tokens: METHODS : Forty - three Caucasian patients with primary open - angle glaucoma or ocular hypertension with a mean ( + / - SD ) age of 63 ( + / - 8 ) years were randomized and crossed over in a double - masked manner to 14 days of treatment with placebo ( morning and evening in both eyes ) , timolol solution ( morning and evening in both eyes ) , or timolol gellan ( morning in both eyes with placebo in the evening ) .