title: Laser scanning in vivo confocal analysis of keratocyte density in keratoconus.
abstract: OBJECTIVE
  Keratoconus is a form of progressive noninflammatory corneal ectasia. Although abnormalities have been documented at every level of the keratoconic cornea, the exact underlying pathophysiologic process remains unknown. This study aimed to determine the keratocyte density in human corneas with keratoconus imaged by laser scanning in vivo confocal microscopy.
  
  
  METHODS
  Prospective cross-sectional study.
  
  
  METHODS
  Thirty-six eyes of 26 subjects with keratoconus compared with 33 eyes of 33 control subjects.
  
  
  METHODS
  Subjects were assessed via ophthalmic examination, computed topography, and laser scanning in vivo confocal microscopy.
  
  
  METHODS
  Anterior and posterior stromal keratocyte density.
  
  
  RESULTS
  Mean age was 34.7+/-12.1 years in the control group, 38.4+/-11.0 years in the keratoconic with no contact lens wear group, and 38.5+/-10.3 years in the keratoconic with contact lens wear group. No significant difference was noted in age or gender between the groups. Mean keratocyte density in the control group was 786+/-244 cells/mm(2) in the anterior stroma and 293+/-35 cells/mm(2) in the posterior stroma. Anterior keratocyte density was higher than posterior keratocyte density (P<0.001). Anterior keratocyte density was significantly lower in contact lens-wearing keratoconic subjects in comparison with controls (463 vs. 786 cells/mm(2); P<0.001). Posterior keratocyte density was significantly lower in keratoconic subjects with no contact lens wear (236 vs. 293 cells/mm(2); P<0.001) and in keratoconic subjects with contact lens wear (208 vs. 293 cells/mm(2); P<0.001). In subjects with keratoconus, anterior keratocyte density correlated with central corneal thickness (r = 0.426, P = 0.012) and inversely with steepest keratometry values (r = -0.383, P = 0.028).
  
  
  CONCLUSIONS
  Keratocyte density is significantly lower in subjects with keratoconus, and the decline in keratocyte density correlates with indices of disease severity. In vivo confocal microscopy offers the opportunity to study early microstructural changes in the keratoconic cornea.
authors.affiliation: Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
authors.forename: Judy Y F
authors.initials: JY
authors.lastname: Ku
authors.forename: Rachael L
authors.initials: RL
authors.lastname: Niederer
authors.forename: Dipika V
authors.initials: DV
authors.lastname: Patel
authors.forename: Trevor
authors.initials: T
authors.lastname: Sherwin
authors.forename: Charles N J
authors.initials: CN
authors.lastname: McGhee
mesh_terms: D000328:Adult; D002452:Cell Count; D003319:Corneal Stroma / Q000473:pathology*; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D007640:Keratoconus / Q000473:pathology*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed