JPH02295538A - Method for determining depth of front section in operating eye and test lens device used for determining it depth of front - Google Patents

Abstract

PURPOSE:To easily and accurately determine the depth of a front section by inserting a test lens, which is equipped with optical data corresponding to the optical data of an in-eye lens to be inserted to an operating eye, to the operating eye, measuring the eye refraction force of the operating eye and calculating the depth of the front section based on the eye refraction force when the in-eye lens is inserted. CONSTITUTION:A test lens 55, which is equipped with the optical data corresponding to the optical data of the in-eye lens, is inserted to an operating eye 1 for which a crystal body 24 is removed. Then, the eye refraction force of the operating eye 1, to which the test lens 55 is inserted, is calculated. Next, based on the eye refraction force measured in a state that the test lens 55 is inserted, depth d5 of the front section is calculated when the in-eye lens is inserted. Accordingly, when the in eye lens is inserted so as to obtain this depth d5 of the front section, it is suppressed that the accuracy of the eye refraction force value is lowered based on dispersion in the depth of the front section for the operating eye 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the anterior chamber of a surgical eye for rapidly determining the anterior chamber depth of an intraocular lens (IOL) inserted during surgery when the lens nucleus has been removed. This article relates to a depth determination method and a test lens device used to determine the anterior chamber depth. (Prior Art) Conventionally, for cataract surgery on patients, there is a technique in which the cornea of the surgical eye is incised, the crystalline lens nucleus is removed, and an intraocular lens with a predetermined power is inserted into the surgical eye. Determining the power of the in-limit lens requires, for example, the following B i
There is one that uses nkhorst's formula. P=1000N (4R-L)/(L-C)(4R-
C) Here, P is the power of the intraocular lens in the anterior aqueous humor (power of the intraocular lens) necessary for emmetropia, L is the axial length (unit: mm), and R is the corneal curvature measuring means (keratometer). ), N is the refractive index of the anterior chamber and vitreous body, and C is the anterior chamber depth after surgery (anterior chamber depth). Here, the anterior chamber depth C is corrected by the axial length L, but is generally determined as a fixed value. (Problems to be Solved by the Invention) By the way, optically considered, if the insertion position of the intraocular lens in the ocular axis direction is shifted by 1 mI1, an error of about 1 diobter will occur in the refractive power value of the entire surgical eye. Therefore, even if the power of the intralens can be determined precisely, there is a problem that the accuracy of the refractive power value of the operated eye decreases due to variations in the depth of the anterior chamber. It is also possible to measure the anterior chamber depth using the conventional ultrasonic measurement method, but since the anterior position of the crystalline lens and the anterior position of the intralens do not necessarily match, it is possible to measure the anterior chamber depth using the It is difficult to suppress the decline in the accuracy of eye refractive power values. Furthermore, it is difficult to reduce the variation in the measured values themselves using the ultrasonic measurement method. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for determining the anterior chamber depth of an operated eye, which can easily and accurately determine the anterior chamber depth of an intraocular lens inserted during surgery after the lens nucleus has been removed, and the method for determining the anterior chamber depth. The objective is to provide a test lens device for use in (Means for Solving the Problems) A method for determining the depth of the anterior chamber of a surgical eye according to claim 1 of the claims of the present specification corresponds to optical data of an intraocular lens inserted into a surgical eye. an eye refractive power measurement step of inserting a test lens having optical data into the surgical eye to measure the eye refractive power of the surgical eye into which the test lens is inserted; and an eye refractive power measurement step with the test lens inserted. The present invention