National Clinical Trial Directed by Kellogg
Long-term study on glaucoma treatment yields new answers
In 1989, researchers at the U-M Kellogg Eye Center set out to determine the best treatment for patients who were newly diagnosed with glaucoma: eye drops or surgery. They led a national study, the Collaborative Initial Glaucoma Treatment Study (CIGTS), that would ultimately follow the care of 607 patients at 14 clinical centers around the U.S. Now, after following these patients for many years, researchers have found that the data continue to reveal unexpected findings.
Paul R. Lichter, M.D., Principal Investigator on the original CIGTS grant and Director of the Kellogg Eye Center, was hoping to put the controversy to rest once and for all. “For years, practitioners have wondered which initial treatment was better for our patients. Some were sure it was medicine, others were sure it was surgery. But there were no data that could prove either side.”
Now we have data. With funding from the National Eye Institute for the original grant and a subsequent grant for data analysis, Dr. Lichter and colleagues have had the opportunity to follow patients for over a decade. “While early reports indicated that initial surgery and medications yielded similar outcomes, analyses of longer term follow-up data have revealed an important result,” says Dr. Lichter. “It appears that patients who had more visual field loss at the time of diagnosis ultimately do better if they are treated initially with surgery rather than with medication.”
From the beginning David C. Musch, Ph.D., M.P.H., has directed what is now a huge database, produced study reports, and crunched the numbers. After evaluating the visual field data, Dr. Musch has some pertinent take-home messages. “For starters, both groups did well. Intraocular pressure reduction from treatment was substantial in both groups, but significantly more so in the surgery group. Visual field loss was less than expected, likely due to the superb treatment and follow-up care these patients received throughout the trial.” He surmises that the regular clinic visits and frequent calls from interviewers might have encouraged the patients to comply better with instructions and treatment.
There was, quite unexpectedly, an intriguing finding within the surgery arm of the trial. According to Dr. Musch, the data show that smokers had substantially higher intraocular pressures than non-smokers. A smoker who underwent surgery for glaucoma was worse off than a patient in the surgery arm who did not smoke. Whether this has any effect on long-term visual field loss remains to be determined.
Although Dr. Musch and his colleagues will continue to analyze the data, one finding appears to be indisputable. Intraocular pressure fluctuation is a strong independent predictor of visual field loss. Thus, consistent control of pressure remains vital. The better and more reliable the pressure control, the less loss of visual field. Pressures that fluctuate increase the risk that the patient will lose visual function.
For more information, see the Glaucoma and Cataract Clinic at the U-M Kellogg Eye Center.
| << Previous Story | Annual Report Story Index | Next Story >> |
