JP2010200915A - Ophthalmic measurement program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently perform visibility simulation of a multifocal intraocular lens. <P>SOLUTION: In an ophthalmic measurement program for simulating a retina image when an intraocular lens is worn, an operation part performs the following: a first step of acquiring first aberration data the cornea has and second aberration data the multifocal intraocular lens has; a second step of acquiring pupil diameter data and visual target position data; a third step of operating a distance PSF (Point Spread Function) due to an visual target luminous flux formed on a distance focus and a reading PSF due to an visual target luminous flux formed on a reading focus on the basis of the first aberration data, the second first aberration data, and the visual target position data; and a fourth step at which a simulation image of a prescribed visual target is acquired on the basis of the distance PSF and the reading PSF, each image strength data of the visual target luminous flux formed on the distance focus and the reading focus on the basis of pupil diameter data are acquired, and a contract of a simulation image is changed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ophthalmologic measurement program for simulating a retinal image when an intraocular lens is worn.

  Conventionally, an intraocular lens is used in place of the lens in cataract surgery. Many of the intraocular lenses currently used are single-focus lenses. However, in recent years, multi-focus intraocular lenses having a plurality of different focal lengths have been proposed (see Patent Document 1). .

Special Table 2000-511299

  By the way, an apparatus has been proposed that obtains measurement data of the eye to be examined and simulates how the target image looks when the intraocular lens is worn on the eye to be examined. However, at present, the above-described simulation of how the multifocal intraocular lens looks is not implemented.

  In view of the above-described problems, an object of the present invention is to provide an ophthalmic measurement program that can suitably perform the appearance simulation of a multifocal intraocular lens.

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

(1) In an ophthalmic measurement program for simulating a retinal image when an intraocular lens is worn,
A first step of acquiring first aberration data of the eye cornea to be examined and second aberration data of the multifocal intraocular lens;
A second step of acquiring pupil diameter data and target position data when performing the simulation;
Based on the first aberration data, the second aberration data, and the target position data, a distance point spread function by a target light beam that forms an image at a distance focus, and a target that forms an image at a near focus A third step of calculating a near-point image distribution function by the luminous flux;
A step of acquiring a simulation image of a predetermined target based on the distance point image distribution function and the near point image distribution function acquired in the third step, and the distance focus based on the pupil diameter data; A fourth step of acquiring each image intensity data of the target luminous flux imaged at the near focus and the target luminous flux imaged at a near focus, and changing the contrast of the simulation image based on the acquired image intensity data;
The calculation unit executes.
(2) In the ophthalmic measurement program of (1),
The second step includes a step of changing the pupil diameter data in accordance with the target position data.
(3) In the ophthalmic measurement program of (2),
The second step includes a step of acquiring brightness data of a place where the target is presented, and a step of changing the pupil diameter data in accordance with the acquired brightness data. And
(4) (In the 3 ophthalmic measurement program,
The fourth step is characterized in that the contrast of the simulation image is changed based on the brightness data.

  ADVANTAGE OF THE INVENTION According to this invention, the appearance simulation of a multifocal intraocular lens can be performed suitably.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an overall configuration of a simulation apparatus (ophthalmic measurement apparatus) including an ophthalmic measurement program according to the present embodiment.

  A simulation apparatus 1 for simulating a retinal image when an intraocular lens is worn includes a CPU (calculation control unit) 30, an input unit 40, a memory (storage unit) 35, a printer 43, a monitor 50, an image processing unit 31, and the like. , And each part is connected via a bus or the like.

  The CPU 30 controls the operation of each unit based on a retinal image simulation program and various control programs stored in the memory 35. The input unit 40 includes a keyboard 42 having a cursor key, numeric input keys, various function keys, and the like, and a mouse 41. The image processing unit 31 controls the display screen of the monitor 50 that displays various data, simulation images, and the like. The memory 35 includes an HDD or the like, and is executed by the CPU 30 (programs for operating the apparatus, programs for simulating retinal images when wearing various intraocular lenses), and various intraocular lenses. (IOL) information, various IOL power calculation formulas (SRK-T, SRK, HOLLADAY, etc.), etc. are stored. Note that a commercially available PC (personal computer) may be used as the CPU 30, the input unit 40, the memory 35, the monitor 50, and the image processing unit 31, and the retinal image simulation program may be installed.

