JP4478434B2 - Ophthalmic surgery simulation method - Google Patents

Description

  The present invention relates to an ophthalmic surgery simulation method and apparatus capable of recognizing the effects of ophthalmic surgery such as surgery on the cornea, crystalline lens, etc. before the operation.

  A method for measuring the accurate eye optical characteristics of the eye to be examined, for example, as shown in Patent Document 1 relating to the previous application of the present applicant, projects a light beam onto the fundus of the eye to be examined, and reflects the light beam reflected from the fundus of the eye to be examined. A method and apparatus for measuring the optical characteristics of an eye that receives light and measures the accurate eye optical characteristics of the eye to be examined are known. Also, a light beam is projected onto the fundus of the eye to be examined, and the light flux reflected from the fundus of the eye to be examined is received. Japanese Patent Application Laid-Open No. 2005-228867 shows a method and apparatus for measuring eye optical characteristics for simulating a target image formed when a required target is projected onto the fundus of the eye to be examined from the intensity distribution of light intensity obtained. ing.

  By the above device, what kind of image is formed on the fundus of the eye to be examined is simulated and displayed on a required display device, so that it can be objectively recognized.

  Also known are surgery to irradiate the cornea with a laser beam to deform the cornea and correct the refractive power of the eye to be examined, or to remove the lens of a cataract patient with a clouded lens and insert an intraocular lens. ing.

  However, there is no known device that accurately simulates what kind of surgery is performed and what kind of ocular optical characteristics are obtained after the surgery.

  For this reason, treatment effects such as improvement of optical characteristics after surgery are judged based on the experience of the practitioner, and which part of the eye to be operated in what manner is based on the practitioner's experience, The treatment effect was also influenced by the skill level of the practitioner.

  In addition, there is no specific method for knowing how the visual function changes with the progression of the disease stage, and only prediction is made based on the experience of the doctor and past data.

JP 2003-111729 A

JP 2003-70741 A

  In view of such a situation, the present invention changes the cornea of the eye to be examined, the state of the crystalline lens by surgery, how the visual function changes, how the eye optical characteristics of the eyeball optical system change, Another object is to provide a method and apparatus that can easily know how the visual function changes as the stage progresses.

  The present invention measures a light quantity distribution characteristic of a light beam formed by a reflected light beam from the fundus of the eye to be examined, and measures a first eye optical characteristic function of the eye to be examined calculated from the measured value, and the eye to be examined. The second eye optical characteristic function calculated from the optical data of each element of the eyeball optical system is compared, and at least one of the optical data is changed with respect to the first eye optical characteristic function. A step of matching one eye optical characteristic function with the second eye optical characteristic function, a second step of establishing optimal optical data of each element of the eyeball optical system by matching, and the second step Of the established optical data, at least one optical data to be corrected by eye surgery is changed, and an ophthalmic surgery system having a third step of calculating post-operative eye optical characteristics based on the changed optical data. Those of the Interview configuration method.

  The present invention also provides a first ocular optical characteristic function of the eye to be calculated, which is calculated based on a light amount distribution characteristic of a light beam formed by a reflected light beam from the fundus of the eye to be examined, and an eyeball optical system in which the eye to be examined is measured. The second eye optical characteristic function calculated from the optical data of each element is compared and calculated so that the first eye optical characteristic function matches the second eye optical characteristic function. A first calculation unit that changes the optical data of each element and determines the optical data of each element in a matching state, and calculates an eye optical characteristic function when at least one of the determined optical data is changed A second calculation unit; a third calculation unit that calculates a simulation image based on a calculation result in the second calculation unit; and a display unit that displays at least a calculation result of the third calculation unit. To perform ophthalmic surgery simulation It relates to.

  According to the present invention, the light quantity distribution characteristic of the light beam formed by the reflected light beam from the fundus of the eye to be examined is measured, the first eye optical characteristic function of the eye to be calculated calculated from the measured value, and the eye of the eye to be examined A second eye optical characteristic function calculated from optical data of each element of the measured eyeball optical system is compared, and at least one of the optical data is changed with respect to the first eye optical characteristic function, Matching the first eye optical characteristic function and the second eye optical characteristic function, a second step of establishing optimal optical data of each element of the eyeball optical system by matching, the second Since at least one optical data to be corrected by the eye surgery is changed among the optical data established by the steps, and the third step of calculating the post-operative eye optical characteristics based on the changed optical data is provided. By changing the optical data of each element of the eyeball optical system, it is possible to simulate the optical characteristics of the eye after the change, and it is possible to anticipate changes in visual function by surgery, and how to treat which part and how It is possible to predict what should be done and to perform an effective operation. In addition, it is possible to predict how the visual function deteriorates as the disease stage progresses, and exhibits excellent effects such as enabling optimal treatment.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, the outline of the surgical simulation apparatus will be described with reference to FIG.

