JP2002306416A - Eye characteristics measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely superpose the aberration or refractivity data of an eye of an examee obtained from a first light detection part and the cornea data of the eye obtained from a second light detection part with each other. SOLUTION: A measuring part 111 measures optical characteristics of the eye especially on the basis of the first light detection signal from the first light detection part 23 and performs cornea topographic measurement on the basis of the second light detection signal from the second light detection part 35. Further, the measuring part 111 calculates an aberration quantity on the basis of the aberration result and outputs the result to surgery operating equipment through an input-output part 115. A coordinates setting part 112 converts the signals of the first and second coordinates systems corresponding to the pupil of the eye to be examined contaned in the first and second light detection signals to the signals of reference coordinates systems. A conversion part 116 correlates the first and second optical characteristics of the eye calculated by the measuring part 111 with each other by the each reference coordinates systems formed by the coordinates setting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye characteristic measuring device, and more particularly, to measuring an optical characteristic of an eye and relating the measured optical characteristic to a predetermined coordinate system of an eye, a measuring device, and a surgical device, and displaying the coordinate system. The present invention relates to an eye characteristic measurement device that performs, for example, an operation.

[0002]

2. Description of the Related Art In recent years, optical instruments used for medical purposes include:
It is extremely diverse. This optical device is widely used in ophthalmology as an optical characteristic measuring device for inspecting an eye function such as refraction and accommodation of an eye and an inside of an eyeball. In addition, the measurement results of these various tests are, for example, important under what measurement conditions the subject's eye to be tested was placed.

In general, corneal topography predicts the results of operations such as corneal incision and corneal ablation, the design and evaluation of clinical lenses after corneal transplantation, myopia and hyperopia, and diagnosis and diagnosis of cornea. It is effective for many uses. Conventional methods for measuring the corneal shape include, for example, a plastic seed disk technique, a stereographic technique, a moiré technique, and a topography interference technique.

[0004]

However, in the conventional eye characteristic measuring device, processing has been performed such that the coordinates of the measuring device itself, for example, the center of the light receiving section is set as the coordinate origin. Therefore, according to such a coordinate system, for example, in a surgical apparatus, there is a case where the relationship between the measurement data and the eye is not sufficiently obtained, and it is not always appropriate. Further, as a conventional measuring device, there is a device called a photo-refractometer for obtaining the refractive power and the corneal shape of the eye to be examined, but the display is not always performed in the same coordinate system.

In general, when alignment is adjusted manually or automatically, measurement is started manually or automatically. A coordinate system (CCD coordinates) attached to the CCD at the time of measurement is transmitted through the CCD and the lens. Corresponding to the CCD coordinates of the object side (eye side) on the opposite side. The Hartmann wavefront sensor (first measurement system) and the corneal shape measurement (second measurement system) are almost simultaneously performed by the respective CCDs, but may be measured at strictly non-simultaneous times. For this reason, during measurement, for example, movement of the eyes is the main cause, and there is no guarantee that the CCD coordinate system of the first measurement system is equal to the CCD coordinate system of the second measurement system. In addition, it has already been performed to obtain a pupil edge from the anterior eye image and use it for alignment. However, if the acquisition timing of the Hartmann image and the acquisition timing of the anterior segment alignment image do not completely match, alignment using only the anterior segment alignment image may cause a deviation in the alignment of the Hartmann measurement due to eye movements etc. There is.

[0006] In recent years, in corneal correction surgery,
Optical characteristic measurement data such as aberration and refractive power data of the eye to be inspected obtained from the first light receiving unit which is an eye optical characteristic measuring system, and corneal data of the eye to be inspected obtained from the second light receiving unit which is a corneal topography measuring system. There has been a demand for overlaying corneal topography measurement data.

[0007] In view of the above, the present invention makes it possible to precisely superimpose the aberration and refractive power data of the eye to be inspected obtained from the first light receiving section and the corneal data of the eye to be inspected obtained from the second light receiving section. It is an object of the present invention to provide an eye optical characteristic measuring device for associating as described above. In addition, the present invention compares the two pupils in terms of images and matches the positions, thereby aligning the coordinates of the corneal shape measurement and the wavefront measurement using the same image as the alignment system, and the coordinate system of the alignment system. The purpose is to associate the coordinate system of the wavefront measurement with that of the wavefront measurement.

[0008]

According to the present invention, there is provided a first light source unit for emitting a first light beam of a first wavelength, and a fundus of an eye to be inspected is irradiated with a first light beam from the first light source unit. A first illumination optical system for illuminating, and a first light receiving unit that forms a first light receiving signal as a first coordinate system from the received light beam, and converts the light beam reflected from the fundus of the eye to be examined back into a plurality of beams. A first light receiving optical system for converting the light to the first light receiving unit and a second light receiving unit for forming a second light receiving signal as a second coordinate system including information on the anterior segment from the received light beam; Second including eye information
A second light receiving optical system that guides the light beam to the second light receiving unit; a first optical characteristic of the subject's eye based on a first light receiving signal from the first light receiving unit; and a second light receiving signal from the second light receiving unit. A measuring unit for obtaining the second optical characteristic of the eye to be inspected; and coordinates for converting signals of the first and second coordinate systems corresponding to the pupil of the eye included in the first and second light receiving signals into signals of a reference coordinate system, respectively. An eye characteristic comprising: a setting unit; and a conversion unit configured to associate and combine the first and second optical characteristics of the eye to be examined obtained by the arithmetic unit with each reference coordinate system formed by the coordinate setting unit. Provide a measuring device.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1. FIG. 1 is a view showing a schematic optical system 100 of an eye optical characteristic measuring apparatus according to the present invention.

