Method for inspecting ophthalmic lenses for translucency defects

Abstract

A method of inspecting an ophthalmic lens for the presence of unacceptable translucency defects in a lens body of the ophthalmic lens includes the steps of illuminating the lens body with laser light in an area bounded by an edge of the lens body, detecting an intensity of the laser light scattered by the illuminated lens body in a predetermined detection direction different from the direction of reflection, comparing the detected intensity of the scattered laser light to a predetermined threshold intensity, determining a size of at least one coherent region where the detected intensity of the scattered laser light is higher than the predetermined threshold intensity, determining whether the size of the at least one coherent region is greater than the predetermined threshold size, and rejecting the ophthalmic lens if the size of the at least one coherent region is greater than the predetermined threshold size.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Non - Provisional Application No. 17 / 648,059, filed on January 14, 2022, which claims priority to U.S. Provisional Patent Application No. 63 / 141,544, filed on January 26, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a system and method for inspecting ophthalmic lenses for the presence of unacceptable translucent defects. The entire contents of this application are incorporated herein by reference.

Background Art

[0003] [[ID=十七]] Ophthalmic lenses (e.g., intraocular lenses) are inspected for the presence of unacceptable cosmetic defects, especially before being delivered to customers. An intraocular lens typically includes a lens body bounded by an edge and two haptics attached to the lens body. In particular, when the lens is later implanted into a user's eye (e.g., during cataract surgery), it is necessary to carefully inspect the lens body for the presence of unacceptable cosmetic defects. Even when using an automatic lens inspection device that collects an image of the intraocular lens and image analysis of the collected image, the inspection of the lens body of the intraocular lens for unacceptable cosmetic defects is often performed by a skilled operator.

[0004] Cosmetic defects of intraocular lenses include cosmetic defects (e.g., inclusions, bubbles, microparticles, etc.) that are visible during inspection under conventional lighting conditions (e.g., in a dark - field illumination configuration using incoherent visible light), and further include cosmetic defects that are not normally actually visible under conventional lighting conditions. Cosmetic defects that are not normally actually visible are often referred to as "translucent" defects and are detectable only by a very skilled operator, if at all.

[0005] It should be noted that in the above translation, for the tags , ,

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[0005] , , since they are likely some specific identifiers in the original patent text and have no specific semantic meaning for translation, they are directly retained as they are. If there is a specific requirement for these tags in the actual patent context, it may need to be adjusted according to the specific situation. And for the Chinese characters in the original text that seem to be wrongly inputted in line 18 (十六, 十七), they are translated as normal text according to the context. If this is not the correct situation, please provide more accurate information for a more appropriate translation.However, these invisible defects, although occurring only very rarely, can adversely affect the user's vision, and therefore should be reliably detected. For example, a translucent, visible defect that can occur in intraocular lenses is an orange peel texture on the surface of the lens body, while another translucent defect is haze (e.g., a kind of significant cloudiness on the lens body). As described, such translucent defects occur very rarely. However, translucent defects are not easy to detect, even for highly skilled operators.

[0006] Therefore, the object of this disclosure is to provide a system and method that overcomes the aforementioned drawbacks and enables reliable detection of unacceptable translucent defects. [Overview of the project] [Means for solving the problem]

[0007] In certain embodiments, the Disclosure provides a method for inspecting an ophthalmic lens (particularly an intraocular lens) for the presence of an unacceptable translucency defect in the lens body of the ophthalmic lens, comprising the steps of: illuminating the lens body of the ophthalmic lens (particularly an intraocular lens) with laser light in a region bounded by the edge of the lens body; detecting the intensity of the laser light scattered by the illuminating lens body in a predetermined detection direction different from the direction of reflection of the illuminating laser light; comparing the detected intensity of the scattered laser light with a predetermined threshold intensity; determining the size of at least one coherent region in which the detected intensity of the scattered laser light is higher than the predetermined threshold intensity; determining whether the size of the at least one coherent region is greater than a predetermined threshold size; and, if the size of the at least one coherent region is greater than the predetermined threshold size, rejecting the ophthalmic lens for containing a translucency defect in the lens body.

