Effect of topical timolol maleate on the ophthalmic artery blood pressure.

The effects of topical timolol maleate 0.5% on the ophthalmic artery diastolic (OABPd), systolic (OABPs) and mean blood pressure (OABPm) were investigated in 19 healthy subjects using compression ophthalmodynamometry. In a randomized, double-blind study, one eye of each subject received one drop of timolol maleate 0.5% and the fellow eye received a drop of placebo. Measurements of OABPd and OABPs were performed just prior to instillation of the drops, and then 2 hr later. OABPm was calculated as OABPm = OABPd + 1/3 (OABPs - OABPd). No significant changes in OABPd, OABPs or OABPm were observed following the drops in the timolol-treated eyes or in the placebo-treated eyes. A significant difference (P = 0.0198) was found, however, when the changes in OABPm occurring in the timolol-treated eyes were compared with the changes occurring in the placebo-treated eyes, suggesting that the drug may have an effect upon ophthalmic artery pressure and retinal artery pressure that is expressed differently in each eye.