[Time course of changes in contrast sensitivity function after application of antiglaucomatous eyedrops]

Some antiglaucomatous eyedrops can cause blurred vision after application. Contrast sensitivity after application, however, has not been examined. The purpose of this study was to investigate the influence of antiglaucomatous eyedrops on contrast sensitivity function.

In 23 eyes of 23 normal volunteers (34.9 +/- 14.5 years [mean +/- SD]), contrast sensitivity was measured before and 2, 5, 10, and 15 minutes after application of antiglaucomatous eyedrops. Three drugs, timolol maleate ion-activated gel, timolol maleate thermosetting gel, and brinzolamide were tested in this study, and the time course of changes in contrast sensitivity after instillation was statistically analyzed and compared between the drugs.

All drugs significantly reduced contrast sensitivity function (p<0.001). The reduction in contrast sensitivity persisted for approximately 5 minutes after instillation of timolol maleate ion-activated gel and brinzolamide. For timolol maleate thermosetting gel, the reduction in contrast sensitivity lasted for about 10 minutes, but the reduction immediately (two minutes) after instillation was significantly smaller than that of the other two drugs (p<0.05).

Instillation of these three drugs temporarily degrades contrast sensitivity function, leading to blurred vision, which should be sufficiently explained to patients before treatment with these eyedrops.