Comparative Analysis of Two Clinical Diagnostic Methods of the Corneoscleral Geometry

Purpose: To compare the sagittal height (SH) measurements and best fit sphere (BFS) scleral curvature obtained with two different diagnostic technologies. Methods: Prospective, nonrandomized, and comparative study analyzing 23 healthy eyes of 23 patients (age, 14–52 years) was conducted. A complete eye examination was performed including a corneoscleral topographic analysis with the Scheimpflug camera–based system Pentacam (Oculus GmbH, Wetzlar, Germany) and afterward with the Fourier domain profilometer Eye Surface Profiler (ESP) (Eaglet-Eye, Houten, the Netherlands). Differences between devices in temporal SH (TSH), nasal SH (NSH), and mean SH (MSH) measurements at 13- and 15-mm chord length and in scleral BFS were analyzed. Results: Statistically significant differences were found in TSH, NSH, and MSH obtained with Pentacam and ESP ( P ≤0.017), with a range of agreement from 0.21 to 1.28 mm, and a clear trend of the Pentacam system to provide higher SH measurements. Significant differences were found between Pentacam scleral BFS and ESP outer BFS ( P <0.001) (range agreement, 3.57 mm). Significant correlations were found between spherical equivalent and differences between devices in 15-mm TSH ( r =0.485; P =0.048), as well as between the difference between devices for some SH measurements and the magnitude of such SH values ( r ≥0.504; P ≤0.014). Conclusion: Sagittal height and scleral BFS measurements obtained with the two devices are not interchangeable, with an increased difference in SH measures between devices in eyes with less myopic refractive error and increased SH values.