*4.1. Overview*

As shown in Figure 2, the first paper was published in 2008; note that the first generation of iPhone was released in 2007. While the topic of this area is not that active, at least three papers have been published each year since 2013. As for the country of authors' affiliations, United States had the dominant number of papers, which was 17. It was followed by Germany ( *N* = 4), Canada ( *N* = 3), Australia ( *N* = 2), and Japan ( *N* = 2). Other countries had only one paper each: Austria, Brazil, China, France, Italy, Lebanon, South Korea and Spain.

**Figure 2.** The number papers related to touchscreen-based image accessibility.

### *4.2. Supported Image Types*

The types of images that have been studied in prior works for providing better accessibility for screen reader users (*RQ1*) are summarized in Table 1. While three papers were designed to support any type of images in general [35–37], most of the papers focused on specific types of images. To be specific, approximately half of the papers studied images of maps ( *N* = 10) and graphs ( *N* = 6). Interestingly, while the accessibility of photographs for BLV was largely investigated in terms of web accessibility [21,38], only three out of 33 papers aimed to support photographs using touchscreen devices in particular. In addition, as touchscreen devices themselves have accessibility issues for people with visual impairments, requiring accurate hand–eye coordination [26], four papers focused on improving the accessibility of the touchscreen-based interface itself such as soft buttons [39–41] and gestures [42].

**Table 1.** Types of supported images for people who are blind or have low vision (BLV).

