Comparison of 0.5% cyclopentolate plus 0.5% tropicamide and 1% cyclopentolate alone for mydriasis of dark irides

We studied the mydriatic and cycloplegic effect of a single dose of a combination of 0.5% cyclopentolate hydrochloride and 0.5% tropicamide in 20 healthy subjects with dark brown irides. The mean change in dilatation with the combination drop was 3.5 mm, compared with 0.6 mm with 1% cyclopentolate alone (p less than 0.001). In 92% of 26 eyes studied the difference in refraction between the combination drop and 1% atropine was +1.00 dioptre or less. The combination drop safely provided satisfactory mydriasis and cycloplegia in 20 minutes, allowing for rapid and accurate examination of these patients.