Retinal vascular disorders most commonly refer to a blockage of the arteries or veins in the retina. The blockage can occur in the central or a branch off of the central artery or vein. The degree of vision loss usually corresponds with the severity and location of occlusion. Retinal vascular occlusions can be categorized into:
Central retinal artery occlusion (CRAO)
Central retinal artery occlusion (CRAO) usually causes severe, immediate, and painless vision loss. Patients may have a history of temporary vision loss (amaurosis fugax). This is usually caused by a clot of blood or other material in the artery. The major risk factors include high blood pressure, diabetes, carotid artery disease, and occasionally auto-immune illnesses. Patients are usually diagnosed by ocular examination and angiogram. Sytemic evaluation may include blood pressure,blood tests, carotid artery ultrasound, echocardiogram, and other tests as necessary. Unfortunately, treatment rarely improves vision. Patients need to be seen in follow-up for secondary complications.
Branch retinal artery occlusion (BRAO)
Branch retinal artery occlusion (BRAO) usually causes sudden, painless loss of central or peripheral vision. Patients may have a history of temporary vision loss (amaurosis fugax). This is usually caused by an embolus (clot of platelets, cholesterol, or other) that lodges in the branches of the retinal arteries. Patients are diagnosed by ocular examination and angiogram. Systemic evaluation may include carotid ultrasound, echocardiogram and possibly blood tests. Visual prognosis is related to the location and severity of the blockage. Treatment is usually not effective in this disorder.
Central retinal vein occlusion (CRVO)
Central retinal vein occlusion (CRVO) can cause sudden or gradual vision loss and patients may have no symptoms or have severe vision loss. Major risk factors include high blood pressure, cardiovascular disease, diabetes, and other clotting disorders. Patients are usually evaluated with angiogram and OCT (retina scan). Systemic evaluation may include blood pressure and blood tests. Vision loss can occur from poor blood supply to the macula, swelling of the macula, and bleeding and glaucoma resulting from the occlusion. Patients are monitored for these complications and may be treated with laser or injections in the eye. Rarely, surgical intervention may be necessary to control secondary complications such as bleeding or glaucoma.
Branch retinal vein occlusion (BRVO)
Branch retinal vein occlusion (BRVO) can cause decreased central or peripheral vision. Major risk factors include hypertension and diabetes. Patients are usually evaluated with angiogram and OCT (retina scan). Systemic evaluation includes blood pressure and sometimes other blood tests. Vision loss usually results from swelling of the retina and less commonly from bleeding. Spontaneous vision improvement is possible. If vision does not improve, treatment with laser or intraocular injections may be performed. Patients are monitored for retinal swelling and abnormal vessel growth.