Effects of Ambient Illuminance on Visual Comfort for Reading for different age groups

An experiment was carried out to explore visual comfort when reading grey texts on uniform neutral backgrounds at five illuminance levels (0, 10, 100, 500, and 1000 lx) among three age groups. A total of 20 children, 20 adults and 20 aged observers participated in the experiment using a 6-category points method. The display white was set at 500 cd/m2 and 6500K. Visual comfort is defined as visibility in this case. The findings suggested that lightness contrast of the aged group around L * of 100 to give better visual comfort. For children and the adult groups, positive lightness contrast around 50 to give better visual comfort. The results also showed that white or black was not the best background for children and adults observers, and background colours had little effect for the aged observers. Visual comfort for the children and adult observers decreases when there is a reduction of illuminance level. For the aged observers, illuminance reaches 10 lx to achieve the best visual comfort, then visual comfort decreases as the illuminance level increases.