The influence of rotational error and axial shift of toric intraocular lenses on residual astigmatism

Accurate alignment of Toric Intraocular Lens (T-IOLs) in cataract surgery is crucial for good visual outcomes. The purpose of this study was to evaluate the influence of rotation, axial shift and their combined effects on the refractive error and image quality of a wide range of T-IOL powers (from +1.50 D to +6.00 D cylinder) and two pupil diameters (3.34 and 4.44 mm). Numerical ray tracing was utilized to quantify the residual error. Simulated retinal images and Visual Strehl (VS) ratios were calculated to evaluate image quality. First, T-IOL rotation showed better agreement with Holladay's formula than 3.33% rule. Second, axial displacement resulted in acceptable residual cylinder (