JP5727188B2 - Ophthalmic measuring device - Google Patents

Description

  The present invention relates to an ophthalmologic measurement apparatus that measures a refraction error of an eye to be examined.

  2. Description of the Related Art Conventionally, an ophthalmologic measurement apparatus (for example, an aberrometer) that projects measurement light toward the fundus and receives the reflected light as an index image on an image sensor to measure an eye refraction error is known. Now, in such an apparatus, when a multifocal intraocular lens insertion eye is measured, two index images corresponding to distance use and near use appear (for example, refer to Patent Document 1). In the apparatus of Patent Document 1, the wavefront aberration is obtained by using only an index image group having a higher peak, or two groups of an index image group having a higher peak and a lower index image group.

JP 2010-99355 A

  However, in the case of an eye with a multifocal intraocular lens inserted, the position where the index image is focused differs between distance use and near use. Therefore, even if there is a focus in one index image (for example, near), the other index image (for example, distance) is blurred, and the measurement result based on the other index image includes a measurement error. It becomes a thing.

  In view of the above problems, an object of the present invention is to provide an ophthalmologic measurement apparatus capable of accurately measuring a refraction error of a multifocal intraocular lens insertion eye.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) The ophthalmologic measurement apparatus according to the first aspect of the present disclosure projects a measurement light beam toward the subject's fundus and receives the reflected light beam as a two-dimensional index image by an imaging device; Separating by the multifocal intraocular lens based on the detection result from the focus detection means when the eye of the subject is a multifocal intraocular lens insertion eye and a focus detection means for detecting the focus state of the index image Diopter correction means for driving the measurement optical system so that each index image is focused on the image sensor, and obtained by the image sensor when diopter correction is performed on one separated index The distance refraction error and the near refraction error of the subject's eye are calculated based on the index image obtained and the index image obtained by the imaging device when diopter correction is performed on the other separated index. It is characterized in that it comprises a calculating means for measuring.
(2) The ophthalmologic measurement apparatus according to the second aspect of the present disclosure is a measurement optical system that projects a measurement light beam toward the fundus of a subject's eye and receives the reflected light beam as a two-dimensional index image by an imaging device. When the subject's eye is a multifocal intraocular lens insertion eye, the measurement optical system that receives each index image separated by the multifocal intraocular lens by the imaging device, and the light reception that receives the reflected light beam and means, indication image received by the image sensor, the multifocal or index image corresponding to the near power of the intraocular lens, or index image corresponding to the distance power of the multifocal intraocular lens not It is characterized by comprising discrimination processing means for discriminating whether or not based on the light reception result of the light receiving means.

  According to the present invention, it is possible to accurately measure the refraction error of a multifocal intraocular lens insertion eye.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external view of an ophthalmologic measuring apparatus according to the present invention. This apparatus is provided with a base 2, a face support unit 4 attached to the base 2, a movable base 6 movably provided on the base 2, and a movable base 6, which will be described later. A measuring unit 1 that houses the optical system is provided. The movable table 6 is moved on the base 2 in the left-right direction (X direction) and the front-rear direction (Z direction) by operating the joystick 5. The measuring unit 1 is moved in the vertical direction (Y direction) by the drive mechanism 3 including a motor or the like when the rotary knob 5a is rotated. The movable table 6 is provided with a monitor 80 for displaying various information such as an observation image of the eye E and a measurement result, and an operation unit 90 on which switches for performing various settings are arranged.

  FIG. 2 is a schematic configuration diagram illustrating the configuration of the optical system and the control system of the ophthalmologic measurement apparatus according to the present embodiment. The wavefront aberration measuring optical system 10 for measuring the wavefront aberration of the eye to be inspected is a light projecting optical system 10a that projects a spot-like measurement light beam from the measurement light source to the fundus of the eye to be examined, and is reflected from the fundus and emitted from the eye to be examined. The reflected light flux is divided into a plurality of light receiving optical systems 10b that receive the two-dimensional image as a two-dimensional pattern index image, and the wavefront aberration of the eye to be examined is measured based on the output from the two-dimensional light receiving element. .

  In the light projecting optical system 10a, the relay lens 12 is sequentially arranged from the measurement light source unit 11 toward the eye to be examined. The measurement light source unit 11 is disposed at a position conjugate with the fundus of the eye to be examined, and switches and emits light having a plurality of wavelengths. For example, it comprises a plurality of measurement light sources 11a and measurement light sources 11b that emit light having different wavelengths. The switching of the wavelength, that is, the switching of the light source is performed by the control unit 70. In addition, near-infrared and visible wavelengths (for example, λ = 550 nm) were selected as the plurality of wavelengths. For example, an SLD (super luminescence diode) is used as the light source 11a. For example, an LD (laser diode) is used as the light source 11b. The light source 11b is mainly used for measuring a multifocal IOL insertion eye. For example, in the case of a diffractive IOL, the first-order diffracted light is designed so that a desired power is obtained with respect to visible light. There is sex. Therefore, visible light is used.