The optical system 100 of the eye optical characteristic measuring device is, for example, a device for measuring the optical characteristics of the eye to be measured 60, which is an object, and includes a first illumination optical system 10, a first light receiving optical system 20, , A second light receiving optical system 30, a common optical system 40, an adjusting optical system 50, a second illumination optical system 70, and a second light transmitting optical system 80. In addition, about the eye 60 to be measured,
In the figure, a retina 61 and a cornea 62 are shown.

The first illumination optical system 10 includes, for example, a first light source unit 11 for emitting a light beam of a first wavelength, and a condenser lens 1.
2 and the light beam from the first light source 11
A small area on the retina (fundus) 61 is illuminated so that the illumination conditions can be appropriately set. Here, as an example, the first wavelength of the illumination light beam emitted from the first light source unit 11 is a wavelength in the infrared region (for example, 780 nm).

It is desirable that the first light source unit 11 has high spatial coherence and low temporal coherence. Here, the first light source unit 11 is, for example, a super luminescence diode (SLD), and can obtain a point light source with high luminance. The first light source unit 11
Is not limited to the SLD. For example, even a laser or the like having a large spatial coherence or time coherence can be used by inserting a rotating diffuser or the like and appropriately reducing the time coherence. Furthermore, even an LED having a small spatial coherence and a small temporal coherence can be used by inserting a pinhole or the like at the position of the light source on the optical path, for example, as long as the light amount is sufficient.

The first light receiving optical system 20 converts at least one part of the light beam (first light beam) reflected and returned from the collimator lens 21 and the retina 61 of the eye 60 to be measured.
Hartmann plate 2 which is a conversion member for converting into seven beams
2 and a first light receiving unit 23 for receiving a plurality of beams converted by the Hartmann plate 22, for guiding the first light beam to the first light receiving unit 23. Also, here, the first light receiving unit 23 has a low readout noise C
Although a CD is adopted, an appropriate type of CCD such as a general low-noise type or a 1000 × 1000-element cooled CCD for measurement can be used as the CCD.

The second illumination optical system 70 includes a second light source 72,
A placido ring 71 is provided. Note that the second light source 72 can be omitted. FIG. 2 shows an example of a configuration diagram of the Placido ring. Placido Ring (PLACIDO'S
DISC) 71 is for projecting an index of a pattern composed of a plurality of concentric rings as shown in the figure. The index of the pattern including a plurality of concentric rings is an example of an index of a predetermined pattern, and another appropriate pattern can be used. Then, after the alignment adjustment described later is completed, an index of a pattern including a plurality of concentric rings can be projected.

The second light transmission optical system 80 mainly performs, for example, alignment adjustment and coordinate origin and coordinate axis measurement / adjustment, which will be described later, and a second light source unit 31 for emitting a light beam of a second wavelength. , A condenser lens 32 and a beam splitter 33.

The second light receiving optical system 30 includes a condenser lens 34,
A second light receiving unit 35 is provided. The second light receiving optical system 30 is
The pattern of the placido ring 71 illuminated from the illumination optical system 70 guides the light flux (second light flux) reflected from the anterior segment of the eye 60 to be measured or the cornea 62 and returned to the second light receiving unit 35. Also, the eye to be measured 60 emitted from the second light source 31
The light flux reflected and returned from the cornea 62 of the second
5 can also be led. The second wavelength of the light beam emitted from the second light source unit 31 is different from, for example, the first wavelength (here, 780 nm), and a longer wavelength can be selected (for example, 940 nm).

The common optical system 40 is disposed on the optical axis of the light beam emitted from the first illumination optical system 10, and includes first and second illumination optical systems 10 and 70, and first and second light receiving optical systems 20 and 30. , And can be commonly included in the second light transmission optical system 80 and the like, and includes, for example, an afocal lens 42, beam splitters 43 and 45, and a condenser lens 44. Further, the beam splitter 43 transmits (reflects) the wavelength of the second light source unit 31 to the eye 60 to be measured, reflects the second light flux reflected from the retina 61 of the eye 60 to be measured, and returns.
The first light source 11 is formed of a mirror that transmits the wavelength (for example, a dichroic mirror). The beam splitter 45 adjusts the wavelength of the first light source 11 to the eye 60 to be measured.
Is formed by a mirror (for example, a dichroic mirror) that transmits (reflects) the first light flux that is reflected from the retina 61 of the eye 60 to be measured and returns. By the beam splitters 43 and 45, the first and second light beams are
No noise enters the other optical system.

The adjustment optical system 50 mainly performs, for example, a working distance adjustment described later.
, The fourth light source unit 55, the condenser lenses 52 and 53, and the third
A light receiving section 54 is provided, and mainly adjusts the working distance.

Next, the alignment adjustment will be described. The alignment adjustment is mainly performed by the second light receiving optical system 30 and the second light transmitting optical system 80.

First, the light beam from the second light source unit 31 illuminates the eye to be measured 60, which is an object, with a substantially parallel light beam via the condenser lens 32, the beam splitters 33 and 43, and the afocal lens 42. . The reflected light flux reflected by the cornea 62 of the eye to be measured 60 is as if it were 1 / the radius of curvature of the cornea 62.
The light is emitted as a divergent light beam as if emitted from point 2.
This divergent light beam is transmitted through the afocal lens 42, the beam splitters 43 and 33, and the condenser lens 34 to the second lens.
The light is received by the light receiving unit 35 as a spot image.

