Agreement between stratus and visante optical coherence tomography systems in tear meniscus measurements

AIM: To compare the tear meniscus height (TMH) measurements provided by the Stratus and Visante optical coherence tomography systems. METHODS: A cross-section image of the lower tear meniscus was captured with both instruments in 26 volunteers. An external application was used to manually measure the TMH as imaged by the Stratus; measurements by the Visante were analyzed by the internal software. Only 1 eye for each subject was considered for statistical analysis. RESULTS: The mean (±SD) TMH was higher when measured by the Visante (0.28 ± 0.12 mm) compared with the Stratus (0.23 ± 0.07 mm, P = 0.029). Measurements were correlated (R = 0.38, P = 0.0008), but Bland-Altman analysis showed low agreement (95% limits of agreement: -0.15 to +0.26 mm). CONCLUSIONS: Visante and Stratus cannot be used interchangeably to measure the TMH. The differences between the 2 instruments are likely to be related both to the dynamic nature of the tear meniscus and to the distortion of Stratus images, which are not dewarped and calibrated for anterior segment imaging.