  The light receiving optical system 10b includes an objective lens 14, a dichroic mirror 7, a beam splitter 8, a beam splitter 13, a condensing lens 16, a total reflection mirror 17, a half mirror 26, a diaphragm 18, a collimator lens 19, and a micro lens from the front of the eye to be examined. A lens array 20 and a two-dimensional imaging element 22 that receives the light flux that has passed through the lens array 20 are sequentially arranged.

  A light receiving element (imaging element) 27 is disposed in the reflection direction of the half mirror 26. Here, the light receiving element 27 is a dedicated light receiving element that receives the fundus reflected light beam by the measurement light beam as a point image, and the light reception result of the light receiving element 27 is used to detect the focus state.

  The beam splitter 13 has a characteristic of reflecting the measurement light beam from the light source unit 11 and transmitting the reflected light from the fundus. In addition, the light receiving optical system 10b is configured such that the pupil of the eye to be examined and the lens array 20 have a substantially optically conjugate relationship. Here, the microlens array 20 is composed of microlenses that are two-dimensionally arranged on a plane orthogonal to the measurement optical axis L1, and divides the fundus reflected light into a plurality of light beams. The above configuration uses a so-called Shack-Hartmann wavefront sensor. However, a mask on an orthogonal grating is arranged at the pupil conjugate position, and the light transmitted through the mask is received by the two-dimensional light receiving element. A so-called Talbot wavefront sensor may be used (for details, see Japanese Patent Application Laid-Open No. 2006-148771 by the present applicant).

  In the present embodiment, the measurement light source unit 11, the beam splitter 9, the diaphragm 18, the collimator lens 19, the lens array 20, and the two-dimensional imaging device 22 are a first driving unit (moving mechanism) as an integrated optical driving unit 30. 29 is configured to be moved in the optical axis direction. Here, the optical drive unit 30 is moved so that the measurement light source unit 11 and the two-dimensional imaging element 22 are optically conjugate with the fundus of the eye to be examined in accordance with the spherical refraction error of the eye to be examined. It functions as a diopter correction mechanism that corrects refraction errors. The light receiving element 27 is configured to be moved in the optical axis direction by the second drive unit 25. The light receiving element 27 is moved in synchronization with the movement of the optical drive unit 30 in the optical axis direction.

  Further, a fixation target projection optical system 40 for fixing the eye E is disposed in the reflection direction of the dichroic mirror 7. The projection optical system 40 includes a visible light source 41, a fixation target 42, a light projecting lens 43, and a total reflection mirror 45. The light source 41 and the fixation target 42 move in the direction of the optical axis to fog the eye to be examined. The light source 41 illuminates the fixation target 42, and the light flux from the fixation target 42 passes through the light projection lens 43 and the total reflection mirror 45, then is reflected by the dichroic mirror 7, and passes through the objective lens 14 and the opening 51 a. Heading toward the eye to be examined, the eye to be examined fixes the fixation target 42.

  The anterior ocular segment illumination system 50 includes, for example, an unillustrated ring-shaped light source or point-shaped light source disposed around the optical axis L1 in the ring opening 51, and irradiates the anterior segment with a predetermined pattern. It is also used to measure the corneal shape (curvature distribution, astigmatic axis angle, etc.) by projecting multiple ring indices onto the cornea. Further, the ring opening 51 is formed with a plurality of ring shapes with different diameters in the peripheral part, and has an opening part 51a used as an observation optical path in the center part.

  The anterior segment observation system 60 is for observing the anterior segment image illuminated by the anterior segment illumination system 50. The anterior ocular segment observation system 60 includes an objective lens 14, a dichroic mirror 7, a beam splitter 8, a telecentric diaphragm 63, a condenser lens 62, and a light receiving element 61. The light receiving element 61 is constituted by, for example, a CCD or the like, and receives a pattern such as an anterior ocular segment image, plactide ring, and kerat ring.

  A control unit 70 has a program for obtaining an output image signal from the two-dimensional imaging device 22 and analyzing wavefront aberration and the like of the eye to be examined, and also serves as means for analyzing optical characteristics of the eye. The control unit 70 includes a light source unit 11, a light source 41, a two-dimensional imaging element 22, a light receiving element 27, a light receiving element 61, a memory 75 as a storage unit, a driving unit 25, a driving unit 29, an anterior eye portion to be examined, A display monitor 80 on which measurement results are displayed, a joystick 5, an operation unit 90 for performing various settings of the apparatus such as measurement conditions, and the like are connected.