If the spot image on the second light receiving portion 35 is off the optical axis, the main body of the eye optical characteristic measuring device is moved up and down and left and right so that the spot image coincides with the optical axis. . As described above, when the spot image coincides with the optical axis, the alignment adjustment is completed. In the alignment adjustment, the cornea 62 of the eye to be measured 60 is illuminated by the third light source unit 51, and an image of the eye to be measured 60 obtained by this illumination is formed on the second light receiving unit 35. May be used so that the center of the pupil coincides with the optical axis.

Next, adjustment of the working distance will be described.
The working distance adjustment is mainly performed by the adjustment optical system 50. First, working distance adjustment is performed, for example, by using the fourth light source unit 55.
The parallel light flux near the optical axis emitted from the
And the light reflected from the eye 60 to be measured is transmitted through the condenser lenses 52 and 53 to the third light receiving unit 5.
4 is performed by receiving light. Also, the eye to be measured 60
Is within the proper working distance, a spot image from the fourth light source unit 55 is formed on the optical axis of the third light receiving unit 54. On the other hand, when the eye to be measured 60 deviates from the proper working distance back and forth, the spot image from the fourth light source unit 55 is transmitted to the third light receiving unit 5.
4 above or below the optical axis. Note that the third light receiving unit 54 only needs to be able to detect a change in the light source position in the plane including the fourth light source unit 55, the optical axis, and the third light receiving unit 54. A CCD, a position sensing device (PSD), or the like can be applied.

Next, the positional relationship between the first illumination optical system 10 and the first light receiving optical system 20 will be schematically described. A beam splitter 45 is inserted into the first light receiving optical system 20, and the light from the first illumination optical system 10 is transmitted to the eye to be measured 60 by the beam splitter 45 and the eye to be measured 60 The reflected light from is transmitted. The first light receiving unit 23 included in the first light receiving optical system 20 receives light that has passed through the Hartmann plate 22, which is a conversion member, and generates a light receiving signal.

Further, the first light source unit 11 and the retina 61 of the eye 60 to be measured form a conjugate relationship. Eye to be measured 60
Of the retina 61 and the first light receiving unit 23 are conjugate. Also,
The Hartmann plate 22 and the pupil of the eye to be measured 60 form a conjugate relationship. Further, the first light receiving optical system 20 forms a substantially conjugate relationship with the Hartmann plate 22 and the cornea 62 and the pupil, which are the anterior segment of the eye 60 to be measured. That is, the front focal point of the afocal lens 42 is
0 is substantially coincident with the cornea 62 and the pupil, which is the anterior eye part.

Further, the first illumination optical system 10 and the first light receiving optical system 20 determine that the light beam from the first light source unit 11 is reflected at the condensing point, and It moves together so that the signal peak becomes the maximum. Specifically, the first illumination optical system 10 and the first light receiving optical system 20
The first light receiving unit 23 moves in a direction in which the signal peak increases, and stops at a position where the signal peak becomes maximum. Thereby, the light beam from the first light source unit 11 is condensed on the eye 60 to be measured.

The lens 12 converts the diffused light from the light source 11 into parallel light. The diaphragm 14 is located at a position optically conjugate with the pupil of the eye or the Hartmann plate 21. The aperture 14 has a diameter smaller than the effective range of the Hartmann plate 21 so that so-called single-pass aberration measurement (a method in which eye aberration affects only the light receiving side) is established.
The lens 13 is arranged such that the fundus conjugate point of the real ray is at the front focal position to satisfy the above, and further, the rear focal position is coincident with the stop 14 to satisfy the conjugate relationship with the pupil of the eye. ing.

After the light beam 15 has a common optical path with the light beam 24 and the beam splitter 45, the light beam 15 travels paraxially in the same way as the light beam 24. However, in the case of the single-pass measurement, the diameter of each light beam is different, and the beam diameter of the light beam 15 is set to be considerably smaller than that of the light beam 24. Specifically, the beam diameter of the light ray 15 is, for example, 1 at the pupil position of the eye.
In some cases, the beam diameter of the light beam 24 may be about 7 mm (from the beam splitter 45 of the light beam 15 to the fundus 61 in the drawing).

Next, the Hartmann plate 22 as a conversion member
Will be described. The Hartmann plate 22 included in the first light receiving optical system 20 is a wavefront converting member that converts a reflected light beam into a plurality of beams. Here, the Hartmann plate 22 includes:
A plurality of micro Fresnel lenses arranged in a plane orthogonal to the optical axis are applied. In addition, generally, for the measurement target portion (measured eye 60), the spherical component of the measured eye 60,
In order to measure even the third-order astigmatism and other higher-order aberrations, it is necessary to measure with at least 17 beams through the eye 60 to be measured.

The micro Fresnel lens is an optical element, for example, an annular zone having a height pitch for each wavelength;
And a blaze optimized for parallel light emission. The micro Fresnel lens here has, for example, an optical path length difference of eight levels to which a semiconductor fine processing technology is applied, and achieves a high light collection rate (for example, 98%).

The light reflected from the retina 61 of the eye 60 to be measured is reflected by the afocal lens 42 and the collimator lens 21.
Through the Hartmann plate 22 and the first light receiving portion 23
Focus on top. Therefore, the Hartmann plate 22 includes a wavefront converting member that converts the reflected light beam into at least 17 or more beams.

FIG. 3 is a block diagram showing a schematic electric system 200 of the eye optical characteristic measuring apparatus according to the present invention. The electrical system 200 related to the eye optical characteristic measuring device includes, for example, an arithmetic unit 210, a control unit 220, a display unit 230, and a memory 2
40, a first driving unit 250 and a second driving unit 260.

