JP2002345755A - Corneal shape analyzing method and corneal shape analyzing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corneal shape analyzing method and corneal shape analyzing device capable of precisely determining a corneal shape and corneal removing quantity necessary for obtaining a desired visual acuity. SOLUTION: The refractive power and corneal front shape of a patient before operation are inputted as information for the patient's eye, model eye information is read from a storage medium for storing the model eye information, and the patient's eye is optically modeled on the basis of the read model eye information and inputted patient eye information. The corneal front shape is successively changed in the modeled patient's eye, and the corneal rear shape corresponding to the changed corneal front shape is calculated. It is judged whether the refractive power desired by the patient can be obtained with the changed corneal front shape and the corresponding corneal rear shape or not, and the corneal front shape capable of providing the refractive force desired by the patient is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corneal refractive surgery using a laser, and more particularly to a corneal shape analyzing method for calculating a corneal shape capable of obtaining a desired refractive power of a patient, and a corneal shape analysis. Related to the device.

[0002]

2. Description of the Related Art Glasses and contact lenses have conventionally been used as means for correcting visual acuity. However, both glasses and contact lenses may become unusable due to scratches, breakage, loss, etc., and until new glasses or contact lenses are obtained,
The patient will feel inconvenient. In addition, adhesion of dirt cannot be avoided, and periodic cleaning is required.
Furthermore, many contact lenses require maintenance using dedicated chemicals and the like.

As described above, correction of visual acuity by eyeglasses and contact lenses has many troublesome aspects, and in recent years, corneal refractive surgery using a laser has attracted attention.

There are several types of corneal refractive surgery using a laser. From the viewpoints of safety, a wide range of correction, and stability of visual acuity (refractive power) after the operation, a method called LASIK is used. It has become mainstream.

[0005] Corrective surgery using LASIK is performed in the following procedure.

[0006] First, the surface layer of the cornea is
Sharpen it to a thickness and turn it over. The exposed stromal layer of the cornea is irradiated with a laser to remove a part of the stromal layer.
Return the surface layer that was last turned up.

[0007] As described above, LASIK corrects the refractive power by removing a part of the cornea by laser irradiation and changing the shape of the cornea. Therefore, it is necessary to accurately predict what kind of corneal shape can obtain a desired refractive power and what kind of removal operation can be performed to obtain a desired corneal shape.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a corneal shape analyzing method and a corneal shape analyzing apparatus capable of accurately determining a corneal shape necessary for obtaining a desired visual acuity.

Further, the present invention provides a corneal shape analyzing method and a corneal shape analyzing apparatus capable of accurately obtaining a corneal removal amount for obtaining a required corneal shape.

[0010]

A corneal shape analysis method according to the present invention comprises the steps of: inputting a refractive power of a patient before surgery and a frontal shape of a patient's cornea before surgery as information of a patient's eye;
Reading the model eye information from the storage medium in which the model eye information is stored; optically modeling the patient's eye from the read model eye information and the input patient's eye information; and In the eye, the anterior corneal shape is sequentially changed, and the posterior corneal shape corresponding to the changed anterior corneal shape is calculated, and the patient's desired refraction is calculated based on the changed anterior corneal shape and the corresponding posterior corneal shape. Determining whether or not a force can be obtained, and calculating a shape of the anterior cornea that can obtain a desired refractive power of the patient.

In addition, the amount of corneal ablation when performing a corneal ablation operation is calculated from the calculated anterior corneal shape and the anterior corneal shape of the patient before the operation.

Further, it is characterized in that it is determined from the calculated corneal ablation amount whether or not the eyeball can be held at the corneal thickness after the operation.

Further, information on the patient's eye further includes posterior corneal shape, anterior lens shape, posterior lens shape, retinal shape, corneal thickness, anterior chamber depth, lens thickness, vitreous thickness, ocular axial length, corneal length. Input at least one of the refractive index of the aqueous humor, the refractive index of the aqueous humor, the refractive index of the lens, and the refractive index of the vitreous body, and perform modeling of the patient's eye using the input information of the patient's eye. Features.

Further, at least one of intraocular pressure, corneal elasticity, corneal strength, lens strength, and age is input as patient information, and the amount of corneal deformation after corneal removal surgery is calculated from the input patient information. It is characterized in that it is determined whether or not a desired refractive power of a patient can be obtained by using the anterior corneal shape considering the deformation amount and the corresponding posterior corneal shape.

