Accessibility or Usability of the User Interfaces for Visually Impaired Users? A Comparative Study

The use of the Internet to search and browse information has increased in the recent past from the younger children to adults and older adults with or without any disability. The access to the information is becoming more common through the use of mobile apps as it is ubiquitous. This requires an evaluation to ensure that it can be used by everyone including people with disability. However, there is no generic set of guidelines or heuristics that can be used by anyone to evaluate an interface in terms of usability and accessibility. This paper provides expert evaluation of two apps i.e. Accessible Qatar and LinkedIn using a set of heuristics by Gómez and colleagues, and Web Content Accessibility Guidelines (WCAG) 2.0 in terms of both usability and accessibility evaluation. The data analysis was carried out based on the usability problems and the opinion of experts using the system usability scale (SUS) questionnaire. The usability problems were analysed based on the number of usability problems found and the average severity ratings of the usability problems. The results show that the most frequently violated heuristics from the usability heuristics are visibility and recognition. The average severity rating of all the problems found using usability heuristics set is a mix of both minor and major. The results also show that the most frequently violated WCAG 2.0 guideline alternatives; the average severity rating of all the problems found using WCAG 2.0 guidelines is major.