Iris color as a predictive factor for intraoperative floppy iris syndrome

Purpose: To assess the influence of iris color on the predisposition for intraoperative floppy iris syndrome (IFIS) during cataract surgery. Methods: Medical records of patients who underwent cataract surgery in two medical centers between July 2019 and February 2020 were reviewed. Patients younger than 50 years, with preexisting ocular conditions affecting pupillary size or anterior chamber depth (ACD), and combined procedures were excluded. The remaining patients were questioned via telephone regarding their iris color. The association of IFIS occurrence and severity with iris color was tested using univariant and multivariant analyses. Results: Overall, 155 eyes of 155 patients were included, 74 with documented IFIS and 81 without. The mean age was 74.03 ± 7.09 years, and 35.5% were female. The most common iris color among study eyes was brown (110/155, 70.97%), followed by blue (25/155, 16.13%) and green (20/155, 12.90%). Compared to brown-colored eyes, blue irises exhibited a 4.50-fold risk for IFIS (OR = 4.50, 95% CI: 1.73–11.70, p = 0.002), and green irises 7.00-fold risk (OR = 7.00, 95% CI: 2.19–22.39, p = 0.001). After adjusting for possible confounders, the results remained statistically significant (p < 0.01). Light-colored irises tended to exhibit a more severe IFIS compared to the brown iris group (p < 0.001). IFIS bilaterality was also affected by iris color (p < 0.001), with a 10.43-fold risk for fellow eye IFIS in the green iris group compared to eyes with brown irises (OR = 10.43, 95% CI: 3.35–32.54, p < 0.001). Conclusions: Light iris color was associated with a significantly increased risk of IFIS occurrence, severity, and bilaterality on univariate and multivariate analysis in this study.