title: Normative visual acuity in infants and preschool-aged children in Sydney.
abstract: OBJECTIVE
  To provide population-based normative visual acuity (VA) by age, in children participating in the Sydney Paediatric Eye Disease Study aged 6 to <72 months.
  
  
  METHODS
  Monocular VA was measured using the Amblyopia Treatment Study (ATS HOTV) protocol (24 to <72 months). Some children were also tested using linear ETDRS or HOTV logMAR VA charts (30 to <72 months). If unable to perform recognition acuity, the Teller Acuity Cards II (TAC II) was performed (6 to <42 months). Children with significant refractive error or ocular disease were excluded.
  
  
  RESULTS
  Improvement in VA with age was shown on all three vision tests (all p < 0.0001). Mean VA using ATS HOTV (n = 836) was 0.13 logMAR (6/8) at <36 months, which improved to -0.01 (6/6) at 66 to <72 months. Mean ETDRS/HOTV (n = 399) VA was 0.26 logMAR (6/11) at <36 months, which improved to 0.1 (6/7.5) at 66 to <72 months. Mean monocular TAC II (n = 442) was 5.7 cycles/degree (0.72 logMAR) at 6 to <9 months and improved to 12.4 cycles/degree (0.38 logMAR) at age 30 to <33 months. Associations with ATS HOTV VA included prematurity (p = 0.027) and socio economic status (SES) factors such as home ownership (p = 0.039) and employment of one (p = 0.019) or both parents (p = 0.003).
  
  
  CONCLUSIONS
  VA norms in children improved with age and were different according to the VA test used. Low SES was associated with poorer VA, supporting the need for test specific VA norms to be established for different populations. The ATS HOTV appears to be the best test to use for vision screening due to its lower false positive referral rate.
authors.affiliation: Discipline of Orthoptics, The University of Sydney, Lidcombe, NSW, Australia.
authors.forename: Jody F
authors.initials: JF
authors.lastname: Leone
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Annette
authors.initials: A
authors.lastname: Kifley
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Rose
mesh_terms: D002648:Child; D002675:Child, Preschool; D004651:Employment; D005006:Ethnicity; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009517:New South Wales; D012016:Reference Values; D012923:Social Class; D011795:Surveys and Questionnaires; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*
keywords: ATS HOTV EVA; logMAR VA; population-based; preschool children; teller acuity cards II; visual acuity