  The simulation apparatus 1 is connected with a corneal shape measuring apparatus 10 as an apparatus for acquiring wavefront aberration data of the eye cornea to be examined. The corneal shape measuring apparatus 10 is an apparatus that measures wavefront aberration of the eye cornea by irradiating the eye cornea with measurement light and receiving the reflected light. For example, the eye cornea as shown in FIG. A device that measures the corneal shape of the eye to be examined by projecting a placido index and receiving the reflected light can be considered.

  The corneal shape measuring apparatus 10 of this embodiment includes a platide plate 11 on which a large number of platide rings are formed, an illumination light source 12 that illuminates the ring pattern of the platide plate substantially uniformly, and a ring pattern projected onto the cornea. An anterior ocular segment imaging optical system 15 including a photographic lens 13 for capturing an image and a two-dimensional imaging element 14, and a control unit 16 are included. In this case, the anterior ocular segment imaging optical system 15 captures a placido image, and also includes a corneal apex luminescent spot formed on the cornea by a predetermined projection optical system (not shown) and an image of the anterior ocular segment including the pupil. Used for shooting. Furthermore, the corneal shape measuring apparatus 10 of this embodiment projects a measurement light beam on the fundus of the eye to be examined and receives the reflected light, thereby measuring an eye refractive power distribution or wavefront aberration of the eye to be examined ( For example, a phase difference method disclosed in Japanese Patent Laid-Open No. 10-108837 or an ophthalmometer using a Shack-Hartmann sensor is provided (not shown).

  Note that the simulation apparatus 1 and the corneal shape measuring apparatus 10 are connected by a LAN or the like, and various data (for example, wavefront aberration data of the eye cornea to be examined) obtained by the corneal shape measuring apparatus 10 is stored in a memory as a database. 35. An apparatus for measuring the wavefront aberration of the cornea is not limited to the above-described configuration, and an anterior ocular segment imaging apparatus (for example, Shine proof camera) or anterior ocular tomography apparatus (for example, anterior ocular segment OCT (optical coherence tomography)). In this case, the corneal shape is measured based on the photographed corneal cross-sectional image, and the wavefront aberration component of the cornea is measured based on the measured corneal shape.

  The IOL information stored in the memory 35 is information (intraocular lens model data) regarding various models of intraocular lenses provided from each IOL manufacturer. For example, for each model, a model name, a manufacturer name , A constant, postoperative ACD (anterior chamber depth): expected anterior chamber depth (mm), spherical aberration (μm) of intraocular lens. The spherical aberration (corrected spherical aberration) of the intraocular lens in the present embodiment represents spherical aberration that is corrected when a predetermined intraocular lens is inserted into the eye, and the eye cornea to be examined has. Along with the spherical aberration, it is used for calculating the spherical aberration of the post-operative eye as an expected value. When the IOL information stored in the memory 35 is information related to the multifocal intraocular lens, the far spherical aberration data corrected for the target luminous flux imaged at the far focus and the vision image formed at the near focus. It is conceivable to include near-field spherical aberration data that is corrected with respect to the standard luminous flux. Further, when the multifocal intraocular lens has a far focus, a near focus, and a medium focus, it is conceivable to include spherical aberration data corrected for each focus position. Note that the spherical aberration to be corrected is not limited to this as long as the amount of spherical aberration to be corrected is substantially constant with respect to each focal position. In the above description, the spherical aberration is used. However, the present invention is not limited to this, and aberration data relating to other higher-order aberration components may be included.