Further, the determination as to whether or not a desired refractive power of the patient can be obtained is performed by paraxial ray tracing, optical calculation of a focal position using a commercially available software package, original calculation software, or the like. And

According to the present invention, there is provided a corneal shape analyzing apparatus comprising: input means for inputting information on a patient's eye; storage means for storing information on a model eye; and a patient's eye input by the input means. And a calculating means for calculating the focal position using the information on the eye model and the information on the model eye read from the storage means, and a display means for displaying the calculation result by the calculating means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When viewed from the viewpoint of vision, as shown in FIG. 1, a human eyeball is composed of a cornea 40, an aqueous humor 50, a crystalline lens 60, a vitreous body 70, a retina 90, and the like. It can be considered an optical system. Where an image is focused in such an optical system is determined by parameters such as the thickness, shape, refractive index, and position of each element constituting the optical system, that is, the eyeball.

In the unadjusted state, that is, in a state in which the lens does not adjust the thickness (and, at the same time, the curvature of the front and rear surfaces), parallel light from a distance forms an image on the retina 90 as emmetropia.

On the other hand, in the unadjusted state, myopia is a refraction state in which parallel rays from a distance form an image in front of the retina. Myopia includes axial myopia caused by a long distance to the retina, and refractive myopia caused by too strong refractive power in the cornea and lens.

In the unadjusted state, hyperopia is a refraction state in which the image position of a parallel ray from a distance is located behind the retina. Hyperopia also includes axial hyperopia caused by a short distance to the retina, and refractive hyperopia caused by weak refractive power in the cornea and lens.

Furthermore, astigmatism is a state in which the refracting surfaces of the optical system, that is, the front and rear surfaces of the cornea and the front and rear surfaces of the crystalline lens are not correctly spherical, and parallel rays do not form an image at one point. Astigmatism includes regular astigmatism caused by the curvature of the refraction surface depending on the direction and a shape like a rugby ball, and irregular astigmatism caused by the refraction surface being not smooth but having irregularities.

As described above, lenses such as eyeglasses and contact lenses are sometimes used to correct myopia, hyperopia, or astigmatism. The lens is shown at 20 in the optical system of FIG. The thickness and shape of the lens, the refractive index and the position are also parameters that affect the position of the focal point. Therefore, by appropriately selecting the shape, material, arrangement position, and the like of the lens 20, the position of the focal point can be adjusted to correct myopia, hyperopia, or astigmatism.

Table 1 summarizes parameters affecting the position of the focal point in the optical system shown in FIG. By applying each of these parameters to various calculation formulas and commercially available software, the position of the focal point can be calculated, and it can be determined whether or not the subject is emmetropic.

[0024]

[Table 1]

An example of the calculation formula is the following paraxial ray tracing (formulas 1 to 3). A _{j + 1} = A _j + ｛(n _{j + 1} −n _j ) / R _j ｝ × H _j (Equation 1) H _{j + 1} = H _j − (T _j / n _{j + 1} ) × A _{j + 1} (Equation 2) S = (H _j−1 × n _1.000 ) / A _j (Equation 3) where n is the refractive index, j is the total number of curved surfaces, R is the curvature of each curved surface, and T is the thickness of each curved surface. , S are focal positions. In paraxial ray tracing, A ₁ = 0 and H ₁ = 1, and j = 1 to j
= M, calculation of (Equation 1) and (Equation 2) is performed sequentially,
The focal position S can be obtained by substituting the result into (Equation 3).

Commercially available software includes OSLO SIX of SinclairOptics, Inc. and ZEMAX of Focus Software, Inc.
X). It is also possible to develop original calculation formulas and calculation software based on clinical experience.

Incidentally, many of the parameters in Table 1 are difficult to measure. Therefore, several types of model eyes have been proposed as a model of a standard human eyeball. As an example, Table 2 shows the values of each parameter for a model eye of Gullstrand and a model eye of LeGrand.

[0028]

[Table 2]

Embodiment 1 Next, a corneal shape analyzing apparatus and a corneal shape analyzing method according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic diagram showing a configuration of a corneal shape analyzing apparatus according to the present invention, and FIG. 3 is a flowchart showing a corneal shape analyzing method according to the present invention.

As shown in FIG. 2, the corneal shape analyzing apparatus 10 according to the present invention comprises an arithmetic unit 1, an input unit 2, and a storage unit 3.
And display means 4. The input means 2 is used for inputting information about the patient's eye. The storage unit 3 stores model eye information. Calculation means 1
Performs optical calculation such as calculation of a focal position by the above-described paraxial ray tracing, using the information on the patient's eye input by the input means 2 and the information on the model eye read out from the storage means 3. . Of course, the optical calculation may be performed by the above-mentioned commercially available software or original calculation software. The display means 4 is used for displaying the result of calculation by the calculation means 1.

