Randomized Clinical Trial on the Efficacy and Side Effects of Tropicamide and Phenylephrine in Mydriasis for Ophthalmoscopy

Purpose: To compare the efficacy and side effects of two combinations of tropicamide and phenylephrine as mydriatics for ophthalmoscopy. Methods: In this prospective randomized controlled trial, 51 Chinese outpatients were randomized to receive topical tropicamide 1.0% and phenylephrine 2.5% (Regime A), and 50 to receive a fixed combination of tropicamide 0.5% and phenylephrine 0.5% (Regime B). The change in horizontal pupillary diameter, subject discomfort upon instillation and the time elapsed between instillation and recovery from glare and near blur were studied. Results: After 60 minutes, the mean increase in pupillary diameter was 3.56±0.65 mm with Regime A, and 3.04±0.62 mm with Regime B (P<0.01), but there was no difference in the proportion of subjects having a post-mydriatic pupillary diameter of 6 mm or larger (P=0.54). No subjects required additional instillation. Regime B was better tolerated (P<0.001). The median times elapsed between instillation and recovery from glare or near blur was 7 hours, without a significant difference between the two regimes (P=0.5). Conclusions: Both regimes were effective and safe for ophthalmoscopy. However, Regime B was better tolerated. Subjects may be reassured that the side effects of glare and near blur are likely to disappear by the following day