  An operation in the case of measuring a diffractive IOL insertion eye in the apparatus having the above configuration will be described. In this case, a light source 11b that emits visible light is used. Here, since the anterior segment image captured by the two-dimensional image sensor 61 is displayed on the display screen of the monitor 80, the examiner moves the apparatus housing in which the entire optical system is built using the joystick 5. The measurement optical axis L1 is aligned with the eye to be examined. When the measurement start switch 5a provided on the top of the joystick 5 is pushed by the examiner after the alignment is completed, a measurement start trigger signal is generated. When a predetermined trigger signal is output by the examiner, the controller 70 first performs preliminary measurement of wavefront aberration (eye refractive power), and based on the preliminary measurement result, the light source 41, the fixation target plate 42, and the optical When the drive unit 30 is moved in the direction of the optical axis L1, a cloud is applied to the eye E and diopter correction is performed. At this time, the light receiving element 27 also moves in synchronization with the movement of the optical drive unit 30 (details will be described later). Thereafter, wavefront aberration is measured for the eye to be examined.

  The control unit 70 turns on the light source 11b. The light source 11b emits light having a wavelength in the visible range. At this time, the light source 11a that emits a wavelength in the near infrared region is turned off. Then, wavefront aberration is measured at a visible wavelength. Wavefront aberration measurement is described below. A light beam having a wavelength in the visible range emitted from the light source 11b is reflected by the beam splitter 9, is reflected by the beam splitter 13 and the beam splitter 8 through the relay lens 12, passes through the beam splitter 7, the objective lens 14, and the eye to be examined. The light is projected onto the fundus of the subject's eye through the pupil. Thereby, a point light source image is formed on the fundus of the eye to be examined.

  The point light source image projected onto the fundus of the subject's eye exits the subject's eye as a reflected light beam, is collected by the objective lens 14, is transmitted by the beam splitter 7, is reflected by the beam splitter 8, and is reflected by the beam. The light is transmitted through the splitter 13, once collected by the condenser lens 16, and then reflected by the total reflection mirror 17.

  A part of the light beam reflected by the total reflection mirror 17 is reflected by the half mirror 26 and the other light beam is transmitted. The reflected light beam is received by the light receiving element 27, and the received point image is stored in the memory 75. Further, the transmitted light beam is divided into a plurality of light beams by the lens array 20 via the diaphragm 18 and the collimator lens 19 and then received by the two-dimensional imaging device 22. The pattern image received by the two-dimensional image sensor 22 is stored in the memory 75 as image data. Note that the pupil of the eye to be examined, the light receiving element 27, and the diaphragm 18 are configured to have an optically substantially conjugate relationship. The light receiving element 27 is moved in synchronization with the movement of the diaphragm 18. That is, when the reflected light beam is condensed by the diaphragm 18, the reflected light beam is similarly condensed on the light receiving element 27.

  Here, the pattern image that is divided into a plurality of light beams by the lens array 20 and received by the two-dimensional light receiving element changes due to the influence of the aberration (low-order aberration, high-order aberration) of the eye to be examined. If the pattern image generated by the reflected light from the eye to be examined is analyzed with respect to the pattern image formed when passing, the wavefront aberration distribution and refractive power distribution of the eye to be examined can be measured.

  3A is a pattern image when an eye that is not a diffractive IOL insertion eye is measured, and FIG. 3B is a pattern image when a diffractive IOL insertion eye is measured. In the case of FIG. 3B, each dot image of the Hartmann image is separated and imaged by the measurement light beam being diffracted by the intraocular lens. In the case of FIG. 3B, the Hartmann image drawn by a solid line is a Hartmann image formed by the near power of the diffractive IOL (hereinafter referred to as a near Hartman image). A Hartmann image drawn by a dotted line is a Hartmann image (hereinafter referred to as a distance Hartmann image) formed by the distance power of the diffractive IOL. Of course, each Hartmann image is influenced by the corneal power of the eye E. In the following description, a Hartmann image drawn with a solid line indicates an image with focus, and a Hartman image drawn with a dotted line indicates an image without focus. Therefore, in FIG. 3B, the near-field Hartmann image is in focus.

  Here, in the case of a multifocal IOL (diffractive IOL) insertion eye, the control unit 70 drives the wavefront aberration measuring optical system 10 so that the Hartmann image corresponding to the near power of the IOL is focused on the image sensor 22. The wavefront aberration measurement optical system 10 is driven so that the Hartmann image corresponding to the IOL distance power is focused on the image sensor 22 while the diopter correction for the near power of the subject's eye is performed. Diopter correction related to the distance power of the examiner's eye is performed. Based on the Hartmann image acquired by the image sensor 22 when the diopter correction for the near power is performed and the Hartmann image obtained by the image sensor 22 when the diopter correction for the far power is performed. The distance refraction error and the near refraction error of the examiner's eye are measured.

  For example, the control unit 70 detects the focus state based on the light reception result of the light receiving element 27, drives the measurement optical system 10 so that each Hartmann image is focused on the imaging element 22, and sequentially performs diopter correction. Do. Then, the control unit 70 performs the diopter correction for the one separated index and the Hartmann image acquired by the imaging element 22 and the diopter correction for the other separated index. The distance refraction error and the near refraction error of the eye E are respectively measured based on the Hartmann acquired by 22.

  That is, in order to accurately measure the wavefront aberration in the far and near areas, the focus position (diopter correction position) for measuring the wavefront aberration in the far area and the wavefront aberration in the near area are measured. Hartmann images are respectively acquired at the focus positions for measuring the wavefront aberration based on the respective Hartmann images. In other words, focusing is performed in accordance with each area, and a Hartmann image corresponding to each area is acquired. In this case, it is not necessary that the focus is exactly, and it is sufficient that the focus is in such a degree that the measurement accuracy can be ensured.

  On the light receiving surface of the image sensor 22, the position where the focus is matched by the diopter correction of the Hartmann image is different for near and far. For example, when the near Hartmann image is in focus, the far Hartman image is blurred (see the right figure in FIG. 4A). Therefore, a dot image forming a near-field Hartmann image (hereinafter referred to as a near-field dot image) is detected with high luminance and has a high S / N ratio, and a dot image forming a distance-based Hartmann image (hereinafter referred to as a distance image). Dot image) is detected at low luminance and has a low S / N ratio. In this state, the near wavefront aberration of the eye E can be accurately measured by detecting the image position of the dot image having the higher luminance and analyzing the Hartmann image. For example, the control unit 70 measures the wavefront aberration based on a dot image having a luminance equal to or higher than a threshold set for extracting the near-field Hartmann image.

  On the contrary, when the distance Hartmann image is in focus, the near Hartmann image is blurred (see the right figure in FIG. 4C). For this reason, the distance dot image is detected with high luminance and has a high S / N ratio, and the near dot image is detected with low luminance and has a low S / N ratio. In this state, the far-end wavefront aberration of the eye E can be accurately measured by detecting the image position of the dot image having the higher luminance and analyzing the Hartmann image. For example, the control unit 70 measures the wavefront aberration based on a dot image having a luminance equal to or higher than a threshold value set for extracting a distance Hartmann image.

  Here, the position where the focus of each Hartmann image coincides will be described. For example, when the near Hartmann image is in focus, the reflected light beam by the near power is condensed at the position of the stop 18. Here, since the reflected light beam is condensed on the diaphragm 18, less light beam is emitted by the diaphragm 18 than when the diaphragm 18 is at another position. Further, since the diaphragm 18 and the light receiving element 27 are arranged at conjugate positions, when the light condensing point is on the diaphragm 18, the light condensing point is also present on the light receiving element 27. That is, the near-field Hartmann image is detected with high luminance. At this time, since the condensing position of the reflected light beam by the distance power is not in the diaphragm 18, most of the reflected light beam is lost by the diaphragm 18, the luminance value is lowered, and the focus in the far area is blurred. It is in the state. As a result, the brightness value / position of the two Hartmann images for distance and near changes as the diaphragm 18 moves. And this change can discriminate between distance and near, and you can see which one is in focus. Thereby, the near wavefront aberration can be measured from the near Hartmann image measured at the near focus position. Further, when detecting the wavefront aberration in the far field, the diaphragm 18 may be moved to a position where the far field is in focus as described above.

  FIG. 4 is a diagram for explaining the correspondence between the point image (left figure) on the light receiving element 27, the point image intensity distribution (PSF) of the point image, and the Hartmann image. FIG. 5 is a diagram showing the relationship between the PSF luminance maximum value Max and the diopter correction position. The point image of the light receiving element 27 is used to detect the focus state of the Hartmann image.

  Here, as shown in FIG. 4 (a), when the near-field Hartmann image is in focus, the point image (left figure) is focused with bright spots (solid lines) due to near-field power. Surrounding it, the bright spot by the distance power (dotted line) has a low luminance value and spreads in a blurred state. For the PSF (middle diagram), the maximum value Max of the luminance signal due to the bright spot exceeds the threshold S, and the peak Pn corresponding to the near focus position is detected (see FIG. 5).

  Here, as shown in FIG. 4C, when the distance Hartmann image is in focus, the acquired point image (left figure) is focused with bright spots (dotted lines) by the distance power. Surrounding it, the bright spot due to the near power (solid line) has a low brightness value and spreads in a blurred state. That is, when the position of the diaphragm 18 is changed, the reverse of FIG. 4A is achieved, and the distance Hartmann image comes into focus. For the PSF (middle figure), the maximum value max of the luminance signal due to the bright spot exceeds the threshold value S, and the peak Pf corresponding to the far focus position is detected (see FIG. 5).

  FIG. 4B is a diagram when the measurement optical system 10 is adjusted to an intermediate position between the far focus position and the near focus position. The acquired point image (left figure) is a near-use image. The luminance values of both the bright spot due to power (solid line) and the bright spot due to far-distance power (dotted line) are low and spread in a blurred state. And about the PSF (middle figure), the maximum value max does not exceed the threshold value S. Therefore, by monitoring the point image on the light receiving element 27 when the diopter correction position changes, the focus state of the Hartmann image can be accurately detected.

  The operation of this apparatus will be described below using the flowchart of FIG. First, the control unit 70 acquires a Hartmann image and performs preliminary measurement in a state where the measurement optical system 10 is disposed at an initial position (a position corresponding to 0 diopter). Here, the control unit 80 may detect the image positions of the near-field Hartmann image and the far-field Hartmann image, and measure the near-field wavefront aberration and the far-field wavefront aberration, or either one may be used. . In addition, for each dot image, the near dot image appears closer to the pupil center (optical axis center) than the far dot image, so in the adjacent dot images, the near dot image is the one closer to the pupil center, You may make it discriminate | determine the far side as a distance dot image. In the preliminary measurement stage, it is only necessary to measure the spherical refraction error.

  Then, the control unit 70 determines the moving direction of the optical drive unit 30 according to the result of the preliminary measurement, and moves the measuring optical system continuously or in predetermined steps according to the determined moving direction.

  Then, the control unit 70 sequentially detects the focus state of the Hartmann image based on the light reception signal from the light receiving element 27 during the movement of the measurement optical system by the optical drive unit 30. For example, the control unit 70 detects the PSF of the point image received by the light receiving element 27 and determines whether the maximum value Max of the PSF at each position exceeds a predetermined threshold S. Then, the control unit 70 sets the position where the maximum value Max of the PSF shows a peak among the positions where the luminance value becomes lower than the threshold S from the position where the maximum value Max first exceeds the threshold S as the focus position. Detect (see FIG. 5).

  For example, when the preliminary measurement result is a positive value, the control unit 70 drives the drive unit 29 to move the optical drive unit 30 in the A direction (plus direction), and based on the light reception signal of the light receiving element 27. The position where the maximum value Max of PSF shows a peak is searched. The control unit 70 acquires a Hartmann image when the first peak is reached, and moves the image to the memory 75 together with the position of the optical drive unit 30. Further, the control unit 80 moves in a predetermined amount A direction from the position where the first peak is detected.

  This amount of movement may be set according to the addition in a general diffractive intraocular lens. For example, if the addition 4D is maximum in a commercially available diffractive intraocular lens, the movement amount is set to 4D or more from the first peak position.

  When the second peak is detected, a Hartmann image when the second peak is reached is acquired and moved to the memory 75 together with the position of the optical drive unit 30. In this case, the position where the first peak is detected corresponds to the near focus position N. Further, the position Pf where the second peak is detected corresponds to the far focus position F (see FIG. 7A).

  On the other hand, when the second peak is not detected, the movement direction of the optical drive unit 30 is switched and the movement in the reverse direction (in this case, the B direction (minus direction)) is started. In this case, the control unit 70 searches for the second peak in the minus region. Then, when the second peak is detected, a Hartmann image when the second peak is reached is acquired and moved to the memory 75 together with the position of the optical drive unit 30. In this case, the position where the first peak is detected corresponds to the far focus position F. Further, the position where the second peak is detected corresponds to the near focus position N (see FIG. 7C).

  On the other hand, when the preliminary measurement result is a negative value, the control unit 70 drives the drive unit 29, moves the optical drive unit 30 in the B direction, and searches for the first peak. The control unit 70 acquires a Hartmann image when the first peak is reached, and moves the image to the memory 75 together with the position of the optical drive unit 30. Further, the control unit 80 moves in the direction of the predetermined amount B from the position where the first peak is detected.

  When the second peak is detected, a Hartmann image when the second peak is reached is acquired and moved to the memory 75 together with the position of the optical drive unit 30. In this case, the position where the first peak is detected corresponds to the far focus position F. Further, the position where the second peak is detected corresponds to the near focus position N (see FIG. 7B).

  On the other hand, when the second peak is not detected, movement in the reverse direction (in this case, the B direction) is started. In this case, the control unit 70 searches for the second peak in the minus region. Then, when the second peak is detected, a Hartmann image when the second peak is reached is acquired and moved to the memory 75 together with the position of the optical drive unit 30. In this case, the position where the first peak is detected corresponds to the near focus position N. Further, the position where the second peak is detected corresponds to the far focus position F (see FIG. 7C).

  When the first and second peaks are detected, the controller 70 stops driving the optical drive unit 30, and the position information of the optical drive unit 30 and the Hartmann image image at the two positions where the peaks are detected are displayed. Recall from the memory 75 and measure the wavefront aberration. Here, the one acquired on the minus side is the wavefront aberration due to the near power of the diffractive IOL, and the one acquired on the plus side is the wavefront aberration due to the far power of the diffractive IOL.

  A method for obtaining wavefront aberration from the Hartmann image and the positional information of the optical drive unit 30 will be described below.

  First, the diopter correction amount is calculated from the position information of the optical drive unit 30. In advance, the memory 75 stores diopter correction amount values corresponding to the respective movement amounts of the optical drive unit 30. Then, the control unit 70 calculates a diopter correction amount corresponding to the movement amount from the initial position of the optical drive unit 30 to the peak.

  Next, the control unit 70 measures the wavefront aberration based on the image position of the Hartmann image. At this time, the control unit 70 may measure the wavefront aberration by detecting the image position of the dot image having the higher luminance among the adjacent dot images. Then, the control unit 70 calculates the wavefront aberration (eye refractive power distribution) of the eye to be examined based on the diopter correction amount and the aberration information based on the Hartmann image. Then, the control unit 70 outputs the measurement results for near and far use on the monitor 80.

  With the above configuration, when measuring the wavefront aberration corresponding to the near and far powers of the IOL, the measurement is performed based on the Hartmann image with high brightness, and thus a highly accurate measurement result is obtained. It is done.

  When outputting the measurement result, an arbitrary aberration component in the wavefront aberration may be output using Zernike analysis or the like. For example, by extracting the secondary aberration component in the wavefront aberration, the distance-use refractive power (SCA) and the near-field refractive power (SCA) of the eye to be examined are obtained.

  In the above description, the diffractive IOL insertion eye has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to the case of measuring a zone type IOL insertion eye.

  In the above description, the wavefront aberration is measured using the dot image having the higher luminance among the adjacent dot images in the Hartmann image acquired at each focus position. However, depending on the diffraction efficiency of the diffractive intraocular lens, there is a possibility that the distance Hartmann image and the near Hartmann image are erroneously detected in the luminance comparison. For example, even when the focus position is adjusted to the near focus position, the distance Hartmann image dot image may have higher brightness or substantially the same brightness.

  Here, based on the light reception result of the light receiving unit (for example, the light receiving element 27, the image sensor 22) that receives the fundus reflected light beam by the measurement light, the control unit 70 determines that the index image received by the image sensor 22 is intraocular. It is preferable to determine whether the index image corresponds to the near power of the lens or the index image corresponding to the far power of the intraocular lens. Then, the control unit 70 measures the distance refraction error and the near refraction error due to the intraocular lens based on the determined index images. Note that the method described below can also be applied to an eye refractive power measurement apparatus described later.

  As a first technique, the control unit 70 uses the index image corresponding to the near power as the index image corresponding to the near-use power among the captured index images, and uses the distance as far as the optical axis L1. It is determined as an index image corresponding to power.

  For example, the control unit 70 discriminates the near dot image from the near-pupil center (optical axis L1) as the dot image based on the near-field Hartmann image and the far side from the pupil center as the dot image based on the far-range Hartmann image. It may be. The pupil center position (optical axis L1) is set, for example, at the center of the imaging surface of the two-dimensional imaging device 22 (intersection with the optical axis L1). Therefore, when two adjacent dot images are detected, the control unit 70 measures the distance between the pupil center position and the dot image, and determines the dot image based on the measurement result. Then, the control unit 70 identifies the distance Hartmann image and the near-field Hartmann image by determining each dot image on the image sensor 22.

  As a second method, the control unit 70 detects position information of the index image when the near-infrared light source 11a is turned on, and each index image separated by turning on the visible light source 11b is applied to the image sensor 22. When the received index image is received, the index image corresponding to the detected position information is determined as the index image corresponding to the distance power, and the other index images are determined as the index images corresponding to the near power. Determine.

  For example, the control unit 70 first turns on the near-infrared light source 11a and acquires a Hartmann image. Then, the control unit 70 detects the position of each dot image of the Hartmann image, and stores the detection information in the memory 75. At this time, only the Hartmann image for distance is acquired as the Hartmann image.

  Here, because of the characteristics of the diffractive intraocular lens, for near infrared light, the diffraction efficiency due to the distance power (0th order light) is high and the diffraction efficiency due to the near power (first order light) is considerably low. (For example, the ratio of distance: near use is 9: 1). In the case of the diffractive type, the light passing through the intraocular lens is divided into light of each diffraction order by a plurality of diffraction gratings formed in the optical unit, the 0th order light is focused in the distance, and the primary light is near. Will be focused on.

  Next, the control unit 70 turns off the near-infrared light source 11a, turns on the visible light source 11b, and acquires a Hartmann image. At this time, the distance Hartmann image and the near Hartmann image are obtained separately.

  Here, the control unit 70 determines a Hartmann image corresponding to the position information stored in the memory 75 as a far-field Hartmann image, and determines other Hartman images as near-field Hartmann images. Note that the light receiving position of the Hartmann image may be different between near infrared and visible light due to the difference in chromatic aberration between near infrared light and visible light. Therefore, the amount of change in the light receiving position due to chromatic aberration is obtained in advance by simulation or experiment. And the control part 70 calculates | requires the estimated light receiving position of the Hartmann image in visible light by adding a variation | change_quantity with respect to the light receiving position of a Hartmann image with near-infrared light. Then, the control unit 70 determines that the Hartmann image close to the expected light receiving position is a far-field Hartmann image, and other Hartman images are near-field Hartmann images.

  As a third method, a diopter correction unit (for example, the optical drive unit 30) that drives the measurement optical system 10 to correct the diopter of the subject's eye is used. Here, the control unit 70 determines the index image based on the change in the luminance of the reflected light beam when the measurement optical system 10 is driven by the diopter correction unit.

  For example, the control unit 70 may determine the distance dot image and the near dot image based on a change in the brightness of the dot image when the diopter correction amount is changed. That is, the focus state of each dot image changes due to diopter correction. Therefore, each dot image is determined by monitoring the change in luminance at each position. Here, it is discriminated that a luminance peak is detected on the minus side as a near dot image, and a luminance peak detected on the plus side is a distance dot image. That is, it is only necessary to detect the focus state of the dot image, and the degree of blur (for example, the image size) of the dot image may be monitored. Further, the luminance distribution (for example, the sum of luminance values) of the Hartmann image may be used.

  In addition, about the method of detecting the focus state of a Hartmann image, the structure using the brightness | luminance change of the parameter | index image imaged with the image pick-up element 22 may be sufficient. For example, the Hartmann image luminance distribution (for example, the sum of luminance values) is used.

  Further, the control unit 70 may detect a focus state using a point image obtained by extracting a divided image centered on each distance dot image and adding the divided images. In this case, in the adjacent dot images, the dot images may be determined depending on whether or not they are far from the optical axis L1, as described above, or the detection result in the near infrared may be used.

  In the above description, the wavefront aberration measurement optical system 10 is used as the measurement measurement optical system. However, the measurement optical system projects the measurement light beam toward the fundus and receives the reflected light beam as a two-dimensional index image by the image sensor. The present invention can be applied to any configuration that includes a system and an arithmetic unit that measures the distance refraction error and the near refraction error of the eye E by the multifocal intraocular lens. In this case, the refraction error may include wavefront aberration and eye refractive power.

  For example, the present invention can be applied to an eye refractive power measurement optical system. For example, the lens array 20 is changed to a ring lens, and the other members have the same configuration as the wavefront aberration measuring optical system 10. In this case, the ring image on the image sensor 22 is changed by the refraction error of the eye E. Therefore, by analyzing the shape of the ring image, the refraction error in each meridian direction can be obtained, and by applying predetermined processing thereto, S (spherical power), C (astigmatic power), A (astigmatic axis) Angle) can be obtained.

  In the case of a diffractive IOL insertion eye, a ring image is separated into a plurality of images and captured as a multiple ring. Here, the control unit 70 acquires multiple ring images at each focus position in order to measure the refraction value due to the distance power and the refraction value due to the near power of the diffractive IOL. A ring image with near power is formed closer to the pupil center, and a ring image with far power is formed farther from the pupil center.

