To determine the incidence and risk factors of intraoperative floppy iris syndrome (IFIS) in patients undergoing cataract surgery.

The present study included 981 eyes of 655 patients who underwent cataract surgery and development and grade of IFIS were recorded. Correlation analysis was performed to determine the relationship between the IFIS and risk factors such as α₁-adrenergic antagonist (tamsulosin, terazosin, alfuzosin), benzodiazepine, 5-α-reductase inhibitor, age, gender, hypertension, diabetes and glaucoma.

IFIS developed in 178 eyes (18.1%) out of 981 eyes. There was a correlation between the development of the IFIS and α₁-adrenergic antagonist and benzodiazepine and male gender; however, there was no correlation with 5-α-reductase inhibitor, age, gender, hypertension, diabetes and glaucoma. IFIS grade tended to be higher as the cumulative dosage of the α₁-adrenergic antagonist increased. Odds ratio of the patients using tamsulosin was the highest among the other risk factors, which was 3.8 times higher than the patients using terazosin, 9.0 times higher than the patients using alfuzosin and 11.1 times higher than the patients using benzodiazepine. Among patients who underwent cataract surgery on both eyes and who were confirmed with IFIS in 1 or both eyes, no significant grade differences between the 2 eyes were noted.

Alpha 1-adrenergic antagonist and benzodiazepine were risk factors for the development of the IFIS, and as the cumulative dosage of the α₁-adrenergic antagonist increased, the probability of developing a higher grade of IFIS increased. Therefore, predicting and preparing for potential IFIS in patients who have the above-mentioned risk factors are necessary before planning cataract surgery. Additionally, the IFIS aspect of the first eye could be utilized as a predictive value for developing IFIS profile of the fellow eye.