Such a corneal shape analyzer can be realized by installing a program for performing paraxial ray tracing or the above-mentioned commercially available software on a general-purpose computer. It can also be realized by developing original calculation software based on clinical experience and installing it on a computer.

It is not always necessary to provide all of the arithmetic means 1, input means 2, storage means 3 and display means 4 in one computer. The corneal shape analyzer 10 may be configured as a system in which a plurality of computers and information terminals connected by a network function as the arithmetic unit 1, the input unit 2, the storage unit 3, and the display unit 4, respectively. For example, a computer or information terminal at a remote location is used as input means 2 to input information about the patient's eyes, and another computer managed by a responsible institution performs calculations as arithmetic means 1 and a computer at a remote location Alternatively, an information terminal may display the calculation result as the display unit 4.

With such a configuration, the calculation means 1, ie, the calculation formula and the software for calculation can be centrally managed by the responsible organization, and the corneal shape is always analyzed using the latest and accurate calculation method. It becomes possible. In addition, even when the amount of calculation is increased by using a complicated calculation method, it is possible to cope with the problem only by increasing the capacity of the computer that performs the calculation as the calculation means 1.

Next, the corneal shape analysis method according to the present invention will be described with reference to the flowchart of FIG.

First, the shape R ₃ and the refractive power of the anterior cornea are input as information on the eye of the patient before the operation (step S).
101). The refractive power can be obtained as the refractive power of the lens necessary for emmetropizing the patient.

Input is performed using input means 2 such as a keyboard or a mouse. In addition, various measuring devices 2a
May be configured to be directly input to the arithmetic unit 1 by the measurement result. Alternatively, the information of the eye of the patient before surgery is recorded in some recording means, and the shape R ₃ and the refractive power of the front surface of the cornea are read out from this recording means and input to the arithmetic means 1. Good.

Next, model eye information is read (step S102). From the information of the model eye stored in the storage means 3, the shape R _{4 of the} posterior cornea, the shape R ₅ of the anterior lens, the shape R _{6 of the} posterior lens, and the radius of curvature R _{7 of the} retina are read out and input to the arithmetic means 1. Is done. Similarly, corneal thickness T ₃ , anterior chamber depth T ₄ , lens thickness T ₅ , refractive index of air n ₃ , refractive index of cornea n ₄ , refractive index of aqueous humor n ₅ , refractive index of lens n ₆ and The refractive index n ₇ of the vitreous is read from the storage means 3 and input to the arithmetic means 1. Here, the vitreous thickness T ₆ and the axial length T ₇ are not read out but are set as unknowns.

As for the shape R ₄ of the posterior corneal surface, the information of the model eye is not read as it is, but the ratio (R ₃₎ of the shape R _{4 of the} posterior corneal surface and the shape R ₃ of the anterior corneal surface of the model eye is used instead.
₄ / R ₃ ) may be multiplied by the shape R ₃ of the anterior corneal surface of the patient input in step S101 and used as the shape R ₄ of the posterior corneal surface.

The calculating means 1 calculates the model eye information (that is, R ₄ , R ₅ , R ₆ , R ₇ , T ₃ , T ₄ , T ₅ , n ₃ ,
n ₄ , n ₅ , n ₆ , n ₇ ) and the patient's anterior corneal shape R ₃ input in step S 101, first, the position of the focal point is calculated. Next, the refractive power of the eye of the patient and focus position obtained, input at step S101 (i.e., power required for emmetropization) from estimated axial length T ₇ and vitreous thickness T ₆ of the patient I do.

As described above, the patient's eye before the operation is obtained by converting the anterior corneal shape R ₃ input in step S101 and the model eye information read from the storage means 3 (ie, R ₄ , R ₅ , R ₆ ,
R ₇ , T ₃ , T ₄ , T ₅ , n ₃ , n ₄ , n ₅ , n ₆ , n ₇ ) and the estimated vitreous body thickness T ₆ (step S 103). ).

In the modeled patient's eye, first, the shape R ₃ of the anterior corneal surface after the operation is temporarily determined (step S104). This tentative determination may be performed automatically by the arithmetic means 1, or the physician may predict and input a corneal shape which is considered preferable.

