First generation versus second generation toric calculator for toric IOL implantations

Purpose: To compare the accuracy of predicted postoperative residual refractive astigmatism after toric IOL implantation between a first generation and a second generation toric calculatorMethodA total of 458 eyes underwent cataract extraction and implantation of a toric IOL between 2011 and 2017. A first generation toric calculator (Acrysof Toric Calculator) was used in 323 eyes, whereas a second generation toric calculator (Barrett Toric Calculator) was used in 135 eyes. The primary outcome was to compare the amount of over‐ and undercorrection of pre‐existent astigmatism, using vector analysis.ResultsPreoperative both groups had comparable corneal astigmatism (respectively 2.43 ± 1.10 D and 2.31 ± 1.26 D for the Acrysof and Barrett group, p > 0.05). Postoperatively, no significant differences were seen in terms of misalignment, CDVA, residual refractive astigmatism, and spherical equivalent. A significant better uncorrected visual acuity was seen in the Barrett group compared to the Acrysof group (respectively 0.05 ± 0.12 vs 0.12 ± 0.17 logMar). Vector analyses showed a significantly lower percentage of overcorrection of ≥0.5 D or ≥1.0 D in the Barrett group (respectively 14% and 3%) compared to the Acrysof group (respectively 32% and 8%). A significant higher percentage of undercorrection of ≥0.5 D was seen in the Barrett group compared to the Acrysof group (respectively 7% and 2%). The correction index was significantly closer to the ideal 1.00 in the Barrett group (1.06 ± 0.24) compared to the Acrysof group (1.16 ± 0.24).ConclusionsThe use of a second generation toric calculator significantly reduces overcorrection after toric IOL implantation.