  In the figure, 1 is an input unit, 2 is an arithmetic processing unit, 3 is a display unit, 4 is an arithmetic unit represented by a CPU or the like, and 5 is a storage device such as a semiconductor storage device or a hard disk.

  The input unit 1 receives, for example, eye optical characteristics (a point image intensity distribution function, hereinafter referred to as a first PSF) of an eye to be measured measured by an eye optical characteristic measuring apparatus disclosed in Patent Document 1, and is commercially available. Data relating to each element of the subject's eye measured by the ophthalmic optical measurement device is input.

  As data measured by a commercially available eye optical measurement device, data of each element of the eyeball optical system of the eye to be examined, such as the shape of the lens, the refractive index, the refractive index distribution, the optical axis length of the eye 6 to be examined, that is, the cornea 7 The distance between the rear surface of the lens 8 and the thickness of the lens 8, and the distance from the rear surface of the lens 8 to the retina 10 (see FIG. 2). In FIG. 2, 9 indicates the vitreous body.

  The storage device 5 stores the first PSF 20 input from the input unit 1 and the data 21 of each element of the eyeball optical system of the eye 6 to be examined. Based on these data, the second PSF (described later) is calculated. An arithmetic processing program for performing calculation of a simulation image, calculation of contrast data, displaying the data on the display unit 3, and the like is stored.

  The arithmetic unit 4 controls data arithmetic processing and data input / output based on the arithmetic processing program.

  The operation will be described with reference to FIG.

  STEP: 01 The surgical simulation apparatus is started, and the first PSF measured by the eye optical characteristic measuring apparatus and the data of each element of the eyeball optical system of the eye 6 measured by the commercially available eye optical measuring apparatus, for example, the lens The shape, refractive index, refractive index distribution, and optical axis length are input to the input unit 1.

  (Step 02) Based on the data of each element of the eyeball optical system of the eye 6 to be examined, the second PSF of the eye 6 to be examined is calculated. As a calculation method, a Mie scattering analysis method, a finite element analysis method, or the like is used.

  With the above-described apparatus for measuring eye optical characteristics, it is possible to measure accurate eye optical characteristics. On the other hand, a commercially available eye optical measuring device can measure the optical data of the eyeball optical system of the eye to be examined, that is, the optical data of the cornea, the crystalline lens, and the vitreous body, but each element cannot be measured separately. Impact may be included, and some data may not be accurate. For this reason, the second PSF obtained in STEP: 02 generally does not match the first PSF.

STEP: 03, STEP: 04 At least one of the data (parameters) of each element of the second PSF is changed to calculate the changed second PSF, and the changed second PSF and the first PSF are compared. If the second PSF after the change and the first PSF do not match, further, at least one parameter is changed and the second PSF is calculated again to determine whether or not it matches the first PSF. Thus, the operation is repeated with the parameters changed until the second PSF and the first PSF match (matching is possible). The iterative calculation is performed by the calculation unit 4 executing the calculation processing program stored in the storage device 5, and functions as a first calculation unit .

  The data of each element of the eyeball optical system of the eye 6 to be examined in a state where the first PSF and the second PSF are matched can be regarded as the error corrected, and the data of each element is confirmed. To do.

  (Step 05) The treatment location and the operation method necessary for the treatment of the eye 6 to be examined are hypothesized and data of each element to be changed is determined. For example, in the case of myopia and hyperopia treatment, the refractive power is corrected. Factors that determine the refractive power include corneal shape, crystalline lens shape, vitreous transmittance, etc. When intended, the corneal shape data determined from the input unit 1 is changed.

  STEP: The third PSF is calculated from the changed data. For the calculation of the third PSF, the Mie scattering analysis method, the finite element analysis method and the like are used as in STEP: 02. The calculation of the third PSF is performed by the calculation unit 4 executing the calculation processing program stored in the storage device 5, and functions as a second calculation unit.

