The aim of this study was to calculate the risk of clinically evident ASI following simultaneous 3-rectus muscle surgery and safety profile of the same in a relatively large number of patients from a single tertiary care centre. This was a retrospective cohort study of 87 patients; 54 male and 33 female with mean age at presentation of 21±13.25 years. Mean age at time of surgery was 22.5±12.9 years. Fourteen patients were older than 35 years and four were older than 50 years at time of surgery. Average follow-up was 5.9±8.2 months. Incidence of clinically apparent ASI was 2.29%; two patients developed signs of ASI in the postoperative period. Both had surgery involving both vertical rectus muscles and one horizontal muscle. Both were aged <35 years and both had fornix incision surgery.