  When each manufacturer calculates the spherical aberration of such an intraocular lens, the corneal spherical aberration (for example, +0.30 μm) is calculated based on the corneal shape of a predetermined model eye whose design conditions are known. The spherical aberration (for example, +0.10 μm) of the entire model eye is obtained based on the wavefront aberration of the entire model eye when the intraocular lens is inserted, and the corneal spherical aberration is subtracted from the spherical aberration of the entire model eye. The spherical aberration (+0.10 − (+ 0.30) = − 0.20) is obtained by obtaining the spherical aberration corrected in step (b). The arithmetic processing can be performed by optical simulation software capable of simulating wavefront aberration when an intraocular lens having predetermined optical characteristics is arranged for a predetermined model eye. In the above description, spherical aberration is provided from each manufacturer. However, the optical characteristics of the intraocular lens (lens curvature radius, refractive index, lens thickness, It is also possible to calculate the wavefront aberration when it is inserted into a predetermined model eye after obtaining a conic constant, an aspherical constant, etc. In the case of a multifocal intraocular lens, it is conceivable to obtain spherical aberration for each of the target luminous flux imaged at the far focus and the target luminous flux imaged at the near focus.

  FIG. 2 is a diagram showing a visual appearance simulation screen displayed on the display monitor 50. The simulation screen 100 includes an area 101 for displaying a result of a visual simulation corresponding to a predetermined intraocular lens model, an area 103 for changing the presentation position of the target, and an area 105 for changing the pupil diameter. And an area 107 for selecting whether to perform simulation in consideration of corneal astigmatism.

  The region 101 includes a simulation retina image S1 (for example, an ETDRS chart (a type of target chart)) after wearing an intraocular lens (after surgery) and a simulation retina at a given target before wearing (before surgery). An image S2 is displayed.

  The area 103 includes a scale 103a (lower limit: 0m position to upper limit: 6.0m position (upper limit value can be changed)) indicating a target position, and a slider (cursor) 103b for inputting a target position to be simulated. , Is displayed. The scale 103a displays a graphic indicating a predetermined far point position (for example, 5.0 m) and a predetermined near point position (for example, 0.3 m). In the initial stage, the target position is set to a predetermined far point position (5, 0 m). When the slider 103b is moved with respect to the scale 103a by the operation of the mouse 41 by the examiner, the target position when the retinal image is simulated is changed.

  In the area 105, a scale 105a (lower limit: 1.0 mm to upper limit: 6.0 mm (upper limit value and lower limit value can be changed)) for indicating the pupil diameter, and a slider (cursor for inputting the pupil diameter to be simulated) ) 105b is displayed. In the area 105, a check field 105c for selecting whether or not to change the pupil diameter in synchronization with the change of the target position is displayed. In the initial stage, the pupil diameter to be simulated is set so as to correspond to the pupil diameter of the eye to be examined that has been input in advance. When the slider 105b is moved with respect to the scale 105a by the operation of the mouse 41 by the examiner, the pupil diameter when the retinal image is simulated is changed.

  When the check field 105 c is checked, the CPU 30 automatically changes the pupil diameter used for the simulation based on the target position set on the area 103. This takes into account that the pupil becomes larger when the eye looks closer and the pupil becomes smaller when the eye looks far. In this case, the relationship between the target presentation position and the pupil diameter may be obtained in advance and stored in the memory 35.

  In the area 107, a check column 107a for selecting whether to perform simulation in consideration of corneal astigmatism, an input column 107b for inputting astigmatism power, and an astigmatic axis angle (fixed value) of the eye to be examined are displayed. Yes. When the check field 107a is checked, the CPU 30 acquires astigmatism power input in the input field 107b as simulation data, and constructs a simulation image based on the input astigmatism power.

  Based on the simulation data set as described above, the CPU 30 determines how a predetermined target is formed on the retina surface of the eye when a predetermined intraocular lens is inserted into the eye. The simulation image S1 is acquired and displayed on the monitor 50. In the present embodiment, the wavefront aberration data possessed by the intraocular lens model, the wavefront aberration data of the eye cornea to be examined, the target position data, the pupil diameter data, the cornea, and the like are set as the fluctuation parameters set for acquiring the simulation retinal image. Astigmatism data, etc. are set. In the present embodiment, the simulation is performed on the assumption that the spherical refraction error (spherical power) of the subject's eye is corrected.

