Neovascular glaucoma is a type of secondary glaucoma – meaning that it is caused by something else. This type of glaucoma is a type of angle-closure glaucoma. It is most commonly linked to proliferative diabetic retinopathy and central retinal vein occlusion. It may also be caused by narrowing of the carotid artery and other factors which result in ischemia, a reduction in blood flow to the retina.
New blood vessels (known as neovascularization) are formed in the angle of the eye and block drainage of eye fluid through the trabecular meshwork. These new blood vessels can also be formed in the iris, optic nerve and retina.
Anyone with poor blood flow to the eyes is at risk for neovascular glaucoma. That is why diabetics are at particularly high risk, since diabetes is associated with reduced blood flow to many parts of the body, including the eyes. If you are a diabetic – particularly if you have had the disease for 10 or more years, you should have a dilated eye exam annually.
Blood vessels in the eye provide nourishment and eliminate waste. When neovascularization occurs over the iris or the trabecular meshwork, it can totally block the drainage of fluid from the eye. This will result in increased eye pressure and cause damage to the optic nerve.
The neovascular vessels are also weak. They can leak and bleed into the eye, causing a hyphema.
Medical Treatment
The first thing that needs to be done is to reduce your eye pressure. This can be accomplished by using various blocking eyedrops or oral medication, such as acetazolamide, to reduce the production of aqueous fluid.
The second step is to eliminate the neovascularization. This is particularly important if the disease is diagnosed early, as it helps preserve the optic nerve.
The neovascularization is caused by damaged cells in the back of the eye (the retina) which are malnourished as a result of the poor blood flow. These damaged structures produce chemicals that cause the new blood vessels to form, and they must be destroyed.
Laser Treatment
The first way to destroy the damaged structures in the retina is by panretinal photocoagulation. In this procedure, done at all 5 of our locations, a special laser is used to make hundreds of tiny burns in the retina. These burns seal leaky vessels and prevent the formation of the chemicals which cause neovascularization.
During the treatment, your eye will be numbed with anesthetic eyedrops. A special lens will focus the beam of light onto your eye. You will feel little or no pain, although you will notice flashes of bright light.
The laser treats the middle and peripheral parts of the retina to prevent loss of central vision. Your vision may be blurry following the treatment, which can take between 10-15 minutes. The doctor can only work on one eye at a time, and more than one treatment may be required in each eye.
Following the surgery, your vision may be blurry but gradually improve. However, in some patients, there can be a permanent loss of peripheral (sideways) vision. This peripheral vision is sacrificed to preserve your remaining central vision. Your night vision may also be diminished, so you should use caution in driving.
You will not be able to drive home following the treatment. Therefore, you should make transportation arrangements. In addition, you may want to bring your sunglasses, as your eyes will be dilated for this procedure.
Another treatment for neovascular glaucoma is peripheral cryotherapy – the use of a cold application to seal the leaky vessels. This procedure is used in situations where it would be difficult to apply the laser. After eye drops are used to numb your eye, your doctor will apply a probe that generates cold treatment to the surface of your eye, above the peripheral areas of the retina.
This treatment is done at our Plymouth Laser & Surgical Center. Since your vision may be blurry following this treatment, you will not be able to drive home. In addition, following cryotherapy, your eye may remain somewhat red and swollen for a period of time. This is normal and should not be of concern.
These treatments are done on an outpatient basis, and you may experience mild discomfort. Following both types of treatment, regular follow up visits with your doctor are essential to monitor your glaucoma.
Surgical Treatment
If panretinal photocoagulation or peripheral cryotherapy is unsuccessful in controlling neovascularization, or if the eye pressure remains high, filtering surgery would be required. This would either take the form of trabeculectomyor the implantation of a minute drainage tube.
Overview of Glaucoma
Open Angle Glaucoma
Medical Treatment for Open Angle Glaucoma
Laser Treatment for Open Angle Glaucoma
Surgery for Open Angle Glaucoma
Narrow Angle Glaucoma
Laser Treatment for Narrow Angle Glaucoma
Neovascular Glaucoma
Inflammatory Glaucoma
