Designing Interfaces for an Overlooked User Group: Considering the Visual Profiles of Partially Sighted Users
Julie A. Jacko, Andrew Sears · 1998 · Proceedings of the Third International ACM Conference on Assistive Technologies (Assets '98) · doi:10.1145/274497.274512
Summary
This position paper argues that partially sighted computer users represent a critically underserved population in interface design research. The authors identify a gap between two groups that have received significant attention — fully sighted users and totally blind users — while the much larger population of partially sighted users has been largely overlooked. The paper notes that partially sighted people may outnumber functionally and fully blind users by as much as three to one, yet cannot use traditional GUIs without alteration and will not adopt devices designed for fully blind users. The authors critique existing approaches such as the Windows Accessibility Options, which offer limited adjustments to font sizes, cursor sizes, and colors but do not account for how an individual's specific combination of impaired visual processes affects their interaction strategies. The core argument is that a person's visual profile — comprising visual acuity, contrast sensitivity, visual field, and color perception — determines their strategies and behaviors when using computers, and that understanding these profiles is essential for designing effective interfaces.
Key findings
The paper identifies four key visual functions that constitute a user's visual profile and should be assessed when designing for partially sighted users: visual acuity (resolving fine detail, measured by standard letter-based charts like the Bailey-Lovie style), contrast sensitivity (detecting objects at low-to-moderate contrast levels, measured by the Pelli-Robson chart), visual field (the total area of view and useful field within it, assessed using Goldman perimetry), and color perception (the ability to discern and identify colors, assessed by tests like the Farnsworth D-15). The authors argue that these four dimensions interact in complex ways — for example, understanding how visual acuity influences computer use may lead to screen magnification recommendations, but the optimal magnification depends on contrast sensitivity and visual field constraints as well. The paper calls for systematic clinical and functional assessments that link individual visual profiles to performance on computer-based tasks, moving beyond trial-and-error hardware and software matching currently used by low-vision users.
Relevance
This paper's central argument — that partially sighted users are not a monolithic group and that interface design must account for individual visual profiles — remains profoundly relevant to accessibility practice today. While screen magnification, high contrast modes, and display customization have improved significantly since 1998, the underlying challenge persists: most accessibility accommodations offer binary solutions (magnification on/off, high contrast on/off) rather than adapting to the specific combination of visual capabilities a user has. The framework of four visual function dimensions (acuity, contrast sensitivity, visual field, color perception) provides a useful lens for practitioners evaluating whether an interface serves the full spectrum of low-vision users. The paper also highlights an important tension in accessibility work: the tendency to design for the extremes (fully sighted or fully blind) while neglecting the larger population in between — a pattern that still occurs when organizations focus exclusively on screen reader compatibility without considering low-vision usability.
Tags: low vision · visual impairment · partial vision · visual profile · graphical user interface accessibility · user interface design · contrast sensitivity · visual acuity · human-computer interaction