Apparatus for delivering ocular implants into an anterior chamber of the eye
An ocular implant adapted to be disposed within Schlemm's canal of a human eye with a body extending along a curved longitudinal central axis in a curvature plane, a first strut on one side of the implant and a second strut on an opposite side of the implant, the circumferential extent of the first strut with respect to the plane of curvature being greater than the circumferential extent of the second strut with respect to the plane of curvature. The invention also includes methods of using the implant.
1. A cannula for delivering an ocular implant into Schlemm's canal of an eye, comprising:
a rigid curved tube adapted to extend along a medial plane through an anterior chamber of the eye to achieve tangential entry into Schlemm's canal;
a trough portion formed by an opening extending along a distal portion of the rigid curved tube; and
an asymmetric tip disposed at a distal end of the trough portion offset from, and asymmetric about, the medial plane, the asymmetric tip being located at an intersection between an upper camming surface and a lower camming surface, the upper camming surface being configured to contact scleral tissue of the eye to guide the trough portion into Schlemm's canal, the lower camming surface being configured to contact a scleral spur of the eye to guide the trough portion into Schlemm's canal.
2. The cannula of claim 1 , wherein the asymmetric tip is configured to not pierce the scleral tissue.
3. The cannula of claim 1 , wherein the asymmetric tip is configured to pierce the trabecular meshwork.
4. The cannula of claim 1 , wherein the asymmetric tip is formed by the upper camming surface being shorter than the lower camming surface.
5. The cannula of claim 1 , wherein the rigid curved tube and the trough portion define a path for directing the ocular implant from a location outside of the eye to a location within Schlemm's canal of the eye.
6. The cannula of claim 1 , wherein the asymmetric tip is sufficiently blunt to slide along an outer wall of Schlemm's canal without cutting the scleral tissue underlying the outer wall of Schlemm's canal.
7. The cannula of claim 1 , wherein the asymmetric tip has an asymmetric V-shape.
8. The cannula of claim 1 , wherein the cannula is shaped and dimensioned so that at least part some of the trough portion can be advanced into Schlemm's canal while a first portion of the rigid curved tube is disposed inside the anterior chamber and a second portion of the rigid curved tube is extended through an incision in the eye to a location outside of the eye.
9. An ocular implant and delivery system, comprising:
a rigid curved cannula adapted to extend along a medial plane through an anterior chamber of an eye to achieve tangential entry into Schlemm's canal of the eye;
a trough portion formed by an opening extending along a distal portion of the rigid curved cannula;
an ocular implant configured to be carried inside the rigid curved cannula and advanced distally through the rigid curved cannula and along the trough portion into Schlemm's canal; and
an asymmetric tip disposed at a distal end of the trough portion offset from, and asymmetric about, the medial plane, the asymmetric tip being located at an intersection between an upper camming surface and a lower camming surface, the upper camming surface being configured to contact scleral tissue of the eye to guide the trough portion into Schlemm's canal, the lower camming surface being configured to contact a scleral spur of the eye to guide the trough portion into Schlemm's canal.
10. The system of claim 9 , wherein the asymmetric tip is configured to not pierce the scleral tissue.
11. The system of claim 9 , wherein the asymmetric tip is configured to pierce the trabecular meshwork.
12. The system of claim 9 , wherein the asymmetric tip is formed by the upper camming surface being shorter than the lower camming surface.
13. The system of claim 9 , wherein the rigid curved cannula and the trough portion define a path for directing the ocular implant from a location outside of the eye to a location within Schlemm's canal of the eye.
14. The system of claim 9 , wherein the asymmetric tip is sufficiently blunt to slide along an outer wall of Schlemm's canal without cutting the scleral tissue underlying the outer wall of Schlemm's canal.
15. The system of claim 9 , wherein the asymmetric tip has an asymmetric V-shape.
16. The system of claim 9 , wherein the rigid curved cannula is shaped and dimensioned so that at least part some of the trough portion can be advanced into Schlemm's canal while a first portion of the rigid curved cannula is disposed inside the anterior chamber and a second portion of the rigid curved cannula is extended through an incision in the eye to a location outside of the eye.
17. A method of inserting an ocular implant into Schlemm's canal of an eye, the method comprising:
inserting a curved cannula having a distal trough portion through an anterior chamber of the eye to gain tangential entry of the trough portion into Schlemm's canal;
allowing an upper camming surface of a distal tip of the distal trough portion to contact scleral tissue of the eye to guide the distal trough portion into Schlemm's canal;
allowing a lower camming surface of the distal tip of the distal trough portion to contact a scleral spur of the eye to guide the distal trough portion into Schlemm's canal; and
advancing an ocular implant through the curved cannula and along the distal trough portion into Schlemm's canal.
18. The cannula of claim 1 wherein the diameter of the rigid curved tube is approximately 350-550 microns.
19. The cannula of claim 18 wherein the diameter of the rigid curved tube is approximately 400-500 microns.
20. The cannula of claim 1 wherein the asymmetric tip is in a position offset from a central axis of the trough.
21. The cannula of claim 1 wherein the rigid curved tube extends along a medial plane, the asymmetric tip being asymmetric about the medial plane and the trough portion being symmetric about the medial plane.
22. The cannula of claim 9 wherein the asymmetric tip is in a position offset from a central axis of the trough.
23. The cannula of claim 9 wherein the rigid curved tube extends along a medial plane, the asymmetric tip being asymmetric about the medial plane and the trough portion being symmetric about the medial plane.
24. The method of claim 17 further comprising viewing the ocular implant as it advances along the distal trough.
25. The method of claim 24 further comprising identifying a position of a proximal end of the ocular implant with respect to an incision made by the cannula to access Schlemm's canal.
26. The method of claim 17 further comprising using an anatomical landmark to guide placement and advancement of the cannula.
27. The method of claim 26 wherein the anatomical landmark is the scleral spur.
28. The method of claim 26 wherein the anatomical landmark is a pigment line.
29. The method of claim 26 wherein the anatomical landmark is Schwalbe's line.
30. The method of claim 17 further comprising advancing the distal tip of the distal trough portion into Schlemm's canal without cutting the scleral tissue.
31. The method of claim 17 wherein the cannula has a body portion proximal to the distal trough portion, the method further comprising centering the body portion on Schlemm's canal and advancing the distal tip to pierce trabecular meshwork and a wall of Schlemm's canal at a point above a center of Schlemm's canal.
32. The method of claim 17 wherein the cannula has a body portion proximal to the distal trough portion, the body portion having a diameter greater than a diameter of Schlemm's canal of the eye.