The arithmetic section 210 receives the light receiving signal obtained from the first light receiving section 23, the light receiving signal obtained from the second light receiving section 35, and the light receiving signal (10) obtained from the third light receiving section 54, and receives the coordinate origin. , Coordinate axes, coordinate movement, rotation,
Total wavefront aberration, corneal wavefront aberration, Zernike coefficient, aberration coefficient,
The Strehl ratio, white light MTF, Landolt's ring pattern, and the like are calculated. Also, a signal corresponding to such a calculation result is output to the control unit 220 that controls the entire electric drive system, the display unit 230, and the memory 240, respectively. The details of the operation 210 will be described later.

The control section 220 controls the turning on and off of the first light source section 11 and controls the first drive section 250 and the second drive section 260 based on the control signal from the arithmetic section 210. For example, a signal is output to the first light source unit 11 and a signal is output to the Placido ring 71 based on a signal corresponding to a calculation result in the calculation unit 210,
A signal is output to the second light source unit 31 and the third light source unit 5 is output.
1, a signal is output to the fourth light source unit 55, and further, a signal is output to the first driving unit 250 and the second driving unit 260.

The first driving section 250 is, for example,
The first illumination optical system 10 is moved in the optical axis direction based on the light receiving signal from the first light receiving unit 23 input to 0, and outputs a signal to an appropriate lens moving unit (not shown). At the same time, this lens moving means is driven. Thereby, the first driving section 250 can move and adjust the first illumination optical system 10.

The second driving section 260 includes, for example, the arithmetic section 21
The first light receiving optical system 20 is moved in the optical axis direction based on the light receiving signal from the first light receiving unit 23 input to 0, and outputs a signal to an appropriate lens moving means (not shown). At the same time, this lens moving means is driven. Thereby, the second driving section 260 can move and adjust the first light receiving optical system 20.

FIG. 4 shows a detailed configuration diagram relating to the arithmetic unit of the eye characteristic measuring apparatus of the present invention. The calculation unit 210 includes the measurement unit 1
11, coordinate setting unit 112, alignment control unit 113,
Marker installation unit 114, input / output unit 115, conversion unit 116
Is provided.

The first light receiving section 23 forms a first light receiving signal from the received light beam reflected from the fundus of the eye to be examined and returns to the measuring section 111. The second light receiving unit 35 includes a second part including information on the anterior segment from a received light beam including information on a characteristic portion of the anterior segment of the subject's eye and / or a marker formed on the anterior segment of the subject's eye.
A light receiving signal is formed, and a measuring unit 111 and a coordinate setting unit 112 are formed.
Lead to.

The measuring section 111 obtains optical characteristics including the refractive power or the corneal shape of the eye to be examined based on the first light receiving signal from the first light receiving section. The measuring unit 111 is, in particular, the first light receiving unit 2
Based on the first light receiving signal from the third, the optical characteristics of the eye are measured. In addition, the measurement unit 111 particularly performs the corneal topography measurement based on the second light reception signal from the second light reception unit 35. In addition, the measurement unit 111 calculates the aberration result and, if necessary, calculates the ablation amount, and outputs the calculation result to the surgical apparatus via the input / output unit 115.

The coordinate setting unit 112 converts signals of the first and second coordinate systems corresponding to the pupil of the eye included in the first and second light receiving signals into signals of the reference coordinate system, respectively. The coordinate setting unit 112, based on each signal of the first and second coordinate systems,
Find the pupil edge and pupil center.

The coordinate setting unit 112 determines the coordinate origin and the direction of the coordinate axis based on the second light receiving signal including the characteristic signal of the anterior segment of the subject's eye. In addition, the coordinate setting unit 112
Based on at least one of the characteristic signals of the anterior eye part of the subject's eye in the second light receiving signal, the coordinate origin and the rotation or movement of the coordinate axis are obtained, and the measurement data is associated with the coordinate axis. In addition,
The characteristic portion includes at least one of a pupil position, a pupil center, a cornea center, an iris position, an iris pattern, a pupil shape, and a limbus shape. For example, the coordinate setting unit 112 sets coordinate origins such as a pupil center and a cornea center. Coordinate setting unit 11
2 forms a coordinate system based on a feature signal corresponding to an image of a feature portion of the anterior segment of the eye included in the second light receiving signal. In addition, the coordinate setting unit 112 forms a coordinate system based on a marker signal for a marker provided for the eye to be inspected and a signal for the anterior eye of the eye included in the second light receiving signal.
The coordinate setting unit 112 can determine the coordinate origin and the direction of the coordinate axis based on the second light receiving signal including the marker signal. The coordinate setting unit 112 obtains the coordinate origin based on the marker signal in the second light receiving signal, and determines the coordinate axis rotation and The movement can be determined, and the measurement data can be associated with the coordinate axes. Or, the coordinate setting unit 1
12 is for obtaining a coordinate origin based on at least one of the characteristic signals for the anterior eye part in the second light receiving signal,
The rotation or movement of the coordinate axis may be obtained based on the marker signal in the light reception signal, and the measurement data may be associated with the coordinate axis. Alternatively, the coordinate setting unit 112 may determine at least one of the characteristic signals of the anterior ocular segment of the subject's eye in the second light reception signal.
Based on the above, the coordinate origin and the rotation or movement of the coordinate axis may be obtained, and the measurement data may be associated with the coordinate axis.

The conversion unit 116 combines the first and second optical characteristics of the eye to be examined obtained by the measurement unit 111 with the reference coordinate systems formed by the coordinate setting unit. The conversion unit 116 converts the pupil center obtained by the coordinate setting unit 112 into a reference coordinate system by using the origin as the origin.

