title: Refraction in children:  a comparison of two methods of accommodation control.
abstract: OBJECTIVE
  The prevalence of refractive errors in children has been extensively researched. Comparisons between studies can, however, be compromised because of differences between accommodation control methods and techniques used for measuring refractive error. The aim of this study was to compare spherical refractive error results obtained at baseline and using two different accommodation control methods-extended optical fogging and cycloplegia-for two measurement techniques-autorefraction and retinoscopy.
  
  
  METHODS
  Participants included 25 school children aged 6 to 13 years (mean age, 9.52 ± 2.06 years). The refractive error of one eye was measured at baseline and again under two different accommodation control conditions: extended optical fogging (+2.00DS for 20 minutes) and cycloplegia (1% cyclopentolate). Autorefraction and retinoscopy were both used to measure the most plus spherical power for each condition.
  
  
  RESULTS
  A significant interaction was demonstrated between measurement technique and accommodation control method (p = 0.036), with significant differences in spherical power evident between accommodation control methods for each of the measurement techniques (p < 0.005). For retinoscopy, refractive errors were significantly more positive for cycloplegia compared with optical fogging, which were in turn significantly more positive than baseline; whereas for autorefraction, there were significant differences between cycloplegia and extended optical fogging and between cycloplegia and baseline only.
  
  
  CONCLUSIONS
  Determination of refractive error under cycloplegia elicits more plus than using extended optical fogging as a method to relax accommodation. These findings support the use of cycloplegic refraction compared with extended optical fogging as a means of controlling accommodation for population-based refractive error studies in children.
authors.affiliation: School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia. shelley.hopkins@qut.edu.au
authors.forename: Shelley
authors.initials: S
authors.lastname: Hopkins
authors.forename: Geoff P
authors.initials: GP
authors.lastname: Sampson
authors.forename: Peter
authors.initials: P
authors.lastname: Hendicott
authors.forename: Philippe
authors.initials: P
authors.lastname: Lacherez
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Wood
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D011793:Queensland / Q000453:epidemiology; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000453:epidemiology / Q000503:physiopathology*; D042262:Retinoscopy; D014787:Vision Tests