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Updated: Mar 9, 2026
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Development of a Gaze-Contingent Display Framework Designed for Perceptual and Oculomotor Research with Simulated Central Vision Loss
Published on: April 11, 2025
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Scotoma Visibility and Reading Rate with Bilateral Central Scotomas
Joshua D Pratt1, Scott B Stevenson, Harold E Bedell
1*OD, PhD †PhD ‡PhD, FAAO University of Houston College of Optometry, Houston, Texas (all authors).
Summary
Overlaying a gaze-contingent polygon to highlight scotoma location improved reading speed for patients with bilateral central scotomas. This visual aid shows potential benefits for reading performance in low vision rehabilitation.
Area of Science:
- Ophthalmology
- Vision Science
- Rehabilitation Medicine
Background:
- Bilateral central scotomas, often caused by age-related macular degeneration, significantly impair reading ability.
- Current reading aids may not fully compensate for the functional deficits associated with central vision loss.
Purpose of the Study:
- To investigate if a gaze-contingent polygon overlay, perceptually delineating scotoma location and border, enhances reading speed and eye movements in patients with bilateral central scotomas.
- To assess the immediate impact of a visual aid designed to make the scotoma more perceptible during reading tasks.
Main Methods:
- Eight patients with bilateral central scotomas read sentences using gaze-contingent display technology.
- A polygon overlay, representing the scotoma, was superimposed on text during half of the reading trials.
- Reading speed and eye movement metrics (fixations, saccades) were recorded and analyzed before and after practice with the overlay.
Main Results:
- A statistically significant increase in reading speed (0.075 log wpm) was observed for the majority of participants after using the polygon overlay.
- Individual eye movement analysis revealed significant shifts in vertical fixation locus for many subjects.
- No significant changes were found in overall saccade rate, fixation duration, saccade amplitude, or saccade directionality across the group.
Conclusions:
- Perceptually highlighting the scotoma with a gaze-contingent polygon overlay shows potential as a beneficial tool for improving reading speed in individuals with bilateral central scotomas.
- The observed improvements suggest that increased scotoma visibility can aid reading performance, warranting further investigation into extended training protocols.
