title: In vivo three-dimensional corneal epithelium imaging in normal eyes by anterior-segment optical coherence tomography: a clinical reference study.
abstract: OBJECTIVE
  To evaluate the safety and efficacy of real-time measurement of corneal epithelial thickness and investigate the distribution characteristics in a large normal-eye population using a clinically available spectral-domain anterior-segment optical coherence tomography (AS OCT) system.
  
  
  METHODS
  Corneal epithelial thickness distribution and topographic thickness variability were clinically investigated using AS OCT imaging in 373 patients with normal, healthy eyes. Descriptive statistics investigated 3 sets of subgroups, male (n = 171) and female (n = 202), younger (n = 194) and older (n = 179), right eyes (n = 195) and left eyes (n = 197).
  
  
  RESULTS
  Pupil center epithelial thickness repeatability was an average 0.88 ± 0.71 μm; a similar repeatability was noted for the superior, inferior, maximum, and minimum epithelial thickness. On average, the pupil center epithelial thickness was 53.28 ± 3.34 μm, superior 51.86 ± 3.78 μm, inferior 53.81 ± 3.44 μm, minimum 48.65 ± 4.54 μm, maximum 56.35 ± 3.80 μm, and topographic variability was 1.78 ± 0.78 μm. Small differences were noted between male (average center 54.10 ± 3.34 μm) and female (52.58 ± 3.19 μm) subjects. The topographic thickness variability seems to increase with age: younger group, 1.65 ± 0.83 μm; older group, 1.93 ± 0.90 μm (P = 0.173).
  
  
  CONCLUSIONS
  We present a comprehensive investigation of corneal epithelial thickness distribution characteristics in a healthy, untreated human eye population by using in vivo, clinically available Fourier-domain AS OCT. The 3-dimensional epithelial maps reveal epithelial nonuniformity and provide a novel benchmark for future and comparative studies.
authors.affiliation: *Laservision.gr Eye Institute, Athens, Greece; and †NYU Medical School, New York, NY.
authors.forename: Anastasios John
authors.initials: AJ
authors.lastname: Kanellopoulos
authors.forename: George
authors.initials: G
authors.lastname: Asimellis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000869:Anterior Eye Segment; D002648:Child; D002675:Child, Preschool; D063171:Corneal Pachymetry / Q000379:methods; D004728:Endothelium, Corneal / Q000033:anatomy & histology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult