Benthic: Perceptually congruent structures for accessible charts and diagrams
Authors: C. Mei; J. Pollock; D. Hajas; J. Zong; A. Satyanarayan
Published: Proceedings of the 27th ACM SIGACCESS Conference on Computers and Accessibility (ASSETS ’25). Association for Computing Machinery (2025)
Abstract
Graphical representations—such as charts and diagrams—have a visual structure that communicates the relationship between visual elements. For instance, we might consider two elements to be connected when there is a line or arrow between them, or for there to be a part-to-whole relationship when one element is contained within the other. Yet, existing screen reader solutions rarely surface this structure for blind and low-vision readers. Recent approaches explore hierarchical trees or adjacency graphs, but these structures capture only parts of the visual structure—containment or direct connections, respectively. In response, we present Benthic, a system that supports perceptually congruent screen reader structures, which align screen reader navigation with a graphic’s visual structure. Benthic models graphical representations as hypergraphs: a relaxed tree structure that allows a single hyperedge to connect a parent to a set of children nodes. In doing so, Benthic is able to capture both hierarchical and adjacent visual relationships in a manner that is domain-agnostic and enables fluid (i.e., concise and reversible) traversal. To evaluate Benthic, we conducted a study with 15 blind participants who were asked to explore two kinds of graphical representations that have previously been studied with sighted readers. We find that Benthic’s perceptual congruence enabled flexible, goal-driven exploration and supported participants in building a clear understanding of each diagram’s structure.
Media
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Benthic: Making Diagrams Make Sense Through Screen Readers
Charts and diagrams aren’t just pictures—they’re structures. Boxes contain other boxes; arrows connect ideas; groups form wholes. Sighted readers pick up these relationships at a glance. Screen reader users, meanwhile, are too often given a flat wall of alt text.
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Diagram exploration with screen readers
Discover Benthic, a groundbreaking system revolutionising how blind and partially sighted people interact with charts and diagrams. This podcast will explain how Benthic uses hypergraphs to unify hierarchical and adjacent visual relationships into a perceptually congruent screen reader interface. Tune in to learn how this innovation enables fluid and domain agnostic navigation for complex graphical representations, fostering a deeper understanding of visual information for blind readers.