Repeatability and comparative study of corneal thickness using the Visante™ OCT, OCT II and Orbscan II™

The first purpose of this study was to measure the repeatability the VisanteTM Optical coherence tomographer (OCT) in a normal sample. The second was to compare corneal thickness measured with the VisanteTM OCT to the Zeiss-Humphrey OCT II (model II, Carl Zeiss Meditec) adapted for anterior segment imaging and to the Orbscan IITM (Bausch and Lomb). Fifteen healthy participants were recruited. At the Day 1 visit, the epithelial and total corneal thickness across the central 10 mm of the horizontal meridian was measured using the OCT II and the VisanteTM OCT. Only total corneal thickness across the central 10 mm of the horizontal meridian was measured using the Orbscan II. These measurements were repeated on Day 2. Mean central corneal and epithelial thickness using the Visante™ OCT at the apex of the cornea was 536±27 mm and 55±2.3 mm. Mean corneal and epithelial thickness using OCT II at the apex was 520±25 mm and 56±4.9 mm. Mean total corneal thickness measured with the Orbscan II was 609±29 mm. The coefficient of repeatability (COR) ranged from ±7.71 to ±8.98 mm for total corneal thickness and from ±8.72 to ±9.92 mm for epithelial thickness. Correlation coefficients of concordance (CCC’s) were high for total corneal thickness for test-retest differences ranging from 0.97 to 0.99, CCCs for epithelial thickness showed moderate concordance for both the instruments. There is good repeatability of corneal and epithelial thickness using each OCT for test-retest differences compared to the between instrument repeatability. Measurements of epithelial thickness were less robust.