[Effect of nonspecific and cardioselective beta receptor blockers on the formation of aqueous humor. An oculopressure tonometry study].
The aim of the present study was to show the effect of different topical beta-blocking agents on aqueous humor formation with a clinically practicable method. In a clinical, randomized, prospective double-blind study, 60 healthy volunteers were examined by means of oculopression tonometry according to Ulrich. The placebo was applied to 29 subjects; a nonselective beta-blocker (timolol maleate 0.5%) was given to 14 volunteers and 17 subjects received a cardioselective, beta-1-blocking agent (betaxolol-HCl 0.5%). On the 1st day, intraocular pressure (IOP) was lowered by the suction cup method and then we measured the time required for IOP to return to the initial value. The examination procedure of the 1st day was repeated on the 2nd day 3 h after application of the ophthalmic solution. After evaluation of the different groups, we could show that the recovery times in the placebo groups were comparable. Furthermore, we showed that both beta-blockers slow down the increase of IOP to the initial value. There was a statistically significant difference in recovery time between timolol and placebo. This difference was statistically not significant between betaxolol and placebo.