What is the connection between diabetes and the eyes?
Diabetes can damage almost every part of the eye. Indeed, it is the leading cause of adult blindness in the United States. The danger increases with the length of the illness. Two-thirds of diabetics will show signs of eye damage after 15 years, and up to 90 percent will have some eye damage after 30 or 40 years. For this reason, it is important for any person with diabetes to have an annual examination in which eye drops are used to dilate the pupil and the physician examines the eyes to detect damage. A doctor may recommend eye examinations as frequently as every two or three months for some patients, although examinations every six months or once a year will be sufficient in most cases. Anyone with diabetes should be alert for the symptoms of eye problems, such as blurred vision, and increase in floaters, or any other unusual change.
What is diabetic retinopathy and how is it treated?
Perhaps the most serious eye problem caused by diabetes is diabetic retinopathy, damage to the light-sensitive retinal cells that line the back of the eye. Some degree of retinopathy can be detected in more than 70 percent of all diabetics 10 years after the diagnosis is made. Diabetic Retinopathy has 2 forms: Nonproliferative (less severe) and Proliferative (most severe).
Nonproliferative diabetic retinopathy is caused by changes in the mural cells that line the blood vessels and prevent them from leaking. Over the years, diabetes leads to a decrease in the number of mural cells, causing the capillaries that nourish the retina to leak blood into the retina. Diabetic macular edema, swelling of the central portion of the retina responsible for central vision, is the most common reason for blindness related to diabetic retinopathy.
Proliferative diabetic retinopathy is the result of decreased blood supply to the retina. The retina then develops abnormal blood vessels (neovascularization). These blood vessels can cause severe bleeding in the retina, bleeding into the vitreous humor causing blurred vision and floaters, and can also detach the retina, causing blindness.
Diabetic retinopathy can be treated by use of laser aimed at blood vessels that are weakened or overgrown. This kind of laser surgery may also be performed to thin out retinal tissue, so that the blood supply to the retina is increased. If blood has leaked into the vitreous humor, vitrectomy may be performed to remove the vitreous humor and replace it with an artificial substance. Avastin injections into the retina is a new treatment for diabetic retinopathy.
What other eye problems may be caused by diabetes?
Diabetes can also affect the lens, leading to cataract formation. Diabetic cataracts tend to form earlier than most cataracts, and they develop more rapidly. Diabetic cataracts are treated in the same ways as other cataracts, by surgery to remove the damaged lens and replacement with an artificial lens. Cataract surgery generally is done under local anesthesia and without a hospital stay, so that the patient who walks in with clouded vision in the morning can walk out by mid-afternoon with a new, clear lens.
Diabetic patients also have and increased risk of glaucoma and dry eye disease. Glaucoma can be treated with medications and/or SLT (laser glaucoma procedure). There are multiple options for dry eye treatment, including artificial tears, warm compresses, Restasis, and punctal plug procedures.