title: Reproducibility of and effect of magnification on optical coherence tomography measurements in children.
abstract: OBJECTIVE
  To determine the reproducibility of optical coherence tomography (OCT) measurements of macular thickness, peripapillary nerve fiber layer (NFL) thickness, and optic disk parameters and to investigate the effect of axial length and refractive error on these measurements in children with healthy eyes.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  The Sydney Childhood Eye Study examined 2,353 year 7 students (75.3% response) from a random cluster sample of 21 secondary schools across Sydney. A consecutive subsample of 120 children had OCT (StratusOCT, Carl Zeiss, Dublin, California, USA) performed by a single operator, which was repeated with a brief rest between the two sessions. Scans of the NFL, macula, and optic disk were performed.
  
  
  RESULTS
  Intersubject variability of measurements of macular thickness, NFL thickness, and optic disk parameters assessed using intraclass correlation coefficients accounted for >85%, >62%, and >38% of total variability of measurements, respectively. Corresponding coefficients of variability were <5%, <8%, and <13%. Magnification effects attributable to axial length and refractive error on the measurement of these parameters were statistically not significant.
  
  
  CONCLUSIONS
  The StratusOCT demonstrated reproducible measurements of macular and NFL thickness. Measurement of most optic disk parameters were also reproducible. Magnification attributable to axial length and refractive error had minimal impact on measurements of macular and NFL thickness.
authors.affiliation: Department of Ophthalmology (Centre for Vision Research), University of Sydney, and Westmead Millennium Institute, Westmead Hospital, Sydney, Australia.
authors.forename: Xiu Ying
authors.initials: XY
authors.lastname: Wang
authors.forename: Son C
authors.initials: SC
authors.lastname: Huynh
authors.forename: George
authors.initials: G
authors.lastname: Burlutsky
authors.forename: Jenny
authors.initials: J
authors.lastname: Ip
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D006801:Humans; D009412:Nerve Fibers; D009898:Optic Disk / Q000033:anatomy & histology*; D009900:Optic Nerve / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012160:Retina / Q000033:anatomy & histology*; D041623:Tomography, Optical Coherence / Q000592:standards*