EurekAlert reports on a new study published in the December issue of Archives of Ophthalmology that shows injecting the corticosteroid triamcinolone into the eye may slow the progression of diabetic retinopathy.

Researchers from Johns Hopkins University School of Medicine and the Diabetic Retinopathy Clinical Research Network conducted a study involving 840 eyes of 693 participants who had macular edema, a leakage of fluid into part of the retina that occurs in many cases of retinopathy. Eyes were randomly assigned to receive one of three treatments: photocoagulation (a laser treatment that destroys blood vessels) or a 1-milligram or 4-milligram injection of triamcinolone acetonide directly into the eye, as often as every four months.

After two years, retinopathy had progressed in 31 percent of 330 eyes treated with photocoagulation, 29 percent of 256 eyes treated with 1-milligram doses of triamcinolone acetonide and 21 percent of 254 eyes treated with 4-milligram doses. These differences appeared to be sustained at three years, even though most eyes in the triamcinolone groups did not receive injections every four months during the second year, and less than half received any injections in the third year.

Despite advances in treating both diabetes and its complications, about 700,000 Americans have proliferative diabetic retinopathy and 63,000 new cases develop each year. Controlling blood glucose levels can help prevent the development of retinopathy and laser treatments can reduce the risk of vision loss, but the identification of other treatments remains desirable. Proliferative diabetic retinopathy occurs when new blood vessels form on the optic disc or another component of the retina.

At this point using triamcinolone acetonide to slow the progression of retinopathy is not warranted because of the increased risk of glaucoma and cataract associated with intravitreal steroid use.