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 a trabecular meshwork of an eye, the device comprising:
an elongate, flexible shaft formed of superelastic material, the shaft comprising:
a distal end region sized and configured for ab interno insertion into an anterior chamber of the eye;
a guide member integrally formed by a blunt distal end of the shaft and having a rounded lower surface; and
a tissue disruptor located on an upper surface of the shaft a distance proximal to the guide member, the tissue disruptor having a distal face that is a blunt tissue-engaging surface,
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 tissue disruptor on the upper surface of the shaft is sized to stretch and tear a trabecular meshwork of an eye 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 a height of the tissue disruptor is at least 150 microns, preferably 500-800 microns and wherein a width of the tissue disruptor 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 shaft has a non-circular cross-sectional shape.
6 . The device of claim 5 , wherein the non-circular cross-sectional shape has a minor axis and a major axis.
7 . The device of claim 6 , wherein the minor axis is less than 250 microns and wherein the major axis is larger than 250 microns.
8 . The device of claim 1 , wherein a thickness of the guide member is about 150 microns.
9 . The device of claim 1 , wherein a height of the tissue disruptor is about 300 microns.
10 . The device of claim 1 , further comprising a proximal portion having an actuator, the proximal portion configured to remain outside the eye during use of the device, the actuator configured to translate the shaft distally and proximally relative to the proximal portion.
11 . The device of claim 10 , 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.
12 . The device of claim 10 , wherein the shaft is configured to be translated about 10 to about 360 degrees of Schlemm's canal.
13 . The device of claim 1 , wherein the lower surface of the guide member is textured.
14 . A device for removing a trabecular meshwork tissue from an eye, the device comprising:
an elongate shaft comprising a distal end region; and
a non-cutting tissue engager coupled to the distal end region of the shaft sized to stretch and tear trabecular meshwork tissue along opposite sidewalls as the shaft is advanced along a circumferential contour of the eye, the tissue engager comprising:
a lower plate having a lower surface and an upper surface, the lower surface of the lower plate configured to slide against an outer wall of Schlemm's canal during use;
an upper plate projecting over at least a portion of the upper surface of the lower plate;
a recess extending between the lower plate and the upper plate, the recess comprising a concave portion configured to gather torn trabecular meshwork tissue as the shaft is advanced; and
a guide member projecting from the lower plate, the guide member comprising a blunt distal-most end.
15 . The device of claim 14 , wherein a surface of the tissue engager is textured.
16 . The device of claim 14 , wherein the recess comprises a depth of at least 50 microns.
17 . The device of claim 14 , wherein the guide member extends distally from a main body of the tissue engager by a distance of 30-500 microns.
18 . The device of claim 14 , wherein the device comprises a feature configured to separate the torn trabecular meshwork tissue from native trabecular meshwork tissue in the eye during use.
19 . The device of claim 18 , wherein the torn trabecular meshwork tissue extends through the feature as the shaft is advanced.
20 . The device of claim 14 , wherein the blunt distal-most end is configured to penetrate trabecular meshwork tissue and enter a portion of Schlemm's Canal.