title: Stereoacuity norms for school-age children using the Frisby stereotest.
abstract: BACKGROUND
  The Frisby stereotest and the TNO test for stereoscopic vision are popular clinical tests for assessing stereoacuity: however, reference data for school-age children for the Frisby stereotest are limited. This study compared stereoacuity results of both tests in a large sample of typically developing school-age children.
  
  
  METHODS
  Primary (elementary school grades 1-6) and post-primary (high school grades 7-11) students aged 6-16 years were recruited and assessed in schools. Stereoacuity thresholds were measured using the Frisby and TNO stereotests. Children with ocular pathology, anisometropia of ≥1.00 D, interocular difference of visual acuity ≥0.2 logMAR, or strabismus were excluded.
  
  
  RESULTS
  A total of 212 children were recruited; data for 186 subjects were analyzed. Median Frisby stereoacuity scores were, for crossed disparity, 20 arcsec for primary and 10 arcsec for post-primary children and, for uncrossed disparity, 25 arcsec (primary) and 10 arcsec (post-primary). TNO stereoacuity was 60 arcsec for both age groups. For Frisby stereoacuity, scores of 85 arcsec (crossed) and 170 arcsec (uncrossed) or better were achieved by 95% of primary school children; scores of 85 arcsec (crossed and uncrossed) or better were achieved by 95% of post-primary subjects. A statistically significant difference in median stereoacuity scores was noted across age groups for the Frisby stereotest (crossed: z = 4.67, P < 0.0001; uncrossed: z = 4.67, P < 0.0001). No statistically significant difference in stereoacuity scores was noted with the TNO stereotest (z = 1.35, P = 0.18). A significant weak correlation was found between the Frisby and TNO stereotests (Frisby [crossed], r = 0.21 P < 0.005).
  
  
  CONCLUSIONS
  These data describe normative values for the Frisby stereotest for children aged 6-16 years. Participants recorded significantly better stereoacuity scores with the Frisby stereotest than the TNO stereotest. The Frisby stereotest values are weakly correlated with the TNO stereoacuity test.
authors: Vision Science Research Group, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Northern Ireland. Electronic address: anketell-p@email.ulster.ac.uk.
authors: Pamela M
authors: PM
authors: Anketell
authors: Kathryn J
authors: KJ
authors: Saunders
authors: Julie-Anne
authors: JA
authors: Little
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D012684:Sensory Thresholds / Q000502:physiology; D018709:Statistics, Nonparametric; D014787:Vision Tests / Q000379:methods* / Q000706:statistics & numerical data; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*