Purpose: To evaluate the repeatability, reproducibility, and agreement in anterior, posterior, and in particular the total corneal power of 2 topography devices, rotating Scheimpflug photography and scanning-slit topography.
Setting: Department of Ophthalmology and Visual Science, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan.
Methods: Seventeen eyes of 17 subjects (mean age 24.7 years +/- 4.1 [SD]) were included in the study. The corneal shapes within the central 3.0 mm were measured with rotating Scheimpflug photography (Pentacam) and scanning-slit corneal topography (Orbscan II). The within-rater repeatability and reproducibility of 2 raters and the overall between-instrument agreement of the measurements were evaluated using intraclass correlation coefficients (ICCs) and the Bland-Altman method.
Results: The repeatability of Scheimpflug photography and scanning-slit corneal topography was high (ICC, 0.70 to 0.99). Scheimpflug photography outperformed scanning-slit corneal topography for anterior power, posterior power, and total corneal power. The reproducibility results were similar, with limits of agreement (LoA) consistently narrower for Scheimpflug photography. The between-instrument agreement was moderate, with LoA around the mean value of total corneal power of 0.46 diopter ranging from 0.032 to 0.889.
Conclusions: The results suggest that repeatability and reproducibility are higher in Scheimpflug photography than in scanning-slit topography. The agreement between rotating Scheimpflug photography and scanning-slit topography for total corneal power was moderate.