[0008] According to certain aspects of this disclosure, the step of comparing the detected intensity of scattered laser light with a predetermined threshold intensity may be performed by converting the detected intensity of scattered laser light into a detected grayscale value representing the detected intensity of scattered laser light, converting the predetermined threshold intensity into a threshold grayscale value representing the predetermined threshold intensity, and comparing the detected grayscale value with the threshold grayscale value; and the step of determining whether the size of at least one coherent region is greater than a predetermined threshold size may be performed by determining the size of at least one coherent region whose grayscale value exceeds the threshold grayscale value.

[0009] According to further aspects of this disclosure, a laser diode may be used to illuminate the lens body of an ophthalmic lens.

[0010] In a further aspect of the present disclosure, the step of illuminating the lens body may include illuminating the lens body with a laser beam that strikes the surface of the lens body only within the boundaries of the edges of the lens body, the laser beam having a steady-state collision profile that covers at least 80% of the surface area of ​​the lens body.

[0011] In some embodiments of the present disclosure, the laser beam may be sighted with uniformly distributed intensity, and the steady-state collision profile may be a circular profile having a diameter 5% to 10% smaller than the diameter of the edge bordering the lens body.

[0012] In some further embodiments of the present disclosure, the steady-state collision profile of the laser beam may have the shape of a grid having rectangular grid lines with uniformly distributed intensity along the grid lines.

[0013] In a further aspect of the present disclosure, the step of illuminating the lens body may include illuminating the lens body with a laser beam having an impact profile on the surface of the lens body, wherein the impact profile comprises less than 20% of the area of ​​the surface of the lens body, and the impact profile may be moved along a predetermined path on the surface of the lens body to continuously illuminate different parts of the lens body.

[0014] In some embodiments of the present disclosure, the beam may be focused, the impact profile may be a circular spot, and the circular spot may be moved on the surface of the lens body along a predetermined path.

[0015] In some further embodiments of the present disclosure, the impact profile is a straight line, which may be moved on the surface of the lens body along a predetermined path, the predetermined path being perpendicular to the straight line of the impact profile.

[0016] The method provided by this disclosure has several advantages. First, the method is objective, as it determines whether an ophthalmic lens should be rejected for containing translucent defects in the lens body based on measured values ​​and automated evaluation of measurement results obtained by technical instruments and mechanical algorithms, without subjective judgment by a human operator. This results in a consistent interpretation of measurement results and eliminates subjective interpretation by a human operator. Second, the use of a laser beam (higher intensity coherent light) for illuminating the ophthalmic lens to be inspected makes visible translucent defects that were previously invisible due to insufficient intensity to be recognized / detected. Advantageously, while monochromaticity is not a requirement, the illumination laser beam is monochromatic. In the case of a monochromatic laser beam, a detector that detects any laser beam scattered by a translucent defect toward the detector can block / filter stray light (scattered light) having a different wavelength from the monochromatic laser beam so that it is not detected by the detector. Therefore, it is necessary to be able to sense only at the wavelength of monochromatic light (or within a very narrow band centered on the central (monochromatic) wavelength) so that the signal-to-noise ratio can be increased in the detector. Thirdly, the detector for detecting the intensity of (preferably monochromatic) scattered laser light is positioned to detect only the light scattered in a predetermined detection direction different from the direction of reflection of the laser light. Therefore, since the reflected laser light does not collide with the detector, the laser light reflected by the ophthalmic lens does not adversely affect the intensity measurement at the detector. Or, in other words, the inspection of the ophthalmic lens is performed in a dark-field illumination configuration.

[0017] Haze representing a specific type of translucent defect to be identified by the method of this disclosure typically appears as a kind of "cloudy" volume within the lens body of an ophthalmic lens, and it should be noted that a (typically two-dimensional) detector (e.g., a CCD detector) detects the laser light scattered by such a volumetric translucent defect as a coherent region where the detection intensity of the scattered laser light (at any position within the coherent region) is higher than a predetermined threshold intensity. Furthermore, if this coherent region where the detection intensity of the scattered light is higher than a predetermined threshold intensity is larger than a predetermined threshold size, it is determined that the ophthalmic lens should be rejected due to the inclusion of a translucent defect in the lens body.

[0018] For the automatic determination of whether or not an ophthalmic lens contains translucent defects (e.g., haze), the detection intensity of scattered laser light may be converted to a detection grayscale value, and a predetermined threshold intensity may be further converted to a threshold grayscale value. In such cases, the detection grayscale value is compared to the threshold grayscale value, and if the size of the coherent region exceeds the threshold grayscale value, the ophthalmic lens is rejected.

[0019] The use of laser diodes to illuminate ophthalmic lenses to be examined is advantageous because laser diodes are small, relatively inexpensive components readily available on the market.

[0020] Generally, a laser beam can illuminate a lens body with a collision profile that is stationary and located only within the boundaries of the lens body's edges, while simultaneously encompassing at least 80% of the surface area of ​​the lens body. The laser beam that collides with the lens body's surface enters the lens body (at least partially) through the (illumination) surface and is scattered by any translucent defects present. "Within the boundaries of the lens body's edges" means that the edges themselves are not collided with by the laser beam, as edges are known to generate a great deal of undesirable stray light (scattered light) in detectors not due to translucent defects. "Collision profile" is intended to show the geometric shape of the area on the lens body's surface that is actually collided with by the laser beam. "Stationary" means that the area on the lens body's surface that is collided with by the laser beam does not change position during measurement / determination (the area collided with by the laser beam is always the same during measurement / determination).

[0021] For example, the beam may be a sighted laser beam with uniformly distributed intensity, and the steady-state impact profile may be a circular profile. This means that on the surface of the ophthalmic lens, the laser beam is bounded by a circle, while the intensity is the same in the region bounded by the circle. Advantageously, the circular impact profile may have a diameter 5% to 10% smaller than the diameter of the (circular) edge that borders the lens body.

[0022] Alternatively, the impact profile of the laser beam may have the shape of a grid with rectangular grid lines, and the intensity may be evenly distributed along these rectangular grid lines. The mesh size of the individual cells of such a grid bounded by rectangular grid lines should be selected to be small enough to reliably detect translucent defects. In any case, the entire size of the steady-state impact profile (i.e., the outer boundary of the laser beam on the surface of the lens body) is selected so that these parts of the lens body where translucent defects exist and which may affect the user's vision are located within the impact profile.

[0023] Generally, a laser beam having a collision profile that includes an area less than 20% of the area of the lens body is illuminated on the lens body, and this collision profile can be moved on the lens body along a predetermined path so as to continuously illuminate different parts of the lens body. Such a predetermined path may be selected according to the collision profile of the laser beam. For example, the collision profile may be a circular spot (meaning that the illumination spot on the surface of the lens body is bounded by a circle), and the predetermined path may include one or more circles (concentric circles with the central optical axis passing through the lens body) that move the spot on the lens body. Instead, the predetermined path along which the circular spot can be moved may be a helix or may have any other geometric shape. Another example of the collision profile may be a straight line (extending across the surface of the lens body), and the predetermined path may be perpendicular to the straight line (may extend in a plane parallel to the "plane" of the lens body), so that the straight line of the collision profile is moved on the surface of the lens body like the scanning line of a scanner.

[0024] Further advantageous aspects of the systems and methods of the present disclosure will become apparent from the following description of the embodiments using schematic diagrams.

