Intraocular lens power calculation formula accuracy in 1178 eyes with short axial length: systematic review and network meta-analysis

TOPIC: To systematically review the literature and conduct a comprehensive quantitative analysis to compare the accuracy of different intraocular lens (IOL) calculation formulas in eyes with short axial lengths (ALs). CLINICAL RELEVANCE: The precision of the IOL formulas decreases when applied in eyes with short AL (AL <22 mm), and many new formulas for calculating IOL power have been proposed in the past few decades. However, the accuracy of these formulas has not been systematically compared when applied in eyes with short AL. METHODS: This study systematically searched PubMed, Embase, Web of Science, and Cochrane Library databases to collect relevant research literature published between January 2003 and September 2023. Included were prospective or retrospective clinical studies involving cataract patients with short AL (AL <22 mm) and reporting the following outcomes: mean absolute error, median absolute error (MedAE), and percentage of eyes with a prediction error (PE) within ±0.25 diopters (D), ±0.50 D, and ±1.00 D. A network meta-analysis was performed using R software (v. 4.2.1). RESULTS: 15 prospective or retrospective studies involving 1178 eyes and 12 calculation formulas were included in this study. The network meta-analysis showed that compared with the widely used Haigis formula, the Kane formula had a higher percentage of eyes with PE within the range of ±0.25 D, ±0.50 D, and ±1.00 D (all odds ratio >1, but P > .05). In addition, based on the surface under the cumulative ranking area (SUCRA), the Kane formula had the highest probability of predicting the PE of the eyes within the range of ±0.25 D, with its SUCRA value of 95.74%, followed by Haigis formula (94.79%) and Olsen Standalone formula (84.04%). The Kane and Olsen Standalone formulas had the lowest MedAE. CONCLUSIONS: The Kane, Haigis, and Olsen Standalone formulas may perform better than other formulas in calculating the IOLs power in eyes with short AL. Nonetheless, significant uncertainty remains in this area. The accuracy of these formulas in patients with short AL needs to be verified by large multicenter registry studies.