Diabetic Retinopathy

Diabetes has become one of the most common disorders in the United States. Among the complications of the disease process, nerve damage occurs in 60-70% of individuals affected by this illness. According to the article, Diabetes is the leading cause of kidney failure and new cases of blindness in adults. Diabetic retinopathy affects the nerves of the retina. There are two categories : nonproliferative diabetic neuropathy and proliferative diabetic neuropathy, both ranging from mild to severe. Mild includes microaneurysms only, while severe involves severe retinal hemorrhages or venous beading in quadrants of the eye.

Diabetic neuropathy causes damage of the blood vessels in the retina. This occurs as a result of hyperglycemia which causes vascular damage. This also causes increased vascular permeability, decreased vascular tone, vascular leakage and edema. New blood vessels grow to compensate for the existing damaged blood vessels. These new blood vessels may be fragile which easily adhere to the vascular leakage which may cause blurred vision. They may also cause hemorrhage aneurysms which give symptoms of floaters or black spotted areas in the vision. All these lead to reduced visual acuity and ultimately to blindness.

Diabetic retinopathy mainly affects the retina of the eye. The retina contains the highest concentration of photoreceptors. According to the article, diabetic retinopathy may begin to develop years before an actual clinical diagnosis of diabetes is made. The standard tool used in testing Diabetic retinopathy is the visual acuity chart. This measures how well one can see at different distances or the visual acuity loss that occurred due to the disease process.

Description: Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity chart

Dilated eye exam may be done to widen or dilate the pupil enabling better visual of the eye and inner structures. eg. damaged nerve changes in the blood vessels, pale fatty deposits of retina (signs of leaking blood vessels) and retinal swelling. Tonometry may also be used in eye testing; this instrument measures the pressure inside the eye. The article further goes on to state that the three main mechanisms that contribute to blindness in diabetic retinopathy causing blindness includes: macular ischemia, retinal and vitreous hemorrhage and retinal detachment. Macular ischemia can be a slow process, which destroys light sensitive cells and retinal detachment can occur suddenly. This is an ophthalmic emergency as permanent loss of vision can occur if medical intervention is not immediately obtained.

Ref. article: Etiology and natural history of diabetic retinopathy: An overview. Morello, Candis M. American Journal of Health-System Pharmacy; 9.1.07 Supplement, Vol. 64,

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