2010-11-01 / Medical Info

Diabetic retinopathy is leading cause of blindness in patients under 65

By Kenneth N. Darvin, M.D.
Anyone may develop diabetes — some people are at higher risk. These include people who have relatives with diabetes, people who are overweight, African Americans, Hispanics, Native Americans, the elderly, Asian Americans and pregnant women (gestational diabetes). It is estimated that 5 million people in the United States are unaware they have diabetes. Symptoms develop gradually, but in some instances there are no symptoms at all. Some symptoms include: increased thirst, frequent urination, unexplained weight loss, increased hunger, blurry vision, recurring skin infections, wounds that do not heal, and unexplained fatigue.

There are two main types of diabetes: type I and type II. Type I diabetics have lost the ability to produce insulin, the hormone that regulates glucose in the blood. Type II diabetics are able to produce some insulin, but their bodies are resistant to it. It most often occurs in adults, accounts for 90 percent of cases in the U.S. and is often associated with obesity and abdominal fat. For these patients, exercise and weight loss is important in the treatment regimen, along with oral medication. For type I diabetics, treatment consists of administration of insulin and dietary changes.

Diabetic retinopathy is the leading cause of blindness in patients under 65. Diabetes affects the delicate blood vessels of the retina. Diabetic retinopathy is broken down into two types: non-proliferative and proliferative.

Non-proliferative (background) diabetic retinopathy is usually the early stage where blood vessels dilate and can leak blood, fluid or both. Sometimes the leakage is greater than the body’s ability to reabsorb it, and the retina becomes swollen. If the swelling occurs within the central part of the retina, the macula — where fine central vision is located — laser treatment is undertaken. The purpose of the laser is to shut down the leaking blood vessels and have the retina reabsorb the fluid. This laser treatment hopes to maintain central vision and prevent further visual loss. This type of complication from diabetic retinopathy can be reduced by 50 percent with laser treatment.

In proliferative diabetic retinopathy, new blood vessels begin growing on the surface of the retina and/or the optic nerve. The main cause is widespread closing of blood vessels leading to ischemia, causing chemical factors to be released in the back of the eye that make new blood vessel grow. The current main treatment is pan-retinal photocoagulation. The peripheral retina is lasered to cause these blood vessels to regress. Once again, appropriate laser treatment can prevent severe visual loss by 50 percent. The visual loss is secondary to new blood vessels that scar, shrink and wrinkle the retina, and can even cause a retinal detachment.

Proliferative diabetic retinopathy can also lead to a vitreous hemorrhage, when these new delicate blood vessels bleed into the vitreous cavity, causing a decrease in vision or a tractional retinal detachment. A vitreous hemorrhage or tractional retinal detachment can be operated on by a procedure called a vitrectomy. Final vision will depend upon the health of the underlying retina.

At times, neovascular glaucoma can occur. This happens when new blood vessels grow on the iris (the colored part of the eye) and even into the angle (between the iris and the cornea), which drains the fluid within the eye. These blood vessels grow and block this angle, causing a very high intraocular pressure, which is very hard to relieve even with surgical intervention.

Diabetics also have a higher risk of cataract formation but there are wonderful solutions. Recent studies for diabetic retinopathy have shown great promise in the use of medication for wet macular degeneration. It is very important that diabetics have their eyes examined with dilation once a year. If any retinopathy were found, that interval would be decreased depending upon severity.

Dr. Kenneth Darvin practices at Santamaria Eye Center, with locations in Perth Amboy and Edison. For more information, call 732-826-5159 or visit www.santamariaeyecenter. com.

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