Intraobserver repeatability and interobserver reproducibility of corneal measurements in normal eyes using an optical coherence tomography-Placido disk device.

PURPOSE: To study intraobserver and interobserver reproducibility of corneal topography and aberrometry measurements using a device combining optical coherence tomography (OCT) and a Placido disk (Visante Omni).

SETTING

Singapore National Eye Centre, Singapore.

DESIGN

Prospective nonrandomized study.

METHOD: Measurements of simulated keratometry (K), anterior mean curvature, spherical anterior and posterior elevations, 4.5 mm diameter zone aberrometry (spherical aberration, asphericity, astigmatism), pachymetry, and white-to-white (WTW) diameter were taken in normal right eyes. Mean biases and limits of agreement (LoA) were obtained using Bland-Altman analysis.

RESULTS

Regarding intraobserver repeatability, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant (P > .05). The LoA for the anterior mean curvature measurements were flat K, -3.96 diopters (D) and 4.86 D; steep K, -4.50 D and 4.27 D; mean K, -2.48 D and 2.09 D. The LoA for WTW were -9.90 mm and 8.74 mm. Regarding interobserver reproducibility, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant (P > .05). The LoA for anterior mean curvature were flat K, -4.05 D and 4.13 D; steep K, -5.08 D and 3.85 D; mean K, -2.65 D and 2.29 D. The LoA for WTW diameter were -8.79 mm and 8.24 mm.

CONCLUSIONS

The OCT-Placido device had high intraobserver and interobserver clinical reproducibility for measurements of simulated K, 4.5 mm zone aberrometry, pachymetry, and standard anterior/posterior corneal elevation. However, intraobserver and interobserver reproducibility of anterior mean curvature measurements and WTW diameter was lower.

FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.