In vivo Assessment of Higher-Order Aberrations after Acrysof Toric Intraocular Lens Implantation: A Comparative Study

Abstract

Purpose To compare higher-order aberrations (HOAs) and optical quality in eyes implanted with AcrySof SN60TT toric intraocular lens (IOL) or with non-toric AcrySof SN60AT IOL (Alcon Laboratories, Inc., Fort Worth, TX). Methods This was a prospective, consecutive, nonrandomized, interventional, comparative study. One hundred eyes with cataract in 56 patients were included (SN60TT group, n=50; SN60AT group, n=50). Patients underwent phacoemulsification through a 2.2-mm temporal corneal incision. Postoperative HOAs, point spread function (PSF) and modulation transfer function (MTF), residual objective refractive astigmatism, and IOL alignment were evaluated using Optical Path Difference (OPD)–Scan II (Nidek, Gamagori, Japan). A novel technique to calculate IOL axis alignment was introduced. Results One year postoperatively, no statistical difference in corneal, intraocular, and total HOAs, Strehl ratio, and MTF based on HOAs was found between groups. Toric IOL patients had a net residual refractive astigmatism (M) of 0.44 D±0.47; the difference between expected and obtained astigmatism (M) was 0.043 D (p=0.16). Toric IOL axis misalignment was 2.65±2.39 degrees and no correlation with HOAs was found. Conclusions AcrySof SN60TT determines HOAs comparable to the non-toric version providing a good optical quality, and predictably corrects corneal cylinder with a stable postoperative alignment. The OPD-Scan II might be regarded as a fast and reliable method of toric IOL analysis.