The primary manifestation of diabetic disease in the eye is diabetic retinopathy. Diabetes and diabetic eye disease have traditionally been very difficult to treat, but in the last decades research has provided fast moving improvements in the treatment of both diabetes and the subsequent retinal disease.
Although many diabetic patients have suffered blindness at the hands of untreated diabetic retinopathy, the last few decades have proven that regular followup and treatment not only prevent blindness in diabetics, but that these treatments sustain vision in diabetic patients for many years and decades. For the overwhelming majority of diabetic patients, it is simply unnecessary to suffer vision loss. More treatments and better treatments than ever are available now to stave off major vision loss.
Diabetic retinopathy can best be understood as a disease of sick blood vessels. Diabetes when not adequately treated leads to a weakening of blood vessels throughout organs in the body, including the eyes. In the retina, fine blood vessels that feed the retina become sick and even begin to close, which leaves the retina unable to get good blood supply (much as the heart in someone with heart disease). This poor blood supply causes the retina to react by putting out chemical signals that promote changes which can lead to serious bleeding and scarring in the retina, all of which can lead to serious disease and blindness if untreated.
In the peripheral retina, this bleeding and scarring can lead to traction that can pull the retina off from the wall of the eye, a process better known as “retinal detachment.” This type of serious diabetic retinopathy can be treated, but earlier treatment can prevent progression to such sight-threatening disorders in diabetics. This is why all diabetics should call for an examination and then followup regularly.
Another form of diabetic eye disease is responsible for even more vision loss than the serious disease described above. It is called macular edema, and it is best known for its ability to strike diabetics at any stage of their disease. For instance, whether you have had diabetes for decades or just months, you are still at risk for this retinal disease which can result in significant loss of vision. As described above, sick blood vessels in the retina cause the retina to put out chemical signals. These chemical signals result in inflammation. This inflammation can often result in swelling of the retina, in the part responsible for central vision, leading to loss of central vision. You can think of this as inflammation anywhere else in the body, such as your knee. However, instead of pain and a lack of function in your knee, this swelling results in a loss of function in the retina and, therefore, reduced vision.
Macular edema is able to be treated, but the longer it is present, the less vision may be recoverable, even after treatment. Many diabetic patients experience blurry vision but do not realize that this could be serious disease and not just a need for new glasses. For this reason, everyone with diabetes should be seen to screen for this and other retinal disease. These visits are even more urgent if blurring of vision is already present.