Lack of long-term drift in timolol's effectiveness in patients with ocular hypertension

To report the change over time in intraocular pressure in patients treated with topical timolol or placebo.

Ninety patients with untreated ocular hypertension, defined as elevated intraocular pressure and normal visual fields, were randomly assigned to treatment and prospectively observed at 3-month intervals for up to 10 years in a double-masked fashion. The study end point was one eye showing reproducible glaucomatous field defects; patients were also withdrawn if one eye showed intraocular pressure of 35 mm Hg or higher. For each treatment group and visit, the mean and median of all intraocular pressure measurements were calculated. Medians were also calculated for the timolol group, assuming a worst-case scenario in which all patients who reached the end point, or intraocular pressure of 35 mm Hg or more, were assumed to show higher intraocular pressure than those remaining in the study. Distributions of slopes for intraocular pressure over time were compared between treatment groups.

Means and medians of follow-up intraocular pressure over time did not differ between timolol- and placebo-treated patients. This was also true when assuming a worst-case scenario. Slopes of intraocular pressure over time did not differ statistically between treatment groups.

In agreement with other masked and controlled studies and in conflict with uncontrolled ones, the present study did not demonstrate long-term drift of intraocular pressure in patients with ocular hypertension treated with topical timolol.