Glaucoma ducts, and narrowing or closure of the angle between the iris and cornea. The primary division in categorizing different types of glaucoma is open-angle and closed-angle (or angle-closure) glaucoma. In open angle glaucoma, the iris meets the cornea normally, allowing the fluid from inside the eye to drain, thus relieving the internal pressure. Where this angle is narrowed or closed, pressure increases over time, causing damage to the optic nerve, leading to blindness. Primary open-angle glaucoma (also, "primary glaucoma", "chronic glaucoma") refers to slow clogging of the drainage canals resulting in increased eye pressure which causes progressive optic nerve damage.
Glaucoma valve drainage, such as iStent, CyPass, or Hydrus. A Cochrane Review of various aqueous shunts and modifications found that the Baerveldt implant may result in lower IOP than the Ahmed implant, but it was unclear if the difference in IOP reduction was clinically significant. The review suggests that practitioners should operate with the devices that they are most comfortable with, and have the most experience using. The glaucoma valve implant is indicated for glaucoma patients not responding to maximal medical therapy, with previous failed guarded filtering surgery (trabeculectomy) or in cases where conventional drainage surgery is unlikely to succeed. Common situations