The number of subjects was determined from the primary outcome measure of non-inferiority to achieve a minimum of a one-day difference between the control and investigative groups, with povidone-iodine being compared to the control medication at each study site. The control medications are Neosporin ophthalmic solution in Manila and ciprofloxacin ophthalmic solution in the two combined Indian sites (Hyderabad and Tiruchirapalli) for a total of four study arms. The number of recruits was calculated to achieve 90% power for detecting non-inferiority using t-tests with a level of significance of 0.05 for comparing mean time to cure. Cure is defined as closure of the epithelial defect with no inflammatory signs other than minimal injection.