Eye Irritation Caused by Topical Beta-Blocker Therapy. A New Methodological Screening Approach

Abstract

A double blind single-dose trial screening for eye irritation caused by topical beta-blocker therapy is presented. In 36 healthy subjects eye irritation was measured, comparing carteolol, 1% and 2%, timolol, 0.5%, and balanced salt solution as a placebo reference. The evaluation was based on eye irritation scores by means of a self evaluation analogue scale and a negative preference score. Eye irritation scores were obtained with a 10 point scale (three minutes after treatment) through observer evaluation as well. The results indicate that immediately after topical application, timolol 0.5% is more irritating than carteolol 2%, and carteolol 2% more irritating than carteolol 1%. Three minutes after treatment and 10 minutes after treatment eye irritation on self-evaluation analogue scales were not different between test solutions. It is concluded that the present screening approach is valid and informative for differentiation of topical beta-blockers in ophthalmology with respect to subjective symptoms related to the anesthetic properties of the drugs.