Five-year follow-up study of timolol in patients at moderate risk of developing open-angle glaucoma

A prospective, randomized, double-masked clinical trial was conducted to evaluate the effect of timolol in preventing or delaying the onset of glucomatous damage in patients with moderate-risk ocular hypertension. The 62 patients who entered this study were instructed to instill a timolol ophthalmic solution twice daily in one eye and a placebo solution in the other eye. Perimetry was conducted at four-month intervals, and stereo-optic disk photographs were obtained yearly. Intraocular pressure (IOP) was reduced by a mean of 4.9 ± 3.3 mm Hg in the timolol-treated eyes. IOP in the contralateral placebo-treated eye was reduced by approximately half this amount. During the five-year follow-up period, visual field loss developed in 10 placebo-treated eyes and four of the eyes treated with timolol. Progressive cupping was detected in eight eyes treated with placebo and four eyes with timolol. In addition, a significantly greater increase in optic disk pallor was noted in placebo-treated eyes. The results of this long-term follow-up study indicate that lowering IOP with timolol treatment prevents or delays the onset of glaucomatous damage in patients with ocular hypertension considered to be at moderate risk of developing open-angle glaucoma.