Comparison of the accuracy of twenty intraocular lens power calculation formulas in long eyes.

Objective: To compare the accuracy of twenty intraocular lens (IOL) power calculation formulas in long eyes (26.00-29.99 mm)

Design: Retrospective accuracy and validity analysis

Methods: The data of patients who underwent uneventful phacoemulsification between August 2019 and July 2024 were reviewed. Pre-surgery IOL power was calculated using Haigis, Holladay 2, SRK/T and Barrett Universal II formulas. Three months after cataract surgery, refraction was measured. Post-surgery IOL power calculations were performed utilizing the following formulas: Castrop, EVO 2.0, Hill-RBF 3.0, Hoffer Q, Holladay 1, Hoffer QST, K6, Kane, Karmona, Ladas Super Formula AI (LSF AI), Naeser 2, Olsen (standalone), PEARL-DGS, T2, VRF and VRF-G. Root mean square absolute error (RMSAE), median absolute error (MedAE) and percentage of eyes with prediction error (PE) within ± 0.25 D, ± 0.50 D, ± 0.75 D and ± 1.00 were calculated.

Results: One hundred fifty-three eyes with axial length ranging between 26.00 mm and 29.47 mm, were studied. The SRK/T formula yielded the lowest RMSAE (0.349) with statistical superiority over Holladay 1 (0.519, P = 0.000), Olsen (standalone) (0.505, P = 0.000) and Hoffer Q (0.497, P = 0.000). In terms of MedAE, the lowest outcome was obtained by VRF-G (0.256) followed by Barrett Universal II, Hill-RBF 3.0 and LSF AI (all equally of 0.260). The highest percentage of eyes with prediction error within ± 0.50 D was achieved by SRK/T (84.97 %) statistically significant vs Holladay 1 (60.78 %), Hoffer Q (64.05 %) and Olsen(standalone) (68.63 %).

Conclusions: SRK/T has delivered highly accurate results in long eyes. Barrett Universal II, Hill-RBF 3.0, VRF-G and LSF AI are also very true.