Abstract
A comparative study in healthy subjects and diabetic patients of the mydriatic response to topical tropicamide 0.5% with and without added phenylephrine 10% is reported. The findings indicate that diabetic pupils respond relatively poorly to tropicamide alone but adequately and completely to the drug combination. The pupils of diabetic patients whose eyes had previously received laser treatment dilated less than those from untreated eyes by a small but significant extent. This combination of drugs is recommended for all diabetic patients to provide an adequate mydriasis with a minimum of postclinic accommodative paralysis.