Evaluation of axial length measurement and other biometric parameters using three different generations of biometers.

PURPOSE: To compare biometric measurements obtained with partial coherence interferometry (IOLMaster 500, IOLM), optical low-coherence reflectometry (Lenstar 900, LS900), and swept-source optical coherence tomography (Eyestar 900, ES900).

METHODS

In this prospective, observational study, axial length (AL), anterior chamber depth (ACD), aqueous depth (AD), lens thickness (LT), and central corneal thickness (CCT) were measured with the three devices. Exclusion criteria were ocular disease, previous ocular surgery, and contact lens use within 72 h. Normality was assessed using the exact Kolmogorov-Smirnov test. Comparisons were performed with paired T-tests and repeated-measures ANOVA with Bonferroni correction. Agreement was evaluated using Bland-Altman plots, and correlation was evaluated using Pearson correlation (r), and intraclass correlation coefficients (ICC). Subgroup analysis by eye side was conducted.

RESULTS

Two-hundred-six eyes of 103 healthy subjects (38 females) were recruited at Public hospital "San Giovanni di Dio e Ruggi d'Aragona", Salerno, Italy. All devices showed excellent correlation for AL and ACD (r ≥ 0.947, ICC≥0.939; p < 0.001). AL and ACD were comparable between LS900 and IOLM (ΔAL = +0.00 ± 0.09 mm; ΔACD = +0.01 ± 0.10 mm; p > 0.050). ES900 measured longer AL and deeper ACD than LS900 (ΔAL = +0.03 ± 0.10 mm; ΔACD = +0.04 ± 0.11 mm; p ≤ 0.031) and IOLM (ΔAL = +0.03 ± 0.08 mm; ΔACD = +0.04 ± 0.11 mm; p ≤ 0.013). Strong correlation was observed between ES900 and LS900 for CCT, AD, and LT (r ≥ 0.979, ICC≥0.961; p < 0.001). ES900 measured thicker CCT, deeper AD, and thinner LT (p < 0.017).

CONCLUSION

Despite excellent correlation, ES900 provided systematically higher AL and ACD values and different anterior segment measurements. Therefore, caution should be taken when using these devices interchangeably, especially in longitudinal studies and follow-up evaluations; device-specific interpretation is recommended to optimize refractive outcomes in cataract surgery.