Purchase this article with an account.
Yao Nie, Qienyuan Zhou, Yan Li, David Huang, Ben Jang, Kelly Soules; Corneal Epithelial Thickness Measurement Using RTVue FD-OCT System. Invest. Ophthalmol. Vis. Sci. 2012;53(14):102.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess the corneal epithelium segmentation and the epithelial thickness measurement using RTVue Fourier-domain (FD) optical coherent tomography (OCT) system with CAM (Optovue, Fremont, CA) on normal, post laser vision correction (LVC) and keratoconus (KCN) eyes.
Totally 18 normal, 30 post-LVC and 20 KCN subjects from two clinical sites were included in the study with informed consent. One or both eyes per subject were scanned. At least 3 repeated "Pachymetry+Cpwr" scans were acquired for each eye with central pupil alignment. To evaluate the epithelium segmentation, visual inspection was conducted with epithelial boundary overlaid on each cross sectional corneal image. An image with any visible segmentation error was counted as a failure and excluded from following data analysis. The average thicknesses of the central (2 mm diameter), superior and inferior (2-5 mm) zones were calculated from the epithelial thickness map. The mean and standard deviation (SD) of the zonal thicknesses were generated cross eyes within each pathology group. The pooled-SD of repeated scans was calculated for central epithelial thickness in each group to evaluate the repeatability of the epithelial thickness measurement.
Total 904, 1344 and 944 cross sectional images were visually inspected for the normal (26 eyes), post-LVC (39 eyes) and KCN (40 eyes) group, respectively; and the segmentation failure rate is 0.55%, 1.34% and 4.91% for each group, respectively. The repeatability of the central epithelial thickness measurement is 0.78, 0.83 and 1.17μm within the normal, post-LVC and KCN group, respectively. The assessments of the central, superior and inferior zone thickness are summarized in Table 1.
RTVue FD-OCT epithelium segmentation has good performance on normal as well as pathological eyes. The central epithelial thickness measurement is highly repeatable. The epithelial thickness measurements show different distribution in different pathology groups.
This PDF is available to Subscribers Only