Until now, we’ve may have know corticosteroid injections to be related only to inflammation relief. However a new study indicates that the steroid injections may also help slow diabetes-related eye disease.
Experts led by specialists at the Johns Hopkins Wilmer Eye Institute seem to have found the benefits of injecting a corticosteroid namely triamcinolone directly into the eye. Apparently, it was observed to slow the progression of proliferative diabetic retinopathy. The latter is known to be a complication of diabetes that frequently leads to blindness.
A word of caution from the study authors however also indicates that the use of steroids in the eye may augment the risk of glaucoma and cataract. Hence, until further development of drugs that could reproduce the good effects of steroids minus the damage, laser photocoagulation seems to remain as the treatment of choice.
“Steroid treatment worked, but because of safety issues, cannot be recommended routinely at this time,” explains Neil M. Bressler, the James P. Gills Professor of Ophthalmology and chief of the Retina Division of the Johns Hopkins Wilmer Eye Institute, chair of the government-sponsored Diabetic Retinopathy Clinical Research Network. “It is a condition that can be treated safely and effectively with lasers.”
As part of the study, one of two treatments was described and compared on 840 eyes from 693 men and women between July 2004 and May 2006. The participants were divided approximately evenly between men and women and had an average age of 63. They also had diabetic retinopathy with macular edema which is supposedly a swelling of the central portion of the retina caused by leakage of fluid.
The growth of new and unwanted blood vessels appears to mark proliferative diabetic retinopathy. This growth is mostly seen in the optic nerve in the back of the eye or another area of the retina. For the analysis, the scientists randomly assigned each patient’s eye to receive either photocoagulation laser treatment for diabetic macular edema or a triamcinolone acetonide injection of 1 or 4 milligrams directly into the eye as often as every four months.
The lead author reveals some evidence that steroids could enhance vision outcomes from diabetic macular edema (DME) was found in the course of the study. Swelling of the center of the retina which is the part of the retina used for reading or driving was found to have improved. Nevertheless, the results indicated that steroids were not superior to laser treatments for DME.
“The primary objective of the study was to determine if steroids were superior to laser for DME, and if so, to balance that superiority with steroids’ side effects. A secondary objective was to determine if the steroids affected the progression of diabetic retinopathy,” additionally mentions Bressler. “Steroid treatments did reduce the risk of progression of diabetic retinopathy, but, not DME, which can also cause vision loss from proliferative diabetic retinopathy, bleeding in the middle cavity of the eye or scarring of the retina, which can detach the retina from the back wall of the eye.”
“However, there was evidence that steroids can affect the pathways that lead to the development of new blood vessels on the surface of the retina in diabetes, a secondary objective of the study” explains Bressler. “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 important.”
Along with colleagues in the Diabetic Retinopathy Clinical Research (DRCR) Network, Bressler found that after two years, retinopathy seemed to have progressed in 31 percent of 330 eyes treated with laser treatment. It was apparent in 29 percent of 256 eyes treated with 1-milligram doses of triamcinolone acetonide and nearly 21 percent of 254 eyes treated with 4-milligram doses.
At three years, the differences appeared to be sustained. This was claimed to be true in spite of the fact that most eyes in the triamcinolone groups did not receive injections every four months during the second year. Also less than half seemed to have received any injections in the third year as no longer was macular edema present. It could have also been less common because side effects from the injections precluded applying additional steroids when following the study’s treatment protocol.
“Researchers now need to find ways of using the steroid effect on these blood vessels for treatment, but, not at the expense of causing glaucoma and the side effects of cataract formation or worsening of cataracts which could lead to the need for a patient to undergo cataract surgery.”
Even though treatment of both diabetes and its complications has advanced in the past few years, nearly 700,000 Americans are believed to have proliferative diabetic retinopathy with 63,000 new cases develop each year. Presently, the treatment is not yet ready for ‘general use’ because of side effects.
The study is published in the December issue of the Archives of Ophthalmology.