Diabetes Information | Eye Health
How Does Diabetes Affect The Eyes?
The retina, a tissue that lines the back of the eye, is the part of the eye that senses light and sends visual information to the brain. The retina is supplied by blood vessels, arteries and veins which carry vital nutrients within the blood stream. The retinal blood vessels may be affected by diabetes just as in other parts of the body. It is primarily these changes in the blood vessels that lead to problems in the eyes of people with diabetes.
Diabetic changes in the blood vessels impair their ability to supply the retina with nutrients which may cause portions of the retina to become starved for oxygen. These areas of the retina, which are deprived of their blood supply, call out for new blood vessels to feed them. The new blood vessels are abnormal and are called neovascularization. They grow along the surface of the retina in a membrane that may contract, causing the blood vessels to tear and bleed into the eye. When this happens, the vision will appear dark in the region where the blood accumulates. If the blood does not clear, it may form membranes within the eye that can detach the retina from the back of the eye. A retinal detachment will also cause a dark spot in the vision, and may cause permanent damage to the retina if not repaired by an ophthalmologist. It is important to note that neovascularization may occur without any noticeable change in your vision.
Diabetes may also cause the blood vessels to become leaky. The fluid which leaks from the vessels may then accumulate in the macula, the central visual area of the retina, and cause distorted or blurred vision. This is known as diabetic macular edema and is a leading cause of decreased vision in adult-onset diabetics.
People with diabetes are also more likely to develop cataracts at an earlier age. A cataract occurs from clouding of the normally clear lens which focuses light onto the retina. Cataracts probably form sooner in diabetics due to fluctuations in blood sugar levels, which draw water into the lens, making vision cloudy.
Can Diabetic Eye Disease Be Treated?
Numerous studies have been completed to determine the natural course of diabetic eye disease and to evaluate different methods of treatment. Currently, lasers are used to treat proliferative diabetic retinopathy as well as diabetic macular edema. The type of laser surgery which is done for proliferative diabetic retinopathy is known as pan retinal photocoagulation. The goal of this laser surgery is to destroy all of the areas of the retina where the blood vessels have closed and where the new blood vessels are needed. When these areas are treated, the retina stops making new blood vessels and the ones that are already present tend to shrink away. This can present the complications of bleeding into the eye (vitreous hemorrhage) and retinal detachment from membrane formation. The Diabetic Retinopathy Study showed that the risk of severe visual loss from complications of proliferative diabetic retinopathy could be reduced by greater than 50 percent by pan retinal photocoagulation laser treatment. If any of these complications do occur, Dr. Goodman who is a vitreo-retinal specialist (an ophthalmologist with special training in diabetic eye disease and surgery) may need to perform surgery to remove the vitreous hemorrhage and treat retinal detachment.
The laser can also be used to treat leaking blood vessels that are causing diabetic macular edema. A fluorescein angiogrammay may be ordered by the doctor in order to find the areas of leakage so that they may be treated with a laser.