As described above, laser ablation surgery is performed on the anterior corneal surface. However, by the anterior corneal surface shape R ₃ varies with surgery, changes occur in the shape R ₄ of the cornea posterior surface. Therefore, step S
When provisionally determining the anterior corneal surface shape R ₃ at 104, may be configured to provisionally determine together the shape R ₄ of the cornea posterior surface corresponding to the anterior corneal surface shape R _3. As a method of provisionally determining the shape R ₄ of the cornea posterior surface simply is a constant ratio between the anterior corneal surface shape R _3, i.e. the shape R ₄ and corneal anterior surface of the cornea posterior surface of the pre-operative even after surgery shape R Ratio to ₃ (R ₄ / R ₃ )
There is a way to be kept.

Next, the calculating means 1 calculates the position of the focal point on the basis of the provisionally determined anterior corneal shape R ₃ and the corresponding posterior corneal shape R ₄ (step S 105). When the obtained focal position is on the retina 90, the shape R _{3 of the} front surface of the cornea temporarily determined in step S104
And the shape R ₄ of the corresponding posterior surface of the cornea, so that the refractive power desired is obtained (step S106).

If the desired refractive power is not obtained, the process returns to step S104, where the shape R ₃ of the anterior corneal surface and the shape R _{4 of the} posterior corneal surface after the operation are temporarily determined again, and the focal position is calculated. It is determined whether or not a desired refractive power can be obtained.

If the desired refractive power is obtained,
Proceeding to step S107, the corneal removal amount is calculated. Calculation means 1 calculates the cornea removal amount as a difference between the anterior corneal surface shape R ₃ after provisionally determined surgery in the anterior corneal surface shape R ₃ steps S104 preoperative input at step S101.

Next, in step S108, it is determined whether or not surgery is possible. If the cornea becomes too thin due to surgery, it is dangerous to be unable to withstand the pressure inside the eyeball (intraocular pressure). Therefore, if the thickness of the cornea after the operation is smaller than a predetermined value, the calculating means 1 determines that the operation is impossible. If the amount of corneal removal calculated in step S107 is not feasible in view of the capability of the surgical facility, it is determined that surgery is not possible. If it is determined that surgery is not possible, the process returns to step S104,
Again, the anterior corneal shape R ₃ and the posterior corneal shape R ₄ after the operation
Is provisionally determined.

If the operation is possible, step S1
The corneal removal calculated in step 07 is displayed on the display 4 (step S109). The doctor may perform an operation based on this display. Further, the calculated corneal removal amount may be transmitted to the surgical facility 5, and the surgical facility 5 may automatically perform the operation based on the received corneal removal amount, or may assist the doctor in performing the operation.

In the above-described embodiment, first, in step S103, the vitreous thickness T _{6 is set} to an unknown value (the corneal thickness T ₃ , anterior chamber depth T _4, and lens thickness T ₅ are read from the model eye information). Therefore, it can be said that the axial length T ₇ is an unknown value: see FIG. 1), and the focal position is calculated using the measured parameters R _{3 of} the anterior corneal shape and the parameters of the model eye.
Obtained focus position and patient's visual acuity (refractive power required for emmetropization)
The eye model of the patient before surgery was modeled by estimating the vitreous thickness T ₆ from (ie, parameters other than the anterior corneal shape R ₃ , vitreous thickness T _6, and axial length T ₇ ,
Model eye parameters were used).

[0049] However, using the parameters of the model eye as vitreous thickness T ₆ (axial length T _7), the shape of one, for example, the lens front surface shape R ₅ and retrolental surface of the other parameters instead such as R ₆ may be subjected to modeling as unknowns. Further, since the actual measurement of the axial length is relatively easy, using the axial length T ₇ were measured, one may perform modeling the as unknowns of the other parameters instead.

When it is possible to actually measure parameters other than the anterior corneal shape R ₃ , it is possible to use a measured value instead of the parameter of the model eye to make a more accurate model, and to obtain a more accurate corneal shape. Needless to say, it becomes possible to perform the analysis.

By the way, the axial length T₇If you actually measure
Is the corneal thickness T of the model eye_Three, Anterior chamber depth T _Four, Lens thickness T
_FiveAnd vitreous thickness T₆Contradictions can naturally occur
You. In this case, the corneal thickness T_Three, Anterior chamber depth T_FourAnd water
Crystal thickness T_FiveUsing the information of the model eye, the vitreous thickness T
₆Is the measured axial length T₇And the T of these model eyes_Three, T_FourAnd
And T _FiveAnd the difference may be determined. Or T_Three,
T_Four, T_FiveAnd T₆Was measured assuming that the ratio of
T₇T consistent with_Three, T_Four, T_FiveAnd T₆May be determined
No.

