title: Repeatability of ETDRS visual acuity in children.
abstract: OBJECTIVE
  To evaluate repeatability of the best corrected log minimum angle of resolution (MAR) Early-Treatment Diabetic Retinopathy Study (ETDRS) acuity in a group of 6- to 11-year old children with myopia.
  
  
  METHODS
  Best corrected monocular visual acuity (VA) of a subset of children (n = 86) enrolled in the Correction of Myopia Evaluation Trial (COMET; mean spherical equivalent refractive error -2.35 D with no more than 1.25 D astigmatism) was measured at baseline and 1 month later with ETDRS logMAR charts. Children started with logMAR 0.4 (6/15 or 20/50) and read each letter on all subsequent lines until they missed all letters in 1 line.
  
  
  RESULTS
  At baseline, the mean best corrected logMAR VA was 0.003 +/- 0.076 (6/6 or 20/20 +/- 3.8 letters) in the right eye and 0.008 +/- 0.059 (6/6 or 20/20 +/- 2.95 letters) in the left eye. The signed difference between VA measured at baseline and that measured at 1 month was not significantly different from zero in either eye. Repeatability was not associated with age, but a small, statistically significant association with gender was detected in the left eye, with boys approximately 2 letters more variable than girls. The kappa statistic (agreement within 1 line) was good to excellent.
  
  
  CONCLUSIONS
  Based on the 95% limits of agreement, the criterion for a statistically significant change in VA is no more than +/-0.15 logMAR (or +/-8 letters). This value is similar to those reported for adults and indicates that logMAR VA provides a repeatable measure of acuity in children.
authors.affiliation: College of Optometry, University of Houston, Houston, Texas, USA. rmanny@uh.edu
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Manny
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hussein
authors.forename: Jane
authors.initials: J
authors.lastname: Gwiazda
authors.forename: Wendy
authors.initials: W
authors.lastname: Marsh-Tootle
mesh_terms: D002648:Child; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000628:therapy; D015203:Reproducibility of Results; D014787:Vision Tests / Q000592:standards*; D014792:Visual Acuity / Q000502:physiology*