Glaucoma is a group of eye disorders that damage the nerve at the back of the eye (optic nerve), resulting in loss of eyesight, especially peripheral (side) vision. Neovascular glaucoma is a type of severe glaucoma in which blood vessels in the iris block the normal drainage of fluid out of the eye, causing increased pressure in the eye that eventually damages the optic nerve.

Neovascular glaucoma often causes pain and redness in the eye. It most often develops in people who have poorly controlled diabetes, but it also occurs in association with other vascular diseases, such as high blood pressure (hypertension).

Treatment of neovascular glaucoma may require removal of the blocked blood vessels and medications to reduce the pressure in the eye.