title: Aging and corneal layers: an in vivo corneal confocal microscopy study.
abstract: OBJECTIVE
  To describe age-related changes of different corneal layers using a quantitative analysis of in vivo corneal confocal microscopy.
  
  
  METHODS
  Descriptive observational cross-sectional study.
  
  
  METHODS
  A total of 108 healthy corneas of 108 subjects, distributed in four age categories, underwent in vivo corneal confocal microscopy. The effect of aging on the main features of corneal epithelium, sub-basal nerve plexus, stroma, and endothelium was investigated.
  
  
  RESULTS
  Mean diameter of superficial epithelial cells increases with age (0.05 μm per year; p < 0.0001). Mean cell density of basal epithelium does not change with age (p = 0.37). The sub-basal nerve plexus fiber number, density, and the number of beadings do not statistically change with age (p = 0.14, p = 0.10 and p = 0.17, respectively). Keratocyte density significantly reduces with age in each stromal layer (p < 0.0001). Endothelial cell count decreases by 10.92 cells/mm(2) per year (p < 0.0001). Endothelial polymegathism index and pleomorphism index do not change with age (p = 0.79 and p = 0.39, respectively).
  
  
  CONCLUSIONS
  Corneal confocal microscopy allows a non-invasive examination of the living cornea, analyzing the microstructure of each corneal layer. Aging significantly influences the corneal confocal microscopy parameters of individual corneal layers, except sub-basal nerve plexus and basal epithelium.
authors.affiliation: Department of Ophthalmology, University of Padova, via Giustiniani 2, Padova, 35128, Italy.
authors.forename: Catia
authors.initials: C
authors.lastname: Gambato
authors.forename: Evelyn
authors.initials: E
authors.lastname: Longhin
authors.forename: Anton Giulio
authors.initials: AG
authors.lastname: Catania
authors.forename: Daniela
authors.initials: D
authors.lastname: Lazzarini
authors.forename: Raffaele
authors.initials: R
authors.lastname: Parrozzani
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D002452:Cell Count; D002648:Child; D003315:Cornea / Q000294:innervation*; D003319:Corneal Stroma / Q000166:cytology*; D003430:Cross-Sectional Studies; D004728:Endothelium, Corneal / Q000166:cytology*; D019573:Epithelium, Corneal / Q000166:cytology*; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009882:Ophthalmic Nerve / Q000166:cytology*; D055815:Young Adult