Abstract
Purpose: :
Visual discrimination skills, like discrimination of motion and color, improve through adolescence in normal trichromats. Some adult carriers of red-green color deficiency exhibit reduced color discrimination, but little is known about color discrimination abilities in young carriers. The aim of this study was to assess color discrimination abilities of young carriers.
Methods: :
One hundred normal trichromatic females and 20 obligatory carriers of red-green color-vision deficiencies, aged 9-39 yrs, were tested with three pseudoisochromatic color-vision tests (PIC tests): Neitz Test of Color Vision, 4th edition of the HRR, and the Ishihara plates; FM100-Hue test; and Medmont C-100. All participants aged 18 yrs or older were also tested on the Rayleigh match.
Results: :
Carriers aged 9-12 yrs made more errors on PIC tests than their normal trichromatic peers: 70% of carriers made errors, whereas only 20% of their peers do, this was reduced to 45% and 12%, respectively, in the 30-39 yrs age group. Color discrimination as assessed by the FM100-Hue test improves with age for both groups, but the carriers’ performance was poorer than that of normal trichromats. The variablity in the FM100-Hue error scores was significantly greater (p<0.001) for the 9-12 yrs age group as compared with the two older groups, both for normal trichromats and carriers. Deutan carriers required on average more green and protan carriers more red as compared with normal trichromats on the Rayleigh match. The Medmont C-100 failed to identify protan and deutan carriers.
Conclusions: :
The large variability in the FM100-Hue scores for the 9-12 yrs age group is possibly related to variations in maturation of visual discrimination skills. The improvement in color discrimination with age seen in normal trichromats is also evident in carriers of red-green color-vision deficiencies. The results imply that some young female carriers may have exacerbated problems with color discrimination due to the combined effect of being a carrier as well as having a visual system that is not mature.
Keywords: color vision • visual development