Colour contrast thresholds are normal in functional amblyopia.
We evaluated colour contrast thresholds in patients with unilateral functional amblyopia. A computer-controlled colour vision test was used to determine colour contrast thresholds along a blue-yellow tritan axis. Prior to the threshold measurement, a heterochromatic flicker brightness test was performed to ensure isoluminance between the test stimulus and the background for every subject individually. Luminance contrast thresholds were also measured using the same computer-based system. Twenty amblyopic patients were tested. All showed normal tritan colour contrast thresholds both for their amblyopic eye and non-amblyopic fellow eye. Luminance contrast thresholds were elevated in all 6 refractive amblyopic eyes, in 4 of 9 strabismic eyes and in 2 of 5 mixed amblyopic eyes. Colour contrast thresholds are normal in functional amblyopia (with central fixation). Whenever elevated tritan colour contrast thresholds are found in patients with a decreased visual acuity, other causes of visual impairment are to be evaluated.
Mangelschots
E
E
UZ St Rafael, Leuven, Belgium.
Beerlandt
N
N
Janssens
H
H
Spileers
W
W
D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003118:Color Perception / Q000502:physiology*; D003119:Color Perception Tests; D015350:Contrast Sensitivity / Q000502:physiology*; D005425:Flicker Fusion; D006801:Humans; D008875:Middle Aged; D012684:Sensory Thresholds / Q000502:physiology*