Continued diagnosis key in disease management

MAUI, Hawaii — In investigating how to detect early glaucoma, the Ocular Hypertension Treatment Study found that repeat perimetry, measuring corneal thickness and careful examination of the optic nerve are valuable.

Once glaucoma is diagnosed, the study showed that lowering intraocular pressure (IOP) is beneficial in some patients; however, it may not be needed in many patients. Assess the risk-to-benefit ratio to determine if a low IOP is necessary, L. Jay Katz, MD, said. Dr. Katz spoke on the clinical applications of the Ocular Hypertension Treatment Study (OHTS) during the Hawaii 2003: the Royal Hawaiian Eye Meeting.

The OHTS investigated the safety and efficacy of ocular hypertensive drugs in preventing or delaying primary open-angle glaucoma (POAG) in patients with ocular hypertension. Researchers also tried to identify the baseline factors indicating the onset of POAG, Dr. Katz said.

The study found that multiple drugs are often necessary to achieve a lower IOP. After 6 months, 40% of patients needed two or more drugs. Nine percent needed three or more drugs to lower the IOP to achieve a pressure below 25 mm Hg, Dr. Katz said.

On repeat perimetry, 748 tests showed an abnormality, though the majority of initial visual field defects were not reproduced on repeat tests, Dr. Katz said. More than 21,000 visual field tests were done on 1,636 patients, he said.

In the study, pachymetry results showed that patients with ocular hypertension had thicker corneas than those with normal tension glaucoma. For this reason, pachymetry is recommended in the initial examination for patients with glaucoma, he said.