PREFERRED ANTERIOR CAPSULOTOMY LOCATION PROVIDED BY TRYPAN BLUE OPTHALMIC SOLUTION

Abstract

Trypan Blue ophthalmic solutions are used to create and identify a landmark on the anterior capsule of an eye and thus identify a preferred location for an anterior capsulotomy during cataract surgery.

Claims

1. An ophthalmic solution comprising an isotonic and pH neutral aqueous solution of Trypan Blue at a concentration of greater than or equal to 0.25% and less than or equal to 0.45% by weight contained in a delivery device configured to introduce the ophthalmic solution into an anterior chamber of a human eye.

2. The ophthalmic solution of claim 1, wherein the concentration of Trypan Blue is greater than or equal to 0.35% and less than or equal to 0.45% by weight.

3. The ophthalmic solution of claim 1, wherein the concentration of Trypan Blue is greater than or equal to 0.4% and less than or equal to 0.45% by weight.

4. The ophthalmic solution of claim 1, wherein the delivery device is a syringe.

5. A method for creating and identifying a landmark on the anterior lens capsule of the eye, the method comprising: providing or obtaining an ophthalmic solution comprising an isotonic and pH neutral aqueous solution of Trypan Blue at a concentration of greater than or equal to 0.25% and less than or equal to 0.45% by weight; applying the ophthalmic solution to the anterior lens capsule for a time period of less than or equal to ninety seconds to stain tissue of the anterior lens capsule with Trypan Blue; rinsing the ophthalmic solution from the eye; and after rinsing the ophthalmic solution from the eye, identifying as the landmark a region of anterior lens capsule tissue that is more darkly stained with Trypan Blue than surrounding anterior lens capsule tissue stained with Trypan Blue.

6. The method of claim 5, wherein identifying the landmark comprises identifying a region of anterior lens capsule tissue having a diameter of about 2 mm to about 4 mm that is more darkly stained than surrounding stained anterior lens capsule tissue.

7. The method of claim 5, wherein the concentration of Trypan Blue is greater than or equal to 0.3% and less than or equal to 0.45% by weight.

8. The method of claim 5, wherein the concentration of Trypan Blue is greater than or equal to 0.35% and less than or equal to 0.45% by weight.

9. The method of claim 5, wherein the concentration of Trypan Blue is greater than or equal to 0.4% and less than or equal to 0.45% by weight.

10. The method of claim 5, comprising identifying the landmark on the anterior lens capsule utilizing machine vision.

11. A method for determining the location of the intersection of the visual axis of an eye with an anterior lens capsule of the eye, the method comprising: creating and identifying a landmark on the anterior lens capsule of the eye by the method of claim 5; determining a center point of the landmark region; and identifying the center point of the landmark region as the location or as approximately the location of the intersection of the visual axis of the eye with the anterior lens capsule of the eye.

12. The method of claim 11, comprising identifying the center point of the landmark region as within about 200 microns of the intersection of the visual axis of the eye with the anterior lens capsule of the eye.

13. A method for determining the location of an anterior pole of an anterior lens capsule of the eye, the method comprising: creating and identifying a landmark on the anterior lens capsule of the eye by the method of claim 5; determining a center point of the landmark region; and identifying the center point of the landmark region as the location or as approximately the location of the anterior pole the anterior lens capsule of the eye.

14. The method of claim 13, comprising identifying the center point of the landmark region as within about 300 microns of the anterior pole of the anterior lens capsule of the eye.

15. A method for replacing the natural crystalline lens of an eye with an IOL, the method comprising: creating and identifying a landmark on an anterior lens capsule of the eye by the method of claim 5; forming an opening in the anterior lens capsule centered on the landmark; removing the natural crystalline lens through the opening in the anterior lens capsule; and inserting the IOL into the anterior lens capsule through the opening in the anterior lens capsule.

16. The method of claim 15, wherein the opening formed in the anterior lens capsule is symmetric.

17. The method of claim 15, comprising centering the IOL on the opening in the anterior lens capsule.

18. The method of claim 15, wherein a center point of the landmark identifies a resting position of a center of the IOL to within about 300 microns.

19. The method of claim 15, wherein the concentration of Trypan Blue is greater than or equal to 0.3% and less than or equal to 0.45% by weight.

