Phakic intraocular lens selection device and phakic intraocular lens selection program

Abstract

The present invention provides a device 1 that can reduce the risk of angle-to-angle narrowing after ICL (intraocular lens) implantation surgery. [Solution] The device 1 includes a calculation unit 5. The calculation unit 5 (acquisition unit) acquires at least the preoperative AOD (preoperative angle of view) from the patient before ICL insertion. The calculation unit 5 (calculation unit) calculates the vault threshold using the acquired preoperative AOD, based on a threshold calculation formula that calculates a pre-set vault threshold, which is an indicator of narrow angle, with preoperative AOD and vault (distance) as variables. Furthermore, the calculation unit 5 (selection unit) selects the ICL lens size by referring to the calculated vault threshold.

Description

Technical Field

[0001] The present invention relates to an intraocular lens selection device for phakic eyes reference and an intraocular lens selection program for phakic eyes.

Background Art

[0002] In Patent Document 1 below, a computer is trained using a patient's past history of corneal refractive surgery, and based on an OCT (anterior segment optical coherence tomography) image obtained after the surgery, a method for automatically estimating the vault (the distance from the anterior surface of the lens to the posterior surface of the intraocular lens for phakic eyes) after the insertion of an intraocular contact lens is disclosed.

[0003] In Non-Patent Document 1 below, a method for predicting the vault after the insertion of an intraocular lens for phakic eyes using the eye shape parameters before the insertion of the intraocular lens for phakic eyes by a learning model using a computer is disclosed.

[0004] By the way, if the value of the above vault is too low, there is a risk of causing cataracts due to, for example, contact trauma, while if the value is too high, a narrow anterior chamber angle may occur after the surgery, leading to an increase in intraocular pressure and ultimately angle-closure glaucoma. In Non-Patent Document 1 below, in order to avoid the above risks, a generally desirable vault range of 0.25 to 0.75 mm is mentioned. In the current insertion surgery of intraocular lenses for phakic eyes, for example, using the method described in Non-Patent Document 1 below, the vault is predicted, and the lens size of the intraocular lens for phakic eyes is selected so that the predicted value falls within the above range. Specifically, it is common to select the lens size corresponding to the predicted value of the vault closest to the predicted value of 0.50 mm for the vault.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Documents

[0006] [Non-Patent Document 1] Di Y et al. Translational Vision Science $ Technology 2024 Jan 15, 13(1):8. Predicting Implantable Collamer Lens Vault Using Machine Learning Based on Various Preoperative Biometric Factors [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, even when the lens size of the intraocular lens (IOL) is selected so that the vault prediction falls within the above range, cases of angle narrowing after IOL implantation are still observed. Therefore, it is desirable to reduce the risk of angle narrowing after IOL implantation.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a phakic intraocular lens selection device, a phakic intraocular lens selection method, and a phakic intraocular lens selection program that can reduce the risk of angle narrowing after phakic intraocular lens implantation surgery. [Means for solving the problem]

[0009] To solve the above problems, the phakic intraocular lens selection device according to the present invention An acquisition unit that acquires at least the preoperative angle of ocular shape parameters from patients who have undergone intraocular lens implantation, A calculation unit calculates a threshold for the distance, which is a pre-set index of narrow angle, based on a threshold calculation formula that uses the preoperative angle opening and the distance (vault) from the anterior surface of the crystalline lens to the posterior surface of the crystalline lens in patients who have undergone phakic intraocular lens implantation as variables, using the preoperative angle opening obtained in the acquisition step. The system includes a selection unit that selects the size of the phakic intraocular lens by referring to the distance threshold calculated by the calculation unit. 、 The selection unit refers to a lens size selection table for phakic intraocular lenses that is set in advance in accordance with the predicted distance value calculated based on the eye shape parameter, and selects a lens size for a phakic intraocular lens that corresponds to a predicted distance value smaller than the distance threshold calculated by the calculation unit.