In the present embodiment, it is assumed that a desired refractive power is obtained when the focal position is on the retina, that is, when the subject is in a state of normal vision. However, for example, in the case of a patient who often looks closely, it is more convenient to leave a little myopia to reduce eye fatigue. Further, for the same reason, it is not preferable that hyperopia is obtained after the operation. Therefore, it is better to set the state where weak myopia remains as the desired refractive power in consideration of the analysis accuracy and the dispersion of the treatment.

In such a case, a desired visual acuity (refractive power) of the patient is input in advance as to how much myopia is to be left, and the focal position comes at a position corresponding to the visual acuity (refractive power). The state may be a state where a desired refractive power is obtained in step S106.
Alternatively, assuming a lens corresponding to the desired visual acuity (refractive power) of the patient, this lens (that is, R ₁ , R ₂ , T ₁ ,
The state where the focal position comes on the retina after including T ₂ , n ₂ ) may be the state where the desired refractive power is obtained in step S106.

Even if the corneal ablation amount is calculated according to the procedure shown in FIG. 3 and the corneal ablation operation is performed, the refractive power after the operation is completely changed to the desired refractive power due to the dispersion of the operation and the progress after the operation. May not match.

Therefore, for each patient, step S10
Anterior corneal surface shape R ₃ and power input 1, may be as storing the refractive power of the cornea ablation amount and postoperative surgical. If there are other measured parameters, they may be stored. By using the stored information to modify the calculation formula or calculation software, more accurate corneal shape analysis can be performed. Further, the model eye information stored in the storage means 3 may be modified using the stored information.

By storing these information for a large number of patients, even for patients who can obtain only a minimum of measured data, the results of analysis of past patients having similar measured data can be used. Accurate corneal shape analysis becomes possible.

Embodiment 2 In Embodiment 1, when the anterior corneal shape R ₃ and the posterior corneal shape R ₄ are provisionally determined in step S104, the posterior corneal shape R ₄ and the anterior corneal shape R _{3 are determined.} And the ratio (R ₄ /
R ₃ ) is constant, that is, the ratio before surgery (R ₄ ) even after surgery
/ R ₃ ). This method is simple and has sufficient accuracy for practical use. However, in the future, it will be possible to measure each parameter in Table 1 more easily and precisely, and if more accurate surgery is possible, , More accuracy may be required.

In the first embodiment, step S
At 107, the anterior corneal shape R before the operation _ThreeAnd desired refractive power
Anterior corneal shape R that can obtain_ThreeAnd the difference
The film removal amount was calculated. For this reason, removal surgery
The corneal rigidity changes, and the intraocular pressure causes the cornea to deform.
Is not taken into account, and after removal surgery
Anterior corneal shape R of_ThreeCan obtain the desired refractive power
Anterior corneal shape R_ThreeHad not become.

Therefore, in the present embodiment, the shape R ₃ of the anterior cornea after surgery and the shape R _{4 of the} posterior cornea are predicted more accurately, and the amount of corneal removal required to obtain a desired visual acuity is more accurately determined. The purpose is to seek.

In the present embodiment, the cornea of the patient, preferably the entire eyeball, is regarded as a structure, and when the front surface of the cornea is removed by surgery, what kind of deformation occurs in the cornea or the entire eyeball is predicted and calculated. . Such a prediction calculation of the deformation amount can be realized by executing a method such as the finite element method (FEM) by the arithmetic means 1.

Calculation of the amount of deformation requires at least the size and elasticity of the patient's cornea and the patient's intraocular pressure.
Further, for accurate calculation, it is desirable that the dimensions and the elastic modulus of each element other than the cornea constituting the eyeball are available. Therefore, for the average cornea or eyeball, the dimensions, elastic modulus and intraocular pressure of each element,
It is stored in the storage means 2. The calculating means 1 performs step S
From the shape of the anterior cornea tentatively determined in 104 and the dimensions, elastic modulus, and intraocular pressure stored in the storage means 3, the corneal shape after the operation taking into account the deformation is predicted and calculated.

If the patient's intraocular pressure, corneal elastic modulus, corneal strength, lens strength, etc. can be measured, these measurement results are input from the input means 2 and stored in the storage means 3. By using these in place of the dimensions, elastic modulus, and intraocular pressure, it is possible to more accurately calculate the amount of deformation.

