The extent of mobile accessibility coverage in WCAG 2.1: sufficiency of success criteria and appropriateness of relevant conformance levels pertaining to accessibility problems encountered by users who are visually impaired

People who are blind or visually impaired exhibit different interaction and access needs on mobile touchscreen devices. This is rooted in the reliance on non-visual access for using electronic devices. In comparison to regular computers, non-visual access to mobile touchscreen devices poses more challenges for reasons related to the lack of physical buttons, the limited size of touchscreens, and the reliance on gesture-based interaction. This paper aims at shedding light on the persistent accessibility-related problems that users who are blind or visually impaired are likely to encounter while interacting with mobile touchscreen devices, and whether or not these problems are sufficiently covered in the recent release of Web Content Accessibility Guidelines (WCAG 2.1). The study presented in this paper involved a total of 16 participants with visual impairment cases ranging from moderate vision loss to legal blindness. The results revealed a multitude of critical accessibility problems that are still being overlooked while developing mobile Apps and websites. After compiling all problems, a total of 34 major problems were identified. These problems were then classified into categories with identified nature, severity, and affected demographic. While many of these problems are mapped to existing accessibility guidelines delivered in WCAG 2.1, some problems either lack relevant success criteria in WCAG 2.1 or have insufficient conformance levels in WCAG 2.1. The paper concludes that despite the existence of different mobile-oriented guidelines in WCAG 2.1, there is still an obvious lack of adherence to these guidelines in mainstream mobile content. Moreover, the findings suggest there is room for improvement in WCAG 2.1 to cover more of the problems that users who are blind or visually impaired encounter on mobile touchscreen devices.