Comparison of anterior segment measurements with rotating Scheimpflug photography and partial coherence reflectometry.

PURPOSE

To compare central corneal thickness (CCT), anterior chamber depth (ACD), and keratometry (K) readings measured using optical low-coherence reflectometry (OLCR) biometry and high-resolution rotating Scheimpflug photography.

SETTING

Eye Hospital of Wenzhou Medical College, Wenzhou, China.

DESIGN

Comparative case series.

METHODS

The CCT, ACD endothelium to lens, ACD epithelium to lens, and K (mean; in flattest meridian; in steepest meridian) were measured 5 times using the LenStar/Biograph OLCR biometer and 3 times with the Pentacam Scheimpflug system in eyes of healthy volunteers. Concordance was evaluated using paired t tests, the Pearson correlation, and Bland-Altman analyses.

RESULTS

The CCT, ACD endothelium to lens, and ACD epithelium to lens measured with the Scheimpflug system were slightly, albeit significantly, higher than with the OLCR biometer (P<.05); the respective 95% limits of agreement (LoA) were -8.2 μm to 15.7 μm, -0.11 to 0.15 mm, and -0.13 to 0.17 mm. However, the Scheimpflug system gave significantly flatter readings for K in the flattest meridian (95% LoA, -0.54 to 0.32 diopters [D]), K in the steepest meridian (95% LoA, -0.63 to 0.45 D), and mean K (95% LoA, -0.53 to 0.33 D) (P<.001). The CCT, ACD, and K readings were all highly correlated between the 2 devices (r >0.95, P<.001).

CONCLUSIONS

The CCT and ACD measurements with the OLCR biometer and Scheimpflug system can be used interchangeably in healthy young subjects. However, for K measurements, these devices have wide LoA so may not be interchangeable under certain clinical circumstances.