COMPARISON OF THE DILATING EFFECT OF THREE MYDRIATIC AGENTS ON DARK IRIDES

Abstract

Dilation of pupil has been a major component of diagnostic eye examination inOptometric practice. Although mydriatic agents are used in clinical procedures, thereis no satisfactory explanation for the preference of one over another. This studycompared the dilating effect of three different mydriatic agents on dark irides ofninety healthy subjects; comprising 48 males and 42 females aged 16-30 (mean age18.77±0.52) years divided into three groups of 30 subjects each. One drop of 1%tropicamide eye drop was instilled into the right eye of Group 1 subjects, One drop of1% homatropine eye drop was instilled into the right eye of Group 2subjects, whileOne drop of 2.5% phenylephrine eye drop was instilled into the right eye of Group 3subjects, The left eye (control eye), received a placebo of one drop of 10mg/mlBenzyl Alcohol in all the subjects in the three groups. Baseline measurements wererecorded prior to instillation, thereafter mydriatic effect was assessed over a periodof 40 minutes starting at 5 minutes and thereafter at 10 minute interval using thehand held pupillometer. Results showed that after 40 minutes of instilling the 3mydriatic agents to the right eyes, there was a statistically significant difference(p<0.05) in the pupil diameter of all the subjects in the three groups .Maximum meanpupillary dilation was 7.10±0.27mm, 6.00±0.56mm, and 4.80±0.36 mm for 1%tropicamide, 1% homatropine, and 2.5% phenylephrine respectively after 40minutes. Therefore it can be concluded that significant differences exist in themydriatic effect of the three mydriatic agents.