  (Step 07) Based on the third PSF, a simulation retina image, visual acuity-contrast data, and the like are calculated. Calculations such as a simulated retinal image and visual acuity-contrast data are performed by the calculation unit 4 executing a calculation processing program stored in the storage device 5 and function as a third calculation unit. As for the calculation of visual acuity-contrast data, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2002-209852 filed earlier by the present applicant.

  (Step 08) A simulation retina image, visual acuity-contrast data, and the like are displayed on the display unit 3. As a display example on the display unit 3, the pre-operation and post-operation are displayed in comparison. For example, FIG. 4 is a three-dimensional display of the PSF of the eye to be examined, with FIG. 4 (A) showing before surgery and FIG. 4 (B) showing after surgery. It can be seen that the PSF changes from a conical shape to a needle shape, and the focused state of the eye to be examined is concentrated at one point. FIG. 5 shows a simulation of the retina image of the eye to be examined. FIG. 5 (A) shows the pre-operation and FIG. 5 (B) shows the post-operation, and it can be seen that the image after the operation is clear. Further, FIG. 6 is data showing the relationship between visual acuity and contrast, in which the horizontal axis is visual acuity and the vertical axis is contrast. In FIG. This curve shows the contrast distribution after the operation, and it can be seen that the contrast after the operation has increased, and that the boundary of the contrast of the visual target image on the retina has become clear.

  STEP: 09 If the treatment effect can be determined based on the data displayed on the display unit 3 and the treatment effect is not sufficient, the procedure returns to STEP: 05 and the treatment effect is changed again by changing at least one of the data of each element. Confirm. If a satisfactory treatment effect is obtained, or data is obtained by repeating a plurality of times to obtain the best treatment effect, the simulation is terminated.

  By performing the above simulation, it becomes easy to determine the operation policy and the operation contents. In addition, by changing the data of each element, it is possible to predict the state of progression of the medical condition and the like, which is also effective as data for determining a treatment policy.

  In the above embodiment, the simulation image formed on the retina of the eye to be examined is calculated and displayed based on the eye optical characteristics of the eyeball optical system from the eye cornea to the retina of the eye to be examined. It is composed. However, it is considered that a person performs a kind of image processing based on an image formed on the retina by the retina-cerebral nervous system and recognizes the image processed image. As image processing by the retina-cerebral nervous system, edge enhancement processing, enhancement processing at a specific frequency, and the like are known as typical ones. Therefore, a true image that a person recognizes via the retina-cerebral nervous system is calculated and displayed on the retina simulation image by performing image processing calculation corresponding to the processing by the retina-cerebral nervous system. You can also

  In this case, in a healthy general person, substantially constant processing is performed in the retina-cerebral nervous system, and calculation display by constant image processing may be performed. However, if there is a non-healthy person who cannot perform proper processing by the retina-cerebral nervous system, the person recognizes by performing image processing calculation corresponding to the defect of the person's retina-cerebral nervous system Simulation images can also be calculated and displayed.

It is a schematic block diagram which shows embodiment of this invention. It is a schematic explanatory drawing about an eyeball. It is a flowchart which shows the effect | action of this invention. It is a solid graph of PSF, (A) shows before virtual surgery, (B) shows after virtual surgery. It is the simulation image of the target image on a retina, (A) shows before virtual surgery, (B) shows after virtual surgery. It is a graph which shows the relationship between the contrast of the contrast part of the visual target image on a retina, and visual acuity, the curve plotted with four corners shows virtual surgery before, and the curve plotted with a circle shows virtual surgery after.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input part 2 Arithmetic processing device 3 Display part 4 Operation part 5 Memory | storage device 6 Eye to be examined 7 Cornea 8 Lens 9 Vitreous body 10 Retina

Claims (1)

An ophthalmic surgery simulation method executed by an ophthalmic surgery simulation apparatus, wherein the ophthalmic surgery simulation apparatus measures a light amount distribution characteristic of a light beam formed by a reflected light beam from a fundus of the eye to be examined, and is calculated from the measured value. The first eye optical characteristic function of the eye to be examined is compared with the second eye optical characteristic function calculated from optical data of each element of the eyeball optical system measured for the eye to be examined. A first step of matching the first eye optical characteristic function and the second eye optical characteristic function while changing at least one of the optical data with respect to the function, thereby matching the eyeball optical system A second step of establishing optimal optical data for each of the elements, and at least one of the optical data established by the second step to be corrected by eye surgery Of the optical data is changed, the changed eye surgery simulation method characterized by performing a third step of calculating the eye's optical characteristics after surgery based on the optical data.