The corneal elasticity, intraocular pressure, corneal strength, lens strength, and the like tend to change in proportion to the age of the patient. Therefore, the dimensions, elastic modulus, and intraocular pressure of each element constituting the eyeball are stored in the storage means 3 for each age,
The prediction calculation may be performed using the input dimensions, elastic modulus, and intraocular pressure corresponding to the age of the patient.

Using the anterior shape R ₃ and the posterior shape R ₄ of the cornea obtained in consideration of the deformation obtained by the prediction calculation, in step S 105, the calculating means 1 calculates the position of the focal point. When the obtained focus position is on the retina, that is, when matching the axial length T ₇ estimated, so that the power desired to obtain.

If the desired refractive power is not obtained, the procedure returns to step S104 to temporarily determine the shape of the anterior corneal surface, calculate the amount of deformation, and calculate the focal position (step S104). S105).

[0066]

According to the present invention, the corneal shape required to obtain a desired visual acuity can be accurately obtained, and the problem that a desired visual acuity cannot be obtained after the operation can be prevented.

Further, since it is determined whether or not a sufficient corneal thickness remains after the operation to judge whether or not the operation is possible, the risk of erroneously performing an operation with an excessively large amount of corneal reduction is reduced.

Furthermore, since the amount of corneal removal at the time of surgery is determined in consideration of the corneal deformation due to surgery, it is possible to more accurately predict postoperative sight.

[Brief description of the drawings]

FIG. 1 is a diagram showing a human eyeball as an optical system.

FIG. 2 is a schematic diagram showing a configuration of a corneal shape analyzer according to the present invention.

FIG. 3 is a flowchart illustrating a corneal shape analysis method according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 arithmetic means 2 input means 3 storage means 4 display means 5 surgical equipment 10 corneal shape analyzer 20 lens 40 cornea 50 aqueous humor 60 crystalline lens 70 vitreous body 90 retina

Claims (7)

[Claims] 1. A step of inputting a refractive power of a patient before surgery and a shape of an anterior corneal surface of a patient before surgery as information of the eyes of the patient, and a step of reading the model eye information from a storage medium storing the model eye information. And, from the read model eye information and the input information of the patient's eye, a step of optically modeling the patient's eye, and in the modeled patient's eye,
While sequentially changing the anterior corneal shape, the posterior corneal shape corresponding to the changed anterior corneal shape is calculated, and the desired refractive power of the patient is obtained with the changed anterior corneal shape and the corresponding posterior corneal shape. Determining whether or not the patient has a desired refractive power, and calculating a shape of the anterior corneal shape that obtains the desired refractive power of the patient. 2. The corneal shape analysis method according to claim 1, further comprising a step of calculating a corneal ablation amount when performing a corneal ablation operation from the calculated anterior corneal shape and the anterior corneal shape of the patient before the operation. 3. The corneal shape analysis method according to claim 2, further comprising the step of judging whether or not the eyeball can be held at the corneal thickness after the operation from the calculated corneal ablation amount. 4. The information of the patient's eye further includes a posterior corneal shape, an anterior lens shape, a posterior lens shape, a retinal shape, a corneal thickness, an anterior chamber depth, a lens thickness, a vitreous thickness, an axial length, At least one of the refractive index of the cornea, the refractive index of the aqueous humor, the refractive index of the crystalline lens, and the refractive index of the vitreous body is input, and modeling of the patient's eye is performed using the input information of the patient's eye. The corneal shape analysis method according to claim 1, 2 or 3, wherein 5. At least one of intraocular pressure, corneal elasticity, corneal strength, lens strength, and age is input as patient information, and the amount of corneal deformation after corneal ablation surgery is calculated from the patient information. 5. The corneal shape analysis method according to claim 1, wherein it is determined whether or not a desired refractive power of a patient can be obtained using the anterior corneal shape and the corresponding posterior corneal shape in consideration of the amount. 6. The method according to claim 1, wherein the determination as to whether or not a desired refractive power of the patient can be obtained is made by optically calculating a focal position. Corneal shape analysis method. 7. An input means for inputting information about a patient's eye, a storage means for storing information on a model eye, and information about the patient's eye input by the input means and the storage means. A corneal shape analyzer comprising: a calculation unit for calculating a focal position using information of a model eye read from a computer; and a display unit for displaying a calculation result by the calculation unit.