[0011] Furthermore, in order to solve the above problems, the phakic intraocular lens selection program according to the present invention is A step to obtain at least the preoperative angle of ocular shape parameters from patients who have undergone intraocular lens implantation, A calculation step in which a threshold value for the distance, which is a predetermined index of narrow angle, is calculated using the preoperative angle opening obtained in the acquisition step, based on a threshold calculation formula that calculates a threshold value for the distance, which is a predetermined index of narrow angle, with the preoperative angle opening and the distance (vault) from the anterior surface of the crystalline lens to the posterior surface of the crystalline lens in patients who have undergone phakic intraocular lens implantation as variables, The computer is to perform a selection step in which it selects the size of the phakic intraocular lens by referring to the distance threshold calculated in the calculation step. 、 The selection step involves selecting a lens size selection table for intraocular lenses that is set in advance in accordance with the predicted distance calculated based on the eye shape parameters, and selecting a lens size for intraocular lenses that corresponds to a predicted distance smaller than the distance threshold calculated in the calculation step.

[0012] In these cases, for example, the threshold calculation formula can be configured to be set based on the preoperative angle opening obtained from cases that were judged to have a narrow angle based on pre-set judgment criteria, and the distance obtained from the cases, for patients who have undergone intraocular lens implantation with phakic lenses.

[0013] Furthermore, for example, the judgment criteria may be configured to include the condition that the preoperative angle opening is judged to be narrow at one or more points around the entire circumference of the eye of the patient who has undergone phakic intraocular lens implantation surgery.

[0014] Further, for example, the selection unit, the selection process, and the selection step all refer to a lens size selection table for phakic intraocular lenses preset corresponding to the predicted value of the distance calculated based on the eye shape parameters, and select the lens size of the phakic intraocular lens corresponding to the predicted value of the distance smaller than the calculated threshold value of the distance.

[0015] In the present invention, based on a threshold calculation formula preset for calculating the threshold value of the distance (vault), the threshold value of the distance is calculated using the preoperative trabecular opening degree obtained from the patient before the phakic intraocular lens insertion surgery. The threshold calculation formula uses the preoperative trabecular opening degree and the distance (vault) from the front surface of the lens to the rear surface of the phakic intraocular lens after the phakic intraocular lens insertion surgery as variables. Therefore, when deriving the threshold calculation formula, by appropriately selecting cases after the phakic intraocular lens insertion surgery, it is possible to use the calculated threshold value of the distance as an index for narrow angles. As a result, by selecting the lens size of the phakic intraocular lens by referring to the threshold value of the distance calculated based on the above threshold calculation formula, it is possible to reduce the risk of narrow angle formation after the phakic intraocular lens insertion surgery.

Brief Description of the Drawings

[0016] [Figure 1] Block diagram of device 1 to which an ICL (phakic intraocular lens) selection device in an embodiment of the present invention is applied. [Figure 2] Flowchart showing the flow of a series of processes executed by the calculation unit in FIG. 1. [Figure 3] Flowchart showing the procedure for creating the threshold calculation formula used in the process of S2 in FIG. 2. [Figure 4] Explanatory diagram showing eye shape parameters (hACD, hATA, hCLR). [Figure 5] Explanatory diagram showing eye shape parameters (vACD, vATA, vCLR). [Figure 6] Explanatory diagram showing eye shape parameter (LT). [Figure 7]Explanatory drawing showing the eye shape parameter (preoperative AOD (preoperative angle opening degree)). [Figure 8] Explanatory drawing showing the vault (distance). [Figure 9] (a) is an explanatory drawing showing an example of an open-angle eye (normal eye). (b) is an explanatory drawing showing an example of a narrow angle (closed-angle eye). [Figure 10] Explanatory drawing showing the angle state for each divided region (32 divisions) around the entire circumference of the eye. [Figure 11] (a) is a graph showing the relationship between preoperative AOD and vault in the Open group. (b) is a graph showing the relationship between preoperative AOD and vault in the Narrow group. [Figure 12] (a) is an explanatory drawing showing an example of threshold calculation (right eye). (b) is an explanatory drawing showing an example of threshold calculation (left eye). [Figure 13] (a) is an explanatory drawing showing the selection of the ICL corresponding to FIG. 12(a). (b) is an explanatory drawing showing the selection of the ICL corresponding to FIG. 12(b). [Figure 14] (a) is an explanatory drawing showing the postoperative angle state corresponding to FIG. 13(a). (b) is an explanatory drawing showing the postoperative angle state corresponding to FIG. 13(b).

