Central Retinal Vein Occlusion (CRVO) occurs when the main retinal vein is blocked. Because the blood can no longer travel out of the retina smoothly, the retina becomes filled with blood and swollen. If the blockage is partial, the retina may continue to function adequately. If the blockage is more severe, permanent retinal damage may occur with loss of vision. Central retinal vein occlusions occur most commonly in people who have high blood pressure, diabetes or glaucoma. Occasionally, the damage to the retina will result in abnormal new vessel growth. Further visual loss can occur if these abnormal blood vessels break and bleed into the vitreous cavity, causing a vitreous hemorrhage.

Central Retinal Vein Occlusion

Neovascular Glaucoma
Neovascular Glaucoma is a condition in which abnormal blood vessels grow on the iris or colored part of the front of the eye. These abnormal blood vessels can block the flow of fluid from the eye and cause the eye pressure to become very high. Neovascular glaucoma can cause pain, halos around lights, and rapid loss of vision. Prompt laser treatment, intravitreal medication, and sometimes surgery is required to reduce the risk of blindness.

Neovascular Glaucoma

Symptoms of CRVO
Patients with central retinal vein occlusion usually have blurred vision from retinal hemorrhage and swelling. Spots, strands or curtains in the vision may occur due to vitreous hemorrhage. Eye pain may be caused by neovascular glaucoma.

Evaluation
In addition to a dilated eye exam, a test called Fluorescein Angiography may be required. During this test a dye is injected into a vein in the arm. Special photographs are taken of the retina as the dye passes through the eye. Blocked or abnormal blood vessels will become detectable to the physician. Optical Coherence Tomography (OCT) may be performed to determine if macular edema is present. These tests aid the diagnosis and may help determine the type of treatment needed.

Fluorescein Angiography of CRVO with Delayed Filling of Veins