Shunting to Suprachoroidal Space
Suprachoridal shunts aim to lower IOP by exploiting the outflow facility of the suprachoroidal space and providing a controlled and sustainable fluid egress from the anterior chamber. A secondary physiologic passageway exists, the uveoscleral pathway, in which aqueous flows into intracellular spaces in the ciliary muscle, moves through the supraciliary and suprachoroidal spaces, and finally exits the eye via absorption into the choroidal capillaries or by permeation across the sclera. The suprachoroidal space can be accessed through an ab interno approach using a clear corneal incision and intra-operative gonioscopy. There are two devices, one now available (CyPass) and the other in FDA clinical trials (iStent Supra), that offer this mechanism.
The CyPass Micro-Stent (Alcon) is a small device designed to reduce IOP by enhancing suprachoroidal aqueous outflow. The device is a 6.35-mm long tube with an outer diameter of 0.51 mm; it is made of a polyim- ide material similar to that used in intraocular lens haptics. It is FDA approved to be implanted at the time of cataract surgery.
Watch a video of Cypass surgery
Read more about the Cypass procedure in an article in MillennialEYE entitled, “Shifting Gears in Glaucoma with Suprachoroidal Shunts.”