Mode for Carrying Out the Invention

[0017] (Embodiment) Hereinafter, an embodiment of the present invention will be described while referring to the drawings. FIG. 1 shows a block diagram of an apparatus 1 to which an intraocular lens selection device for phakic eyes according to the present invention is applied. The apparatus 1 selects the lens size of an intraocular lens (ICL (registered trademark), hereinafter referred to as ICL) based on various eye shape parameters. The ICL is a posterior chamber intraocular lens that is inserted in front of the lens and behind the iris by an ICL insertion surgery (hereinafter referred to as ICL insertion surgery, with the preoperative stage being referred to as preoperative and the postoperative stage being referred to as postoperative) for correcting myopia and astigmatism. ​​The apparatus 1 comprises an imaging unit 2, an input unit 3, a display unit 4, and a calculation unit 5. The imaging unit 2 is, for example, an OCT (Optical Coherence Tomography) device. An OCT device is a well-known optical instrument that captures a cross-sectional image of the anterior segment of the eye under examination using optical coherence tomography (for example, the CASIA2 Advance anterior segment OCT manufactured by Tomei Corporation). Specifically, the OCT device splits a low-coherent light source into a measurement light and a reference light, respectively, which are irradiated onto the eye under examination. Based on the interference light between the measurement light reflected from the eye under examination and the reference light, a cross-sectional image of the anterior segment is acquired. The OCT device also acquires a cross-sectional image from a wide area of ​​the eye under examination by scanning the measurement light over the eye under examination. The image data of the cross-sectional image acquired by the OCT device is processed by the calculation unit 5 and displayed by the display unit 4.

[0019] Input unit 3 is the part that receives input from the user and includes, for example, buttons, a numeric keypad, a mouse, etc. Information about the case (for example, the case ID) is entered into input unit 3. The content entered into input unit 3 is sent to calculation unit 5.

[0020] The display unit 4 is the part that displays images and is composed of a well-known display such as a liquid crystal display, plasma display, or organic EL display. The display unit 4 is capable of displaying color images.

[0021] The arithmetic unit 5 is the part that controls the entire device 1, starting with the selection of the ICL lens size, and is composed of a CPU 50 and a storage unit 60, similar to a normal computer. The storage unit 60 is a non-volatile storage unit and is a non-transitory tangible storage medium that non-temporarily stores programs and data that can be read by the CPU 50. The non-transitory tangible storage medium is implemented by semiconductor memory or magnetic disk, etc. The storage unit 60 may be configured as an internal storage unit built into the arithmetic unit 5, or as an external storage unit attached to the arithmetic unit 5. The storage unit 60 stores various data, such as various programs 61 executed by the CPU 50, a vault threshold calculation formula 62, a vault prediction value calculation formula 63, and an ICL lens size selection table 64.

[0022] Next, the process of selecting the lens size of the ICL using the apparatus 1 configured as described above will be explained with reference to the explanatory diagrams in Figures 4 to 15. When this process is performed, the calculation unit 5 executes the program 61 shown in the flowchart of Figure 2.

[0023] First, the calculation unit 5 obtains eye shape parameters from the storage unit 60 (S1). The eye shape parameters are stored in the storage unit 60 as parameters indicating various eye shapes based on the image data of the cross-sectional image captured by the imaging unit 2. Specifically, as shown in Figures 4 to 6, ACD (Anterior Chamber Depth) (distance from the posterior surface of the cornea to the anterior surface of the lens at the corneal apex (anterior chamber depth)), ATA (Angle To Angle) (distance between the angular bases (AR) of both corners), CLR (Crystalline Lens Rise) (distance between the anterior surface of the lens and the line segment on the perpendicular bisector of the line segment connecting the angular bases (AR) of both corners), and LT (Lens Thick) (lens thickness) are obtained. Note that Figure 4 is a tomographic image of the eye in the horizontal direction (the direction connecting 0° and 180° in the figure), and the subscript "h" in the figure indicates "horizontal". Figure 5 shows a tomographic image in the vertical direction of the eye (from 90° to 270° in the figure), and the subscript "v" in the figure indicates "vertical".

[0024] Furthermore, the calculation unit 5 acquires the preoperative AOD (Angle Opening Distance) as an AOD before ICL insertion surgery from the storage unit 60 as an eye shape parameter. In this embodiment, the preoperative AOD refers to the distance (shown as AOD500 in Figure 7) from a point on the posterior surface of the cornea 500 μm away from the scleral promontory (SS) (shown as AOD500-T in Figure 7) to the point (shown as AOD500-IF in Figure 7) where a perpendicular line originating from that point strikes the anterior surface of the iris, as shown in Figure 7. The units of the above eye shape parameters are all based on the unit of length in mm. The calculation unit 5 that performs the processing of S1 corresponds to the acquisition unit of the present invention, the execution of the processing of S1 by the calculation unit 5 corresponds to the acquisition process of the present invention, and the processing of S1 corresponds to the acquisition step.

