Colour vision testing in young children with reduced visual acuity.

Purpose: To investigate feasibility, reliability and discriminative validity of pseudoisochromatic (PIC) colour vision tests, the Mollon-Reffin minimalist (MRM) test and the Cambridge Colour Test (CCT) among children (3-10 years) with reduced visual acuity.

Methods: Thirty-three patients with reduced visual acuity and 38 healthy control subjects with age-related normal visual acuity were recruited for this prospective study. Visual acuity in patients was reduced due to amblyopia, binocular maculopathy, or optic neuropathy. Tests were performed in a single 1-hr session.

Results: All but two children successfully completed the PIC and MRM tests. Success rate for the CCT was lower, 87%, CI [72%, 96%] for control subjects and 79%, CI [61%, 91%] for patients, with a strong positive effect of age on the odds of successful completion (OR 5.63, p = 0.007). Reliability was high in PIC and MRM tests but comparably lower in CCT. The rate of correct answers in PIC tests was between 88% and 100%. One proband was diagnosed with deuteranomaly with an average Ishihara score of 21%. All children (with the exception of one daltonian) scored at least two points in the MRM test. Sensitivity thresholds in CCT decreased with age with a strong effect size in control subjects and weak to moderate effect size in patients.

Conclusions: Pseudoisochromatic and MRM tests show sufficient feasibility in young children with reduced visual acuity. For CCT feasibility in 3-5-year olds is reduced, most probably due to the longer test duration. Consistent with earlier findings, colour discrimination thresholds decrease with age independent on visual acuity status.