Methods and devices for increasing aqueous drainage of the eye
Devices and methods to remove trabecular meshwork to treat glaucoma and other conditions which may not utilize cutting elements when stripping the trabecular meshwork. The trabeculorhexis parts tissue by applying non-cutting shear and tension to the tissue to disinsert the tissue from its attachments. Reducing or eliminating the need for sharp cutting implements in the eye reduces the likelihood of incisional bleeding, iris and scleral tissue maceration and further inadvertent tissue damage of the gonio structure of the eye. In another aspect, a cutting element may be used to form a circumferential slit in a wall of Schlemm's canal in conjunction with removal of trabecular meshwork or independently.
1 . A device for disrupting tissue in an eye, the device comprising:
an introducer comprising a lumen and a curved distal end region; and
an elongate, flexible shaft of superelastic material extendable through the curved distal end region of the introducer, the shaft comprising:
a distal end region sized and configured for ab interno insertion into an anterior chamber of the eye, the distal end region shaped into a curve having a central plane, the distal end region of the shaft having a radially inner surface connected to a radially outer surface by opposing sidewalls;
a guide member integrally formed by a blunt distal end of the shaft and having a rounded lower surface; and
a tissue disruptor located a distance proximal to the guide member, the tissue disruptor having a distal face that is a blunt tissue-engaging surface, the tissue disruptor having a height between the radially inner surface and the radially outer surface and a width between the opposing sidewalls,
wherein the rounded lower surface of the guide member is configured to slide atraumatically against an outer wall of Schlemm's canal, and wherein the height and the width of the tissue disruptor are sized to stretch and tear the trabecular meshwork along the opposing sidewalls as the shaft is advanced in an advancing direction along a circumferential contour of the eye.
2 . The device of claim 1 , wherein the superelastic material is Nitinol.
3 . The device of claim 1 , wherein the height is at least 150 microns, preferably 500-800 microns and wherein the width is at least 400 microns, preferably about 500-700 microns.
4 . The device of claim 1 , wherein the distance proximal is at least 500 microns.
5 . The device of claim 1 , wherein the radially outer surface slides against the outer wall of Schlemm's canal during use.
6 . The device of claim 1 , wherein the shaft has a non-circular cross-sectional shape.
7 . The device of claim 6 , wherein the non-circular cross-sectional shape has a minor axis and a major axis.
8 . The device of claim 7 , wherein the minor axis is less than 250 microns and wherein the major axis is larger than 250 microns.
9 . The device of claim 1 , wherein the curved distal end region of the introducer curves between 15-60 degrees.
10 . The device of claim 1 , wherein the tissue disruptor further comprising a first projection along the radially inner surface and a second projection along the radially outer surface, wherein the second projection on the radially outer surface is configured to disrupt tissue of an outer wall of Schlemm's canal.
11 . The device of claim 10 , wherein a spring response of the shaft urges the second projection in a radially outward direction to engage against the outer wall.
12 . The device of claim 1 , wherein a thickness of the guide member between the radially inner surface and the radially outer surface of the shaft is about 150 microns.
13 . The device of claim 1 , wherein the height of the tissue disruptor is about 300 microns.
14 . The device of claim 1 , further comprising an actuator on a proximal portion configured to remain outside the eye, the actuator configured to translate the shaft distally and proximally relative to the proximal portion.
15 . The device of claim 14 , wherein the distal end region of the shaft develops a spring load as the shaft is advanced distally relative to the proximal portion, the spring load providing a radially outward force in a direction perpendicular to the advancing direction and lying in the central plane.
16 . The device of claim 14 , wherein the shaft is configured to be translated about 10 to about 360 degrees of Schlemm's canal.
17 . The device of claim 1 , wherein the lower surface of the guide member is textured.