20. The method of claim 15, wherein the concentration of Trypan Blue is greater than or equal to 0.35% and less than or equal to 0.45% by weight.

21. The method of claim 15, wherein the concentration of Trypan Blue is greater than or equal to 0.4% and less than or equal to 0.45% by weight.

22. The method of claim 15, comprising identifying the landmark on the anterior lens capsule utilizing machine vision.

23. The method of claim 5, wherein the eye is a human eye.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee.

[0049] FIGS. 1A, 1B, and 1C illustrate the anatomy of the eye in anteroposterior (AP) view with the visual axis intersection of the anterior capsule, TC landmark, planned capsulotomy location, and predicted IOL location.

[0050] FIGS. 2A, 2B, 2C, 2D, 2E, and 2F are photographs demonstrating the TC landmark on patient eyes.

[0051] FIG. 3 is a bar chart distribution of displacement from the TC and coaxial Purkinje image.

[0052] FIGS. 4A, 4B, 4C, 4D, 4E, and 4F are photographs demonstrating capsulotomies centered on the TC landmarks.

[0053] FIG. 5 is a bar chart distribution of displacement from the center of the capsulotomy to the coaxial Purkinje image.

[0054] FIG. 6 is a bar chart distribution of displacement from the center of the IOL to the coaxial Purkinje image.

[0055] FIGS. 7A and 7B are photographs showing the results if capsulotomies are located on the dilated pupil.

[0056] FIG. 8 shows a schematic diagram of an example cataract surgery system.

DETAILED DESCRIPTION

[0057] The following detailed description should be read with reference to the drawings, in which identical reference numbers refer to like elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

[0058] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise.

[0059] FIGS. 1A-1C illustrate the anatomy of the eye in an Anterior-Posterior orientation. FIG. 1A is a representation of an eye showing an unstained anterior capsule 10, the point of intersection 12 of the visual axis and the anterior capsule, and the iris 13.

[0060] FIG. 1B is a representation of an eye showing a dye-stained capsule 11 stained with the Trypan Blue ophthalmic solution and the method described above, the resulting TC landmark 14 centered on the point of intersection 12 of the visual axis and the anterior capsule, the planned position 15 for a capsulotomy centered on the TC landmark and the intersection 12 of the visual axis and the anterior capsule, the predicted IOL resting position 16, and the iris 13. The stained TC landmark 14 is noticeably darker (less light intensity) than the surrounding stained capsule, which increases the visibility of the TC landmark 14.

[0061] FIG. 1C is a representation of an eye showing the dye-stained anterior capsule 11 stained with the Trypan Blue ophthalmic solution and the method described above, the rim 17 of a capsulotomy centered on the intersection 12 of the visual axis and the anterior capsule, an IOL optics body 18 positioned within the capsule and centered on the rim 17 of the capsulotomy and the intersection 12 of the visual axis and the anterior capsule, and the iris 13.

[0062] FIGS. 2A-2F are a series of six representative photographs of eyes in which the anterior lens capsule has been stained with the Trypan Blue ophthalmic solution as described above. The TC landmarks are the dark intense stain regions on the anterior capsule. These patients are fixated on the microscope illumination lights and the coaxial Purkinje images are present and denoted by the two light reflections at the center of the TC landmarks.

[0063] The inventor has experimentally determined that the threshold for the TC landmark is 0.25% or greater concentration of Trypan Blue ophthalmic solution for a staining duration of at least 90 seconds. For higher concentrations the required staining duration is less. For example with a 0.3% solution the required staining duration is at least 75 seconds, with a 0.35% solution the required staining duration is at least 60 seconds, and with a 0.4% solution the required staining duration is at least 45 seconds, to observe the TC landmarks in the vast majority of cases.

[0064] It is noteworthy that porcine eyes do not readily show a TC landmark. Experimental work was conducted in human clinical studies of over 150 eyes. Over 94% of eyes demonstrated the presence of a TC landmark when stained with the Trypan Blue ophthalmic solution. The size of the landmark varied from 2 to 4 mm. On the patients that did not have a visible TC landmark for a 60 second stain, more dye was applied to the anterior chamber and the staining process was repeated. The TC landmark then became visible on all patients, indicating the more concentrated solution and longer staining durations have the benefit of enhancing the visibility of the TC landmark.

