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

Abstract

Purpose 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.

Comparison of the accuracy of 9 intraocular lens power calculation formulas using partial coherence interferometry

“…In our study, this formula confirmed its reputation remaining one of the most accurate formulas across the whole sample and in the long eyes subgroup. However, in short eyes, Barrett showed a lower accuracy achieving one of the highest MAE, MedAE (SD) at 0.300D, 0.249D (0.339), in agreement with previous studies[3–5, 15].…”

“…Kane had the lowest MAE and SD in the whole sample as well as the highest percentage of PE within ±0.50D and was proven to be more effective than old generation formulas like Hoffer Q and Haigis ( P < .001). Several studies have previously reported the same finding using PCI biometers[4, 12] or newer technologies[3, 5, 11, 15]. In fact, multiple articles have recently confirmed that Kane is the most accurate formula overall and in each axial length subgroup[4, 7, 10].…”

“…Based on theoretical optics, this formula has outperformed early-generation formulas[6, 8, 9](SRK/T, Hoffer Q, Holladay 1, and Haigis), and is considered as the second-best formula[10]. Emmetropia verifying optical (EVO 2.0) is also a promising choice and is achieving good results with newer optical biometers, however, few studies have evaluated its accuracy with PCI[3, 11, 12]. Finally, Hill-RBF employs pattern recognition by artificial intelligence and was proven to be less accurate when compared to other newer generation formulas[2, 7, 10, 12].…”

Accuracy of the Kane Formula for Intraocular Lens Power Calculation in Comparison with Existing Formulas: A Retrospective Review

“… 9 11 12 13 With the growing popularity, patients' refractive expectations after the cataract surgery continue to increase, and achieving the desired refractive outcome has become a key principle in recent years. 7 Identifying an IOL formula that best predicts the postoperative refractive outcome is one of the most important factors leading to a successful cataract surgery. Recently, newer generation of IOL formulas, which integrate artificial intelligence and larger number of preoperative eye parameters for prediction, have been introduced.…”

“… 6 Furthermore, some of the modern formulas, such as Hill-RBF and Kane, have incorporated the technology of adaptive learning from a large dataset to predict refractive outcomes. 3 7 …”