title: Variability across the optic nerve head in scanning laser tomography.
abstract: OBJECTIVE
  To characterise measurement variability in scanning laser tomography of the optic nerve head.
  
  
  METHODS
  21 normal and 21 glaucoma subjects underwent same and separate day test-retest Heidelberg retina tomograph imaging by the same and different operators.
  
  
  RESULTS
  Rim area was most reproducible among parameters. Its variability tended to be highest temporally and increased (p<0.05) with testing involving different operators and visits. Nature of regional variability differed between glaucoma and normal eyes and between standard and 320 micro m reference planes.
  
  
  CONCLUSIONS
  Rim area is reproducible and potentially useful as a marker of progression. Pattern of variability and the influence of different reference planes, disease, operators, and visits should be considered when evaluating progression.
authors.affiliation: Moorfields Eye Hospital and Institute of Ophthalmology, London, UK.
authors.forename: J C H
authors.initials: JC
authors.lastname: Tan
authors.forename: D F
authors.initials: DF
authors.lastname: Garway-Heath
authors.forename: R A
authors.initials: RA
authors.lastname: Hitchings
mesh_terms: D016022:Case-Control Studies; D005901:Glaucoma / Q000473:pathology*; D006801:Humans; D007834:Lasers; D008875:Middle Aged; D009900:Optic Nerve / Q000473:pathology*; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods*