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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 significantnew findings from the Early Treatment Diabetic Retinopathy Study (ETDRS), arandomized, controlled, multicenter clinical trial supported by the NationalEye Institute, part of the National Institutes of Health. Three questions concerningdiabetic retinopathy were posed by the study: (1) Is photocoagulation effectivefor diabetic macular edema? (2) When in the course of the disease is the besttime to begin photocoagulation for diabetic retinopathy? (3) Does aspirin treatmentalter the progression of diabetic retinopathy?

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

  • Focal photocoagulation for macular edema reduces the risk of moderatevisual loss and should be considered for eyes with clinically significantmacular edema. Scatter photocoagulation, however, was not effectivefor macular edema, and led to mild decreases in central and/or peripheralvision for some patients.
  • Scatter photocoagulation reduces the risk of severe visual loss.The five-year rates of severe visual loss were low whether scatter treatmentwas given early (2.5 percent) or deferred until the development of high-riskproliferative retinopathy (4 percent). Provided careful follow-up can bemaintained, it is safe to defer scatter treatment until retinopathy approachesor reaches the high-risk stage. The ETDRS does not support scatter treatmentbefore the severe non-proliferative stage of diabetic retinopathy.
  • Aspirin treatment (650 mg/day) does not alter progression of diabeticretinopathy. The aspirin treatment neither altered progression of retinopathynor increased the risk of vitreous hemorrhage. Findings indicate no reasonfor people with diabetes to avoid taking aspirin when indicated for treatmentof other problems.

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


Carl Kupfer, M.D.
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