  A case where a multi-focal intraocular lens appearance simulation is performed in an apparatus having the above-described configuration will be described with reference to the flowchart of FIG. First, the CPU 30 acquires, from the memory 35, wavefront aberration data of the eye cornea to be examined and distance spherical aberration data and near spherical aberration data possessed by a preselected IOL (intraocular lens) model. Then, the postoperative residual wavefront aberration is calculated as an expected value based on the wavefront aberration data of the cornea, the distance spherical aberration data, and the near spherical aberration data. In the following description, a position that is 5.0 m away from the eye to be examined is a far point position, and a position that is 0.3 m away from the eye to be examined is a near point position.

  More specifically, the CPU 30 removes (adds) the distance spherical aberration data from the wavefront aberration data of the eye cornea to be examined, thereby performing postoperative wavefront aberration data Wf (postoperative distance aberration on the far focus). Data Wf) is obtained. Further, the CPU 30 removes (adds) near-field spherical aberration data from the wavefront aberration data of the eye cornea to be examined, thereby obtaining postoperative wavefront aberration data Wn (postoperative near-field aberration data Wn) for the near focus. obtain. In the above, when the check column 107a is checked, corneal astigmatism data that matches the astigmatic axis direction is further added to the wavefront aberration data of the eye cornea to be examined.

  Further, the CPU 30 acquires pupil diameter data and target position data set and input on the simulation screen of FIG. In this case, when the pupil diameter or the target position is changed on the simulation screen, the CPU 30 changes the data used for the simulation accordingly.

  Next, the CPU 30 performs a point spread function (point spread function) corresponding to the set target position data based on the postoperative distance aberration data Wf, the postoperative near distance aberration data Wn, and the target position data. PSF) is obtained by calculation. In this case, when the point image is placed at a predetermined position, the CPU 30 uses the distance PSF data based on the target luminous flux imaged at the distance focus and the near PSF data based on the target luminous flux imaged at the near focus. And can be acquired respectively.

  Here, when obtaining the distance PSF data at the set target position, spherical power data corresponding to the distance between the set target position and the far point position is added to the postoperative distance aberration data Wf. Calculated based on wavefront aberration data. Further, when the near PSF data at the set target position is obtained, similarly, spherical power data corresponding to the distance between the set target position and the near point position is obtained with respect to the postoperative near aberration data Wf. Calculation is based on the added wavefront aberration data.

  More specifically, when the target position is set to the far point position (5.0 m), the CPU 30 calculates the distance PSF data based on the postoperative distance aberration data Wf. Further, the CPU 30 calculates the near-field PSF data based on data obtained by adding the spherical power of (−1 / 0.3D) to the postoperative near-field aberration data Wn.

  When the target position is set to the near point position (0.3 m), the CPU 30 is based on data obtained by adding the spherical power of (1 / 0.3D) to the postoperative distance aberration data Wf. The distance PSF data is calculated. Further, the CPU 30 calculates near-use PSF data based on the postoperative near-use aberration data Wn.

  When the target position is set to an intermediate position between the far point position and the near position (for example, a position 2.0 m away from the eye to be examined), when obtaining the distance PSF data, the far point position The amount of displacement of the target from 3.0 is 3.0 m, and spherical power + (1/3) D is added to the postoperative distance aberration data Wf. When obtaining near-field PSF data, the amount of displacement of the target from the near point position is 1.7 m, and spherical power + (1 / 1.7) D is added to the postoperative near-field aberration data Wn. .

  Next, based on the pupil diameter data set as described above, the CPU 30 performs image intensity data (distance image intensity data) of the target luminous flux imaged at the far focus and a vision image formed at the near focus. The image intensity data of the standard luminous flux (near image intensity data) is acquired. In the case of a zone-type multifocal intraocular lens, each image intensity data includes, for example, the image intensity when the target luminous flux passes through the distance zone (distance portion) and the visual field within the set pupil region. It can be obtained by obtaining the ratio of the standard luminous flux to the image intensity when passing through the near zone (near portion). In addition, using the fact that the intensity of each image changes depending on the area ratio of the distance portion and the near portion, within the set pupil region, the distance zone (distance portion) and the near zone (near use) Part area) may be acquired as image intensity data (see FIG. 4). In the case of a diffractive multifocal intraocular lens, for example, the ratio of the image intensity by the 0th-order diffracted light and the image intensity by the primary light when the target light beam passes through the diffraction grating in the set pupil region is obtained. (See FIG. 5).

