Optical performance of Toric intraocular lens rotation in Hwey-Lan Liou model eye

Background The residual astigmatism following Toric intraocular lens (IOL) rotation have received much attention.However, the variation of the optical performance and the wavefront abrrveation with Toric IOL rotation are unclear. Objective The aim of this study was to evaluate the optical performance, wavefront abrrveation and residual diopter spherical and cylinder lens with Toric IOL rotation. Methods T3, T4 and T5 Toric IOLs of + 22.0 D were placed in Hwey-Lan Liou model eye respectively, with the posterior surface flat on the X axis and steep on the Y axis.Corneal astigmatism model was established by mimicing the model eye with Toric IOL using Zemax optical software.Then the Toric IOLs were rotated 5° to 10° individually under the 4 mm pupil diameter and 550 nm monochromatic light, and the image performance and wavefront abrrveation were recorded with all conditions, including modulation transfer function (MTF), out-of-focus aberration, astigmatism aberration, coma, trefoil aberration and spherical aberration.The refractive error of spherical power and cylinder power were calculated. Results Corneal astigmatism was fully corrected when Toric IOLs in the middle, and the MTF curves were near in T3, T4, T5 Toric IOLs.The image performance was worse under the high spatial frequency with the increase of rotation degrees of Toric IOLs, showing the gradually low of MTF curves, especially T5 Toric IOL.No obvious changes was seen in coma, trefoil aberration and spherical aberration after rotation of Toric IOLs, while out-of-focus aberration, astigmatism aberration were obviously increased.In addition, residual astigmatism and spherical error increase with the rotation of Toric IOLs. Conclusions Toricl IOL rotation leads to increase of astigmatism and spherical refractive error but not high order aberration. Key words: Lens, artificial; Astigmatism; Wavefront aberrations; Modulation transfer function; Model eye; Computer simulation