Longterm effect of topical beta-blockers on intraocular pressure and visual field sensitivity in ocular hypertension and chronic open-angle glaucoma.

In a prospective, randomized study, nineteen patients with ocular hypertension (n = 14) or chronic open-angle glaucoma (n = 5) were treated with either betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual field sensitivity and intraocular pressure were assessed with the Octopus perimeter (program G1) and applanation tonometry, respectively, at 3, 6, 12, 24, 36, and 48 months during treatment. Four of the nineteen patients (two timolol-treated and two betaxolol-treated) were lost to follow-up after the 36-month examination. Whereas both drugs reduced the intraocular pressure, the decrease in the timolol-treated group was statistically more pronounced than in the betaxolol-treated group at month 3, 6, and 48 (p < 0.03). In both treatment groups, the visual field mean sensitivity (MS) index decreased slightly during the first six months of treatment, but remained so only in the timolol-treated group at all subsequent examinations. In the betaxolol-treated group, there was a statistically significant increase in MS at the 12, 24, 36, and 48 month visits (p < 0.01). These findings suggest that factors other than IOP alone may determine visual field outcome.