Laser therapy, also called laser photocoagulation, is more effective and produces fewer side effects than corticosteroids injected into the eye for the treatment of diabetic macular edema according to a large, two-year multicenter study reported in the journal Ophthalmology (Volume 115, page 1447). Here’s what the study revealed.
Swelling around the macula (macular edema) caused by the leakage and accumulation of fluid can occur in people with diabetes. The swelling alters the position of the retina and causes blurred vision. Loss of vision is more pronounced when the center of the macula is affected.
Photocoagulation uses lasers to help close leaking microaneurysms (weak spots that bulge outward from the blood vessels), fostering the regression of new blood vessels. Laser photocoagulation helps to halt or slow vision loss in most people if it is performed before too much damage has occurred.
In the study, scientists randomly assigned 693 people (840 eyes) with diabetic macular edema to undergo laser treatment or to receive a 1- or 4-mg injection of triamcinolone (a corticosteroid) into the eye, each repeated at four-month intervals, as necessary, for two years.
At the first four-month check, vision was sharpest in those who had received a 4-mg injection of triamcinolone. At one year, vision was about the same in all three groups. But at two years, vision was significantly better in the laser treatment group. Of those who received laser therapy, 19% had substantial vision loss compared with 28% in the corticosteroid treated groups.
Cataract surgery was required in only 13% of eyes in the laser group compared with 23% in those who received 1 mg of triamcinolone and 51% in those who received 4 mg. Eye pressure increased by a significant amount in 4% of the laser group compared with 16% and 33% in the 1- and 4-mg corticosteroid groups, respectively.
Researchers are now studying combination therapy, since triamcinolone had better initial results and laser treatment was more effective over two years.
