Effect of astigmatism on visual acuity after multifocal versus monofocal intraocular lens implantation

Abstract

To determine whether there is a difference in how much residual astigmatism impacts uncorrected distance visual acuity (UDVA) after multifocal versus monofocal intraocular lens (IOL) implantation. Database study. Retrospective data review. An online toric IOL back-calculator allows users to input preoperative toric planning information and postoperative IOL orientation and refractive results. These data are used to determine the optimal orientation of the IOL to minimize residual refractive astigmatism. Aggregate data were extracted from this calculator to investigate factors associated withUDVA and relative magnitudes of residual astigmatic refractiveerror up to 2.5 diopters (D) after implantation of toric IOLs. Of 1919 pertinent records (455 multifocal toric IOLs and 1464 monofocal toric IOLs), a statistically significant difference by refractive cylinder category (P<.01) and a statistically significant difference by IOL type (P=.042) were noted.This difference was mostly driven by patients with residual refractive astigmatism of 1.5 D. The mean change in UDVA was 0.16 logarithm of the minimum angle of resolution per 1.0 D of astigmatism. Evaluating amore homogenous dataset withthe same monofocal and multifocal IOL design, therewas a statistically significant effect of refractive cylinder(P<.01) but nosignificant effect of IOL type (monofocal or multifocal, P=.45). The differences in UDVA at differentrefractive cylinder values was not statistically significantly different by orientation of the current astigmatism (P=.28). Residual astigmatism after toric IOL implantation impacts visual acuity similarly in patients who had multifocal and monofocal toric IOL implantation.