In vivo assessment of higher-order aberrations after AcrySof toric intraocular lens implantation: a comparative study.

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.