Longitudinal changes in ocular biometry and their effect on intraocular lens power calculation accuracy in cataract patients

Purpose: To investigate the changes in ocular biometry over time and their impact on intraocular lens (IOL) calculation in adult Korean patients with cataracts. Methods: Inclusion criteria were patients who underwent two consecutive ocular biometric measurements spaced more than one year apart using the IOLMaster 700 between November 2019 and February 2024 at a tertiary hospital in Seoul, Korea. Longitudinal changes in ocular biometry were evaluated. Predictive errors were compared among patients who underwent cataract surgery using the SRK/T, Kane, Barrett Universal II, Cook K6, EVO, Hill-RBF, Hoffer QST, and Pearl DGS formulas. Results: A total of 448 eyes from 448 patients were included. Ocular biometry measured over an average interval of 23.4 months showed that with increasing age, axial length elongated (0.04 ± 0.10 mm, p < 0.001), and the magnitude of total corneal astigmatism increased (0.04 ± 0.39 D, p = 0.018). The mean absolute predictive errors of the final measurements were significantly smaller compared to the initial measurements in the Barrett Universal II, EVO, Kane, and Pearl DGS formulas (difference of -0.05 D, -0.05 D, -0.06 D, and − 0.05 D, respectively). In the subgroup of eyes with an axial length of 25 mm or longer, the final measurements showed even greater reduction in mean absolute predictive errors across multiple formulas, including Barrett Universal II, Cook K6, EVO, Hill-RBF, Hoffer QST, Kane, and Pearl DGS, with reductions of -0.11 D, -0.11 D, -0.10 D, -0.08 D, -0.10 D, -0.09 D and − 0.10 D, respectively. Conclusions: Axial length increases and corneal curvature changes with aging. IOLMaster 700 ocular biometry results measured closer to the date of surgery were more accurate in IOL power calculation than those measured more than one year earlier, with the greatest improvement observed in myopic eyes. Therefore, it is recommended to repeat IOLMaster 700 biometry before surgery if the previous measurements were taken more than a year ago.