| Sumario: | Purpose The important elements of visual signs that enhance visibility are color, contrast, size, and font type (Figure 6). Furthermore, the illumination level of the environment, layout, and distance of visual signs must be considered. This study was conducted to develop methods for designing and evaluating the elements of visual signs such as contrast between figures and backgrounds, color combinations, and legible letters for older adults. Moreover, features of visual functions of older adults were examined. Method Study participants were 50 older adults (60 years and older) and 50 younger adults (20 and older). For some participants, visual acuity was adjusted to each individual's maximum attainable level using corrective lenses to avoid effects of differences among individuals. Some experiments used CRT monitors or projectors to measure the legible font size, contrast sensitivity, and visual field size. Furthermore, for experiments using color combinations, color chips were used to judge the color similarity. Results & Discussion Sensitivity to lighting for older adults declined, especially in shorter wavelengths such as blue1. The span of color similarities for older adults is shifted slightly to higher-saturation colors. The span differs in relation to the level of illumination2. Results show that relative luminance contrast and conspicuity of colors should be considered to select a proper color combination that is distinguishable by older adults. Regarding the font size, effects of viewing distance and luminance are significantly age-dependent3. For example, for a 5m visual distance and 100 cd/m2 background luminance, the minimum legible font size (MLFZ) of gothic type Arabic numerals of older subjects was about 30 pt, although that of younger subjects was about 23 pt. For lower background luminance of 10 cd/m², MLFZ of 60s subjects was 1.44 times that of younger subjects. Furthermore, for greater visual distance of 10 m, the MLFZ of 60s subjects was 1.49 times that of younger subjects. Contrast and size of the target in an actual environment exert effects on the detectable visual field size4,5. Therefore, the size of visual fields for older adults should be considered when placing visual signs in public spaces. To improve design for accessibility of visual signs, one must consider the visual function of older adults and choose appropriate colors, contrast, size, and font type. Simultaneously, attention must be devoted to environmental factors such as placement of visual signs and illumination. Some data obtained from this examination were processed for standardization6 or were released as a database of sensory characteristics of older people and people with disabilities.
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