Toric lens implantation in cataract surgery: risk factors of post‐operative lens rotation, analysis of 50 cases

Purpose Toric lens implantation in cataract surgery has improved with the help of automatic alignment methods, which can determine the immediate postoperative angle with great precision. However, unpredictable misalignment sometimes occurs in the following days. The goal of our study is to identify risk factors of toric lens rotation within the first month of implantation. Methods We conducted a prospective, monocentric, descriptive study of 50 eyes in 26 patients operated for cataract by a surgeon experienced in toricity, and implanted a Zeiss Asphina709 implant, during September and October 2016. The intraoperative lens alignment was determined by conjunctival recognition with the Callisto system (Zeiss), coupled with the IOL Master 700 (Zeiss). Lens alignment at one month was determined by blinded double reading on slit lamp photographs using EyeSuite (Luneau). Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and white to white (WTW) distance were measured with the IOL Master 700. Results All implants were aligned as planned at the end of surgery. The average postoperative lens rotation at one month was 4.4° (+/‐4.85). There was no statistically significant correlation between implant rotation at one month and AL (p = 0.46), ACD (p = 0.18), LT (p = 0.75), WTW (p = 0.67), Age (p = 0.57), or Gender (p = 0.11). Conclusions Our study was not able to identify significant risk factors for postoperative toric implant rotation. Our low average rotation and small sample size may explain why statistical significance was not reached. A larger prospective study is underway. Our study underlines the difficulty to predict which patients will show toric implant rotation and highlights the importance of viscoelastic management at the end of surgery. Understanding and controlling those risk factors may help achieve better refractive results in the future.