Reducing Intraocular Pressure Lowers Risk of Progression in Early Open-Angle Glaucoma

Laurie Barclay, MD

January 21, 2003

Jan. 21, 2003 — The Early Manifest Glaucoma Trial (EMGT), reported in the January issue of the Archives of Ophthalmology, provides conclusive evidence that reduction in intraocular pressure (IOP) lowers the risk of progression in early open-angle glaucoma. This has significant public health implications.

"Patients treated in the EMGT had half of the progression risk of control patients," write M. Cristina Leske, MD, MPH, from Stony Brook University School of Medicine in New York, and colleagues from the EMGT Group. "The magnitude of initial IOP reduction was a major factor influencing outcome."

In this randomized trial, 255 patients with open-angle glaucoma received argon laser trabeculoplasty plus topical betaxolol or no immediate treatment and were followed every three months.

After six years, 53% of patients progressed as defined by perimetric and photographic optic disc criteria. Multivariate analyses revealed that risk of progression was halved by treatment (hazard ratio [HR] = 0.50; 95% confidence interval [CI], 0.35 - 0.71). Exfoliation and bilateral open-angle glaucoma at baseline each doubled the risk of progression.

Other baseline factors predicting progression were higher IOP, worse mean deviation, and older age. Progression risk decreased by about 10% with each mm Hg of IOP reduction from baseline to the three-month follow-up visit (HR = 0.90 per mm Hg decrease; 95% CI, 0.86 - 0.94).

The first IOP at that visit also predicted progression (HR = 1.11 per mm Hg higher; 95% CI, 1.06 - 1.17), as did the mean IOP at follow-up (HR = 1.13 per mm Hg higher; 95% CI, 1.07 - 1.19), and the percentage of patient follow-up visits with disc hemorrhages (HR = 1.02 per percent higher; 95% CI, 1.01 - 1.03). No other risk factors were identified.

"The trial...provides solid scientific evidence on the effectiveness of treatment to reduce glaucoma progression in a randomized clinical trial, which is needed to support the value of early detection and subsequent treatment of persons with glaucoma," the authors write. "The results of the EMGT, therefore, have clinical and public health implications."

Arch Ophthalmol. 2003;121:48-56

Reviewed by Gary D. Vogin, MD