Preventing Glaucoma in a High-Risk Population

T HE OCULAR HYPERTENSION TREATMENT Study (OHTS) was designed to determine the effect of lowering intraocular pressure (IOP) on the conversion from ocular hypertension to identifiable glaucomatous damage in a high-risk population, namely, patients with ocular hypertension (OHTN). Ocular hypertension was defined as an IOP greater than 22 mm Hg. Before the OHTS, some investigators had found that patients with elevated IOPs but no other stigmata of glaucoma developed glaucoma at an annual rate of approximately 2%. However, the value of lowering IOP for patients with OHTN remained unknown. After an average of 5 years of follow-up, the OHTS found that IOP lowering of approximately 20% decreased the prevalence of glaucoma from 9.5% in the observation group to 4% in the treatment group. These findings clarified the natural history of OHTN and validated the protective effect of lowering IOP.