PLEASE NOTE: RECRUITMENT FOR THIS STUDY WAS CLOSED AFTER SUCCESSFULLY RECRUITING 1636 PATIENTS, MORE THAN THE ORIGINAL TARGET OF 1500. NEW PATIENTS ARE NO LONGER BEING ACCEPTED, ALTHOUGH THE ORIGINAL PATIENTS CONTINUE TO BE FOLLOWED IN THE STUDY.
The Ocular Hypertension Treatment Study (OHTS), sponsored by the National Institutes of Health, is taking place at U.S. medical centers nationwide.
Some people are at increased risk for glaucoma. These include individuals who have diabetes or high blood pressure, who are near-sighted or African American, and those with a family history of glaucoma.
Over 1600 patients with increased eye pressure were enrolled in the study between February 1994 and October 1996. Participants in the OHTS were randomized to either observation or a stepped medical regimen and followed for a minimum of five years. Medical treatment consists of all commercially available antiglaucoma medications.
In 2002, the study published results in the Archives of Ophthalmology showing that using eyedrop medicines to lower eye pressure prevents or delays glaucoma in people with ocular hypertension.
Now that OHTS has proven that lowering eye pressure is effective in delaying or preventing glaucoma in individuals with ocular hypertension, it is important to determine when treatment should be started. Following the finding in 2002, all OHTS participants were offered eyedrop medications. By treating all participants in both groups with eyedrop medications, we should be able to determine if there is a penalty for waiting to institute treatment.
Ocular Hypertension and Glaucoma
Glaucoma is one of the leading causes of blindness in the United States, but little is known about preventing it.
When fluid inside the eye fails to drain properly, it causes increased intraocular pressure—a condition called Ocular Hypertension. If the pressure is too high, it can damage the nerve at the back of the eye, causing glaucoma.
Ocular hypertension is a common condition that occurs in 3% to 8% of Americans over age 40.
A higher than normal eye pressure does not by itself mean that you have glaucoma. But people with ocular hypertension have a higher risk of developing glaucoma. So some doctors refer to them as “glaucoma suspects.”
Why is a trial needed?
Increased IOP is thought to be the leading risk factor for development of open-angle glaucoma.
Published studies are almost equally divided between those that find early medical intervention to be effective in preventing or delaying glaucomatous damage and those that do not.
Despite this lack of convincing evidence for the efficacy of medical treatment in ocular hypertension, approximately 1.5 million glaucoma suspects in the U.S. are being treated with costly ocular hypotensive medications that carry the potential for serious and even life-threatening side effects.
Over 1600 ocular hypertensive patients have been randomly assigned to either close observation only or to a stepped medical regimen. Medical treatment consists of all commercially available topical antiglaucoma agents.
After completion of baseline measures (IOP, visual fields, optic disc photos) and randomization, patients will be followed for a minimum of five years with Humphrey 30-2 perimetry twice yearly and stereoscopic optic disc photos once yearly.
Study endpoints are reproducible visual field loss and/or reproducible optic nerve damage in either eye as determined by an Endpoint Committee. All visual fields and optic disc photographs will be read in a masked fashion in Reading Centers.