Neovascular glaucoma is a potentially devastating type of glaucoma that can cause blindness if not treated quickly. Neovascular glaucoma is classified as a secondary glaucoma, as it is caused by other health conditions. Most people who develop glaucoma develop the disease very slowly, over a period of years. However, neovascular glaucoma can occur suddenly.
Who’s at Risk
People at increased risk for developing neovascular glaucoma include those who have diabetes, high blood pressure, high cholesterol, or some other cardiovascular problem. Most people that have neovascular glaucoma are older.
Neovascular glaucoma is sometimes referred to as “90-day glaucoma” because it develops very close to 90 days after some type of ischemic vascular event. An ischemic vascular event is an event in which tissue may develop a sudden lack of blood flow or a slow perfusion of blood supply and oxygen to a certain area. Most people with neovascular glaucoma will have one of the preceding events:
- active diabetic retinopathy
- carotid artery disease
- retinal blood vessel occlusion
- retinal detachment
After an ischemic event, tissue quickly loses oxygen. The tissue in the eye sends signals to grow new blood vessels (a process called neovascularization) in an attempt to bring oxygen and nourishment to the tissue. However, these new blood vessels are fragile and weak and tend to leak blood. This response brings out immune system factors that cause inflammation.
Because the backside of the iris is rich with blood vessels, these new vessel buds begin to grow there. New vessels grow through the pupil and onto the front part of the iris and ultimately into the angle of the eye, where the cornea meets the iris. The angle of the eye houses the trabecular meshwork, which is a drain pipe of sorts that filters and drains the intraocular fluid inside the eye.
These new blood vessels and other fibrous tissue will clog up this drain pipe and cause angle closure. When the angle closes, the eye pressure becomes very elevated, causing blurred vision and a red, painful eye. It takes approximately 90 days for this process to occur—hence the name “90-day glaucoma.”
Quick, aggressive therapy is needed to avoid blindness. Neovascular glaucoma is treated by reducing eye pressure quickly and also reducing inflammation. When inflammation occurs in the front part of the eye, the tissue becomes sticky, causing even more problems. As soon as the pressure and inflammation are reduced, most physicians perform pan-retinal photocoagulation (PRP). PRP is widespread lasering of the peripheral retina to destroy ischemic retina so that those new blood vessels will stop growing. This usually causes regression of the blood vessels. Because PRP destroys part of the retina, patients may have decreased peripheral vision. Most often, central vision remains intact.
A Word From Get Meds Info
New treatments are starting to be used by retinal specialists, which consist of antiangiogenic drugs, such as Avastin. These drugs modify the immune system response to stop new blood vessel growth and inflammation. Studies have shown quick resolution of these vessels but sometimes the condition will reoccur if the underlying cause is not addressed. Because of this, antiangiogenic drugs are used in conjunction with PRP. As soon as eye complications are treated, the underlying cause must be addressed, which is usually diabetes, hypertension, carotid artery disease, or other vascular problems.