The impact of display saturation on visual search performance in congenital colour vision deficiency

BACKGROUND: Colour-related search tasks are common in many professional fields. The study investigated whether increasing chromatic saturation can enhance the visual performance of individuals with colour vision deficiency (CVD) in colour-related search tasks. METHODS: 10 normal trichromats (5M, 5F; Mean (SD) age: 23.1 (3.3) years) and 15 individuals with CVD [8 deutans and 7 protans identified by HRR plates] (14M, 1F; aged 28.6 (8.7) years) participated in this study. Four naturalistic sceneries of everyday tasks/ birds, animals and flowers of 15 different colour combinations (1 pair of colours in each combination. e.g., ‘brown/black’ or ‘red/green’) were presented in ‘low’ saturation, ‘original’ (unaltered images) and ‘high’ saturation condition using the Psychopy program on a colour-calibrated monitor. On each trial, the subject was asked to identify a specific-coloured target. RESULTS: Overall, the visual search performance index (expressed as product of accuracy and a reciprocal of reaction time (%correct*s(-1)) of the normal trichromats [Mean (SD):77.76% correct*s(-1) (16.32)] was significantly higher than CVD [45.71% correct*s(-1) (18.95)] in the “original” test images (p = 0.001), but in individuals with CVD, there was no significant difference between ‘original’ [45.71% correct*s(-1) (18.95)] and ‘high’ saturation condition ([47.43% correct*s(-1) (20.07)]; p > 0.05). However, colour-wise, increased saturation showed improvements (≥ 10%) in protans mainly for ‘red’ combinations with other colours such as white (i.e., ‘red/white’), purple, orange, grey, green, brown and black. CONCLUSION: The study suggests that increasing the saturation of certain colour combinations can potentially aid in the visual search performance of individuals with CVD. This knowledge will help in better counselling and management of the patients.