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The retina is a thin sheet of nerve tissue in the back of the eye where light rays are focused and transmitted to the brain via the optic nerve. Tiny blood vessels supply the retina with oxygen and other nutrients. Arteries deliver the blood, and veins carry it out. Sometimes one of these arteries hardens or swells and presses on a nearby vein. The vein can then become blocked, or occluded, making it difficult for blood to leave the eye. This is called a retinal vein occlusion. The restricted circulation leads to high pressure in the eye, which can in turn cause swelling, bleeding, growth of abnormal blood vessels, and partial or total vision loss.
Retinal vein occlusions are the second most common cause of blood vessel-related vision loss (the first is diabetic retinopathy). The condition occurs most often in men and women over the age of 50, particularly those in their 60s and 70s. Risk factors include atherosclerosis (hardening of the arteries), high blood pressure, high cholesterol, diabetes, smoking, glaucoma, and, in rare cases, blood clotting and inflammatory conditions.
Treatment and prognosis depend on the severity of the blockage and the location of the occluded vein. If the largest vein leaving the eye is affected, the condition is known as a central retinal vein occlusion, or CRVO; otherwise, it is called a branch retinal vein occlusion, or BRVO. Retinal vein occlusions do not cause a change in physical appearance, and BRVOs often occur with no pain or noticeable loss of vision. For these reasons, it is important to have routine eye exams and also to check one’s own vision by closing one eye at a time.
There is no cure for retinal vein occlusions, so emphasis is placed on risk management, treatment of symptoms and prevention of further vision loss. It is critical to control high blood pressure, high cholesterol, diabetes and other health conditions that increase the risk of vascular hardening, narrowing and blood clotting.
Patients with diabetes are at an increased risk of developing eye diseases that can cause vision loss and blindness, such as diabetic retinopathy, cataracts and glaucoma. These and other serious conditions often develop without vision loss or pain, so significant damage may be done to the eyes by the time the patient notices any symptoms.
is a complication of diabetes that weakens the blood vessels that supply nourishment to the retina (the light-sensitive lining in the back of the eye where vision is focused). When these weak vessels leak, swell or develop thin branches, vision loss occurs. In its advanced stages, the disease can cause blurred or cloudy vision, floaters and blind spots – and, eventually, blindness. This damage is irreversible.
Fortunately, diabetic retinopathy is preventable. People with diabetes are most susceptible to developing it, but your risk is reduced if you follow your prescribed diet and medications, exercise regularly, control your blood pressure, and avoid alcohol and cigarettes. Regular eye exams are an integral part of making sure your eyes are healthy.
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