Astigmatism Management with Astigmatism-Correcting Intraocular Lens Using Two Toric Calculators – A Comparative Case Series

Abstract

Background: To compare refractive outcomes after phacoemulsification and toric IOL implantation using two different toric calculators for initial astigmatism assessment in a realworld setting. Methods: This was a retrospective, comparative, interventional case series. Patients over 30-year-old who underwent phacoemulsification and toric IOL implantation (AcrySof ® Toric IOL) by the same surgeon between 2017 and 2018 were included. Eyes with irregular astigmatism, previous corneal refractive surgery, intraocular surgery, corneal pathology, macular pathology and pupil abnormalities were excluded. IOL toricity was determined by using a calculator provided by the AcrySof Toric calculator before 2018 and Barrett Toric Calculator after 2018. Patient demographics, corneal topography, vector and preoperative and postoperative refraction were collected and analyzed at three months postoperative. Results: Thirty-two eyes of 32 patients were included in the final analysis. 0.1D for surgically induced astigmatism was used. Group 1 included 14 eyes assessed with the original (AcrySof) toric IOL calculator, and group 2 included 18 eyes assessed with the Barrett toric IOL calculator. In group 1, postoperative astigmatism less than −1.00D, −0.75 D, and −0.5D was achieved in 88.2%, 76.1% and 53.7% of eyes, respectively, while, in group 2, 89% eyes achieved postoperative residual astigmatism less than 0.5D and all eyes achieved postoperative residual astigmatism less than 0.75D. The proportion of patients with lower postoperative astigmatism was significantly higher in Group 2 (p< 0.05 by chi-square test), a pattern that still held when we divided patients into multiple groups. Vector analysis with the Alpins methods also supported better outcomes in the Barrett group (0.71 D vs 0.35 D). Conclusion:The Barrett Toric calculator resulted in better results in the prediction of residual astigmatism than original (AcrySof) toric calculators.

Astigmatism Management in Modern Cataract Surgery

“…Contributing factors to postoperative astigmatic “refractive surprise” include imperfections in preoperative measurement, corneal surgical-induced astigmatism, errors in alignment of the toric IOL, and the type of toric calculator used [ 16 ]. Huang et al [ 16 ] compared outcomes between two calculators and found significantly lower postoperative astigmatism results when IOL toricity was determined by the Barrett Toric Calculator than by the AcrySof Toric Calculator. In the Barrett group, 89% of eyes achieved postoperative residual astigmatism less than 0.5D, compared to 53.7% of eyes in the AcrySof group.…”

“…In the Barrett group, 89% of eyes achieved postoperative residual astigmatism less than 0.5D, compared to 53.7% of eyes in the AcrySof group. The Barrett Calculator’s incorporation of posterior corneal curvature and astigmatism likely minimizes error in the prediction of residual astigmatism [ 16 ].…”