Abstract
There currently is no widely available and accurate test for diagnosing colour vision deficiency (CVD) in pre-literate children, yet young children with CVD may be particularly disadvantaged by widespread use of colour in early learning environments. We present a new tablet-based app that is aimed as a tool for screening for CVD in children aged 2–6. The app measures chromatic thresholds along protan, deutan and tritan confusion lines using an adaptive staircase procedure. Targets are coloured discs presented on a grey surround, with both luminance and tritan noise included to increase sensitivity. The test is embedded in a child-friendly interface ‘game’ where children reveal characters by correctly selecting the coloured targets. We are able to achieve accurate colour calibration on Apple iPads, with errors along the MacLeod-Boynton L/(L+M) axis under 0.5% and maximum tritan errors of 3% (which are masked by the tritan noise). We present data from a population of 4–7 year old children that shows how the app performs in comparison to existing paper-based tests for CVD.