In the Spotlight
Digital Screening for Early Detection of Diabetic Eye Disease
William Johnston, OD and Paul Whitmore, MD
VAMC, Martinsburg, West Virginia
Diabetes can cause severe eye problems, which can lead to reduced vision or loss of vision. In the United States, diabetes in adults ages 20-70 is the major cause of vision loss. 1 About 20% of VA patients have diabetes, also referred to as high blood sugar. 2 With new technology (digital imaging); doctors can provide early screening for eye problems. Eye screening through digital imaging is done with a special camera that has a wide view to take photos of the inside of the eye. (A digital image is an image that can be enhanced using a computer.) This screening tool is used to identify early diabetic eye problems. Digital imaging makes it possible to find eye problems caused by diabetes early on, so they can be treated.
Complications of diabetes (high blood sugar) can cause a condition called diabetic retinopathy (the early stage of eye disease affecting a part inside the eye called the retina). (Figure 1) The retina is a light sensitive area located at the back of the eye. Eye disease may prevent light from reaching this light sensitive area, and lead to loss of vision or blindness. Diabetes can cause three forms of eye disease: retinopathy, glaucoma, and retinal detachment. When the retina separates from the eye, some or all of vision is lost in that eye.
Blood vessels or capillaries are so small they may be difficult to see. Digital imaging can enlarge images of these blood vessels and show weak or bulging defects. This enlarged image is used to examine parts of the retina where these bulges are found. (Figure 2) Digital imaging provides patients with an early warning. It has the most benefit during the first stage of eye disease. Early finding of problems lowers the risk of severe damage to the retina. Patients can adjust diet and medication to better control their diabetes in time to decrease the risk of eye problems.
Digital imaging has proven safe and effective for early detection of diabetic retinopathy. Many VA hospitals are using digital imaging for diabetic eye screening. Use of this technology does not replace the need for periodic complete eye examinations. Digital imaging does not provide the data necessary for providing eyeglasses. Patients who have digital screening for diabetic retinopathy must also see their eye doctor for periodic complete eye examinations.
Digital images can easily and reliably be sent electronically to places far away from the facility where the image is taken. Patients can have images taken in their primary care provider's office, or in a remote community based clinic. Those images can be sent to a center where they are read. The VA has a network of centers that read the images. 3
Diabetes:
Diabetes is another way of saying that your blood sugar (glucose) level is too high. The body naturally forms glucose because it needs glucose for energy. The body makes glucose from foods that you eat. Your liver and muscles also make glucose. When glucose levels are too high, diabetes occurs.
Retinopathy:
The early form of eye disease occurs when the walls of small blood vessels called capillaries in the light sensitive area of the eye (the retina) are damaged. Damaged capillaries form microaneurysms (bulges) which leak fluid and fat into the retina. Vision fails when the center of the retina is affected. Left untreated this can cause partial blindness. The center of the retina produces the sharpest vision and is called the macula. 4 This early stage of eye disease is called diabetic maculopathy (specific form of retinopathy) and is the most common type of diabetic eye disease.
Glaucoma:
A lack of oxygen occurs when diabetes damages the blood vessels of the eye. The resulting decrease in blood flow causes the retina and iris (colored part) of the eye to make new abnormal blood vessels. These blood vessels are weak and breakable and may bleed. They also cause high pressure in the eye when they affect the iris. This is a severe form of eye disease called glaucoma.
Retinal Detachment:
Bleeding clouds and scars the gel that fills the center of the eye, leading to a disconnection (detachment) of the light sensitive area (retina) from the inner wall of the eye, resulting in vision loss. Surgery is usually required. The outcome after surgery is considered guarded.
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References
(1) Clinical Update: Retina, Diabetic Retinopathy: Covering The Bases. American Academy of Ophthalmology 2007
(2) VA Press Release, Technology Identifies Veterans at Risk for Diabetic Eye Disease, VA Office of Public Affairs, February 15, 2007
(3) VA Press Release, Technology Identifies Veterans at Risk for Diabetic Eye Disease, VA Office of Public Affairs, February 15, 2007
(4) Wise GN, Dollery CT, Henkind P. The Retinal Circulation, pg 280, Harper and Row, New York, 1971
Diabetic Retinopathy (HealthWise)
Diabetic Eye Problems (Medline Plus)
Diabetes Eye Complications (Interactive Tutorial)
Diabetic Retinopathy Fact Sheet
Diabetes Center
Diabetic Retinopathy (National Eye Institute)
Prevent Diabetes Problems: Keep Your Eyes Healthy (National Diabetes Information Clearinghouse)
Problemas de los ojos asociados con la diabetes (Medline Plus) (Spanish language)
La Retinopatía Diabética Lo que usted debe saber (National Eye Institute) (Spanish language)
Cómo prevenir los problemas de la diabetes: Mantenga sanos los ojos (National Diabetes Information Clearinghouse) (Spanish language)
Diabetes - Problemas de los Ojos (Tutorial) (Spanish language)
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Updated/Reviewed: April 30, 2008
