In diabetic retinopathy, blood vessels swell and leak fluid in the retina, the tissue that lines the back of the eye. In some cases, abnormal blood vessels grow on the retina. These vessels can bleed into the tissue, and in some advanced cases, cause the retina to detach. As the disease progresses, the central part of the retina, which is crucial to vision, may swell. These changes may lead to vision loss and blindness.
Diabetic retinopathy has no early warning symptoms.
It can be detected only by a comprehensive eye examination in which the pupils are dilated. The most important step people with diabetes can take to prevent blindness is to have a dilated eye exam at least once a year to find out if there are any changes that could lead to vision loss. Another important reason to have frequent eye exams is that treatment with a laser has to be performed at a certain stage in the disease to be most effective. Research supported by the NEI has shown that early detection and timely treatment is 95 percent effective in preventing severe vision loss brought on by diabetic retinopathy. Although many people with diabetic retinopathy will never progress to the most serious form of the disease, frequent testing will enable the doctor to monitor the patient's condition closely and thus determine the best time to do laser treatment.