title: A comparison of stereopsis testing between red/green targets and polarized targets in children with normal binocular vision.
abstract: BACKGROUND
  Measurement of stereopsis is important in assessing a patient's binocular status. Several measurement methods are available, most commonly using polarized targets. Recently, less expensive red/green targets have become available. In this study, we compare polarized versus red/green methods, using random dot and contour targets.
  
  
  METHODS
  Sixty children with no strabismus, amblyopia, or high refractive error and normal ocular health were recruited. Stereopsis measurements were taken using the red/green and polarized versions of the Random Dot Letter "E"/RDE Test, Random Dot Butterfly/Stereo Butterfly Test, Stereo Circles/Wirt Circles, Stereo Numbers, and Stereo Animals tests. Observed agreement was used to assess agreement between results. Wilcoxon signed-rank tests were used to compare an individual's response with both targets.
  
  
  RESULTS
  There was greater than 95% agreement using any of the Random Dot-based tests and the Stereo Animals tests. However, agreement was less than 60% with the Stereo Numbers test and less than 35% with the Stereo Circles/Wirt Circles test.
  
  
  CONCLUSIONS
  The red/green versions of the Random Dot-based tests and the Stereo Animals test appear to be a cost-effective alternative to their polarized equivalents. Our data, however, show that the red/green versions tend to underestimate the level of stereopsis when using the Stereo Numbers and Stereo Circles/Wirt Circles tests compared to their polarized equivalents.
authors.affiliation: Pennsylvania College of Optometry, Pediatric/Binocular Vision Services, Philadelphia, Pennsylvania 19141, USA. tyamada@pco.edu
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yamada
authors.forename: Mitchell
authors.initials: M
authors.lastname: Scheiman
authors.forename: G Lynn
authors.initials: GL
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D002648:Child; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D014787:Vision Tests / Q000379:methods*; D015348:Vision, Binocular / Q000502:physiology*