Dose-response relationships in tropicamide-induced mydriasis and cycloplegia.

1 Mydriatic and cycloplegic effects of tropicamide in the normal and in the guanethidine-treated human eye have been recorded following prolonged exposure of the eye to drug solutions. 2 Marked effects and satisfactory dose-response relationships were observed at drug concentrations within the range 1.25-40 μg/ml, by comparison with concentrations of 5-10 mg/ml usually applied as eye-drops. 3 The findings are discussed in relation to drug concentrations which produce cholinergic antagonism in vitro.