is characterized by comprising a calculation step of calculating the anterior chamber depth when the intraocular lens is inserted based on the refractive power. A test lens device used for anterior chamber depth determination according to claim 2 of the appended claims of the present specification holds a test lens having optical data corresponding to optical data of an intraocular lens inserted into a surgical eye. and a driving means for moving the test lens holding means so that the test lens is transported in the ocular axis direction. (Function) The method for determining the anterior chamber depth of a surgical eye according to the present invention involves inserting a test lens having optical data corresponding to the optical data of an intra-limit lens inserted into the surgical eye into the surgical eye, and inserting the test lens into the surgical eye. Measure the ocular refractive power of the surgically operated eye. Next, the anterior chamber depth when the intraocular lens is inserted is calculated based on the ocular refractive power measured with the test lens inserted. Therefore, by inserting the intraocular lens to achieve this anterior chamber depth, it is possible to suppress the decrease in the accuracy of the ocular refractive power value due to variations in the anterior chamber depth of the operated eye. Additionally, the test lens device used in this anterior chamber depth determination method is configured to be transportable in the axial direction of the surgical eye, making it easy to measure the refractive power of the surgical eye when inserting the test lens. can. The test lens is prepared according to the type of intraocular lens to be inserted. (Example) Below, a method for determining the depth of the anterior chamber according to the present invention and a test lens device used for determining the depth of the anterior chamber will be described. Conventional methods for determining the power of an intraocular lens include measuring axial length using ultrasound, measuring corneal curvature radius, and measuring ocular refractive power. Let us determine the power of the inner lens. (Configuration of intraocular lens power determining device) Fig. 1 shows the optical configuration of the power determining device according to the present invention. In Fig. 1, 1 is a surgical eye, 2 is an anterior segment illumination optical system, and 3 is an observation optical system. 4 is an optical system for measuring the eye refractive power, and 5 is an optical system for measuring the radius of corneal curvature. Anterior eye illumination optical system 2 includes an anterior eye illumination light source 6
, a condenser lens 7, and a prism with a lens 8, and an objective lens 9 forming a part of the observation optical system 3.
The anterior segment 1' of the surgical eye 1 is illuminated through the. I! The sensing optical system 3 includes an objective lens 9, a mirror 10, and a relay lens 1.
1, 12, 13, and an eyepiece 14, the operator observes the surgical eye 1 through this observation optical system 3. In Figure 1, 15 is the operator's eye. The eye refractive power measuring optical system 4 roughly consists of a projection chart illumination light source l6, a projection chart 17, a beam splitter l8, a relay lens 19, an aperture W1, a relay lens 21, a light receiving mask n, and a light receiving element 23, and the projection chart light flux is It is reflected by the prism lens 18 and projected onto the fundus 24 of the surgical eye 1 via the relay lens 19, the diaphragm 20, the relay lens 21, the mirror 10, and the objective lens 9. The reflected light from the fundus 24 is guided to the mirror 10 via the objective lens 9, is reflected by the mirror 10, and is sent to the relay lens 2l, aperture filter,
The light passes through a relay lens 19, a beam splitter 18, and a light receiving mask 22, and is guided to a light receiving cable 23. The projection chart illumination light source 16 and the projection chart 17 are movable in the direction of the arrow X+, and the light receiving mask 22 and the light receiving element 23 are movable in the direction of the arrow 25, the output of the potentiometer 25 is input to the measuring circuit 26,
The ocular refractive power of the surgical eye 1 is measured based on the output of the potentiometer 25. The corneal curvature radius measurement optical system 5 includes an illumination light source n, a mirror 28, four projection lenses, and a solid-state imaging probe 3.
