Artifacts in fusion and stereopsis testing based on red/green dichoptic image separation.
A red/green anaglyph stereotest (TNO) was administered to a group of patients who had anisometropic amblyopia, and the Worth 4-Dot test for fusion to two groups of strabismus patients. Both tests were administered twice, with the red/green lens position of the glasses reversed between eyes for the second administration. Twelve of 15 patients with anisometropic amblyopia exhibited a stereo acuity difference of 2:1 or more, and 18 of 89 strabismic patients changed Worth 4-Dot fusion or suppression status, between the two positions of the glasses. A group of seven strabismic patients who showed the reversal effect on the Worth 4-Dot test had the results of one glass' position discrepant with those of a geometrically identical achromatic test. It appears that the red/green format can introduce artifacts in binocular vision testing. Testing twice, with the red/green glasses reversed between trials, will prevent misinterpretation of binocular status and may provide diagnostically useful information.
Simons
K
K
Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9009.
Elhatton
K
K
D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000503:physiopathology*; D016477:Artifacts; D002648:Child; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology*; D005425:Flicker Fusion / Q000502:physiology*; D006801:Humans; D008027:Light; D008875:Middle Aged; D015835:Ocular Motility Disorders; D015203:Reproducibility of Results; D013285:Strabismus / Q000503:physiopathology*; D014787:Vision Tests / Q000379:methods*; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity