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.