The first illumination optical system 10 and the first light receiving optical system 2
0, the second light receiving optical system 30, the common optical system 40, the adjusting optical system 50, the second illumination optical system 70, the second light transmitting optical system 80, and the like. Appropriately published in the alignment section of the optical system 100. The alignment control unit 113 enables the alignment unit to move in accordance with the movement of the subject's eye according to the calculation result of the coordinate setting unit 112 based on the second light receiving signal obtained by the second light receiving unit. The marker setting unit 114 forms a marker associated with the coordinate system in the anterior segment of the subject's eye based on the coordinate system set by the coordinate setting unit 112. Input / output unit 115
Is the amount of aberration, coordinate origin,
This is an interface for outputting data such as coordinate axes, rotation and movement of coordinate axes, ablation amount, and the like, and calculation results to a surgical apparatus. The display unit 240 displays the optical characteristics of the subject's eye obtained by the measuring unit 111 in relation to the coordinate system formed by the coordinate setting unit.

The operation apparatus 300 includes an operation control section 121, a processing section 122, and a memory section 123. Surgery control unit 12
1, controls the processing unit 122 to control operations such as corneal cutting. The processing unit 122 includes a laser for surgery such as corneal cutting. The surgery memory unit 123 stores data for surgery such as cutting data, nomograms, and surgery plans.

Next, a flowchart for determining coordinates by the eye characteristic measuring apparatus according to the present invention will be described.
FIG. 5 is a flowchart showing the operation of the eye optical characteristic measuring device according to the present invention. FIGS. 6 and 7 are explanatory diagrams (1) and (2) of the eye characteristic measurement.

First, a signal from the second light receiving unit 35 is formed as an anterior eye image on a monitor screen of the display unit 230.
In step S101, the corneal vertex reflected light is used as an alignment target in the lateral direction (the corneal vertex and the optical axis of the apparatus, X
Alignment in the Y direction is performed, and alignment in the vertical direction (depth direction, Z direction) is performed by the Z alignment device.

FIG. 8 is an explanatory diagram of an anterior segment image. In the figure, "x" indicates the pupil center, "o" indicates the corneal vertex (center), and the star mark indicates the alignment marker. The actual alignment marker may be another shape such as a circle. The center of the pupil is
Mainly treated as the origin of surgical equipment. The corneal center (apex) is mainly treated as the center of the CCD or machine.
As illustrated, in step S101, in addition to the image of the Placido ring 1, light from the second light source unit 31 appears as a bright spot near the vertex of the cornea of the eye to be examined. While observing the image of the anterior segment of the eye to be examined, the eye optical characteristic measuring apparatus performs alignment in the X and Y directions with respect to the eye to be examined. At this time, the alignment in the Z direction is also performed by the adjustment optical system 50.

Next, in the first measurement system, in step S103, the first light receiving signal for the Hartmann image is captured by using the first light receiving unit 23 such as a low noise CCD or the like, and the Hartmann image is captured by an image processing technique. Find the center of gravity of each spot. The obtained center of gravity is associated with a reference point by using a method of image recognition or computational geometry. The processing so far is performed in the first coordinate system by the first light receiving unit 23 (see the upper diagram in FIG. 6A).

On the other hand, in the second measurement system, step S
As indicated by reference numeral 191, the second light receiving unit 35 also takes in the second light receiving signal for the anterior eye image almost simultaneously with the taking in of the first light receiving signal. After capturing the second light receiving signal, the position of the ring image substantially concentric with the bright point of the corneal vertex reflection is analyzed using an image processing technique. The position of the ring is acquired, for example, about 256 points over 360 degrees on the circumference.

Next, in step S192, a corneal measurement coordinate system is set. Since the corneal vertex position may be deviated from the optical axis of the measuring device, the position of the obtained ring image is set with the corneal vertex as the origin, and the number of pixels of the CCD of the second light receiving unit 35 is considered in consideration of the magnification of the optical system. And convert it to a value on the coordinate system converted to the actual distance. This coordinate system for measuring the cornea will be referred to as a second coordinate system (see the upper diagram in FIG. 6B). In step S193, the inclination of the cornea is calculated from the position of the ring obtained in step S191 using the second coordinate system calculated in step S192.

In step S105, the Hartmann image and the anterior segment image measured in the first and second coordinate systems are converted into reference coordinate systems each having the pupil center as the origin (FIG. 6).
(A), (B) See the figure below).

In step S105, for the first measurement system, the pupil edge on the Hartmann wavefront sensor image obtained from the first light receiving unit 23 can be obtained by image processing. Here, the obtained pupil edge is distorted due to the influence of aberration.
A value of 0 corrects the shape of the pupil edge from the relationship between the Hartmann point image and the reference point obtained earlier in step S103.
For example, the calculation unit 210 calculates the correction function by the least square approximation in the same manner as when obtaining the wavefront aberration from the Hartmann wavefront sensor, and calculates the position of the pupil edge on the Hartmann wavefront sensor image into the function just obtained. Input and calculate the correct pupil edge position. The operation unit 210
When the correct position of the pupil edge is determined, the pixel inside the pupil is set to 1 and the outside is set to 0, and the center of the pupil in the CCD coordinate system is determined by determining the center of gravity. For example,
The center of the circle or Sui circle can be the center of gravity. Thus, the center of the pupil (X mark) is measured as shown in the upper diagram of FIG. The conversion from the first coordinate system to the newly defined reference coordinate system is performed by moving the origin to the reference coordinates toward the center of the pupil and by converting the number of pixels of the CCD to an actual distance by the magnification of the optical system.

