Neovascular glaucoma: etiology, diagnosis and prognosis.

Neovascular glaucoma (NVG) is a severe form of glaucoma with devastating visual outcome attributed to new blood vessels obstructing aqueous humor outflow, usually secondary to widespread posterior segment ischemia. Invasion of the anterior chamber by a fibrovascular membrane initially obstructs aqueous outflow in an open-angle fashion and later contracts to produce secondary synechial angle-closure glaucoma. The full blown picture of NVG is characterized by iris neovascularization, a closed anterior chamber angle, and extremely high intraocular pressure (IOP) with severe ocular pain and usually poor vision.