Repeatability and Reproducibility of Corneal Epithelial Thickness Mapping With Spectral-Domain Optical Coherence Tomography in Normal and Diseased Cornea Eyes

To evaluate the performance of the epithelial thickness mapping (ETM) of the iVue spectral-domain optical coherence tomography (SD-OCT) device (Optovue Inc, Fremont, California, USA) in normal and diseased cornea eyes.Reliability and validity analysis.Sixty eyes of 60 subjects were recruited for the study, which included normal subjects (n = 12) and patients with corneal diseases (12 patients each: dry eye syndrome [DES], contact lens wear, post-laser refractive surgery, and keratoconus). Three repeated scans were acquired on 3 iVue SD-OCTs with device-designated operators from consented subjects. Each subject was scanned on each device. Repeatability (based on random error of repeated scans) and reproducibility (including the random error and the instrument/operator variability) were assessed based on spatial zones derived from a 6-mm-diameter corneal ETM centered on the pupil and compared between the groups.Fifty-nine eyes qualified for final analysis. Seventy-one of 598 acquired scans (11.9%) were excluded owing to scan quality concerns. The percentage of disqualified scans was similar across normal (10.7%) and diseased eyes (12.1%). Of 527 qualified scans, 40 (7.6%) scans required manual edits of the segmentation lines. Repeatability and reproducibility results were similar, indicating minimal device/operator variability for both groups. Repeatability and reproducibility were similar in all subgroups of cornea patients, excluding the DES group, for which reproducibility was significantly lower (range 3.2%-5.5% for DES patients and 1.1%-2.9% for normal subjects).The iVue SD-OCT provides good corneal ETM repeatability and reproducibility in normal and diseased cornea eyes through all map zones.