"It helped mine," said Schafer, 48, as he sat at Southeast Retina Center, one of 52 sites nationally taking part in the clinical trial.
Physicians involved in the study say it provides evidence for the first new treatment in 25 years for a diabetes-related eye swelling called macular edema, the leading cause of blindness in working-age Americans.
About 3.6 million people with diabetes in the U.S. had some kind of vision problem in 2008, according to the Centers for Disease Control and Prevention.
The clinical trial compared injections into the eye of a drug called Lucentis paired with laser treatment vs. laser treatment alone in treating macular edema. The trial also looked at the effectiveness of a steroid injection vs. laser treatment alone.
In those who got Lucentis and laser treatment, about 50 percent could read down at least two more lines on the eye chart or see letters one-third smaller than they could before treatment, said Dr. Neil M. Bressler, the chairman of the Diabetic Retinopathy Clinical Research Network, which conducted the study.
"We expect the results of this study will have a major impact on how ophthalmologists treat macular edema in people with diabetes," he said. "This is the first time in 25 years that we have definitive proof that a new treatment can likely lead to even better results for the eye health of people with diabetes, which is a common and growing medical condition worldwide."
Diabetes affects small blood vessels throughout the body, causing them to become leaky and provoking swelling and sometimes closure, said Dr. Dennis Marcus of the Southeast Retina Center.
"Obviously if you have a little bit of swelling from these damaged blood vessels, the eye is so sensitive that you're going to lose vision with just a little leakiness from that damage," he said.
Lucentis is approved by the Food and Drug Administration for the treatment of age-related macular degeneration and not for macular edema, said Dr. Frederick L. Ferris III, the clinical director of the National Eye Institute, which supported the study.
Bressler said he hoped doctors would consider the study when deciding how to treat patients. Lucentis and a similar drug called Avastin have been used "off label" to treat the problem because it was thought they would have this good effect, Marcus said.
"The results are even better than we thought, actually," he said. Schafer said he was eager to help with the study when Marcus asked.
"Anything to keep my vision as long as I can," he said.