Brief Description of the Drawings

[0025] [Figure 1] FIG. 1 shows an arrangement for performing the method of the present disclosure using a translucent defect included in a lens body of an ophthalmic lens to be inspected according to a particular embodiment. [Figure 2] FIG. 2 shows an ophthalmic lens under inspection using a stationary circular collision profile of a laser beam that collides with the surface of the lens body according to a particular embodiment of the present disclosure. [Figure 3] FIG. 3 shows an ophthalmic lens under inspection using a stationary collision profile of a laser beam having a grid shape according to a particular embodiment of the present disclosure. [Figure 4]FIG. 4 shows an ophthalmic lens including a translucent defect of a lens body during inspection, using a collision profile in the form of a circular spot that moves on the surface of the lens body, according to a particular embodiment of the present disclosure. [Figure 5] FIG. 5 shows an ophthalmic lens during inspection, using a collision profile in the form of a straight line that moves on the surface of the lens body, according to a particular embodiment of the present disclosure. [Figure 6] FIG. 6 shows an image of an inspection ophthalmic lens having a lens body including a translucent defect (haze), according to a particular embodiment of the present disclosure. [Figure 7] FIG. 7 shows an image of an inspection ophthalmic lens having a lens body without a translucent defect, according to a particular embodiment of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows an arrangement for performing a method according to a particular embodiment of the present disclosure. As can be seen, the ophthalmic lens 1 to be inspected (in this case, an intraocular lens) includes a lens body 10 and two haptics 11, as is well known in the art. Further, as can be seen, the lens body 10 includes a translucent defect 12, as schematically shown in FIG. 1. The lens body 10 is bounded by a circular edge 100 that is continuous in the circumferential direction (as can be further seen in FIGS. 2 to 5). The lens body 10 is illuminated with laser light 20 emitted by a laser diode 2, and a camera 3 including a sensor (e.g., a CCD array) is arranged in a predetermined detection direction different from the direction of reflection of the illuminating laser light 20 (shown by the dashed line 22) and facing the camera 3. The intensity of the laser light emitted by the laser diode 2 is generally in the range of 0.5 mW / cm 2 to 5 mW / cm 2 and may particularly be about 1 mW / cm 2The wavelength may generally be in the range of 400 nm to 700 nm, and in particular, it may be about 670 nm. A suitable laser diode may be the type L670VH1 laser diode available from Thorlabs GmbH, Munchner Weg 1, 85232 Bergkirchen, Germany.

[0027] The arrangement shown in Figure 1 is known as a dark-field illumination structure. Only structural scattering present in the lens body 10, which scatters the illumination laser light 20 toward the camera 3, appears as a bright structure in the image of the lens body 10. Otherwise, the image of the lens body 10 collected by the camera 3 is dark. This means that the camera 3 can detect the laser light that enters the lens body 10 and is scattered by the translucent defects 12 contained in the lens body 10 in a predetermined detection direction (i.e., toward the camera 3). The intensity of this scattered laser light 21 can be measured. The scattered laser light 21 propagating toward the camera 3 in a predetermined detection direction is only a small fraction of the light scattered by the translucent defects 12, so the intensity of this scattered laser light 21 is relatively low (as can be seen further in Figure 6 in the region enclosed by the ellipse within the lens body). This scattered laser light 21 indicates the presence of the translucent defects 12.

[0028] The translucent defect 12 shown in the figure is haze, which is a defect that does not exist on the surface but is present in the bulk material of the lens body 10. Other translucent defects (e.g., orange peel defects) may exist on the surface. The intensity of the scattered laser light 21 is detected by the sensor of the camera 3 (e.g., a CCD array) and compared with a preset (predetermined) threshold intensity.

[0029] From the perspective of the camera 3's sensor (e.g., a CCD array), a translucent defect 12 (as shown in the figure, this defect is a volume defect, namely haze, as it is contained in the bulk material) appears as a coherent region 120 where the detection intensity of the scattered laser light 21 is higher than a threshold intensity (see Figure 4). Furthermore, if the size of this coherent region 120 is larger than a predetermined threshold size, the ophthalmic lens 1 is rejected due to the inclusion of a translucent defect. If the lens body 10 contains more than one translucent defect 12, the sizes of the individual coherent regions 120 where the intensity of the scattered laser light 21 exceeds the threshold intensity (and thus indicate an individual translucent defect 12) are summed up, and if the sum of the sizes of the individual coherent regions 120 exceeds the threshold size, the ophthalmic lens 1 is further rejected.

[0030] In one embodiment, the detected intensity and a predetermined threshold intensity of the scattered laser light 21 are converted into grayscale values ​​(i.e., a detected grayscale value representing the detected intensity of the scattered laser light 21 and a threshold grayscale value representing the predetermined threshold intensity). Next, by comparing the detected grayscale value with the threshold grayscale value, it is possible to determine whether the size of the coherent region representing the translucent defect 12 exceeds a predetermined threshold size.

[0031] In the following various different options, the method for inspecting the ophthalmic lens 1 will be described, or more precisely, the lens body 10 of the ophthalmic lens 1 may be illuminated with laser light 20. Generally, these options can be subdivided into options in which a laser beam with a steady-state collision profile (i.e., a non-moving profile) illuminates the lens body 10, and options in which a collision profile that moves on the surface of the lens body 10 illuminates the lens body 10. These options will be described later with reference to Figures 2 to 5.

[0032] Figure 2 shows an example according to a particular embodiment of the present disclosure in which the laser light illuminates the lens body 10 only within the boundary of the circular edge 100 that borders the lens body 10, i.e., the circular edge 100 itself is not illuminated (and the translucent defects 12 are not present on the edge) because the edge 100 is known to generate a great deal of undesirable stray light. In this example, the laser light 20 illuminating the lens body 10 is a sighted laser beam with uniformly distributed intensity, and the laser beam collides with the surface of the lens body 10 having a steady circular impact profile 200. The circular impact profile 200 has a diameter D2 that is 5% to 10% smaller than the diameter D1 of the edge 100 that borders the lens body 10. In the example shown in Figure 2, the diameter D2 of the circular impact profile 200 is approximately 80% of the diameter D1 of the circular edge 100 of the lens body 10. By illuminating the lens body in this way, the intensity of the scattered light can be measured in a single measurement operation.

[0033] Figure 3 shows an example according to a particular embodiment of the present disclosure in which the laser light re-illuminates the lens body 10 only within the boundary of the circular edge 100 that borders the lens body 10. However, unlike the example shown in Figure 2, the collision profile 201 of the laser beam has the shape of a grid with rectangularly arranged grid lines 2010, 2011. The collision profile 201 in the shape of a grid can be easily generated using an aperture or similar component, which is also an integral part of the laser diode 2 (Figure 1). The rectangularly arranged grid lines 2010, 2011 define a mesh with small individual cell sizes in the mesh bounded by the grid lines 2010, 2011, so that the intensity of the scattered laser light can also be measured in a single measurement operation.

[0034] Generally, the steady-state collision profiles 200, 201 (whether circular or grid-like) include at least 80% of the surface area of ​​the lens body 10 in order to obtain a reliable determination regarding the presence (or absence) of the translucent defect 12.

[0035] Figure 4 shows an example in which, according to a particular embodiment of the present disclosure, a laser beam is focused onto the lens body 10 such that the impact profile 202 is a circular spot encompassing an area on the surface of the lens body 10 having a size of approximately 1 / 16 of the size of the entire surface of the lens body 10 (either the front or back side facing the laser beam). The circular spot is moved along a predetermined path 2020, indicated by a dashed circle in Figure 4, and may further be moved along a further circle concentric with the dashed circle shown in Figure 4, so as to encompass at least 80% of the area on the surface of the lens body 10. In this embodiment, the intensity of the scattered laser light is measured continuously as the circular spot moves along the predetermined path 2020. Alternatively, the predetermined path may have a helical shape or any other suitable shape encompassing this area on the surface of the lens body 10.