[0025] Next, the vault threshold is calculated using the acquired preoperative AOD (AOD500) based on the vault threshold calculation formula 62 stored in the memory unit 60 (S2). Vault refers to the distance from the anterior surface of the lens to the posterior surface of the ICL when the ICL is inserted, as shown in Figure 8. The procedure for creating the vault threshold calculation formula 62 will now be explained with reference to Figure 3.

[0026] First, preoperative AODs were obtained from cases after ICL insertion (S21). Specifically, as shown in Table 1, preoperative AODs were obtained from 97 eyes of 61 patients who underwent ICL insertion and for whom AOD analysis was possible at 360° around the eye using the imaging unit 2 of device 1 both before and 1 month after the surgery. Table 1 is stored in the memory unit 60. Based on the obtained preoperative AODs, cases judged to be open-angle eyes (healthy eyes) (see Figure 9(a)) were defined as the Open group, and cases judged to be narrow-angle eyes (closed-angle eyes) (see Figure 9(b)) were defined as the Narrow group.

[0027] [Table 1]

[0028] Here, we will explain the definitions of the Open group and the Narrow group. The optical equipment manufacturer of the OCT device mentioned earlier has pre-set reference values ​​for narrow angles. Specifically, preoperative AOD (AOD500) was obtained from 394 healthy eyes, and the preoperative AOD value corresponding to the bottom 5% of the distribution in that population (5% of 394 eyes = 19.7), more specifically the value between the 19th and 20th preoperative AOD from the narrowest angle among the 394 eyes (actually a value interpolated by a correction formula of 19th data + 0.7 × (20th data - 19th data)) was set as the reference value (meaning the 5th percentile value, or cutoff value). Preoperative AOD is obtained for each of the 360° circumference of the eye, divided into 32 regions with an angle of 11.25° at each location. Reference values ​​are also set for each region. Then, for each case, the AOD after ICL insertion is determined to be above the standard value (open), above 0 mm but below the standard value (narrow), or 0 mm (closed) for each divided region, and as shown in Figure 10, for example, the display unit 4 displays the corresponding region in different colors. In this embodiment, if there is even one region in the entire 360° of the eye (32 regions) where the AOD after ICL insertion is smaller than the standard value, it is determined to be a narrow angle.

[0029] Returning to Table 1, the Open group consisted of 68 eyes and the Narrow group consisted of 29 eyes. The preoperative AOD (mean value around the entire circumference) was 0.66 ± 0.20 mm (standard deviation) in the Open group (the same value is omitted below) and 0.49 ± 0.17 mm in the Narrow group. The preoperative ACD was 3.27 ± 0.25 mm in the Open group and 3.05 ± 0.20 mm in the Narrow group. In both preoperative AOD and preoperative ACD, the probability p showing significance between the values ​​of the Open group and the Narrow group was p < 0.0001, indicating a significant difference between the values ​​of the Open group and the Narrow group, and moreover, the values ​​of the Narrow group were significantly smaller than those of the Open group.

[0030] Furthermore, the vault was 0.36±0.11 mm in the Open group and 0.40±0.20 mm in the Narrow group. The probability p of significance between the Open and Narrow group values ​​was p=0.552, indicating that no significant difference was observed between the Open and Narrow group values.

[0031] Returning to Figure 3, after processing in S22, the process moves to S23. Based on the preoperative AOD and vault obtained from the Open and Narrow groups, two threshold calculation formulas are created for calculating the vault threshold: formula (1) for the Open group and formula (2) for the Narrow group, as shown below. Note that the creation of formula (1) for the Open group may be omitted. Figure 11(a) shows formula (1) as a graph, and Figure 11(b) shows formula (2) as a graph. In both graphs, preoperative AOD is the x-coordinate variable and vault is the y-coordinate variable.

