Diabetic retinopathy usually has no early warning symptoms. It can be detected only through a comprehensive eye examination that looks for early signs of the disease, including:

• Leaking blood vessels
• Macular edema (swelling)
• Pale, fatty deposits on the retina
• Damaged nerve tissue
• Any changes to the retinal blood vessels

To effectively diagnose diabetic eye disease, eye care specialists recommend a comprehensive diabetic eye examination that includes the following procedures:

• Distance and near vision acuity tests
• A dilated eye (or fundus) examination, which includes the use of an ophthalmoscope. In a dilated eye examination, it is the pupil that is dilated — not the entire eye. This allows the examiner to see through the pupil to the retina. Acuity tests alone may not be sufficient to detect diabetic retinopathy in its early stages.
• A tonometry test to measure fluid pressure inside the eye.
• A fluorescein angiography test, if more serious retinal changes, such as macular edema, are suspected.
• A newer technique called optical coherence tomography (OCT) may be used to gain a clearer picture of the retina and its supporting layers.
• Also, an Amsler Grid test can detect early and sometimes subtle visual changes in a variety of macular diseases, including diabetic macular edema. An online Amsler Grid test is available from the Diabetes Mall.

The American Association of Diabetes Educators provides the following eye examination guidelines for individuals with diabetes: At minimum, individuals with type 1 and type 2 diabetes should schedule an annual diabetic eye exam.

• Individuals with mild non-proliferative retinopathy should schedule an annual diabetic eye exam.
• Individuals with moderate to severe non-proliferative retinopathy should schedule a diabetic eye exam every 6 to 12 months.
• Individuals with macular edema or proliferative retinopathy should schedule a diabetic eye exam as frequently as every 4 months, if indicated.
• Individuals with proliferative retinopathy and high-risk complications, such as the growth of new blood vessels in the optic disc area or recent bleeding in the retina or vitreous, should schedule diabetic eye exams as frequently as needed.