Title: Corneal epithelial thickness changes as imaged by Fourier Domain Optical Coherence Tomography in eyes with Keratoconus. Keywords: Keratoconus, OCT, corneal epithelium, corneal ectasia. PURPOSE: To document changes in the corneal epithelium as imaged by Fourier Domain Optical Coherence Tomography in cases of keratoconus. PATIENTS & METHODS: This is a comparative cross sectional study including 20 eyes of 14 patients with keratoconus (n=20, study group) and 16 eyes of 8 normal subjects (n=16, control group). Both groups were imaged using Scheimpflug imaging corneal topography and Fourier domain AS-OCT system. Corneal epithelial thickness maps obtained by the AS-OCT system were studied and compared between the two groups. RESULTS: There was no statistically significant difference in mean corneal epithelial thickness between study and control groups (unpaired Student’s t-test, p