Abstract
Purpose :
Text remapping has been proposed to improve reading with central-field loss, where letters occluded by the scotoma are shifted in real-time to a location outside of the scotoma. However, remapped text deviates from horizontal lines, which may negatively affect reading. This study aims to test the feasibility of text remapping by evaluating letter and word recognition performance along unusual trajectories.
Methods :
Stimuli were triplets of random letters (trigrams) and words of 3-8 letters (x-height = 1°), presented for 100 ms along trajectories of 13 letter positions. Two groups of college students respectively read trigrams (N = 16) and words (N = 12). Baseline performance was measured with a typical horizontal linear text trajectory passing through the fovea (0°). Four other trajectories were designed assuming a scotoma covering the central 5 letters: 1) Lowered-line: the entire line was lowered by 3.8°. 2) Step-down: the leftmost 4 letters remained at 0° but the rest were lowered by 3.8°. 3) V-shaped: the central 5 letters were lowered then raised along a diagonal, circumventing the scotoma. 4) Horizontal-gap: the line remained at 0° but skipping the central 5 letter positions. Recognition performance was normalized as a percentage of baseline. A linear mixed-effect model was fitted where Stimulus type (trigrams/words) and Trajectory were fixed effects and Participant was the random effect.
Results :
Recognition of remapped text only reached 69.7% to 93.9% of baseline performance, consistent with the slower reading with central-field loss. The main effect of Trajectory was significant (F3,72 = 117.58, p < .001): Compared to the Lowered-line trajectory, the performance of the V-shape trajectory was significantly better whereas that of the Horizontal-gap trajectory was significantly worse (adjusted p’s < .001). While contextual benefits were observed during word recognition at baseline, the effect of Stimulus type was not significant after normalization (F1,24 = 0.075, p = .79). No significant interaction was found (F3,72 = 1.26, p = .30), indicating that the trajectories affected letter- and word-recognition similarly.
Conclusions :
A V-shaped trajectory produced better performance than horizontal trajectories in peripheral vision despite the unusual text arrangement. Text remapping may be a feasible way to improve reading in people with central-field loss by customizing text arrangements to make more effective use of peripheral vision.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.