  In this case, the control unit 70 moves the optical driving unit 30, performs focusing according to each ring, takes a picture, and acquires a ring image. Then, the near and far refraction values may be measured based on the ring image and the position information of the optical drive unit.

  In the above configuration, an astigmatism correction optical system (for example, a cross cylinder lens) is provided in the optical path of the measurement optical system 10 as a configuration for performing diopter correction so as to correct astigmatism in addition to the spherical refraction error. May be.

  In this case, in the multiple ring image acquired at each focus position, the eye refractive power may be calculated based on the ring image having the higher luminance. In this case, the control unit 70 determines the inner ring image in the multiple ring image as the near ring image corresponding to the near power, and the outer ring image as the far ring image corresponding to the far power, and each ring image. Based on the above, the near power and the far power may be obtained.

  In the above configuration, when diopter correction is performed, the measurement optical system is moved in the optical axis direction. However, a correction lens having a different power is provided on the rotating plate, and a correction lens corresponding to the diopter of eye E is provided. It may be inserted.

1 is an external view of an ophthalmologic measurement apparatus according to the present invention. It is a schematic block diagram explaining the structure of the optical system and control system of the ophthalmic measurement apparatus which concerns on this embodiment. It is a figure which shows the pattern image when measuring the eye which is not a diffractive IOL insertion eye, and the pattern image when measuring a diffractive IOL insertion eye. It is a figure explaining the correspondence of the point image on a light receiving element, PSF of a point image, and a Hartmann image. It is a figure which shows the relationship between the maximum value Max of the brightness | luminance of PSF, and a diopter correction position. It is a figure which shows the example of the flowchart in operation | movement of this apparatus. It is a figure explaining the direction which moves an optical drive unit according to a preliminary measurement result.

DESCRIPTION OF SYMBOLS 10 Wavefront aberration measuring optical system 11 Light source part 18 Aperture 20 Lens array 22 Two-dimensional image sensor 25 2nd drive part 26 Half mirror 27 Light receiving element 29 1st drive part 30 Optical drive unit 40 Fixation target projection optical system 50 Anterior eye part Illumination system 60 Anterior eye observation system 70 Control unit 75 Memory 80 Monitor

Claims (5)

A measurement optical system that projects a measurement light beam toward the subject's fundus and receives the reflected light beam as a two-dimensional index image by an imaging device;
Focus detection means for detecting a focus state of the index image;
When the subject's eye is a multifocal intraocular lens insertion eye, each index image separated by the multifocal intraocular lens is focused on the image sensor based on the detection result from the focus detection unit. Diopter correction means for driving the measurement optical system so that,
An index image acquired by the image sensor when diopter correction is performed on one separated index, and an index image acquired by the image sensor when diopter correction is performed on the other separated index Calculating means for measuring the distance refraction error and the near refraction error of the subject's eye based on
An ophthalmologic measuring apparatus comprising: A measurement optical system that projects a measurement light beam toward the fundus of a subject's eye and receives the reflected light beam as a two-dimensional index image by an imaging device, wherein the subject's eye is a multifocal intraocular lens insertion eye Measuring optical system that receives each index image separated by the multifocal intraocular lens by the imaging device;
It has a light receiving means for receiving the reflected light beam, the index image received by the image sensor, the near or index images corresponding to the power of the multifocal intraocular lens, distance power of the multifocal intraocular lens An ophthalmologic measurement apparatus comprising: a discrimination processing unit that discriminates whether or not an index image corresponds to the above based on a light reception result of the light receiving unit. The ophthalmic measurement device according to claim 2,
The image sensor also serves as the light receiving means,
The discrimination processing means uses the index image received by the image sensor as the index image corresponding to the near power, the one closer to the optical axis of the measurement optical system, and the one farther from the optical axis of the measurement optical system. ophthalmologic apparatus characterized by determining as an index image corresponding to the distance power. The ophthalmic measurement device according to claim 2,
A diopter correcting means for driving the measuring optical system to correct the diopter of the subject's eye;
The ophthalmic measurement apparatus characterized in that the discrimination processing means performs discrimination based on a luminance change of a reflected light beam when the measurement optical system is driven by the diopter correction means. The ophthalmic measurement device according to claim 2,
The measurement optical system has a near infrared light source and a visible light source as a measurement light source,
The discrimination processing means detects position information of the index image when the near-infrared light source is turned on,
When each index image separated by turning on the visible light source is received by the image sensor , among the index images received by the image sensor, the index image corresponding to the position information corresponds to the distance power ophthalmic measuring apparatus characterized by determined as an index image which, to determine other index images as an index image corresponding to the near power.