Web-Based Usability Evaluation of Text-Resizing Methods and Users' Visual Fatigue on Online Reading Task

A web-based usability evaluation was conducted to examine the effects of two text-resizing methods on normal and low vision Internet users' online reading experience. Normal or corrected to normal vision (N/CTN; N = 50) and low vision (N = 5) participants completed two blocks of four mock Scholastic Aptitude Test (SAT) reading tests on the experiment website using fixed width (FW) and text reflow (TR) text-resizing methods. Subjective visual fatigue scores, modified System Usability Scale (SUS) score, time on task, and accuracy were collected as dependent measures for user experience evaluation. Results showed that when FW method was presented in the second block, N/CtN participants' visual fatigue continued to increase, along with a significant decrease in time spent on reading tasks. Such effects were not observed in TR method. Results of low vision participants were different from those obtained in lab settings, suggesting that testing environment may have played a role in low vision participants' performance. Implications of the current research can be used to guide future web accessibility research in regards to online experiment design and recruitment of participants with visual impairments.