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A comparison of intraocular lens power calculation formulas in high myopia

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First Author: J.Bernardes PORTUGAL

Co Author(s):    M. Raimundo   J. Chaves   C. Lobo   J. Murta           

Abstract Details

Purpose:

To comparatively evaluate the accuracy of newer intraocular lens (IOL) calculation formulas (Barrett Universal II, Kane, Ladas Super Formula AI and Hill-RBF 2.0) and common third-generation formulas after Wang-Koch (WK) adjustment in the prediction of postoperative refraction in highly myopic eyes.

Setting:

Tertiary university hospital.

Methods:

Retrospective study including eyes with high myopia submitted to uncomplicated cataract surgery with implantation of an AcrySof MA60MA IOL (power range -5.00 to +5.00 diopters). All patients underwent optical biometry (Carl Zeiss IOLMaster 500 and IOLMaster 700, and Allegro Biograph) and the post-operative spherical equivalent for the same implanted IOL was estimated using SRK/T, Holladay 1 (both WK adjusted) Barrett Universal II, Kane, Ladas and Hill-RBF 2.0 formulas. Outcomes included the median absolute prediction error (MedAE) and the proportion of eyes within 0.25, 0.50 and 1.00 diopters (D) of the pre-operative prediction.

Results:

Eighty-two eyes with a mean axial-length of 30.89 ± 1.85 mm were included, 58 eyes implanted with a positive-diopter IOL implanted, 15 eyes with a negative-diopter and 9 eyes with a zero-diopter IOL. The median absolute error in ascending order was Hill-RBF 2.0 0.31D, Kane 0.33D, Barrett 0.36D, Holladay I wk 0.37D, SRK/T wk 0.37D, and Ladas 0.61D. The formula with the lowest MedAE, Hill-RBF 2.0, yielded a prediction error within 0.25D, 0.50D and 1D in 43.1%, 70.6% and 94.1% of cases respectively.

Conclusions:

Recent formulas like the Barrett Universal II, Kane, Hill-RBF v2.0 as well as WK adjusted formulas (SRK/T wk and Holladay I wk ) perform well in this subset of patients with very high myopia. The Hill-RBF v2.0 formula had the lowest median absolute prediction error and highest proportion of eyes within 0.25D, 0.50D and 1.00D of the predicted target.

Financial Disclosure:

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