eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2015-12-28 8 2 885 889 10.13005/bpj/839 3199 article Keyvan Shirzadi 1 Asgari Rezanejad Amirdehi 1 Ali Makateb 1 Kourosh Shahraki 2 Keivan Khosravifard 1 Department of Ophthalmology, AJA University of Medical Sciences, Tehran, Iran. Department of Ophthalmology, Alzahra Eye Hospital, Zahedan University of Medical Sciences, Zahedan, Iran. Tropicamide is frequently use to dilate the pupil and paralyze the Ciliary body muscle in treatment of ocular disease and diagnosis tests. Since few studies have examined the effect of various concentration of this eye drop on dilation of the pupil, this study designed to investigate concentration effect of tropicamide on mydriasis. In this study, 25 patients referring to the ophthalmology clinic of the Besat Hospital, Tehran, Iran., received different doses of tropicamide (0.5% for right and 1.0% for left eye) to study their pupil’s dilation. Photography was performed in 5 steps, before pouring eye drop, 5, 20 and 60 minutes after pouring the eye drop by Zeiss FF 450 camera. Pupil diameter was measured by VISUPAC software and SPSS ver.  14 was used for statistical analysis. The average of pupil diameter measured at 5, 20 and 60 minutes after pouring the eye drop in both groups (0.5 and 1% tropicamide consumers) were adequate for eye tests and pupil diameter differences measured at any of the steps were not significant between the two groups. A subtle increase in pupil diameter was observed by using a low dose of tropicamide in 20 and 60 minutes after pouring eye drop which was not statistically significant. The results of this study showed that using a lower dose of tropicamide provide satisfactory results and thus it is recommended to use low dose of this drug to prevent the possible and unknown side effects. https://biomedpharmajournal.org/vol8no2/studying-the-effect-of-tropicamide-various-concentrations-on-routine-dilation-of-the-pupil/ Tropicamide Mydriasis Pupil diameter various concentration