AIM: To compare the mydriatic efficacy of an ophthalmic insert (Mydriasert, MY) versus phenylephrine and tropicamide (PT) eye drops. METHODS: Two controlled, prospective, randomized, single-blind studies were performed. In the first study, a total of 80 eyes from 40 outpatient-clinic patients were analyzed. PT drops were applied to the right eye, and a MY device was inserted in the left eye for 30min. Time until maximal pupil dilation for each eye was then assessed. In the second study, 80 eyes from 80 patients undergoing cataract surgery were analyzed. Pupil dilation was achieved using either PT drops three-times for one hour prior to surgery (40 patients), or a MY device was inserted one hour prior to surgery (40 patients). RESULTS: In the first study, MY achieved superior mydriasis compared to PT eye drops at 90min (9.04 +/- 1.33mm vs 8.78 +/- 1.37mm, P=0.012). However MY took longer than PT drops to achieve maximal dilation, and mydriasis was inferior in eyes with MY compared to PT drops at 30min (7.21 +/- 1.73mm vs8.22 +/- 1.43mm, P