Purpose: The toric model is useful for correcting corneal astigmatism with trifocal intraocular lenses to achieve good acuity levels of distance and near vision without eyeglasses. In this study, we compared selected toric models and postoperative visual acuity between the newly developed Holladay total SIA formula (hereinafter the total SIA formula) and other toric calculators in cases where trifocal toric intraocular lenses were selected using the total SIA formula.
Patients and methods: Forty-one eyes for which the AcrySof^® IQ PanOptix^® toric IOL model TFNT20 (hereinafter T2) was selected using the total SIA formula were included in this study. Using the preoperative data of these eyes, the Holladay toric calculator (hereinafter the Holladay formula) and the Barrett toric calculator (hereinafter the Barrett formula) were compared against the total SIA formula in terms of corneal astigmatism, toric models selected, and the number of cases where T2 was selected and refractive astigmatism 30-60 days after insertion in these cases.
Results: Among the 41 eyes for which T2 was selected using the total SIA formula, the same T2 model was selected for 28 eyes using the Holladay formula and for 26 eyes using the Barrett formula. The mean preoperative corneal astigmatism in the eyes for which T2 was selected was lower than 0.75 D with all formulas: 0.64 D using the total SIA formula, 0.67 D using the Holladay formula, and 0.56 D using the Barrett formula. Regarding the distribution of astigmatism based on double angle plots, the Holladay formula and the Barrett formula tended to recommend the T3 model with a cylinder of 1.5 D for with-the-rule astigmatism and against-the-rule astigmatism, respectively, compared to cases selected by the total SIA formula. Among the eyes for which T2 was selected, postoperative refractive astigmatism was improved regardless of the formula used: 0.05±0.15 D (mean±standard deviation) using the total SIA formula, 0.06±0.16 D using the Holladay formula, and 0.05±0.14 D using the Barrett formula.
Conclusion: While T2 was selected for different cases depending on the toric calculator used, postoperative refractive astigmatism in cases where T2 was selected using the total SIA formula was as good as that in cases where T2 was selected using other toric calculators.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 128: 9-13,2024.