0, the surgery [1 is illuminated with illumination light @ 27, and a ring-shaped virtual image is formed on the cornea 31. The corneal reflected light forming the ring-shaped virtual image is reflected by the mirror 28, and the projection lens 29 An image corresponding to the ring-shaped virtual image is formed on the solid-state bridge imaging device 30, and the output of this solid-state imaging probe 30 is input to the measurement circuit 26, and the radius of corneal curvature is measured. These measurement optical systems are built into a surgical microscope. As shown in FIG. 2, the measurement circuit 26 has a corneal curvature radius input means 32 and an eye refractive power measurement value input means 33, and also has a planned eye refractive power value input means for inputting a desired expected eye refractive power value after surgery. It has input means (A), optical data input means (A) for inputting predetermined optical data, and calculation means (36). This optical data will be discussed later. Calculation means 3B is corneal curvature radius input means! , an eye refractive power measurement value input means, a planned eye refractive power value input means, and a limited axial length calculation means for calculating the ocular axial length and recording and displaying the calculated limited axial length based on the optical data input means. It also functions as a power determining means for calculating the power of the intraocular lens based on the calculated axial length and the desired expected refractive power value after surgery. The measurement circuit 2B calculates the axial length based on the corneal curvature radius value and the measured eye refractive power, and includes an axial length calculating means 3l for displaying and recording the calculated axial length, and the calculated limited axial length. and power determination means for calculating the power of the intraocular lens of the surgical eye 1 based on the eye refractive power value desired by the surgeon. Before explaining the limited axis length calculation procedure and the intraocular lens power determination procedure based on flowcharts, the necessary optical data will be explained with reference to FIGS. 3 and 4. FIG. 3 shows a schematic diagram of the surgical eye 1 in which a contact lens 37 is worn, and FIG. 4 shows a schematic diagram of the surgical eye 1 in which an intra-limit lens 38 is set. In FIGS. 3 and 4, the radius of curvature of the front surface of the contact lens 37 is rl,
The radius of curvature of the posterior surface r2, its thickness is d+, its refractive index is n2, the thickness of the tear fluid 39 is d2, its refractive index is ns, the radius of corneal curvature of the anterior surface of the cornea 31 is r3, the curvature of the posterior surface of the cornea Its radius is r4, its thickness is d3, its refractive index is n4,
The thickness of the anterior chamber 40 is d, its refractive index is n6, the radius of curvature of the front surface of the intraocular lens 38 is r6, the radius of curvature of the rear surface is r6,
Its thickness is n●, the thickness of the vitreous body 4l is d7, and its refractive index is n? Suppose that Note that n+ is the refractive index in air. Corneal curvature radius r3 is determined by measurement, and the value of r3 is generally 6. 9mm ~8. It is 5mm. Also, the radius of corneal curvature r4 was calculated based on 6. 8
Assume 1111. The radius of curvature X'I. of the contact lens 37 t*, its thickness d1, the thickness d8 of the intraocular lens 38, the refractive index n2 of the contact and lens 37, and the refractive index n of the intraocular lens 38 are determined by the specifications, r+: rt: r snow, d+=0.2, da=1.
0, n a= n *=1. 491. Furthermore, the thickness d2 of the tear fluid 39, the thickness d of the cornea 3l, the distance ds between the surfaces from the back surface of the cornea 31 to the front surface of the crystalline lens nucleus (intraocular lens 38), and the refraction of air 1! nI, the refractive index n3 of the tear fluid 39, the refractive index n4 of the cornea 31, and the refractive index ns of the anterior chamber 40 are determined as follows with reference to literature and the like. dt=0.1, ds=0.5, ds=3. [l,
nI=1.0, n*=ns==1 336, n a
= 1. 376, nt=ns, r●=■. These optical data are input using an optical data input means. The radius of curvature rs of the anterior surface of the intraocular lens 38, the inter-plane distance dy from the posterior surface of the intraocular lens 38 to the image point 0', the cornea 31
Calculating means 36 calculates the inter-plane distance d4 from the rear surface to the image point 0'.