[0065] The inventor has conducted additional research to determine the mechanism of action for the formation of the TC landmark and has observed that the central zone of the capsule is more porous than the surrounding peripheral region. Furthermore, the lens epithelial cells that are posterior to the anterior capsule have a different structure and function in this central zone compared to the peripheral zone. That is, in the central zone the cells are larger cuboids and one of their main functions is to pump fluids and nutrients from the anterior chamber into the lens capsule. The Trypan Blue molecule is small compared to the pores in the collagen anterior capsule and is absorbed into the capsule in this central region. The highly stained central region at the anterior pole is probably the result of the increased surface area of the pores and the pump action of the epithelial cells.

[0066] FIG. 3 reports the displacement from the TC landmarks to the sighted fixation coaxial Purkinje image. In all eyes the correlation between the TC landmark and coaxial Purkinje images are within 0.3 mm, and over 80% are within 0.1 mm. The coaxial Purkinje image is a good measurement of the visual axis intercept with the anterior capsule. The Zeiss IOLMaster 700 was also used to measure the preoperative visual axis and this reference image was imported into the Zeiss CALLISTO-eye® system, matched to the sclera vessels and confirmed the results of the Purkinje image measurements with the same tolerances.

[0067] FIGS. 4A-4F are a series of six representative photographs of eyes following capsulotomies centered on the TC landmark and IOL insertion. Again, the patient eyes are fixated on the microscope illumination lights and the coaxial Purkinje images are present and denoted by the two light reflections at the center of the IOLs.

[0068] Referring to FIG. 5, the inventor has experimentally determined that capsulotomies centered on the TC landmark are highly correlated with the visual axis intersection with the anterior capsulotomy. All capsulotomies are within 0.3 mm of the coaxial Purkinje image and over 80% are within 0.2 mm. As before the Zeiss IOLMaster visual axis reference image was imported in the Zeiss CALLISTO-eye® and confirmed the results of the Purkinje image measurements with the same tolerances for these capsulotomies. As shown in FIG. 6, the IOLs could all be positioned within 0.3 mm of the capsulotomy centers and within 0.2 mm of the coaxial Purkinje images.

[0069] As a control, 50 eyes were dilated, then stained with Trypan Blue ophthalmic solution, and the capsulotomies located on the dilated pupil centers. FIG. 7A shows-the results with a capsulotomy centered on the dilated pupil. The capsulotomy disc is still present, and the TC and coaxial Purkinje images are to the nasal (right) side of the pupil centered capsulotomy. FIG. 7B shows that the IOL does not follow the capsulotomy, but is also displaced to the nasal side following the TC and coaxial Purkinje images. In these cases, the maximum capsulotomy displacement from the IOL center was 0.6 mm and the capsulotomy is not symmetrically capturing the IOL. This highlights the need for accurate location of the anterior capsulotomy, such as facilitated by the invention disclosed in this patent.

[0070] FIG. 8 shows a schematic diagram of an example cataract surgery system 400 that may be employed with the dye solutions and related methods described herein with visualization of the TC landmark. System 400 comprises a visualization system 410, an optional surgical laser system 420, an optional robot surgical system 430, and an optional processor 440. Visualization system 410 may be used by a human surgeon or by a robotic surgical system to view the lens capsule and other portions of the surgical field during cataract surgery. Visualization system 410 may comprise, for example, a stereoscopic microscope as conventionally employed in ophthalmic surgery, an imaging system including a camera or other imaging device, or a microscope and a camera or other imaging device. In variations in which cataract surgery is performed using laser ophthalmic surgical methods, system 400 may comprise an optional ophthalmic surgical laser system 420. Portions of the optical path of surgical laser system 420, if present, may optionally be integrated into an optical path of visualization system 410. In variations in which cataract surgery is robotically assisted or performed, system 400 may comprise robot surgical system 430 which may perform as described above, for example. System 400 may comprise a processor 440 in communication with any or all of visualization system 410, laser system 420, and robot surgical system 430. Processor 440 may, for example, collect and analyze images from the visualization system, analyze them as described above, and control laser system 420 and/or robot surgical system 430 to assist or perform cataract surgery.

[0071] This disclosure is illustrative and not limiting. Further modifications will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims.