抄録
Elderly people have more opportunities to use information technology terminals because of the increasing dissemination of the Internet. Since visual functions are weakened with senescence, website visibility is important; however there is little tangible data regarding visibility provided or considered when sites are created. In this study, the website visibilities of elderly people and young adults are compared. The visibilities of several web-safe color combinations were examined using psychological methodology, a paired comparison. Twenty-one web-safe colors were employed for visual stimuli. Fifteen elderly persons ranging from age 65 to 75 years old (average 67.6) and 12 young adults ranging from age 21 to 29 years old (average 22.9) were recruited. All subjects had normal color sensation. In examining the relationship between the psychological rankings of color combinations and visual sensations, each color combination was first scored for visibility by Thurstone's paired comparisons technique. Secondly, visual sensation was deduced by applying Weber-Fechner's law to the contrast of foreground and background colors. The following results from the comparisons were obtained: (1) The visibilities of the elderly and young adults depended on the contrast of foreground and background colors and the chromaticity of the foreground colors; in particular, elderly people were more strongly influenced by the contrast. (2) The bluish and reddish colors had high visibility in both groups; however, special care in terms of the elderly is necessary when using bluish and blackish colors simultaneously because the white turbidity of crystalline lens with senescence makes it more difficult to distinguish the two colors. (3) High contrasts do not always provide good visibility;, that is, asthenopia accumulation is accelerated when websites use very-high contrast colors.
