Evaluation of Colour Correcting X Chrome Contact lenses

Approximately 5% of the world’s population suffer from what is commonly called colour blindness. A small number of products are on the market that claim to improve colour discrimination for colour-blind observers. This study evaluates the performance of a particular product (Colour Correcting lenses) product by performing psychophysical experiments with a colour-blind observer. Without correction the observer was only able to respond correctly for 12 of the 25 Ishihara test plates; with correcting lenses, the observer scored 100% on the Ishihara test. However, performance of the observer on the Farnsworth-Munsell 100-hue test deteriorated with colour-correcting lenses with the error increasing substantially from a score of 188 to 380. This suggests that the correcting lenses do not reliably improve colour discrimination and may, in fact, make it worse. However, they did enable the observer to pass the Ishihara test.