Comparison of axial length measurements of myopic eyes from ocular biometers versus axial length estimator.

PURPOSE: To compare axial length (AL) estimates of myopic eyes obtained using an axial length estimator (ALE) and AL measurements made with the IOLMaster 700 in India and the Lenstar 900 in Vietnam.

METHODS

This multicenter retrospective cross-sectional study analyzed masked data of both eyes from myopic children (<18 years of age). Estimated AL was derived from mean keratometry and refraction values using ALE. Differences between actual and estimated ALs and their correlation were assessed using Bland-Altman plots and intraclass correlation coefficients (ICCs).

RESULTS

A total of 237 myopic children (474 eyes) aged 5-16 years were included: 90 Indian and 147 Vietnamese children. ALE estimates on average exceeded actual AL measurements, with mean differences of -0.26 mm (95% limits of agreement, -1.25 to 0.73 mm) for ALE formula, and -0.21 mm (95% limits of agreement, -1.14 to 0.71 mm) for ALE data input. ICCs showed strong agreement: 0.90 (95% CI, 0.83-0.93) for actual AL versus ALE data input and 0.89 (95% CI, 0.78-0.93) for actual AL versus ALE formula. Indian children had shorter actual AL than Vietnamese children (24.56 ± 0.90 vs 24.91 ± 0.86 mm [P < 0.001]) and exhibited slightly smaller differences between actual and estimated AL (-0.13 vs -0.27 mm for ALE data input; -0.17 vs -0.31 mm for ALE formula).

CONCLUSIONS

In our cohorts, ALE demonstrated strong agreement with IOLMaster 700 and Lenstar 900 AL measurements in myopic children. ALE may be a useful clinical tool for this population when direct measurements of AL are unavailable.