title: Comparison of aberrometer and autorefractor measures of refractive error in children.
abstract: OBJECTIVE
  The purpose of this study was to evaluate and compare the Complete Ophthalmic Analysis System (COAS) G200 Aberrometer (Wavefront Sciences Inc., Albuquerque, NM) and Canon RK-F1 Autorefractor (Canon Inc., Tokyo, Japan) for measuring refractive errors in young children.
  
  
  METHODS
  The Sydney Myopia Study is a population-based study of refractive error and eye health in young Australian children. Cycloplegic refractions were performed on 1504 school year 1 students (mostly 6 years old) and 890 school year 7 (mostly 12 years old) students using both the COAS G200 Aberrometer and Canon RK-F1 autorefractor. Refractive data were analyzed using power vectors. Mean differences and 95% limits of agreement were determined for refractive components between the two instruments.
  
  
  RESULTS
  The mean age +/- standard deviation was 6.7 +/- 0.4 years (range, 5.5-9.1 years) and 12.6 +/- 0.5 years (range, 11.1-14.4 years) for the year 1 and year 7 students, respectively. Mean paired differences for the M component (spherical equivalent) between the COAS G200 and Canon RK-F1 were <0.25 D in both age groups and were statistically significant in the year 1 group only (p < 0.001). Small significant differences were found in the astigmatic components (J0 and J45) in both groups. A smaller coefficient of agreement for the M component was found in the older group (0.54 D), whereas the coefficients of agreement of the astigmatic components (J0 and J45) were similar for both groups.
  
  
  CONCLUSIONS
  The COAS G200 aberrometer was an easy-to-use instrument for the measurement of refractive error in children. In addition to being able to measure higher and lower order aberrations, the COAS G200 provides refractive error measurements comparable to those of an autorefractor.
authors.affiliation: School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.
authors.forename: Aldo A
authors.initials: AA
authors.lastname: Martinez
authors.forename: Ashok
authors.initials: A
authors.lastname: Pandian
authors.forename: Padmaja
authors.initials: P
authors.lastname: Sankaridurg
authors.forename: Kathryn
authors.initials: K
authors.lastname: Rose
authors.forename: Son C
authors.initials: SC
authors.lastname: Huynh
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D012189:Retrospective Studies