PurposeTo compare the accuracy of intraocular lens (IOL) power calculation formulas in cataract patients with keratoconus (KC).MethodsThis study followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis statementand and was registered on PROSPERO (CRD42024568997). Pubmed, Web of Science, Cochrane Library, and EMBASE were searched for retrospective and prospective clinical studies published until October 2024. The outcome measurement was the percentage of eyes with a predicted error (PE) within +/- 0.50 or +/- 1.00 diopter (D).ResultsThe study have nine retrospective clinical trials, involving a total of 637 eyes and 18 calculation formulas. According to the ranking based on the surface under the cumulative ranking curve by Bayesian method, the top three formulas were Barrett True-K formula for keratoconus predicted posterior corneal astigmatism (Barrett KC P-PCA), EVO2.0, and Barrett True-K formula for keratoconus measured posterior corneal astigmatism (Barrett KC M-PCA) on the percentage of PE within +/- 0.50 D, and the comparison between the three formulas and Barrett Universal II formula has statistical significance. In the range of +/- 1.00D, the top three formulas were Barrett KC P-PCA, Barrett KC M-PCA and Kane for keratoconus formula, and the difference was significant. Thereforewe recommend using the Barrett KC P-PCA formula and the Barrett KC M-PCA formula for calculating IOL power in cataract patients with KC.ConclusionThis study revealed that the KC-specific IOL formulas, notably the Barrett KC P-PCA and Barrett KC M-PCA formulas, demonstrated superior accuracy. In clinical practice, when managing patients with different degrees of KC, surgeons should take into account the individual characteristics of each patient and adopt multiple formulas to improve the accuracy of refractive prediction.