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Thursday, May 23, 2013
Diabetes and the Eye
Diabetes affects nearly 24 million Americans; however, only 18 million of these individuals are diagnosed1. Diabetes is the leading cause of legal blindness for individuals aged 20-742. The current prevalence (how many people currently have this condition) of any type of diabetic retinopathy is 28.5%3. The prevalence of vision-threatening diabetic retinopathy is 4.4%3. The annual incidence (how many people contract the condition each year) of diabetic retinopathy is approximately 7.5%, meaning that nearly 1.8 million of the 24 million individuals with diabetes will acquire some degree of diabetic retinopathy each year4. Approximately 12,000 to 24,000 individuals will proceed to legal blindness each year secondary to diabetes5. The rate of diabetic complications is highest among African-Americans and Latinos4
Diabetic Related Eye Conditions
Cataract: Diabetes affects the eye in a variety of ways. One way in which diabetes affects the eye is the formation of a cataract. Cataract formation is a clouding of the normally clear lens (Figure1), which can decrease visual acuity, and occurs more frequently and at a younger age in individuals affected with diabetes6
Vision Fluctuation: The lens can be affected by diabetes another way as well. When blood sugar levels are very high, the lens will begin to absorb additional sugar and fluid follows. When the lens takes up additional fluid, it swells and the patient's vision will no longer be clear at distance. When the blood sugar levels decrease typically vision will return to normal. This may be a continuous cycle if the blood sugar is not well controlled.
Retinopathy: Diabetes will also affect the retina, or the light sensitive portion of the eye. Portions of the retina receive nutrients from small blood vessels, and it is these small blood vessels that are damaged due to diabetes. Healthy blood vessels do not leak, but vessels damaged by diabetes do. These leaky blood vessels cause small hemorrhages (areas of bleeding) and areas of lipid (fat) accumulation which can damage the retina and cause swelling. (Image) This swelling can lead to a decrease in vision but may be able to be treated. If there is extensive damage to the small blood vessels, then new vessels may start to grow. These new vessels are very problematic and can cause significant problems. If this occurs, a laser treatment is necessary.
Double vision: This is another complication of diabetes. This may be due to the formation of a cataract, but is more than likely a result of damage to a nerve that controls the eye muscles. Small blood vessels feed the nerves that control eye movements, and since diabetes affects these small blood vessels, the nerves are susceptible to damage. If this occurs a patient may experience double vision (seeing two images) separated side-to-side, up and down, or diagonally. This condition will be very bothersome; however, if it is truly related to diabetes, it usually improves over time and with improved blood-sugar control.
Diabetes needs to be managed by your primary care physician or endocrinologist. Maintaining good blood sugar levels is very important. Specifically to the eye as well as other organs, the better the control of blood sugar levels the lower the risk of complications7,8. Your physician will also recommend an annual dilated exam from an optometrist or ophthalmologist. The dilated exam allows for a detailed assessment of the lens and retina. If significant retinopathy is discovered, an ophthalmologist may need to perform a laser procedure to decrease the retinopathy. These patients are usually seen multiple times per year in an attempt to prevent vision loss.
If significant vision loss does occur, low vision aids may be available and may make a dramatic improvement in an individual's quality of life.
The longer an individual is diabetic, the more likely that individual will develop eye complications secondary to diabetes4. It is very important to have appropriate medical and vision care in order for your doctors to best prevent these complications.
1. http://www.cdc.gov/Features/DiabetesFactSheet/. Last accessed August 25, 2010.
2. Klein R, Klein B. Vision disorders in diabetes. In: National Diabetes Data Group, ed. Diabetes in America.2nd ed. Bethesda, MD: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:293-337.
3. Zhang X. et al. Prevalence of diabetic retinopathy in the United States, 2005-2008. The Journal of the American Medical Association 2010;304(6):649-656.
4. Varma R, et al. Four-year incidence and progression of diabetic retinopathy and macular edema: the Los Angeles Latino Eye Study. American Journal of Ophthalmology 2010;149:752-761.
5. http://www.diabetes.org/diabetes-basics/diabetes-statistics/. Last accessed August 25, 2010.
6. Pollreisz A & Schmidt-Erfurth U. Diabetic Cataract?Pathogenesis, Epidemiology and Treatment. Journal of Ophthalmology 2010;2010:608751. Epub 2010 Jun 17
7. Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. The New England Journal of Medicine 1993;329(14):977-86.
8. UK Prospective Diabetes Study Group. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. British Medical Journal 1998;317(7160):703-713.
Last Reviewed: Sep 02, 2010
Aaron Zimmerman, OD, MS
Clinical Associate Professor of Optometry
College of Optometry
The Ohio State University
Julia Rae Geldis, OD, MS
Clinical Assistant Professor of Optometry
College of Optometry
The Ohio State University