Diabetes is a medical condition where the body is unable to store sugar properly leading to elevated levels of glucose in the blood. Persistent elevated levels of sugar in the blood causes structural changes in the small and medium blood vessels throughout the body. These changes can affect target areas such as the kidney, eye, peripheral nerves, and feet. The damage and changes to circulation in the eye can lead to a condition known as diabetic retinopathy, which can affect the sight in several ways. Cataract and glaucoma are also seen more frequently in individuals with diabetes mellitus.
The retina is the nerve layer in back of the eye, which receives focused images from the eye, much like the film in a camera, and is then processed and transmitted thru the optic nerve to the brain. The small blood vessels within the retina can be damaged from diabetes causing growth of fragile vessels, scar tissue, or swelling from fluid leakage.
The important risk factors in developing diabetic retinopathy are the length of time with diabetes, family history of diabetic retinopathy, and how well controlled your glucose levels are on a day to day basis. Statistically, about 80% of diabetics have some degree of retinopathy after 15 years with the disease. With improved methods of diagnosis and treatment, much of the serious vision loss that can occur from diabetes can be avoided.
Background diabetic retinopathy is often the initial changes that are visible within the retina. Small hemorrhages within the retinal tissue and accumulation of fluid or fatty deposits, called exudates, develop due to the damage which occurs within the small vessels of the retina. There are often no symptoms during this stage of the disease, but it is an indication of diseased circulation, which may progress to more serious problems. For this reason, background diabetic retinopathy is considered a warning sign.
Fluid may collect within the central portion of the retina, known as the macula, which is responsible for our ability to see detail and read. This causes a condition known as diabetic macular edema, and can cause varying degrees of blurred vision. Uncontrolled blood pressure and elevated levels of lipids can contribute to this condition.
Proliferative diabetic retinopathy is the stage when abnormal blood vessels begin to develop within the eye in response to the poor circulation from diabetes. These abnormal blood vessels can cause hemorrhage within the eye, scarring and traction to the retina leading to retinal detachment, and a malignant form of glaucoma. The problems associated with proliferative diabetic retinopathy are the ones which cause the most profound loss of vision.
Laser treatment to the retina is the most common method to treat both diabetic macular edema and proliferative diabetic retinopathy. A laser is a focused beam of light which can seal the leaking blood vessels and reduce swelling of the retina, or cause regression of the abnormal vessels of proliferative diabetic retinopathy. The laser procedures are commonly done in the office during single or multiple sessions. This treatment has been available for the past 15-20 years and is extremely effective in reducing the visual loss from diabetes. Vitrectomy is a more involved surgical procedure done in the hospital for hemorrhage within the eye and for retinal detachment.
Good diabetic control and regular eye examinations are the two most important measures to preserve the health of your eye and vision. Regular medical exams, good diet, appropriate medications and routine monitoring of glucose levels are the tools to monitor the status of your diabetes. Control of blood pressure, weight reduction when appropriate, avoiding smoking and regular exercise can also be of significant benefit to your health and vision. Your primary care physician will decide which methods to monitor your glucose levels. A relatively new blood test, called HgA1c, reflects the cumulative control of glucose levels for the past three months. HgA1c levels below 7% have been correlated with lower risks in developing diabetic eye disease.
Eye examinations are generally recommended every year once a diagnosis of diabetes has been established. In this way, early disease can be detected and treated before any significant visual changes occur. As with many medical conditions, it is most beneficial to prevent disease, and easier and more effective to treat when detected early should it occur.