[0036] Figure 5 shows an example of a particular embodiment of the present disclosure in which a laser beam having a linear impact profile 203 illuminates a lens body 10. This straight line is moved on the surface of the lens body 10 along a predetermined path 2030 perpendicular to the straight line 203, as shown by the dashed line in Figure 5, which is very similar to a scanning line moved on the surface of an object to be scanned. Furthermore, as the impact profile 203 moves along the predetermined path 2030, the intensity of the scattered laser light is continuously measured.

[0037] Figure 6 shows a (dark-field) image of an ophthalmic lens (here, an intraocular lens) according to a particular embodiment of the present disclosure, in which the lens body contains a translucent defect (haze), and the haze is visible within the region enclosed by the ellipse drawn in the image. Even when using laser light, the haze is barely visible on the lens body, or at least detectable. In contrast to Figure 6, Figure 7 shows a (dark-field) image of an intraocular lens without haze according to a particular embodiment of the present disclosure.

[0038] Various embodiments have been described using the embodiments shown in the drawings. However, since various modifications can be made to the embodiments without departing from the teachings that form the basis of this disclosure, this disclosure is not limited to the illustrated and described embodiments. Accordingly, the scope of protection is defined by the appended claims. According to embodiment (1), a method for inspecting an ophthalmic lens (1) (particularly an intraocular lens) for the presence of an unacceptable translucent defect (12) in the lens body (10) of the ophthalmic lens, The steps include illuminating the lens body (10) of the ophthalmic lens (1) (in particular, the intraocular lens) with laser light (20) in a region bounded by the edge (100) of the lens body (10), The steps include detecting the intensity of the laser light (21) scattered by the illumination lens body (10) in a predetermined detection direction different from the direction of reflection (22) of the illumination laser light (20), The steps include comparing the detected intensity of the scattered laser light (21) with a predetermined threshold intensity, A step of determining the size of at least one coherent region (120) in which the detected intensity of the scattered laser light (21) is higher than the predetermined threshold intensity, A step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size, If the size of the at least one coherent region (120) is greater than the predetermined threshold size, the ophthalmic lens (1) is excluded due to the inclusion of a translucent defect (12) in the lens body (10). This method includes [something]. According to embodiment (2), the step of comparing the detected intensity of the scattered laser light (21) with a predetermined threshold intensity is performed as follows: The detection intensity of the scattered laser light (21) is converted into a detection grayscale value representing the detection intensity of the scattered laser light. The predetermined threshold intensity is converted to a threshold grayscale value representing the predetermined threshold intensity. The detected grayscale value is compared with the threshold grayscale value. This is done by The step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size is, Determine the size of at least one coherent region where the grayscale value exceeds the threshold grayscale value. It is done depending on the circumstances. According to embodiment (3), the laser diode (20) is used to illuminate the lens body (10) of the ophthalmic lens (1). According to embodiment (4), the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam that strikes the surface of the lens body (10) only within the boundary of the edge (100) of the lens body (10), wherein the laser beam has a steady-state impact profile (200, 201) that includes at least 80% of the area of ​​the surface of the lens body (10). According to embodiment (5), the laser beam is sighted with uniformly distributed intensity, and the steady-state collision profile (200) is a circular profile having a diameter (D2) that is 5% to 10% smaller than the diameter (D1) of the edge (100) that borders the lens body (10). According to embodiment (6), the steady-state collision profile (201) of the laser beam has a grid shape with grid lines (2010, 2011) arranged in a rectangle, with an intensity evenly distributed along the grid lines (2010, 2011). According to embodiment (7), the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam having impact profiles (202, 203) on the surface of the lens body (10), wherein the impact profiles (202, 203) on the surface of the lens body (10) comprise less than 20% of the area on the surface of the lens body (10), and includes moving the impact profiles (202, 203) along a predetermined path (2020, 2030) on the surface of the lens body (10) to continuously illuminate different parts of the lens body (10). According to embodiment (8), the laser beam is focused, the collision profile (2020) is a circular spot, and the circular spot is moved on the surface of the lens body (10) along the predetermined path (2020). According to embodiment (9), the collision profile (2030) is a straight line, and the straight line is moved along the predetermined path (2030) on the surface of the lens body (10), and the predetermined path (2030) is perpendicular to the straight line of the collision profile (203).

