Preoperative ocular characteristics predicting the development of intraoperative floppy iris syndrome regardless of alpha-antagonist exposure status

Purpose: To assess structural risk factors for intraoperative floppy iris syndrome (IFIS) available on preoperative examination before cataract surgery. Methods: In this retrospective study, medical records of patients who underwent cataract surgery in Shamir Medical Center, between July and September 2019, were reviewed. Patients younger than 50 years, with preexisting ocular conditions affecting the pupillary size or anterior chamber depth (ACD), and combined procedures were excluded. Association of IFIS with preoperative ocular parameters was tested using uni- and multivariant analyses. Results: Overall, 394 eyes of 394 patients were included. The mean age was 72.48 ± 8.63 years, and 58.4% were female. IFIS occurred in 18 eyes (4.6%), seven (38.89%) of which had been previously treated with alpha-antagonists. Patients in the IFIS group were significantly older compared with those in the non-IFIS group (78.1 ± 6.7 vs. 72.2 ± 8.6 years, P = 0.005), with no significant gender difference. The mydriatic pupil diameter was significantly smaller in the IFIS group (5.73 ± 1.16 vs. 6.97 ± 1.03 mm, P < 0.001), and the lens thickness (LT) was larger (4.93 ± 0.42 vs. 4.49 ± 0.42 mm, P = 0.001). ACD was inversely correlated with LT (r = − 0.613, P < 0.001) and positively correlated with pupil diameter (r = 0.252, P < 0.001). On univariate analysis, ACD was significantly shallower in the IFIS group (2.88 ± 0.49 vs. 3.14 ± 0.39 mm, P = 0.008). In multivariant analysis controlling for alpha-antagonist use, both LT and mydriatic pupil diameter remained significantly predictive of IFIS (LT: OR 9.9, 95%CI 1.9–49, P = 0.005; pupil diameter OR 0.427, 95%CI 0.26–0.69, P < 0.001). Conclusions: Increased LT and decreased mydriatic pupil diameter were associated with increased IFIS risk regardless of alpha-antagonist treatment status.