Purpose: To assess the incidence and possible causative factors of a newly recognized syndrome, the intraoperative floppy iris (IFIS).
Setting: Clinical practices in Los Altos and San Rafael, California, USA.
Methods: A retrospective chart review of consecutive cataract surgeries performed in a 2-surgeon practice over a 12-month period (706 eyes; 511 patients) was used to assess the percentage of cataract patients on systemic sympathetic alpha-1 antagonist medications as well as the percentage of patients who manifested the IFIS. A separate prospective study of 900 consecutive cases (741 patients) performed by another surgeon was used to determine the incidence of IFIS and the percentage of these patients who were taking alpha-1 antagonist medications.
Results: Three percent (16/511) of the patients in the retrospective study, representing 3.0% (25/706) of the total eyes, were taking tamsulosin (Flomax) for benign prostatic hypertrophy. The overall prevalence of IFIS was 2.0% (10/511 patients). The syndrome was noted intraoperatively in 63.0% (10/16) of the tamsulosin patients but in none of the 11 patients on other systemic alpha-1 blockers. In the prospective study of 900 consecutive cataract surgeries, the prevalence of IFIS was 2.2% (16/741 patients). Ninety-four percent (15/16) of the IFIS patients were taking or had taken systemic tamsulosin. Twenty-six patients (36 eyes) in the 2 studies had IFIS associated with systemic tamsulosin. Sphincterotomies and mechanical pupil stretching were ineffective in maintaining adequate pupil dilation in this surgical population.
Conclusion: Intraoperative floppy iris syndrome occurred in approximately 2% of a cataract surgery population and appeared to be caused by tamsulosin, a systemic sympathetic alpha-1A antagonist medication that is the most frequently prescribed medication for benign prostatic hypertrophy.