Diabetic retinopathy has become one of the four most common causes of blindness in the United States.1 Although photocoagulation has been employed in its treatment for more than ten years, its true value remains controversial. In spite of the need for objective, definitive evidence, an adequately controlled study of photocoagulation in the treatment of proliferative diabetic retinopathy has not been performed. This is not surprising, considering the complexity and expense of largescale clinical trials in chronic disease. However, as Inglefinger2 has aptly stated, "When serious diseases are treated by serious methods... then ethical as well as scientific considerations require that medicine depend on the most reliable and the best controlled data available—the kind of data that is sought by randomized clinical study."
In keeping with this admonition, a randomized clinical trial of photocoagulation in the treatment of proliferative diabetic retinopathy has been designed and launched. This study
Aiello LM, Berrocal J, Davis MD, Ederer F, Goldberg MF, Harris JE, Klimt CR, Knatterud GL, Margherio RR, McLean EN, McMeel JW, Myers FL, Norton EWD, Patz A, Prout T, Riekhof FT, Straatsma BR, Tasman W, Van Heuven WAJ, Watzke RC. The Diabetic Retinopathy Study. Arch Ophthalmol. 1973;90(5):347-348. doi:10.1001/archopht.1973.01000050349001