In step S105, with respect to the second measurement system, the calculation unit 210 calculates the corneal measurement coordinate system obtained from the second light receiving unit 35 and set in step S192, that is, the second coordinate system. , The pupil edge is obtained by image processing, and the pupil center position in the second coordinate system is calculated.
Thus, the pupil center (X mark) is obtained, and the upper part of FIG. 6B is measured. At this time, the conversion from the second coordinate system to the reference coordinate system is a movement of the pupil center. When a part of the pupil edge is missing in the Hartmann wavefront sensor image when measuring an abnormal eye such as a keratoconus, it can be dealt with by calculating the center of gravity by estimating the missing part.

In this manner, the reference coordinate system converted from the first coordinate system and the reference coordinate system converted from the second coordinate system become the same reference coordinate system in principle (FIG. 6A). B)
Of each figure below).

Next, optical characteristics are obtained based on the first or second light receiving signal (S109). Here, the optical characteristics are, for example, aberration (corneal, intraocular, eye) refractive power, corneal shape, and the like. That is, in step S109, the calculation unit 210 calculates the optical characteristics of the first measurement system according to the measurement principle of the Hartmann wavefront sensor. The result is a wavefront aberration (eyeball wavefront aberration) of the eyeball optical system (see FIG. 7A). In the second measurement system, since the inclination of the cornea is obtained, the calculation unit 210
Thus, the height of the cornea is calculated from this, and the optical characteristics are calculated by treating the cornea in the same manner as the optical lens. What is obtained here is a wavefront aberration (corneal wavefront aberration) generated in the cornea (see FIG. 7B).

Next, the measured optical characteristics are displayed (S111). In step S111, the display unit 24
As shown in FIG. 7, the display of the optical characteristics by 0 indicates that the ocular wavefront aberration map for the first measurement system and the corneal wavefront aberration map for the second measurement system are displayed separately.
(Differential wavefront aberration map) = (eyeball wavefront aberration map)-
(Cornea wavefront aberration map) is also displayed (see FIG. 7C). This difference wavefront aberration map optically shows the influence on the aberration of the internal optical system, excluding the anterior corneal surface of the eyeball optical system, and mainly shows a disease that causes an abnormality in the refractive index distribution of the crystalline lens. For example, a map that is very useful for cataract diagnosis.

Next, output data is calculated (S11).
3). As the output data, for example, the data of the reference coordinate system, the measurement data, the aberration amount of the eye to be inspected itself, the optical characteristic data, the ablation amount required for ablation by the surgical apparatus, and the like are calculated and obtained. Next, these output data are displayed (S115). Further, these output data are output as required (S117). Here, the output form includes, for example, the following forms.

In a mode in which the operation is performed in an offline manner on a recording medium such as a floppy (registered trademark) disk or a CD-ROM or an interface such as a signal line wireless line, the operation is performed at another time thereafter.

When the output data is online, the operation device 30
A mode in which the optical characteristics of the eye to be examined are continuously or switched during the operation by being connected to an interface such as a signal line. As described above, after the data output, if the measurement is not completed, the measurement is repeated, and if the measurement is completed, the measurement is completed (S121).

Here, a method of obtaining the pupil edge from the Hartmann image will be described. As a first method for obtaining the pupil edge from the Hartmann image, the pupil edge can be obtained by obtaining a polygon circumscribing the Hartmann spot or an ellipse close thereto. As a second method, the portion corresponding to the pupil of the Hartmann image is placed outside the back surface due to the influence of the scattered component from the eyes or because the Hartmann plate transmits the 0th-order light through the diffractive optical element. It uses the fact that it is brighter than the ground. Therefore, by detecting the edge of this bright portion, the edge portion of the pupil can be detected.

FIG. 9 is an explanatory diagram for obtaining a pupil edge from a Hartmann image. FIG. 9A is an example of a measured Hartmann image. This is compared with the brightness of the Hartmann spot measured at a predetermined threshold value along a certain line as shown in FIG. 9B. Next, FIG.
By performing this processing over the entire Hartmann image as in the above, the edge of the pupil can be detected.

A reference coordinate system can be set by determining a coordinate origin and an axial direction by using a characteristic signal included in a second light receiving signal indicating an image of the anterior segment of the eye including the characteristic portion. . Here, as a characteristic portion of the anterior segment of the eye to be examined, for example, a pupil position, an iris position, an iris pattern, a pupil shape, a limbus shape, a marker formed in the anterior segment of the eye to be examined (if there is a marker), and the like. No. The reference coordinate system is more preferably the coordinate origin used in the surgical apparatus 300. For example, the pupil position of the eye to be inspected, the iris position of the eye to be inspected, the pupil shape, the limbus shape, the iris pattern of the eye to be inspected (iris pattern) Etc., are required. The coordinate origin may be the center of the pupil, the center of the cornea, or the like. When a marker is formed, the coordinate axis can be set by, for example, setting a straight line passing through the marker and the center of the pupil. Coordinate rotation / movement is performed when a marker is formed, for example,
It can be measured by movement.

In addition to the markers, the coordinate axes and the rotation (cyclotorsion) can be measured by the iris pattern (iris pattern). Here, FIG. 10 shows an explanatory diagram relating to the measurement of the coordinate axes and rotation. First, FIG.
As shown in (a), for example, a pattern is analyzed on the orbicular zone centered on the pupil center by reflection intensity or the like. Then, as shown in FIG. 10B, a pattern of the reflection intensity with respect to the angle is created. With this pattern, coordinate axes can be set. In addition, the analyzed pattern can be matched on the circumference to measure the coordinate rotation. That is, when the eye rotates (cyclotorsion), the graph of such intensity shifts by the rotation angle. The amount of the lateral shift can be obtained at the angle at which the correlation between each measured value and the reference graph is the largest.

