Glaucoma Treatment Can Prevent Blindness
Even those with severe disease can save some vision, experts say
WEDNESDAY, July 2, 2008 (HealthDay News) -- Glaucoma doesn't necessarily have to end in blindness, two new studies suggest.
In one report, researchers say they found traditional surgery for glaucoma has better outcomes than using glaucoma drainage devices. The second report found that even patients with end-stage glaucoma can be successfully treated. Both studies were published in the July issue of Ophthalmology.
In the first report, researchers looked at the number of complications from traditional glaucoma surgery versus complications from inserting a device that drains fluid from the eye.
"We found a higher complication rate for glaucoma drainage devices than for traditional surgery," said lead researcher Frank Sloan, the Alexander McMahon Professor of Health Policy and Management at Duke University. "Of course, adverse outcomes for either procedure are rare."
In deciding between the two procedures, physicians will have to balance the risks versus the benefits, Sloan said. "It's good for ophthalmologists to have these outcome rates in mind when they counsel patients," he said.
In the study, Sloan and his colleagues collected data on 14,491 Medicare patients with glaucoma. These patients all underwent one of three surgeries. These included primary trabeculectomy (PT), trabeculectomy after scarring from previous surgery or trauma (TS), or the implanting of a glaucoma drainage device (GDD).
All these surgeries are designed to improve the drainage of fluid from the eye and reduce intraocular pressure. In trabeculectomy, a small portion of the tissue at the base of the cornea is removed to increase fluid flow, and in GDD a tiny shunt is implanted, which redirects fluid flow.
Sloan's group found that all of procedures had few adverse outcomes. However, GDD resulted in more patients progressing to low vision or blindness (2.6 percent), compared with patients who underwent PT (1 percent) or TS (1.3 percent).
Dr. Robert Cykiert, an ophthalmologist at New York University Medical Center and a clinical associate professor of ophthalmology at New York University School of Medicine in New York City, said that this study "says that one should try trabeculectomy procedure first, if you can."
In these patients, "experience and intuition says that additional trabeculectomy surgery usually won't work. That's why we go to a glaucoma drainage device," Cykiert said. "This study indicates that if there's any belief you can get away with doing a trabeculectomy procedure, you are better off doing that then putting in the drainage device."
These results will make people a little more conservative, Cykiert said. "Some glaucoma specialists jump ahead to the glaucoma drainage device sooner than they might or should," he noted.
In the second study, Dr. Jason W. Much, from the Department of Ophthalmology at the University of Virginia in Charlottesville, and his colleagues looked at the charts of 64 patients with end-stage glaucoma. All these patients were considered legally blind at the start of the study.
All patients underwent trabeculectomy or laser trabeculoplasty, where tissue is removed by laser. The researchers found that, despite impaired vision, these patients did not become blind.
"Relentless progression to [complete] blindness is not the norm in treated patients," Much said in a statement. "Patients should be encouraged that treatment is not futile. They may retain their visual acuity for many years and be able to perform simple tasks of daily living and enjoy reading and hobbies."
Cykiert said this study contradicts what has been thought for a long time. "The thinking has been that treating patients with end-stage glaucoma is often unsuccessful, because they wind up losing their vision," he explained.
The conventional wisdom has been that once optic nerve was damaged beyond a certain point, no matter what one did, the nerve would eventually die, Cykiert said.
"This study shows that's not the case, even people with end-stage glaucoma, if you treat them aggressively and follow them carefully, you can preserve that little amount of vision that's left," Cykiert said.
Glaucoma is a disease that damages the optic nerve, which if untreated will eventually lead to blindness. Glaucoma is detected by an intraocular pressure test. When the pressure climbs above 21 millimeters of mercury, glaucoma is present.
There are several types of glaucoma. The most common in the United States is called primary open-angle glaucoma. In the United States, many people have ocular hypertension, which is a precursor to glaucoma. Ocular hypertension results in elevated fluid pressure in the eye, but no damage to the optic nerve or vision loss.
Blacks and Hispanics are at higher risk for glaucoma, and progression to end-stage glaucoma is very common among blacks.
For more on glaucoma, visit the U.S. National Library of Medicine.