Calculate by. These calculations are performed by paraxial calculations, and as shown in Fig. 5, we generally consider the tracing of paraxial rays in an optical system consisting of a spherical series of k refractive surfaces. In this Figure 5, S is from object point 0 to object point 0. The optical axis distance to the 1st surface, S' is the optical axis distance from the k-th surface to the great point 0', and dy- is the inter-plane distance between the V-th refractive surface and the v+1-th refractive surface (the thickness of the lens between the refractive surface and the y+1th refractive surface), Ny-=Ny. t is the Vth refractive surface and y+1
The refractive index between the Vth refractive surface and the Vth refractive surface, hy is the height from the optical axis at the Vth refractive surface, and Ut is the refractive index of the ray that exits from object point 0 and enters the first object at height h+. The inclination angle with respect to the optical axis, U**+ is the inclination angle with respect to the optical axis of the light ray that is emitted from the location of the height hk of the k-th surface and enters the image point 0', Lly
゛、υV. I is the inclination angle of the light beam incident on the y+1th refractive surface with respect to the optical axis, and ry is the radius of curvature of the Vth refractive surface. Then, the following formula generally holds. Ny” ・IJv − =Ny+Uy+ ((Ny
−My − ) ・hV ) / r v My = Nv. + Ijy. +=Lly hy. +=hy-dy −IJv NV*+ H uV*I=Nv-Uv + ((My
．． +-Ny) ・hy} / r v hy*+=hy-dv "UV*+ However, 8 = h H / tl+ = 1 / LI+h
I can be any value, but here, b +
= 1. S = = hh/Um-+ When S is expressed in diopters, it becomes 3 - - 1000/D t. Here, the desired expected eye refractive power after D1 surgery {direct. Here, when tracing a ray from object point 0, it is done by determining the optical axis distance S from image point 0 to the first surface, and when tracing a ray from image point O', from object point 0' to the kth surface. Nine-axis distance S to
′ is determined. In addition, in this Fig. 5, the object point O
The surface closest to 0' is set as the first surface, but it is also possible to perform ray tracing using the surface closest to the great point 0' as the first surface. Below, a method for determining the power of the intraocular lens 38 will be explained with reference to the drawings. <<Steps for calculating axial length of the eye] First, as shown in FIG. 6, the corneal curvature radius rs is determined and recorded before the incision at surgery +111 using the corneal curvature radius measuring optical system 5 as a corneal curvature radius measuring means (31 ),
Then, the surgical eye 1 is incised and the lens nucleus 24' is removed (S2), and a contact lens 37 is worn in the aphakic surgery III1 in which the lens nucleus 24' has been removed (33). The eye refractive power of the surgical patient II1 in which the lens nucleus 24' has been removed and the contact lens 37 is worn is measured by the aS refractive power measuring optical system 4 as the eye refractive power measuring means (34), whereby the lens nucleus 24' is Contact lens 3 for the refractive power of the removed surgery @1
The eye refractive power that takes into account the eye refractive power of 7 is calculated. Next, the axial distance IIS● between the object plane O conjugate to the fundus 24 and the vertex P of the contact lens 37 is calculated based on the eye refractive power value (35). Based on the above-mentioned paraxial calculation formula, the position of the image point 0' with respect to the object plane O is calculated (36). Then, the calculation means 36 calculates the inter-plane distance d4 from the position of the image point 0゛ to the posterior surface of the cornea 3l (8
7). Calculate ds+d4 and use this value as the axial length L (38). (Procedure for determining power of intraocular lens II) Determine the desired expected ocular refractive power value D+ after inserting the intraocular lens 38 into surgery II11 (81). Next, based on the inter-plane distance II d a obtained in step 87 of the axial length measurement procedure, the inter-plane distance M d t from the rear surface of the intraocular lens 38 to the image point 0' is calculated.
(32), and the distance between the image plane oI conjugate to the fundus 24 and the vertex position of the cornea 31 in surgery @1 is calculated using the following formula S L = (-1000) / D Obtained by I (
S 3 )II Next, the power of the intraocular lens 38 is temporarily set as P'. Then, the interplane distance #IS I- from the surgical eye 1 to the image point is determined using the above-mentioned paraxial calculation formula. The interplane distance S+- is expressed in a geobutter as DI=(-1000)/SL-(S
4), and in S5, l D+ D+
" l < 0. Determine whether or not 1. If NO in S5, the calculation means 36 performs the processing of P"=1"+0.1 to newly obtain D+-. This newly obtained Dt- Let Dz'' be (se), and in % S7, ID+D*'l<O. Determine whether or not. If the answer is no in S7, the process moves to S8 and the ID
+−Dt− I > I D+ Da” It is determined whether or not I. If YES in S8, the process moves to S6, and the process of P”=P′+0.1 is performed again, and D1 is newly '' is determined. Let this newly determined D+- be D2'. By repeating the processing from 86 to S8, 0.1
The power of the intraocular lens is updated every 3 days. In case of no in S8, P-=f"-0.1,
Find D ゛ (S 9 ), and proceed to 310 to find l DI− D t − l <0.