[0032] Open group: y (vault threshold (mm)) = 0.2441x (preoperative AOD (mm)) + 0.2018 (R2 = 0.1978, p < 0.0001) ... Formula (1) Narrow group: y(vault threshold (mm)) = 0.9091 x (preoperative AOD (mm)) - 0.0493 (R² = 0.5787, p < 0.0001) ... Equation (2)

[0033] In both equation (1) and equation (2), the probability p indicating significance of the correlation coefficient R is p < 0.0001, indicating a significant correlation (linear relationship) between preoperative AOD and vault. Since the variables used to create equation (2) were obtained from the Narrow group, the vault threshold obtained by equation (2) can be used as an extremely effective criterion for determining angle narrowing. In other words, if the vault after ICL insertion is higher than the vault threshold obtained by equation (2), the risk of angle narrowing after ICL insertion is high, and conversely, if it is lower, the risk of angle narrowing after ICL insertion is low.

[0034] Returning to Figure 2, in the S2 process, the vault threshold is calculated using the preoperative AOD (average value around the entire circumference) obtained from the ICL insertion patient, based on equation (2) created by executing the S23 process in Figure 3. Figure 12(a) shows an example of calculating the vault threshold when the preoperative AOD of the right eye of the ICL insertion patient is 0.30 mm, and Figure 12(b) shows an example when the preoperative AOD of the left eye of the same ICL insertion patient is 0.35 mm. The calculation unit 5 that executes the S2 process corresponds to the calculation unit of the present invention, the execution of the S2 process by the calculation unit 5 corresponds to the calculation process of the present invention, and the S1 process corresponds to the calculation step.

[0035] After processing in S2, the process moves to S3, where the predicted vault value is calculated based on the eye shape parameters obtained in S1. There are two methods for ICL insertion: vertical fixation (inserting and fixing the ICL in a direction approximately aligned with the corneal optical axis) and horizontal fixation (inserting and fixing the ICL in a direction approximately perpendicular to the corneal optical axis). Since the predicted vault value differs depending on the insertion direction, the vault prediction calculation formulas are also set to be different for horizontal and vertical fixation. The predicted vault value is associated with the ICL lens size, specifically 12.1mm, 12.6mm, 13.2mm, and 13.7mm. For each patient undergoing ICL insertion, the correspondence between the predicted vault value and the ICL lens size is calculated using the following formulas (3) to (10) and stored in the memory unit 60 as the ICL lens size selection table 64. The KS formula is shown below as an example of a vault prediction calculation formula.

[0036] (horizontal fixed) 12.1mm:0.037*hACD-0.355*hCLR-0.137*hATA-0.003*vATA-0.058*LT+2.155...Formula (3) 12.6mm:0.023*hACD-0.404*hCLR-0.142*hATA-0.045*vATA-0.096*LT+3.128...Formula (4) 13.2mm: 0.042*hACD-0.213*hCLR-0.164*hATA-0.147*vATA-0.207*LT+5.255 … Equation (5) 13.7mm:0.374*ICLsize+0.033*hACD-0.358*hCLR-0.135*hATA-0.046*vATA-0.100*LT-1.692…Formula (6) (Vertically fixed) 12.1mm:0.099*vACD-0.104*vCLR+0.014*vATA-0.058*hATA-0.152*LT+1.096…Formula (7) 12.6mm:0.160*vACD-0.166*vCLR-0.061*vATA-0.095*hATA-0.162*LT+2.426…Formula (8) 13.2mm: 0.065*vACD-0.285*vCLR-0.106*vATA-0.045*hATA-0.104*LT+2.648… Equation (9) 13.7mm:0.243*ICLsize+0.121*vACD-0.197*vCLR-0.054*vATA-0.077*hATA-0.147*LT-0.877…Formula (10)

[0037] After processing in S3, the process moves to S4, where the lens size corresponding to the predicted vault value smaller than the vault threshold is selected in the ICL lens size selection table 64. Specifically, as shown in Figure 13(a) as an example of the lens size selection table 64, the predicted vault value (Post vault) for the right eye that is less than the vault threshold of 0.22 mm calculated by equation (2) is 0.21 mm for the vertically fixed type. Therefore, a lens size of 12.1 mm corresponding to this predicted vault value of 0.21 mm is selected. Similarly, as shown in Figure 13(b), the predicted vault value (Post vault) for the left eye that is less than the vault threshold of 0.27 mm calculated by equation (2) is 0.26 mm for the vertically fixed type. Therefore, a lens size of 12.1 mm corresponding to this predicted vault value of 0.26 mm is selected. The calculation unit 5 that executes processing in S4 corresponds to the selection unit of the present invention, the execution of processing in S4 by the calculation unit 5 corresponds to the selection process of the present invention, and the processing in S4 corresponds to the selection step.

