The medical field is still learning how diabetes leads to so many problems with the body. We know that sugar control reduces the risk of problems in the body and that is the same with the same in the eye. Diabetes affects a very important structure of the eye that is responsible for vision called the retina. When we see changes to the retina from diabetes this is called diabetic retinopathy.
After many years of elevated blood sugars, the vasculature to the eye becomes less and less effective at delivering nutrition. Vessel walls may weaken and even break. Microscopic spots of blood appear on the surface of the retina and can be seen during a dilated eye exam. The number and location of these spots of blood is used to grade the degree of retinopathy and assess the risk for future vision loss.
There are several ways diabetic disease can lead to vision loss. One cause is related to diabetic retinopathy. Over time the blood vessels in your retina become less effective at delivering oxygen and nutrition. This reduction in oxygen and nutrition to the retina causes tissue death. In an effort to survive, the retina stimulates the release of small chemical in the eye called VEGF which promotes new blood vessel formation. These new blood vessels are fragile and poorly built. They eventually break and bleed into the eye. Bleeding into the eye is a common cause of significant vision loss in patients with diabetes.
In addition to bleeding, these new blood vessels can also contract or shrink. If this happens it can pull and lift the retina up causing a “tractional” retinal detachment. This is another cause of vision loss and it can be associated with significant vision loss that requires surgery. Even after repair the visual outcome is often poor with limited visual recovery.
Another reason for vision loss is related retina atrophy or tissue loss that occurs after years of poor blood flow. Usually the retina atrophy happens along the outside wall of the eye which is responsible for peripheral vision, however it can also happen in the macula which can be associated with central vision loss.
One of the more common causes of vision loss is related to macular edema or swelling. This is usually located in the area of your eye that is responsible for your central vision, the macula. The disruption of the tissue from the swelling leads to reduced vision. If left untreated, over months it can lead to tissue remodeling and permanent vision loss.
During the early stages, diabetic retinopathy can be monitored. Often times good sugar control can delay the progression of diabetic changes in the eye. However, as the disease progresses treatments such as injections of medicine in the eye and/or lasers may be recommended