What is neovascular glaucoma (NVG)?
Neovascular glaucoma (NVG) is a severe type of glaucoma. Glaucoma is a condition in which the pressure inside the eye damages the cells of the optic nerve. The normal range of pressure in the eye is between 8-21 units of measurement. There is a tissue inside the eye called the ciliary body that pumps a clear fluid (aqueous) into the eye keeping the eye from collapsing. Another tissue called the trabecular meshwork drains the aqueous from the eye preventing the pressure from building up too high. The pump and the drain are not connected and do not communicate with each other. However, there is a normal balance between the pump and drain so that the eye pressure remains normal and healthy for the eye. In neovascular glaucoma (NVG) abnormal blood vessels grow inside the eye where they block the drain resulting in high pressure. High pressure inside the eye damages the cells of the optic nerve. The optic nerve transmits information from the eye to the brain to provide vision. Therefore, NVG can cause pain, loss of vision, and blindness if left untreated.
What causes neovascular glaucoma (NVG)?
The abnormal blood vessels in NVG grow inside the eye as a result of poor retinal blood supply. There are many conditions that cause abnormal blood supply to the retina. They include diabetic retinopathy, retinal vein occlusion, retinal artery occlusion, ocular ischemic syndrome, retinal detachment, and inflammation. In these conditions the blood supply to the retina is impaired, so the retina sends out chemical messages that it needs more blood supply. As a result, new blood vessels begin to grow inside the eye. Unfortunately, these new blood vessels may grow into the drain (trabecular meshwork) where they cause harm.
What are the symptoms of neovascular glaucoma (NVG)?
In the early stages of NVG, there may be no symptoms. However, as the pressure inside the eye rises, symptoms include pain, redness, and loss of vision. Sometimes, the pain is so severe that it causes nausea and vomiting. If left untreated, NVG frequently results in a blind eye.
How is neovascular glaucoma (NVG) diagnosed?
The most common test for glaucoma in an eye examination is tonometry. Tonometry measures the pressure inside the eye. Most people are first suspected to have glaucoma because high pressure is found on an eye exam. In NVG the ophthalmologist then detects abnormal blood vessels growing in the drain (called NVA) by an office exam called gonioscopy. The presence of high pressure in an eye with NVA makes the diagnosis of neovascular glaucoma.
What treatment is available?
The key to treating NVG is addressing the underlying cause of poor blood supply to the retina. Examination and testing usually provides the retinal diagnosis and treatment is directed toward treating that condition. Frequently, medication injections (Avastin, Lucentis, and Eylea) initially help control the growth of abnormal blood vessels until laser or cryopexy can provide a more permanent effect.
If the drain (trabecular meshwork) has not been permanently damaged by scar tissue induced by the abnormal blood vessels, the pressure inside the eye may return to normal. However, if permanent damage has occurred, eye drops and/or surgery may be needed to control the pressure. The first line of treatment in most cases includes prescription eye drops. There are a number of very effective eye drops that work by either opening the drain or by slowing down the pump to lower the pressure. These drops are powerful medicines that should be used exactly as prescribed to prevent blindness from glaucoma and minimize side effects from the eye drops. Side effects are not common, but may include burning, itching, redness, dry mouth, and worsening of bronchitis or asthma. It is very important to take the eye drops exactly as prescribed to prevent blindness. If eye drops fail to control the pressure, surgery may help. Surgery, performed in the operating room (trabeculectomy or glaucoma drainage device), creates an artificial drain to lower the pressure. After trabeculectomy patients are warned to notify the doctor urgently if the eye becomes red or appears to be infected, because infection may enter the eye after glaucoma surgery and result in severe damage or blindness. In general, patients with glaucoma may require regular examinations every three to four months to preserve vision.
The goal of treatment is to protect the vision and relieve pain. If there is no usable vision, the pressure only needs to be controlled enough to prevent pain. In severe cases surgery is performed to remove the eye (enucleation or evisceration) to relieve pain in a blind, painful eye. An artificial eye is made to appear cosmetically acceptable.
For a telemedicine consultation with Dr Pautler, please send email request to spautler@rvaf.com. We accept Medicare and most insurances in Florida. Please include contact information (including phone number) in the email. We are unable to provide consultation for those living outside the state of Florida with the exception of limited one-time consultations with residents of the following states: Alabama, Arkansas, Connecticut, Georgia, Minnesota, and Washington.
Copyright © 2021 Designs Unlimited of Florida. All Rights Reserved.