  More specifically, if the set pupil diameter is Ws, the CPU 30 sets the pupil diameter Ws as the effective optical part region (effective region) Kw of the IOL model. Then, the CPU 30 uses the data related to the optical part area of the IOL model stored in the memory 35 to generate the target luminous flux imaged at the far focus and the target luminous flux imaged at the near focus in the effective area Kw. The ratio with the image intensity is obtained. In this case, in the entire optical part region of the intraocular lens, the region inside the predetermined pupil diameter Ws can be considered as the effective optical part region.

  When obtaining each image intensity data according to the pupil diameter of the eye to be examined, for example, a table created based on data as shown in FIG. FIG. 4 is an example of a graph in which the distance portion ratio F and the near portion ratio N are represented for each pupil diameter (effective region Kw), and is for a zone-type multifocal intraocular lens. In the zone type lens of FIG. 4, a distance portion is formed at the center, and a near portion and a distance portion are alternately formed in the radial direction from the center of the optical portion. Note that the relationship shown in FIG. 4 is obtained by measuring the area ratio between the distance portion and the near portion in the region determined by the predetermined pupil diameter in advance for the zone-type intraocular lens (measurement of image intensity). You may). In addition, when calculating | requiring each image intensity data according to a pupil diameter, besides using a table, the optical information regarding a distance part and a near part (for example, distribution of the distance part and near part from a lens center to a lens peripheral part) ) May be obtained in advance and calculated by optical simulation.

  FIG. 5 is an example of a graph when the ratio of the image intensity at the focal positions of the 0th-order light and the primary light is represented for each pupil diameter, and is for the diffractive intraocular lens. 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. The relationship shown in FIG. 5 can be calculated by measuring in advance the image intensity by the 0th order light and the image intensity by the primary light in the region determined by the predetermined pupil diameter for the diffractive intraocular lens. It is. Further, optical information (for example, the refractive index of the grating material, the shape of the grating, etc.) of the diffraction grating of the diffractive intraocular lens may be acquired in advance and calculated by optical simulation.

  Next, the CPU 30 adjusts the contrast of the far PSF data and the contrast of the near PSF data based on the image intensity data acquired as described above. In this case, the greater the acquired image intensity data, the higher the contrast of the image received on the retina, and the smaller the acquired image intensity data, the lower the contrast of the image received on the retina. Note that the image used as the reference when adjusting the contrast can use the image data of the distance PSF data and the distance PSF data acquired as described above. For example, when the image data has a contrast of 100%, Can be set as an image.

  More specifically, when the ratio data of FIG. 4 is used, the CPU 30 determines the contrast of the distance PSF data when the ratio (F: N) between the distance portion and the near portion is (100: 0). Is set to 100%, and the contrast of the near-field PSF data is set to 0%. When the ratio (F: N) of the distance portion and the near portion is (0: 100), the CPU 30 sets the contrast of the distance PSF data to 0% and the contrast of the distance PSF data to 100%. To do. When the ratio of the distance portion to the near portion (F: N) is (50:50), the CPU 30 sets the contrast of the distance PSF data to 50% and the contrast of the distance PSF data to 50%. To do.

  Next, the CPU 30 performs image processing (convolution integration) on each PSF data adjusted in contrast and image data of a predetermined target (EDTRS (Early Treatment Diabetic Retinopathy Study), ETDRS, and landscape items). A simulation image in each PSF data is obtained. Next, the CPU 30 superimposes (combines) the simulation image based on the distance PSF data and the simulation image based on the near PSF data by image processing. Thereby, the simulation image S1 of the predetermined target as the whole multifocal intraocular lens is acquired. In this case, the CPU 30 may convolve and integrate the image data of the predetermined target after synthesizing the distance PSF data and the near PSF data by image processing. Then, the CPU 30 displays the acquired simulation image S1 on the monitor 50 or stores it in the memory 35.

