Clinical Outcomes and Predictive Factors of Intraoperative Miosis during Femtosecond Laser-Assisted Cataract Surgery: Results from the First 300 Cases

Purpose: To compare clinical outcomes between patients with and without intraoperative miosis during femtosecond laser- assisted cataract surgery (FLACS) and to identify risk factors for intraoperative miosis during the initial learning curve in the surgeon’s first 300 consecutive cases. Methods: This retrospective cohort study included the first 300 consecutive FLACS cases performed by a single surgeon at a single center. A 5.0-mm capsulotomy was created in all cases using a femtosecond laser. Eyes were divided into two groups based on pupil diameter after femtosecond laser treatment: miosis group (<5 mm) and mydriasis group (≥5 mm). Clinical outcomes at 3 months were compared. Perioperative variables were analyzed to identify factors associated with intraoperative miosis. Results: Of the 300 eyes, 52 (17.3%) were in the miosis group and 248 (82.7%) in the mydriasis group. The miosis group had significantly smaller preoperative pupil diameter (p = 0.002), narrower capsulotomy-pupil margin distance (p = 0.002), longer vacuum duration (p < 0.001), longer phacoemulsification time (p = 0.005), and more frequent multiple docking attempts (p = 0.009). The first 150 cases had a higher incidence of multiple docking attempts (p < 0.001) and miosis (p < 0.001) compared to the second 150 cases. At 3 months, the mean corrected distance visual acuity was –0.01 ± 0.03 and 0.00 ± 0.04 in the miosis and mydriasis groups, respectively (p = 0.890), with no significant differences observed in specular microscopy outcomes. No mechanical expanders were used in any case, and no intraoperative complications occurred in either group. Conclusions: Small preoperative pupil diameter, narrow capsulotomy-pupil margin distance, prolonged vacuum duration, multiple docking, and the surgeon’s initial learning curve were associated with intraoperative miosis during FLACS. Although phacoemulsification time was prolonged, it did not lead to a higher rate of intraoperative complications or adversely affect postoperative clinical outcomes.