Nearly 26 million Americans have been diagnosed with diabetes, and another 79 million have prediabetic conditions that put them at risk. Roughly half of these persons can be expected to develop retinopathy, the leading cause of blindness among American adults.
Once retinopathy has become established, there is no cure and no treatment that can reverse damage to eyes that has already occurred. However, the risk of vision loss can be reduced by 90 percent or more with early detection and careful management.
The best strategies for protecting yourself are things you should be doing anyway for overall good health: 1) Keep your blood sugar, cholesterol and blood pressure under control; 2) Don’t smoke. 3) Get a dilated eye examination from an ophthalmologist at least once a year. According to results of the Los Angeles Latino Eye Study, only 35 percent of type 2 diabetics had received an eye examination within the past 12 months.
Diabetes retinopathy typically develops after a person has had diabetes for 10 years or longer. Some persons have type 2 diabetes for years without knowing it. Eye problems may be already present or even in an advanced stage at the time of diagnosis.
The major underlying cause is uncontrolled blood sugar which damages the tiny blood vessels in the retina or light-sensitive lining of the eye. Once these vessels are damaged, they become more vulnerable to changes caused by high cholesterol, high blood pressure and smoking.
The disease process typically occurs in four stages: 1] Mild nonproliferative retinopathy: Tiny blood vessels begin to swell and balloon out because of blockages to blood flow. 2] Moderate nonproliferative: Some blood vessels in the retina become blocked, inhibiting normal blood flow. 3] Severe nonproliferative: More and more blood vessels become blocked, leaving several areas of the retina without adequate blood flow. In order to get proper nourishment, the retina sends out signals for new blood vessels to grow — a process known as angiogenesis. 4] Proliferative retinopathy: This is the most severe stage during which new blood vessels proliferate in the retina. These blood vessels are abnormal and fragile with thin walls that are vulnerable to leaking. When leaking occurs, the result can be severe vision loss or even blindness.
Until this final stage, changes taking place in the eye are unlikely to cause symptoms but can be readily identified by an eye doctor looking into the eye through a dilated pupil.
Thickening or swelling of the central part of the retina, known as macular edema, can occur during any of the four stages. The macula is needed for sharp, central vision, and damage to it can cause blurring, particularly near the center of the image.
When macular edema is detected, it can be treated with focal laser treatment. Using a laser, the doctor makes several hundred small burns in the affected area, reducing the leakage of blood vessels.
Even when macular edema is present, however, symptoms may not show up or may not be noticed until the proliferative stage. Bleeding within the eye may come and go during this stage, but it must be stopped if vision is to be saved.
Treatment involves scatter laser surgery. In an effort to shrink the blood vessels, the doctor delivers 1,000-2,000 small laser burns away from the center of the retina. Medications to stop the growth of new blood vessels have also been found effective.
When extensive bleeding occurs and clouds the vitreous gel that fills the center of the eye, a vitrectomy may be needed. This is a surgical procedure that involves removing the vitreous gel and replacing it with a salt solution.
While these surgical procedures are effective at halting the disease process, they do not restore any vision that was lost. Over the last five years, however, significant developments in medical management have occurred, offering hope not only to persons who detect problems early, but those already suffering retina damage.
Two recent studies have found significant benefit from the use of fenofibrate and simvastatin, combined with lifestyle measures to lower cholesterol — even in patients with established retinopathy.
Rupp is a certified information and referral specialist on aging for NODA Area Agency on Aging. Contact her at 237-2236.