Accuracy of IOL Power Calculation Formulas for AcrySof SN60WF versus Tecnis ZCB00 Intraocular Lenses

To compare the accuracy of various intraocular lens power formulas for two monofocal hydrophobic foldable lenses, the AcrySof SN60WF and the Tecnis ZCB00.

This retrospective study included 409 eyes from 409 patients who underwent uncomplicated cataract surgery (299 eyes with SN60WF and 110 eyes with ZCB00). Biometry was performed for all eyes with an IOLMaster 700. Predicted refraction from five different IOL power formulas (Barrett Universal II, Haigis, Hoffer-Q, Holladay 2, and SRK/T) was compared to postoperative refraction at one to three months for the following axial length strata: short eyes (<22.5 mm), medium eyes (22.5–25.5 mm), and long eyes (>25.5 mm).

In patients with medium eyes, there were no significant differences in the mean absolute error (MAE) and the percentage of eyes within ±0.5 D (%±0.5 D) between both IOLs. In short eyes, although MAE was similar between both lenses, %±0.5 D was significantly higher for Barrett Universal II in ZCB00 than in SN60WF (P = 0.01) while Hoffer-Q and Holladay 2 performed equally for both lenses. In long eyes, ZCB00 had a higher MAE than SN60WF for Barrett Universal II, Haigis, and Hoffer-Q. Additionally, in long eyes, the percentage of eyes within %±0.5 D was significantly higher for SN60WF than ZCB00 for all formulas (P < 0.001).

Although there were no significant differences in the formula accuracy between these two lenses in medium eyes for all formulas and in short eyes for most formulas, the accuracy decreased significantly in long eyes for ZCB00 compared to SN60WF. The effect of IOL model on the postoperative outcomes should be further investigated.