Clinical Alert

October 30, 1989

Clinical Alert to Ophthalmologists—Early Treatment Diabetic Retinopathy Study (ETDRS)

Dear Colleague:

The purpose of this clinical alert is to inform ophthalmologists of significant new findings from the Early Treatment Diabetic Retinopathy Study (ETDRS), a randomized, controlled, multicenter clinical trial supported by the National Eye Institute, part of the National Institutes of Health. Three questions concerning diabetic retinopathy were posed by the study: (1) Is photocoagulation effective for diabetic macular edema? (2) When in the course of the disease is the best time to begin photocoagulation for diabetic retinopathy? (3) Does aspirin treatment alter the progression of diabetic retinopathy?

Analysis of data collected by the ETDRS since patient recruitment began in December 1979 has led to the following study conclusions:

• Focal photocoagulation for macular edema reduces the risk of moderate visual loss and should be considered for eyes with clinically significant macular edema. Scatter photocoagulation, however, was not effective for macular edema, and led to mild decreases in central and/or peripheral vision for some patients.
• Scatter photocoagulation reduces the risk of severe visual loss. The five-year rates of severe visual loss were low whether scatter treatment was given early (2.5 percent) or deferred until the development of high-risk proliferative retinopathy (4 percent). Provided careful follow-up can be maintained, it is safe to defer scatter treatment until retinopathy approaches or reaches the high-risk stage. The ETDRS does not support scatter treatment before the severe non-proliferative stage of diabetic retinopathy.
• Aspirin treatment (650 mg/day) does not alter progression of diabetic retinopathy. The aspirin treatment neither altered progression of retinopathy nor increased the risk of vitreous hemorrhage. Findings indicate no reason for people with diabetes to avoid taking aspirin when indicated for treatment of other problems.

The ETDRS findings will be announced on October 30th during a symposium at the American Academy of Ophthalmology Annual Meeting in New Orleans. The results will later be published in the scientific literature.

Sincerely,

Carl Kupfer, M.D.
Director
National Eye Institute

Lloyd Aiello, M.D.
ETDRS Co-Chairman
Beetham Eye Institute
Joslin Diabetes Center

Federick L. Ferris III, M.D.
ETDRS Co-Chairman
National Eye Institute