Claims

1. A method for examining an ophthalmic lens (1) (especially an intraocular lens) for the presence of an unacceptable translucent defect (12) in the lens body (10) of the ophthalmic lens, The steps include illuminating the lens body (10) of the ophthalmic lens (1) (especially the intraocular lens) with laser light (20) in a region bounded by the edge (100) of the lens body (10), The steps include detecting the intensity of the laser light (21) scattered by the lens body (10) in a predetermined detection direction different from the direction of reflection (22) of the laser light (20) that illuminates the lens body, The steps include comparing the intensity of the laser light (21) scattered by the lens body (10) with a predetermined threshold intensity, A step of determining the size of at least one coherent region (120) in which the intensity of the laser light (21) scattered by the lens body (10) is higher than the predetermined threshold intensity, A step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size, If the size of the at least one coherent region (120) is greater than the predetermined threshold size, the ophthalmic lens (1) is excluded due to the inclusion of a translucent defect (12) in the lens body (10). A method that includes this.

2. The step of comparing the intensity of the laser light (21) scattered by the lens body (10) with a predetermined threshold intensity, The intensity of the laser light (21) scattered by the lens body (10) is converted into a detected grayscale value representing the intensity of the laser light (21) scattered by the lens body (10). The predetermined threshold intensity is converted to a threshold grayscale value representing the predetermined threshold intensity. The detected grayscale value is compared with the threshold grayscale value. This is done by The step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size is, The size of at least one coherent region where the detected grayscale value exceeds the threshold grayscale value is determined. Execute by The method according to claim 1.

3. The method according to claim 1 or claim 2, wherein a laser diode (2) is used to illuminate the lens body (10) of the ophthalmic lens (1).

4. The method according to any one of claims 1 to 3, wherein the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam that strikes the surface of the lens body (10) only within the boundary of the edge (100) of the lens body (10), the laser beam having a steady-state impact profile (200, 201) that covers at least 80% of the area of ​​the surface of the lens body (10).

5. The method according to claim 4, wherein the laser beam is sighted with uniformly distributed intensity, and the steady-state collision profile (200) is a circular profile having a diameter (D2) that is 5% to 10% smaller than the diameter (D1) of the edge (100) that borders the lens body (10).

6. The method according to claim 4, wherein the steady-state collision profile (201) of the laser beam has a grid shape with grid lines (2010, 2011) arranged in a rectangle, with an intensity uniformly distributed along the grid lines (2010, 2011).

7. The method according to any one of claims 1 to 3, wherein the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam having impact profiles (202, 203) on the surface of the lens body (10), wherein the impact profiles (202, 203) on the surface of the lens body (10) include an area of ​​less than 20% of the area on the surface of the lens body (10), and the step of moving the impact profiles (202, 203) on the surface of the lens body (10) along a predetermined path (2020, 2030) to continuously illuminate different parts of the lens body (10).

8. The method according to claim 7, wherein the laser beam is focused, the collision profile (202) is a circular spot, and the circular spot is moved on the surface of the lens body (10) along the predetermined path (2020).

9. The method according to claim 7, wherein the collision profile (203) is a straight line, and the straight line is moved on the surface of the lens body (10) along the predetermined path (2030), and the predetermined path (2030) is perpendicular to the straight line of the collision profile (203).

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