Intraocular lens power formula accuracy in short eyes - a comparison of 10 formulae
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First Author: D.Hipolito-Fernandes PORTUGAL
Co Author(s): M. Luís M. Vieira C. Mota P. Gil V. Maduro N. Alves
To compare the accuracy of 10 intraocular lens (IOL) power formulae predicting refractive error in short eyes (axial length – AL – <=22.0mm)
Ophthalmology Department, Lisbon Central University Hospital Centre
Seventy-nine eyes of 79 patients submitted to uneventful cataract surgery over the last 3 years with Acrysoft IQ SN60WF IOL implantation were retrospectively analysed. Preoperative biometric data were obtained through LenStar 900. Ten IOL formulas were evaluated: SRK/T, Haigis, HofferQ, Holladay 1, Barret Universal II (UII), Kane, PEARL-DGS, EVO, Hill-RBF 2.0 and LADAS. Mean prediction error was nulled by adjusting the individual prediction error by the arithmetic mean error. Mean and median absolute error and the percentages of eyes within ±0.25, ±0.50, ±0.75 and ±1.00 diopters (D) of prediction error were evaluated.
Mean axial length was 21.57 mm (range 20.81-21.99mm) and mean post-operative spherical equivalent was -0.16 ± 0.56 D. The formulae ranked by mean absolute error were as follows: PEARL-DGS (0.321), Kane (0.331), EVO (0.336), Haigis (0.336), Hill-RBF 2.0 (0.347), Barret UII (0.350), Holladay 1 (0.354), Hoffer Q (0.359), SRK/T (0.380) and LADAS (0.407) – no statistically significant difference (p=0,055). Barret UII had the highest percentages of eyes within ±0.25D (51.9%), followed by PEARL-DGS (50.6%) and Kane (49.4%). PEARL-DGS and Kane were the formulae with the highest percentage of eyes within ±1.00D (96.2%).
Despite the lack of statistical significance, our results reveal that new generation formulae (particularly PEARL, Kane and EVO) show promising results improving refractive outcomes in short eyes (AL <=22.0mm)