1 Kawo judgment. If no in 310,
Moving to s9, P-=P--Q. 1, calculate D,- again, and repeat this process. If YES in S10, the intra-limit lens 38 that realizes the desired eye refractive power DI is selected.
The power of p=p- and the process ends (Sll),
In S5 and S7, when the answer is YES, the desired eye refractive power D
The power of the intraocular lens 38 that realizes I is p=p-, and the process ends (Sll). Therefore, by repeating this process, the power P of the intraocular lens 38 is reduced to 0.1.
It can be determined with an accuracy of According to this embodiment, if the contact lens 37 worn on the surgical eye 1 has positive power, the power of the surgery lII1 after removal of the crystalline lens nucleus 24' is negative, so the contact lens 37 is worn on the surgical eye 1.
If you measure the eye refractive power value while wearing the 7, it will be convenient as it will be close to zero dioptre. Note that in the paraxial calculation in this power determination procedure, the radius of curvature r6 of the intraocular lens 38 is input as a variable instead of inputting the power of the intraocular lens 3B. If paraxial calculation is performed by changing this radius of curvature rs, the variation in power P ΔP = 0.0
1, the variation Δl'i of the radius of curvature rs is Δrs=0.
Corresponds to 005. Here, the intra-limit lens 38 having the power obtained through these steps will be inserted in surgery III. The eighth lens is used to determine the insertion position of this intralens 3B.
The anterior chamber depth is measured using the test lens device shown in Fig. 9. 81g is a diagram showing a first embodiment of the test lens device used in the anterior chamber depth determination method according to the present invention, and in this FIG. The cylinder 50 is provided with a movable cylinder 51. A threaded portion 52 is provided at the bottom of the movable barrel 51, and this threaded portion 52 is screwed into the inner peripheral portion of a rotary barrel 53 rotatably attached to the fixed barrel 50. Moving cylinder 51
A sprink wire 54 is attached to the tip of the
A test lens 55 shown in FIG. 10 is attached to the tip of this spring ear 54. Here, the movable cylinder 5l and the spring wire 54 function as a holding means for holding the test lens 55. A bottle 56 is installed around the movable cylinder 51.
6 protrudes to the outside of the fixed cylinder 50 through a slit 57 formed in the direction of the arm of the fixed cylinder 50. The movable tube 51 is reciprocated in the vertical direction when the rotary tube 53 is rotated, and the wire spring 54 is reciprocated in the direction of the arrow as the movable tube 5l reciprocates, and the test lens is used when determining the anterior chamber depth, which will be described later. 55 is adjusted in the direction of the limit axis. Here, the rotating barrel 53 functions as a driving means for driving the test lens holding means. The bin 56 has a function of displaying the position of the test lens 55 from the reference position, and the fixed 117
An indicator scale is formed on the outer periphery of the slit 50 along the direction in which the slit 57 extends. In addition, 53' is the rotation fI4
This is the knob part formed in 53. FIG. 9 is a diagram showing a second embodiment of the test lens device, and in this FIG. An injection tube 62 extending laterally is provided at the lower end of the cylinder 6l, and a balloon 6 constituting the test lens holding means and the test lens is provided at the upper end of the hollow cylinder 6l.
