Clinical Ophthalmology (Dec 2020)

VRF-G, a New Intraocular Lens Power Calculation Formula: A 13-Formulas Comparison Study

  • Hipólito-Fernandes D,
  • Elisa Luís M,
  • Gil P,
  • Maduro V,
  • Feijão J,
  • Yeo TK,
  • Voytsekhivskyy O,
  • Alves N

Journal volume & issue
Vol. Volume 14
pp. 4395 – 4402

Abstract

Read online

Diogo Hipólito-Fernandes,1 Maria Elisa Luís,1 Pedro Gil,1 Vitor Maduro,1 João Feijão,1 Tun Kuan Yeo,2 Oleksiy Voytsekhivskyy,3 Nuno Alves1 1Department of Ophthalmology, Centro Hospitalar Universitário De Lisboa Central, Lisbon 1169-050, Portugal; 2Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, Singapore; 3Department of Ophthalmology, Kyiv Clinical Ophthalmology Hospital Eye Microsurgery Center, Medical City, Kyiv 03680, UkraineCorrespondence: Diogo Hipólito-FernandesDepartment of Ophthalmology, Centro Hospitalar Universitário De Lisboa Central, Alameda De Santo António Dos Capuchos, Lisbon 1169-050, PortugalTel +351 21 313 6300Email [email protected]: To compare the accuracy of a newly developed intraocular lens (IOL) power formula (VRF-G) with twelve existing formulas (Barret Universal II, EVO 2.0, Haigis, Hill-RBF 2.0, Hoffer Q, Holladay 1, Kane, Næeser 2, PEARL-DGS, SRK/T, T2 and VRF).Methods: Retrospective case series including 828 patients having uncomplicated cataract surgery with the implantation of a single IOL model (SN60WF). Using optimised constants, refraction prediction error of each formula was calculated for each eye. Subgroup analysis was performed based on the axial length (short ≤ 22.0mm; medium > 22.0mm to < 26.0mm; long ≥ 26.0mm). Main outcomes included mean prediction error (ME) mean (MAE) and median absolute error (MedAE), in diopters (D), and the percentage of eyes within ± 0.25D, ± 0.50D, ± 0.75D and ± 1.00D.Results: Formulas absolute errors were statistically different among them (p< 0.001), with Kane having the lowest MAE of all formulas, followed by EVO 2.0 and VRF-G, which had the lowest MedAE. The Kane formula had the highest percentage of eyes within ± 0.25D (47.0%) and ± 1.00D (97.7%) and the VRF-G formula had the highest percentage of eyes within ± 0.50D (79.5%). For all AL subgroups, Kane, EVO 2.0 and VRF-G formulas had the most accurate performances (lowest MAE).Conclusion: New generation formulas may help us in achieving better refractive results, lowering the variance in accuracy in extreme eyes – Kane, EVO 2.0 and VRF-G formulas are promising candidates to fulfil that goal.Keywords: intraocular lens power calculation formulas, biometry, cataract, phacoemulsification, formulas accuracy

Keywords