title: Frisby Davis distance stereoacuity values in visually normal children.
abstract: OBJECTIVE
  To establish the range of normal distance stereoacuity in young children using the Frisby Davis distance stereo test (FD2).
  
  
  METHODS
  Children passing preschool vision screening assessments underwent measurement of distance stereoacuity with the FD2 using a standard testing protocol.
  
  
  RESULTS
  59 visually normal children aged between 36 months and 68 months were recruited to this study. All 59 were able to understand the test requirements and were examined with the FD2 stereo test. Four (6.8%) had no measurable stereoacuity; 13 (24%) had stereoacuity measurable only at a 3 metre testing distance (mean 92.3 seconds of arc; SD 52.6). These children were significantly younger than the remaining 42 (76%) who demonstrated a stereoacuity response at a 6 metre testing distance (mean 29.6 seconds of arc; SD 13.1, p=0.008).
  
  
  CONCLUSIONS
  The FD2 stereo test enables the measurement of distance stereoacuity in young children. There appears to be a maturational effect with distance stereoacuity improving between 36 months and 68 months. The data on age related normal values will provide a baseline from which to compare outcomes in clinical populations.
authors.affiliation: Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK. wendy_stoer@yahoo.com
authors.forename: W E
authors.initials: WE
authors.lastname: Adams
authors.forename: S
authors.initials: S
authors.lastname: Hrisos
authors.forename: S
authors.initials: S
authors.lastname: Richardson
authors.forename: H
authors.initials: H
authors.lastname: Davis
authors.forename: J P
authors.initials: JP
authors.lastname: Frisby
authors.forename: M P
authors.initials: MP
authors.lastname: Clarke
mesh_terms: D000375:Aging / Q000502:physiology / Q000523:psychology; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D015357:Vision Disparity / Q000502:physiology; D014787:Vision Tests / Q000379:methods; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*