title: Quantification of photoreceptor layer thickness in normal eyes using optical coherence tomography.
abstract: OBJECTIVE
  To demonstrate the ability to segment and analyze individual intraretinal layers, including the outer retinal complex (ORC; outer nuclear layer and inner and outer segments of the photoreceptor cells), in healthy eyes using images acquired from the latest commercially available optical coherence tomography (OCT) system (StratusOCT; Carl Zeiss Meditec, Inc., Dublin, CA) and from the ultrahigh resolution OCT (UHR-OCT) prototype.
  
  
  METHODS
  Thirty-seven eyes from 37 healthy subjects underwent complete ophthalmologic examination using StratusOCT and UHR-OCT. ORC was identified and measured using a segmentation algorithm.
  
  
  RESULTS
  For StratusOCT, mean weighted ORC thickness +/- SD was 91.1 +/- 7.9 microm, and mean weighted total retinal thickness +/- SD was determined to be 258.9 +/- 10.1 microm. For UHR-OCT, mean weighted ORC thickness +/- SD was 96.4 +/- 6.3 microm, and mean weighted total retinal thickness +/- SD was determined to be 263.4 +/- 9.2 mum. There was a higher rate of algorithm failure with UHR-OCT images.
  
  
  CONCLUSIONS
  Photoreceptor layer thickness can be calculated by measuring ORC on OCT images using a macular segmentation algorithm. ORC values may serve as a useful objective parameter in determining the efficacy of various therapeutic modalities that target the photoreceptor layer in various diseases.
authors.affiliation: New England Eye Center, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111-1533, USA.
authors.forename: Annie
authors.initials: A
authors.lastname: Chan
authors.forename: Jay S
authors.initials: JS
authors.lastname: Duker
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Tony H
authors.initials: TH
authors.lastname: Ko
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
authors.forename: James G
authors.initials: JG
authors.lastname: Fujimoto
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology*; D012016:Reference Values; D012160:Retina / Q000033:anatomy & histology*; D041623:Tomography, Optical Coherence / Q000379:methods*