FIG. 11 shows a flowchart for performing pupil center calculation or measurement orbicular zone measurement. First, to determine the coordinate origin, the center of the pupil is calculated (it is easily obtained from the entire circumference of the pupil edge) (S501). Next, a measurement ring zone is determined (for example, +0.5 mm from the pupil diameter). If it reaches the edge, it is increased by a predetermined length, for example, +0.1 mm (S503). Next, in order to determine a coordinate axis, an angle is determined based on a characteristic portion of the eye to be inspected (S505). Next, the intensity distribution in the circumferential direction is recorded (S507). Next, the intensity distribution data is stored on a hard disk (HD) or the like, and the pupil diameter is also stored (S509).

FIG. 12 shows a flowchart for confirming the difference between the measurement coordinate system and the reference coordinate system. This is a detailed flowchart of step S207, in which a pupil center calculation, a measurement ring measurement, and the like are correlated to obtain a matched coordinate position. First, the stored reference graph data O (θ) and the pupil diameter are stored on a hard disk (H
D) or the like is read from the memory 240 (S701). As the reference graph data O (θ), for example, the intensity distribution on the annular zone shown in FIG. 10 can be used. Next, a pupil center is obtained based on the read digital (S703).
Next, the pupil diameter is measured, and if different from the pupil diameter when the reference graph data O (θ) is obtained, the brightness is adjusted (S705).
Next, similarly to the reference graph data, the measured graph data F (θ), for example, the intensity distribution on the annular zone is measured (S707). Next, the measured graph data F rotated by the angle A so that the correlation between the graph data F (θ) measured this time and the reference graph data O (θ) becomes the highest.
(Θ−A) is obtained (S709). Thus, it can be seen from the measurement that the eye has rotated by the angle A (S711).

Next, a modification of the present invention will be described. In the above-described embodiment, in the second measurement system, observation of the anterior segment and measurement of the corneal shape have been described. However, only the alignment is performed by observing the anterior segment by the second measurement system, It is also possible to omit the configuration for measuring the shape. In this case, the eye to be measured is positioned at a predetermined position using the second measurement system. Next, the second light receiving signal is obtained from the second light receiving unit of the second measuring system via the first light receiving signal from the first light receiving unit of the first measuring system. In the calculation unit, the coordinate axes are associated (coordinate origin position, rotation and / or movement of the coordinate axes) based on the first light receiving signal and / or the second light receiving signal, and the first optical characteristic obtained from the first measurement system is obtained. It can be output as a desired coordinate system. As a specific example,
The first measurement system and the second measurement system are configured so that their optical axes are coincident with each other. In the second measurement system, the eye to be measured is positioned at a predetermined position by using the bright point of the apex of the cornea appearing in the anterior segment image. Perform alignment. Next, the second light receiving signal is obtained from the second light receiving unit of the second measuring system through the first light receiving signal from the first light receiving unit of the first measuring system. Then, the arithmetic unit associates the coordinate axes (the coordinate origin position, the rotation and / or the movement of the coordinate axes) based on the first light receiving signal and / or the second light receiving signal, and the first optical system obtained from the first measurement system. The characteristics can be output as a pupil center coordinate system.

In this example, the position of the eye to be inspected is aligned using the bright point at the apex of the cornea using the second measurement system, and the arithmetic unit receives the received light signals, and the arithmetic unit obtains the first optical system obtained from the first measurement system. The characteristic is converted into the coordinate system of the pupil center. Thereby, the data of the first optical characteristic can be used as a coordinate system of the pupil center.

[0067]

According to the present invention, as described above, the aberration and refractive power data of the eye to be inspected obtained from the first light receiving section and the second
It is possible to provide an eye optical characteristic measuring device that associates the eye cornea data obtained from the light receiving unit with the eye cornea data so as to be able to be superimposed precisely. Further, according to the present invention, the coordinates of the corneal shape measurement and the wavefront measurement using the same image as that of the alignment system can be matched by comparing the two pupils imagewise and matching the positions.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic optical system 100 of an eye optical characteristic measuring apparatus according to the present invention.

FIG. 2 is a configuration diagram of a placido ring.

FIG. 3 is a block diagram showing a schematic electric system 200 of the eye optical characteristic measuring apparatus according to the present invention.

FIG. 4 is a detailed configuration diagram relating to a calculation unit of the eye characteristic measuring device of the present invention.

FIG. 5 is a flowchart showing an operation of the eye optical characteristic measuring device according to the present invention.

FIG. 6 is an explanatory view (1) of eye characteristic measurement.

FIG. 7 is an explanatory view (2) of eye characteristic measurement.

FIG. 8 is an explanatory diagram of an anterior eye image.

FIG. 9 is an explanatory diagram for obtaining a pupil edge from a Hartmann image.

FIG. 10 is an explanatory diagram relating to measurement of coordinate axes and rotation.

FIG. 11 is a flowchart for performing pupil center calculation or measurement ring zone measurement.

FIG. 12 is a flowchart for confirming a difference between a measurement coordinate system and a reference coordinate system.

[Explanation of symbols]

 Reference Signs List 10 first illumination optical system 11, 31, 51, 55 first to fourth light source units 12, 32, 34, 44, 52, 53 condensing lens 20 first light receiving optical system 21 collimating lens 22 Hartmann plate 23, 35, 54 First to third light receiving units 30 Second light receiving optical system 33, 43, 45 Beam splitter 40 Common optical system 42 Afocal lens 50 Adjusting optical system 60 Eye to be measured 70 Second illumination optical system 71 Placido ring 80 Second light transmission Optical system 100 Optical system of eye characteristics measuring device 111 Measurement unit 112 Coordinate setting unit 113 Alignment control unit 114 Marker installation unit 115 Input / output unit 116 Conversion unit 121 Surgery control unit 122 Processing unit 123 Memory unit 200 Electric system of eye characteristics measurement device 230 display unit 300 surgical device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) A61B 3/10 B

Claims (12)

[Claims] A first light source unit for emitting a first light beam of a first wavelength, a first illumination optical system for illuminating a fundus of an eye to be examined with a first light beam from the first light source unit; A first light receiving unit that forms a first light receiving signal as a first coordinate system from the light beam, converts the light beam reflected from the fundus of the eye to be examined and returned into a plurality of beams, and guides the light beam to the first light receiving unit;
A light receiving optical system, and a second coordinate system including information on the anterior segment of the eye from the received light beam.
A second light receiving optical system that has a second light receiving unit that forms a light receiving signal and guides a second light flux including information on the anterior eye of the eye to be examined to the second light receiving unit; a first light receiving signal from the first light receiving unit A measuring unit for obtaining a first optical characteristic of the eye to be examined based on the second light receiving signal from the second light receiving unit based on the first and second light receiving units; and a pupil of the eye to be inspected included in the first and second light receiving signals. And a coordinate setting unit that converts signals of the first and second coordinate systems corresponding to the first and second coordinate systems into signals of a reference coordinate system, respectively, and converts the first and second optical characteristics of the eye to be examined obtained by the measurement unit into the coordinate setting. An eye characteristic measuring device comprising: a conversion unit that associates with each reference coordinate system formed by the unit. 2. A first illumination optical system for illuminating a fundus of an eye to be examined with a first light beam from the first light source unit, the first light source unit emitting a first light beam of a first wavelength. A first light receiving unit that forms a first light receiving signal as a first coordinate system from the light beam, converts the light beam reflected from the fundus of the eye to be examined and returned into a plurality of beams, and guides the light beam to the first light receiving unit;
A light receiving optical system, and a second coordinate system including information on the anterior segment of the eye from the received light beam.
A second light receiving optical system that has a second light receiving unit that forms a light receiving signal and guides a second light flux including information on the anterior eye of the eye to be examined to the second light receiving unit; a first light receiving signal from the first light receiving unit A measuring unit for obtaining the first optical characteristic of the eye to be inspected based on the first and second light receiving signals; An eye characteristic measuring apparatus, comprising: a coordinate setting unit that performs the conversion; and a conversion unit that associates the first optical characteristic of the eye to be examined obtained by the measurement unit with each reference coordinate system formed by the coordinate setting unit. 3. The coordinate setting unit according to claim 1, wherein the coordinate setting unit is configured to determine a coordinate origin based on background light appearing on the first light receiving unit so as to surround the beam converted by the conversion member. Item 3. The eye characteristic measuring device according to item 1 or 2. 4. The coordinate setting section is configured to determine a center of gravity of the contour as a coordinate origin based on a contour of background light appearing to surround the beam converted by the conversion member on the first light receiving section. The eye characteristic measuring device according to claim 3, wherein the measurement is performed. 5. The coordinate setting unit according to claim 1, wherein the coordinate setting unit determines a coordinate origin and a direction of a coordinate axis based on a second light receiving signal including a characteristic portion of the eye to be inspected. Eye characteristics measurement device. 6. The coordinate setting unit according to claim 1, wherein the coordinate setting unit determines the coordinate origin as a pupil center or a cornea vertex based on a second light receiving signal including a characteristic portion of the eye to be inspected. The eye characteristic measuring apparatus according to the above. 7. The coordinate setting section according to claim 2, wherein said coordinate set is based on at least one of a pupil position of the subject's eye, an iris position of the subject's eye, a pupil shape, a limbus shape, and a pattern of the iris of the subject's eye in the second received light signal. The origin is determined by determining the rotation or movement of the coordinate axis based on at least one of the pupil position of the subject's eye, the iris position of the subject's eye, the pupil shape, the limbus shape, and the iris pattern of the subject's eye in the second received light signal. 7. The eye characteristic measuring apparatus according to claim 1, wherein the apparatus is configured to associate data with coordinate axes. 8. A characteristic portion of the eye to be examined includes a pupil position of the eye to be examined, an iris position of the eye to be examined, a pupil shape, a limbus shape, and the like.
The eye characteristic measuring device according to any one of claims 5 to 7, further comprising at least one of a pattern of an iris of the eye to be inspected and a marker formed in an anterior segment of the eye to be inspected. 9. The apparatus according to claim 1, further comprising a calculation unit configured to calculate an ablation amount based on the aberration result, and outputting the calculation result to a surgical apparatus. Eye characteristics measuring device. 10. The apparatus according to claim 1, further comprising a marker forming section for forming a marker associated with the coordinate system in the anterior segment of the subject's eye based on the reference coordinate system set by the coordinate setting section. 10. The eye characteristic measuring device according to any one of 1 to 9. 11. The eye characteristic measurement according to claim 1, wherein the coordinate setting unit obtains a pupil edge and a pupil center based on each signal of the first and second coordinate systems. apparatus. 12. The eye characteristic measurement according to claim 1, wherein the conversion unit converts the pupil center obtained by the coordinate setting unit into a reference coordinate system by using the center as an origin. apparatus.