  According to the simulation as described above, the contrast of the simulation image S1 is adjusted based on the distance image intensity data and the near image intensity data changed according to the pupil diameter. Therefore, a retinal image simulation considering the difference in pupil diameter of the eye to be examined can be performed better. Therefore, the examiner can suitably explain to the patient the change in appearance due to the difference in pupil diameter in the informed consent before surgery when the multifocal intraocular lens is worn in the eye.

  In the above description, the relative data of the distance image intensity data and the near image intensity data is acquired in advance according to the pupil diameter. However, the present invention is not limited to this. Absolute image intensity data relating to the data may be acquired in advance according to the pupil diameter.

  In the above description, when the pupil diameter Ws is set to a predetermined value, an arbitrary value can be input. However, the present invention is not limited to this, and at least two different pupil diameters (for example, 4 mm and 6 mm) are used. May be input.

  In addition, considering that the pupil diameter of the subject's eye changes depending on the surrounding brightness, the brightness of the place where the target is presented (the location of the subject) can be input instead of the input of the pupil diameter. You may do it. For example, when daytime is selected, the first pupil diameter (for example, 4 mm) is selected as the pupil diameter used for the simulation. When night is selected, a second pupil diameter (for example, 6 mm) larger than the first pupil diameter is selected. Then, the CPU 30 performs a retinal image simulation based on the selected pupil diameter. Also, a simulation image at daytime and a simulation image at night may be output simultaneously.

  In the simulation, the contrast of the predetermined target used for the simulation may be changed according to the change in the brightness of the place where the target is presented (the location of the subject). More specifically, it can be used when performing retinal image simulation in the daytime and at night as described above. In this case, the contrast of a predetermined target for simulation is stored in the memory 35 for daytime (high contrast) and nighttime (low contrast). A display area on the monitor 50 where daytime and nighttime can be selected is provided. Here, when daytime is selected, a retina image is simulated in a state where the contrast of the simulation target is set for daytime. When night is selected, a retinal image is simulated in a state where the simulation target is set for night.

It is a block diagram explaining the whole structure of a simulation apparatus (ophthalmic measurement apparatus) provided with the ophthalmic measurement program which concerns on this embodiment. It is a figure which shows the appearance simulation screen displayed on the display monitor. It is a flowchart for demonstrating the case where the appearance simulation of a multifocal intraocular lens is performed. In a zone type lens, it is an example of the graph at the time of expressing the ratio of a distance part and the ratio of a near part for every pupil diameter. In a diffractive intraocular lens, it is an example of the graph at the time of expressing the ratio of the image intensity in each focus position of 0th order light and 1st order light for every pupil diameter.

30 CPU
35 Memory 50 Monitor

Claims (4)

In an ophthalmic measurement program for simulating retinal images when wearing an intraocular lens,
A first step of acquiring first aberration data of the eye cornea to be examined and second aberration data of the multifocal intraocular lens;
A second step of acquiring pupil diameter data and target position data when performing the simulation;
Based on the first aberration data, the second aberration data, and the target position data, a distance point spread function by a target light beam that forms an image at a distance focus, and a target that forms an image at a near focus A third step of calculating a near-point image distribution function by the luminous flux;
A step of acquiring a simulation image of a predetermined target based on the distance point image distribution function and the near point image distribution function acquired in the third step, and the distance focus based on the pupil diameter data; A fourth step of acquiring each image intensity data of the target luminous flux imaged at the near focus and the target luminous flux imaged at a near focus, and changing the contrast of the simulation image based on the acquired image intensity data;
Is an ophthalmic measurement program for the calculation unit to execute. The ophthalmic measurement program according to claim 1,
The second step includes a step of changing the pupil diameter data according to the target position data. In the ophthalmic measurement program according to claim 2,
The second step includes a step of acquiring brightness data of a place where the target is presented, and a step of changing the pupil diameter data in accordance with the acquired brightness data. Ophthalmic measurement program. In the ophthalmic measurement program according to claim 3,
In the fourth step, the contrast of the simulation image is changed based on the brightness data.

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