Abstract
Purpose: :
In the general ophthalmic evaluation of eye and visual functioning in young children, assessment of color vision is rarely conducted, mainly because of the lack of time-efficient methods. Nonetheless, color vision testing is recommended as it can be a sensitive marker of retinal, neuro-ophthalmic and/or systemic pathology. Perhaps even more importantly, early identification of children with congenital color vision deficiencies is essential in order for parents and early educators to modify chromatic stimuli within the child’s learning environment.
Methods: :
As part of a comprehensive preschool eye and vision screening program, 1032 healthy 2-to-6-year-olds children were tested with a card- based test of color vision designed previously for infants (Adams et al, ARVO 2003). This hand-held test, modeled on the Ishihara, HRR, and Pease-Allen pseudoisochromatic plates, consists of a large 13x13 cm dotted square of one hue embedded in a 25x55 cm dotted background of a second hue. The test, constructed with Munsell Hues, consists of three cards: a "warm-up/control" card which consists of black/grey dots on a white background; and two "test" cards with target vs. background dots that fall directly on either a red/green (R/G) or a blue/yellow (B/Y) dichromatic confusion axis. Adults with any form of dichromacy or severe anomalous trichromacy are unable to detect at least one test target.
Results: :
99.4% of the children completed the procedure in an average test time of 1.1 minutes. 2.4% of the children could not detect the R/G target and one child (0.1%) did not detect either the B/Y or the R/G target. Follow-up testing confirmed that these 26 "positive" children also failed with the HRR pseudoisochromatic plates. Interestingly, performance on the remainder of the screening battery revealed that only 2 of these 26 children had other significant eye/vision dysfunction.
Conclusions: :
Given that the present number of color defective children is consistent with expected population proportions, the card-based pseudoisochromatic test appears to be an effective screen of moderate to severe color deficiency. Moreover, because the test is tolerated very well by children and can be completed in about a minute, it is a good candidate for inclusion in pediatric eye/vision screening batteries.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • color vision • clinical (human) or epidemiologic studies: prevalence/incidence