[0038] Previously, the system was set to select the lens size corresponding to the vault prediction value closest to the predicted vault value of 0.50 mm as the recommended size. For example, as shown in Figure 13(a), for the right eye, in the case of horizontal fixed lenses, a lens size of 12.6 mm corresponding to the predicted vault value of 0.52 mm was selected, and for vertical fixed lenses, a lens size of 13.7 mm corresponding to the predicted vault value of 0.54 mm was selected. Similarly, for the left eye, as shown in Figure 13(b), a lens size of 12.6 mm corresponding to the predicted vault value of 0.56 mm was selected for horizontal fixed lenses, and for vertical fixed lenses, a lens size of 13.2 mm corresponding to the predicted vault value of 0.48 mm was selected.

[0039] Therefore, for the right eye, both the predicted vault value of 0.52 mm for horizontal fixation and the predicted vault value of 0.54 mm for vertical fixation are higher than the vault threshold of 0.22 mm calculated using formula (2) above. Thus, if the recommended size is selected, there is a high probability of narrow angle after ICL insertion. Similarly, for the left eye, both the predicted vault value of 0.56 mm for horizontal fixation and the predicted vault value of 0.48 mm for vertical fixation are higher than the vault threshold of 0.27 mm calculated using formula (2) above. Thus, if the recommended size is selected, there is a high probability of narrow angle after ICL insertion.

[0040] As shown in Figure 14(a), in a patient undergoing ICL implantation who selected a lens size of 12.1 mm corresponding to a predicted vault of 0.21 mm (below the vault threshold of 0.22 mm) in the right eye, the measured vault after ICL implantation was 0.25 mm. Similarly, as shown in Figure 14(b), in a patient undergoing ICL implantation who selected a lens size of 12.1 mm corresponding to a predicted vault of 0.26 mm (below the vault threshold of 0.27 mm) in the left eye, the vault after ICL implantation was 0.20 mm. Thus, it was confirmed that in the same case, the right eye, where the measured vault after ICL implantation exceeded the threshold, became a narrow eye, while the left eye, where it remained within the threshold, remained an open eye. Furthermore, as shown in Figure 13(a), according to the conventional lens size selection method, a larger lens size than that selected in this embodiment would be selected, and therefore, the degree of narrow angle can be expected to be even higher. In this embodiment, since the lens size is selected by referring to the vault threshold, it can be determined that the degree of narrow angle in the right eye is kept to a minimum.

[0041] As is clear from the above explanation, in the above embodiment, the vault threshold is calculated using the preoperative AOD (preoperative angle opening) obtained from patients who have undergone ICL (intraocular lens) implantation, based on the vault threshold calculation formula 62 (formula (2)) stored in the memory unit 60 to calculate the vault threshold, which is an indicator of narrow angle (S2). The vault threshold calculation formula 62 (formula (2)) is derived using the preoperative AOD and vault from cases in the Narrow group, which are judged to have a high probability of narrow angle, as variables. In this case, the Narrow group is determined based on a reference value set for each region obtained by dividing the entire 360° circumference of the eye into 32 equal parts, and it is determined whether the AOD after ICL implantation for each case is greater than 0 mm and less than the reference value (narrow) or 0 mm (closed) for each divided region. In other words, the condition for determining a narrow-angle is that there is at least one area judged to be a narrow angle within the entire 360° circumference of the eye, and the criteria for determining a narrow angle are set quite strictly (S21~S23). For this reason, the vault threshold calculated by vault threshold calculation formula 62 (equation (2)) is an extremely effective criterion for determining a narrow angle.

[0042] Furthermore, in the above embodiment, an ICL lens size is selected (S4) that corresponds to a predicted vault value smaller than the vault threshold calculated based on the vault threshold calculation formula 62 (formula (2)), by referring to a pre-set ICL lens size selection table 64 corresponding to the predicted vault value (S3) calculated based on various eye shape parameters. This makes it possible to select an ICL lens size with a lower probability of narrow angle compared to conventional methods, while still being based on conventional ICL lens size selection methods, thus making it easy to change the specifications of the selection device, selection method, and selection program.

