The effect of timolol, betaxolol, and placebo on corneal sensitivity in healthy volunteers.

This study in sixty healthy volunteers investigated the effect of a single drop of either 0.5% timolol ophthalmic solution, 0.5% betaxolol ophthalmic solution, or placebo on corneal sensitivity as measured by the Cochet-Bonnet anesthesiometer. Corneal sensitivity was measured immediately prior to the drop and then 1, 3, 6, 10, 15 and 30 minutes after drop instillation. The timolol treated eyes showed a significant decrease at one minute after instillation. An increase in sensitivity occurred in the placebo group at 15 and 30 minutes. In the eyes treated with betaxolol, a significant reduction in corneal sensitivity was seen at every time point through the 10-minute measurement.