10-Year Glaucoma Research Foundation Study Results Released; Study Offers Treatment Options, Answers for Doctors and Patients.

SAN FRANCISCO--(BW HealthWire)--Oct. 7, 1998--The results of a 10-year study funded by the Glaucoma Research Foundation were released this month in the American Journal of Ophthalmology. The report finally addresses questions of treatment for one of the most puzzling forms of glaucoma.

Glaucoma, a leading cause of blindness in the United States, is an eye disease often characterized by increased pressure (or tension) in the eye. Increased eye pressure may lead to optic nerve death and ultimately blindness.

However, in one form of glaucoma -- Normal Tension Glaucoma (NTG) -- the optic nerve deteriorates even though eye pressures are within normal range. It is estimated that anywhere from 25 to 30 percent of American patients never experience an elevation in eye pressure. In Japan, the number is as high as 70 percent.

Researchers at 24 research and medical centers around the world joined the Glaucoma Research Foundation's collaborative NTG study with the goal of determining whether or not eye pressure (or intraocular pressure, IOP), even at normal levels, plays a role in NTG. They asked if it is clinically feasible and worthwhile to lower the eye pressure in people with NTG; and whether the benefits of lowering eye pressure outweigh any risks and side effects.

Researchers found that lowering normal eye pressures 30 percent -- to below normal levels -- does slow the progression of NTG. Eye pressures were lowered through a variety of methods including laser and cutting surgery and eye drops.

"This is big news. This is the first multi-center clinical trial that documents the effectiveness of current treatment in any form of glaucoma, though it specifically focuses on Normal Tension Glaucoma," says Tara Steele, GRF Executive Director. "We have debated for years whether or not eye pressure matters in this disease. Proving that lowering pressure makes a difference is big news."

Researchers caution doctors and patients that the decision to treat is a highly individual one. While lowering eye pressure helps to reduce progression of NTG, surgical treatments often lead to the progression of cataracts.

Dr. Stephen Drance of the University of British Columbia says that answering these questions, "was important as there was a division in ophthalmology whether normal eye pressure in these patients was involved in the production of the disease. This study shows that treatment of these patients with pressure reducing regimes is beneficial for their disease over time."

Dr. Drance and Dr. Douglas Anderson of the Bascom Palmer Eye Institute led the privately funded study involving more than 200 patients in North America and Europe.

When the study was designed, its clinicians and researchers believed that NTG was a rapidly progressing disease and that results of the study would be available in 3 to 4 years. This influenced the decision to fund the study with private resources(a) rather than go through the extensive federal grants process. Ironically, one of the study's other findings was that NTG progresses very slowly in most patients.

It should also be noted that among those whose pressures were lowered, one-sixth of them still experienced further glaucoma damage. In addition, more than half of the volunteer subjects in the study's control group who received no treatment showed little or no progression of the disease over three years. However, eventually the majority of patients showed some progression. These two facts lead researchers to believe that factors other than eye pressure are also involved in some or all patients with NTG.

While more analyses of the study data will examine these issues, and further studies will have to be designed, the results of the NTG study already have implications for doctors and patients today.

"This study mandates dialogue between patients and their doctors on issues of age, health and vision expectations," Steele notes. "In a lifelong disease like glaucoma, it's vital to have good working relationships between doctors and patients; and not just talk about pressures, but also the specifics of an individual's glaucoma, treatment options, lifestyle, and vision concerns."

(a) The Glaucoma Research Foundation Normal Tension Glaucoma Study was funded by the GRF, the Edward J. Daly Foundation, the Oxnard Foundation, the Kenneth and Eileen Norris foundation, and with hours of time donated by doctors, technicians and study participants.