Chinese e-book design for different age groups

The purpose of this study was to investigate the minimum acceptable viewing angle (MIAVA) for different age groups while reading the Chinese e-book. Ninety subjects participated in this study. Their age ranged from 21 to 70 years, and they were divided into three age groups, i.e. young, middle, and old groups. Each subject was firstly asked to adjust personal preferred viewing distance. The minimum acceptable character size (in terms of MIAVA) was then determined by each subject from 26 different character sizes on the e-book. Each subject then performed a proofreading task with the MIAVA determined early. The completion time and accuracy rate were collected as the performance measures. The old group tended to choose the largest MIAVA (45.1 min of arc), followed by the middle (38.8 min of arc) and young groups (33.2 min of arc), as observed from the experimental results. The effect of age was significant on the preferred viewing distance, MIAVA, and completion time. The old group required a significantly longer time to complete the task than the other two groups. Some recommendations for designing Chinese character size on the e-book were finally provided for the three age groups.