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The abnormal formation of new blood vessels on the iris and over the eye’s drainage channels can cause this form of secondary glaucoma.
Neovascular Glaucoma (NVG) is a type of secondary glaucoma associated with disorders that reduce blood flow to the retina (the light sensitive layer in the back of the eye). When the retina does not get enough blood flow, it produces a growth factor (vascular endothelial growth factor or VEGF) that helps to form new blood vessels. However, these new blood vessels are leaky, and can cause bleeding and inflammation, followed by scarring. They can also grow in the wrong place in the eye. When the new blood vessels form over the eye’s drainage channels, the eye fluid is blocked from exiting through the trabecular meshwork. This leads to high intraocular pressure (IOP) which can damage the optic nerve.
Symptoms of NVG can include pain or discomfort, eye redness, and vision loss. This type of glaucoma never occurs on its own and is always associated with other abnormalities, such as retinal vein occlusion and diabetes.
The treatment of neovascular glaucoma is two-fold. The underlying retinal problem is treated with anti-VEGF drug injections and retinal laser treatment to reduce or eliminate the continued growth of new blood vessels. Concurrently, glaucoma is treated by lowering IOP. In NVG, IOP-lowering medications are usually not very effective and most patients require some type of IOP-lowering procedure such as a glaucoma drainage device or laser cyclophotocoagulation. The treatment chosen depends on the stage of the disease and how much vision has already been lost.
Since NVG is difficult to treat, prevention (when possible) is preferred. Patients at high risk for developing neovascular glaucoma, such as those with proliferative diabetic retinopathy, should have frequent and careful eye exams. The eye doctor will look inside your eye and carefully examine the iris and the angle for signs of new blood vessels.
Neovascular glaucoma is always challenging to treat, but in many cases some vision can be preserved, especially if NVG is detected and treated early in the disease process.
Sunita Radhakrishnan, MD specializes in the medical and surgical treatment of glaucoma at the Glaucoma Center of San Francisco and is Research Director at the Glaucoma Research and Education Group in San Francisco.
Last reviewed on January 12, 2022
This article appeared in the January 2022 issue of Gleams.Subscribe