Evaluating the rotational stability of toric intraocular lenses with different haptic designs using finite element analysis.

This study was designed to measure rotational stability of four TIOLs with differences in haptic design in the capsular bag to provide insights for increasing postoperative rotational stability.Four different shapes of the TIOL models were reconstructed from real measurements and evaluated for their rotational stability in capsular bags of different diameters in vitro under simulated compression testing, as well as post-implantation analysis of rotation and stress. The TIOLs were compressed to a 10 mm diameter and assessed for bio-mechanical stability. There were significant differences in compressive force and axial displacement between models. Model D showed convex deformation of the optical surface when compressed to 10.5 mm, resulting in large variations in some internal parameters. When implanted into a 10.75 mm capsular bag, the rotational angles of different TIOLs ranged from 4.97° to 17.23°. Model C exhibited rotational angles between 3.06° and 9.93° in capsular bags of varying diameters. Model C showed higher stress at the optic-haptic junction, whereas Models A and D exhibited lower stress levels. Model A exhibited the lowest equatorial stress across capsular bags of different diameters.The rotational stability of TIOLs is significantly influenced by haptic design, with notable biomechanical differences among the models. This study provides valuable insights for optimizing TIOL designs to enhance postoperative rotational stability.