beam deflection element drive signal to scan a portion of the wavefront at a wavefront scanning frequency;
A plurality of composite transimpedance amplifiers each having an input coupled to receive one of a plurality of detector output signals and an output for providing an amplified detector output signal, A wavefront sensor comprising a plurality of composite transimpedance amplifiers, wherein the output of the transimpedance amplifier is phase locked to the light source drive signal and the beam deflection element drive signal.   The wavefront sensor of claim 1, wherein each composite transimpedance amplifier includes a low pass filter 1150 to increase stability and reduce high frequency noise. The low pass filter
A first operational amplifier U2A having an input and an output;
A first resistor R3;
3. The wavefront sensor according to claim 2, including a first capacitor C3, wherein the first resistor and the capacitor are connected in series between an input and an output of the first operational amplifier. Composite transimpedance amplifier
A second operational amplifier U1A having an input and an output;
A feedback resistor R1 having a feedback resistance value and coupling the output of the first operational amplifier to the input of the second operational amplifier, wherein the amplitude of the amplified detector output signal is proportional to R1, and 4. The wavefront sensor of claim 3, further comprising a feedback resistor R1, wherein the noise is proportional to the square root of R1.

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