THE EFFECTS ON PUPIL SIZE AND ACCOMMODATION OF SYMPATHETIC AND PARASYMPATHOLYTIC AGENTS

The time-response effect of two currently used mydriatics,phenylephrin e and tropicamide, were evaluated in 524 eyes. Four different types of dilating regimens were use& 2.5%phenylephrine, 10% phenylephrine, 0.5 % tropicamide, and the combination of 2.5% phenylephrine and 0.5% trop icamide. The analysis indicated that the recovery from mydriasis occur s between 5.5 and 7.0 hours with 2.5% phenylephrine and at more than 7 hours with 10% phenylephrine. The 0.5% tropicamide induced rapid dila tion, whereas the combined treatment, 2.5% phenylephrine plus 0.5%-tro picamide, produced the largest maximum pupillary diameter. Tropicamide , alone or in combination, also produced a longer mydriatic effect, la sting more than 7.0 hours. The recovery from the cycloplegic effect of the mydriatics occurred between five and seven hours in the majority of patients, with tropicamide alone or in combination with phenylephri ne requiring the most time to revert to normal ranges of accommodation . The findings in this study indicate that, in normal subjects, the re covery from the effect of mydriatic agents is longer than what is gene rally reported in the literature.