DIABETIC EYE DISEASE
This page covers Diabetic Eye disease, both the condition, its treatment and problems associated with it.
Diabetic Retinopathy is a progressive disease that destroys capillaries (the smallest blood vessels linking arteries to veins) in the eye by depositing an abnormal material along the walls of the tiny blood vessels in the retina. Normally, the blood vessels in the retina do not leak. But with diabetes, the retinal blood vessels can develop tiny leaks. These leaks cause fluid or blood to seep into the retina. The retina then becomes wet and swollen (called “thickened”) and cannot work properly. The form of diabetic retinopathy caused by leakage of the retinal blood vessels is called Non-proliferative (or background) diabetic retinopathy. I will use the term NPDR (Non-proliferative diabetic retinopathy).
Another problem with the retinal blood vessels in diabetes is that they can close. The retinal tissue, which depends on those vessels for nutrition, will no longer work properly. The areas of the retina in which the blood vessels have closed then foster the growth of abnormal new blood vessels, called neovascularization, that can be very bad for the eye because neovascularization can cause bleeding and scar tissue that can result in blindness. The form of diabetic retinopathy caused by closure of the blood vessels and in which neovascularization develops is called Proliferative Diabetic retinopathy. I will use the term PDR for Proliferative Diabetic Retinopathy.
Eye Changes Associated With Diabetes
Changes in vision may happen at the time that diabetes is first diagnosed or at any time that blood sugar control is poor. Fluctuating blood sugars cause the lens to swell and shrink, and result in fluctuating vision. Many times, people who have “borderline” diabetes are unaware of their condition until their vision becomes blurred. This is the reason why your eye care provider is often the first to detect diabetes.
Patients afflicted with diabetes often marvel that they no longer need their glasses to see in the distance. This is due to the swelling of the lens and/or corneal tissues secondary to elevated blood sugar levels. However, once insulin or other therapy has begun and the blood sugar drops, the abnormal swelling diminishes. The vision may then fluctuate dramatically from day-to-day, and at different times of the day until blood sugar levels have stabilized.
Blurred vision in both eyes when insulin or other treatment begins is almost never caused by damage to the eye. Rather, it results from the speed at which the swelling, due to high blood sugars in the previous weeks and months, dissipates from the lens. Vision is usually out of sync for 3 to 4 weeks, sometimes with an accompanying headache.
These vision changes at the time diabetes is diagnosed rarely indicate real damage unless uncontrolled high blood sugars have been present for 5 years or more. It takes about 5 years of elevated blood sugars before damage to the eyes can be seen with an ophthalmoscope. However, secondary illnesses caused by diabetes or side affects from medications used to treat the disease can occasionally expedite visual damage.
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