title: Comparison of human central cornea and limbus in vivo using optical coherence tomography.
abstract: OBJECTIVE
  The purpose of this study was to compare central corneal and limbal total and epithelial thickness using a commercially available optical coherence tomographer.
  
  
  METHODS
  A Humphrey-Zeiss Optical Coherence Tomographer (OCT [Carl Zeiss, Meditec, Dublin, CA]) was used to obtain corneal images from 10 subjects. Central corneal and limbal total and epithelial thickness of both eyes were measured using the OCT. Each OCT image comprised 100 measurements, 10 nasal, 10 central, and 10 temporal measurements from each image were analysed.
  
  
  RESULTS
  The central corneal and epithelial thickness of the right and the left eyes were 507.9 +/- 35.8 microm, 58.4 +/- 2.5 microm, 506.9 +/- 37.4 microm, and 58.5 +/- 2.5 microm, respectively. There were no differences between eyes (p > 0.05). The nasal and temporal limbal total and epithelial thickness of the right and left eyes were 703.8 +/- 32.1 microm, 704.9 +/- 31.0 microm, 76.8 +/- 3.5 microm, 77.9 +/- 2.9 microm, 704.4 +/- 31.8 microm, 706.3 +/- 32.5 microm, 77.5 +/- 2.8 microm, and 77.8 +/- 2.5 microm, respectively. There were no differences between the nasal and temporal total and epithelial thickness of both eyes (p > 0.05). However, there was a statistical difference between the central corneal and limbal total and epithelial thickness (both p < 0.05).
  
  
  CONCLUSIONS
  Central cornea and limbus are measurably different using OCT. Central cornea is thinner than limbus for both total thickness and epithelial thickness. There is no difference between eyes of central corneal and limbal total and epithelial thickness. Optical Coherence Tomography is a useful instrument for in vivo human limbal morphometry.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Yunwei
authors.initials: Y
authors.lastname: Feng
authors.forename: Trefford L
authors.initials: TL
authors.lastname: Simpson
mesh_terms: D000328:Adult; D003315:Cornea / Q000166:cytology*; D004847:Epithelial Cells / Q000166:cytology*; D005260:Female; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology*; D008297:Male; D041623:Tomography, Optical Coherence / Q000379:methods*