3 are provided. This balloon 63 has an injection tube 62
A syringe 64' is inserted into the injection tube 62, and the silicone fluid 64 is injected. When the balloon 63 is filled with silicone fluid 64, it expands as shown in FIG. 11 to form a test lens 55. These test lenses 55 are inserted into the surgical eye 1 from which the crystalline lens nucleus 24' has been removed to determine the anterior chamber depth, as shown in FIG. Prepare various items corresponding to the optical data. (Procedure for Determining Anterior Chamber Depth) First, as shown in FIG. , measure the ocular refractive power D● of the operated eye 1. The reason why the eye refractive power D- is measured by wearing a contact lens is because astigmatism and distortion occur after the corneal incision, even if the incision site has healed. For this measurement, the eye refractive power measurement optical system 4 is used here. Then, according to the flow chart shown in FIG. 14, eye refractive power D●, eye axial length L =
d. + d. , rIA+r●, d+~d4, n1~n? is input to the calculation means 36 (S
1). Here, r6, rs, d@% ns are optical data of the test lens 55, and here, for the axial length L and the corneal curvature radius r3, the measured values obtained in the axial length measurement procedure are used. Next, the calculation means 36 calculates S●=-1000/
Calculate D m (32). Then, if the anterior chamber depth is set as ds● and the anterior chamber depth of the air is ds, then ds=d
% own (83). Then, calculate the value of dt using the following formula (34). dt=L-(dne+ds+ds)
．． Then, a paraxial calculation subroutine process is performed to find a position RS1 that is conjugate with the fundus 24 when the intraocular lens 38 is inserted (S5). Next, at s6, the absolute value of the difference between S1 and S● is l S+−Sat <0. Determine whether it is 05 or not. If no in S6, move to s7,
Determine whether S L-3 g > O. If YES in S7, move to S8 and d s” d &
-0. 01(7) Perform the calculation process and repeat the processes from 84 to s8. As a result, the value of the tentative anterior chamber depth d6- is added by 0.01 and approaches the true anterior chamber depth d%. If the answer is NO in S7, the process moves to S9, where d also processes ds+0.01, and 84 to S7
, repeats the process of S9. As a result, the value of the provisional previous month depth ds- is subtracted by 0.01 to obtain the true anterior chamber depth d6.
This will bring us closer to . And the position yI that is conjugate to the fundus 24
The difference between SI and S● is 0. If it is within 05, it is determined yes in S6, and the process moves to 310 to determine the anterior chamber depth d.
s is printed out, thus the true anterior chamber depth is 0. Determined with an accuracy of 0.1mm. (5! Effect of light) According to the method for determining anterior chamber depth of a surgical eye according to the present invention, the anterior chamber depth of an intraocular lens inserted into a surgical eye from which the lens nucleus has been removed can be easily and accurately determined. Therefore, it can be expected that the results of cataract surgery will improve. According to the test lens device used in the anterior chamber depth determination method according to the present invention, it is possible to easily adjust the position of the test lens in the axial direction when measuring the anterior chamber depth.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of the optical system of the intraocular lens power determining device according to the present invention, FIG. 2 is a block diagram showing the detailed configuration of the measurement circuit shown in FIG. 1, and FIG. 3 is a contact lens diagram. Fig. 4 is a schematic diagram of the surgical eye 1 with an intraocular lens installed. Fig. 5 is an explanatory diagram used to explain paraxial calculations. Fig. 6 shows the axial length of the eye. FIG. 7 is a flowchart of the measurement procedure, and FIG. 7 is a flowchart of the power determination procedure. FIG. 8 is a diagram showing a first embodiment of a test lens device used in the method for determining anterior chamber depth according to the present invention, and FIG. 9 is a diagram showing a second embodiment of the test lens device used in the method for determining anterior chamber depth according to the present invention. Figure 10 is a front view of the test lens shown in Figure 8, Figure 11 is a front view of the test lens shown in Figure 9, and Figure 12 is a state in which the test lens is inserted into the surgical eye. FIG. 13 is a schematic diagram of a surgical eye wearing a contact lens and a test lens; FIG. 14 is a flowchart showing the anterior chamber depth determination procedure according to the present invention;

Claims (2)

[Claims] (1) Ocular refraction in which a test lens having optical data corresponding to the optical data of an intraocular lens inserted into the surgical eye is inserted into the surgical eye and the ocular refractive power of the surgical eye into which the test lens is inserted is measured. A surgical eye characterized by comprising: a force measurement step; and a calculation step of calculating the anterior chamber depth when the intraocular lens is inserted based on the eye refractive power measured with the test lens inserted. Method for determining anterior chamber depth. (2) a test lens holding means for holding a test lens having optical data corresponding to the optical data of an intraocular lens to be inserted into the surgical eye; and a test lens holding means for transporting the test lens in the ocular axis direction. A test lens device used for determining the depth of the anterior chamber, comprising a driving means for driving the lens as shown in FIG.