Accuracy of Newer Generation IOL Power Calculation Formulas in Eyes With High Axial Myopia

Abstract

Purpose: To compare the accuracy of the Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Kane, and SRK/T formulas for intraocular lens power calculation in patients with high axial myopia.

Methods: In this retrospective study, 175 eyes (175 patients) that underwent uneventful cataract surgery were enrolled. According to the axial length (AL), the eyes were divided into long AL (26 ⩽ AL < 28 mm), super long AL (28 ⩽ AL < 30 mm), and extremely long AL (⩾ 30 mm). The mean absolute prediction errors (MAE) 3 months postoperatively and the percentage of eyes within different prediction error were compared, followed by subgroup analysis.

Results: The MAE and percentage of eyes within ±0.50 diopters (D) of the five formulas were as follows: Barrett Universal II (0.342, 74.9%), EVO 2.0 (0.314, 82.3%), Haigis (0.336, 74.9%), Kane (0.318, 78.9%), and SRK/T (0.398, 69.7%) (P = .552 and .071, respectively). Although no significant difference was found among the five formulas in the super and extremely long AL groups (P = .792 and .227, respectively), the EVO 2.0 formula achieved the highest accuracy (88.9%, 72 of 81) in the long AL group (P = .049). Moreover, the accuracy of the EVO 2.0 and Haigis formulas was stable, regardless of AL. The SRK/T formula showed a negative trend in the long and super long AL groups, whereas the Barrett Universal II, Kane, and SRK/T formulas showed positive trends in the extremely long AL group.

Conclusions: Overall, the EVO 2.0 and Kane formulas achieved better results in patients with high axial myopia, whereas the other three formulas showed slightly poor outcomes. [J Refract Surg. 2021;37(11):754-758.].