[0043] Furthermore, the present invention is not limited to the embodiments described above and their variations, but can be implemented in any form that integrates, omits, or modifies as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0044] 1 device 2. Photography Department 3. Input section 4 Display section 5 Arithmetic section 50 CPU 60 Storage section 61 Various Programs 62 vault threshold calculation formula 63 vault prediction calculation formula 64 ICL Lens Size Selection Table

Claims

1. An acquisition unit that acquires at least the preoperative angle of ocular shape parameters from patients who have undergone intraocular lens implantation, A calculation unit calculates a threshold for the distance that serves as an indicator of a narrow angle, based on a pre-set threshold calculation formula, using the preoperative angle opening and the distance from the anterior surface of the crystalline lens to the posterior surface of the crystalline lens in patients who have undergone phakic intraocular lens implantation, using the preoperative angle opening acquired by the acquisition unit as variables. The system includes a selection unit that selects the lens size of the phakic intraocular lens by referring to the distance threshold calculated by the calculation unit, The selection unit is a phakic intraocular lens selection device that selects a lens size for a phakic intraocular lens that corresponds to a predicted distance value smaller than the distance threshold calculated by the calculation unit, by referring to a lens size selection table for phakic intraocular lenses that is set in advance in accordance with the predicted distance value calculated based on the eye shape parameter.

2. The threshold calculation formula is: A phakic intraocular lens selection device according to claim 1, which is used for patients who have undergone phakic intraocular lens implantation, and is derived based on the preoperative angle opening obtained from cases judged to have a narrow angle based on pre-set judgment criteria, and the distance obtained from the said cases.

3. The phakic intraocular lens selection device according to claim 2, wherein the judgment criterion is that, in a plurality of regions obtained by virtually dividing the entire circumference of the eye of a patient who has undergone phakic intraocular lens implantation at a predetermined central angle, at least one region is judged to have a narrow angle.

4. The acquisition unit further acquires the postoperative angle opening from patients who have undergone phakic intraocular lens implantation surgery, A reference value for narrow corner angles is set in advance. The entire circumference of the eye of the patient who has undergone the aforementioned phakic intraocular lens implantation surgery is virtually divided into multiple regions at a predetermined central angle, The reference value for the narrow corner angle is set for each of the multiple regions. The phakic intraocular lens selection device according to claim 2, wherein the judgment criterion is set to determine that the angle is narrow if there is a region in at least one of the multiple regions where the postoperative angle opening is smaller than the corresponding reference value for the narrow angle.

5. A step to obtain at least the preoperative angle of ocular shape parameters from patients who have undergone intraocular lens implantation, A calculation step to calculate a threshold for the distance that serves as an indicator of a narrow angle, based on a predetermined threshold calculation formula, using the preoperative angle opening obtained in the acquisition step, with the preoperative angle opening and the distance from the anterior surface of the phakic intraocular lens to the posterior surface of the phakic intraocular lens in a patient who has undergone phakic intraocular lens implantation as variables, and using the preoperative angle opening obtained in the acquisition step, The computer is instructed to perform a selection step, which involves selecting the lens size of the intraocular lens for a phakic eye by referring to the distance threshold calculated in the calculation step, The selection step is a phakic intraocular lens selection program that selects a lens size for a phakic intraocular lens that corresponds to a predicted distance smaller than the distance threshold calculated in the calculation step, by referring to a lens size selection table for phakic intraocular lenses that is set in advance in accordance with the predicted distance calculated based on the eye shape parameters.

6. The threshold calculation formula is: A phakic intraocular lens selection program according to claim 5, which is derived based on the preoperative angle opening obtained from cases judged to have a narrow angle based on pre-set judgment criteria, and the distance obtained from the said cases, for patients who have undergone phakic intraocular lens implantation surgery.

7. The phakic intraocular lens selection program according to claim 6, wherein the judgment criterion is that, in a plurality of regions obtained by virtually dividing the entire circumference of the eye of the patient who has undergone phakic intraocular lens implantation surgery by a predetermined central angle, at least one region is judged to have a narrow angle.

8. In the acquisition step, the postoperative angle opening is further obtained from the patient who has undergone phakic intraocular lens implantation, A reference value for narrow corner angles is set in advance. The entire circumference of the eye of the patient who has undergone the aforementioned phakic intraocular lens implantation surgery is virtually divided into multiple regions at a predetermined central angle, The reference value for the narrow corner angle is set for each of the multiple regions. The phakic intraocular lens selection program according to claim 6, wherein the judgment criterion is set to determine that the angle is narrow if there is a region in at least one of the multiple regions where the postoperative angle opening is smaller than the corresponding reference value for the narrow angle.

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