What Visual Targets Are Viewed by Users With a Handheld Mobile Magnifier App.

Purpose: Mobile video magnifier apps are used by many visually impaired people for seeing details that are beyond their visual capacity. Understanding the common types of visual targets will be importantly informative for low-vision research and assistive technology development. This study addressed this question through analysis of images captured by magnifier app users pursuing their daily activities. Methods: An iOS magnifier app, free to the public, was used to capture and upload images to the Azure Computer Vision cloud service for object recognition. Returned object tag results for each image were uploaded to the Umeng analytics server for aggregated tallies. Consolidated data from 24,295 users across 1 month were analyzed. More than 1300 types of object tags found in 152,819 images were grouped into 11 categories. The data collection and analyses were conducted separately for users who toggled on or off iOS vision-accessibility features. Results: For accessibility and nonaccessibility user groups, 60% to 70% of objects were nontextual, such as an indoor scene, human, or art. More than 40% of the images contained more than one object category. Accessibility users viewed textual objects more frequently than nonaccessibility users (41.1% vs. 29.8%), but overall, the probability ranking of categories was not significantly different between the two groups. Conclusions: Nontextual objects make up a major portion of visual needs of magnifier users across a wide range of vision loss. Translational Relevance: Low-vision research and vision assistance technology development should address the need for nontextual object viewing.