Differences in vision performance in different scenarios and implications for design.

To design accessibly, designers need good, relevant population data on visual abilities. However, currently available data often focuses on clinical vision measures that are not entirely relevant to everyday product use. This paper presents data from a pilot survey of 362 participants in the UK, covering a range of vision measures of particular relevance to product design. The results from the different measures are compared, and recommendations are given for relative text sizes to use in different situations. The results indicate that text needs to be 17-18% larger for comfortable rather than perceived threshold viewing, and a further 20% larger when users are expected to wear their everyday vision setup rather than specific reading aids.