Year: 2026
Type: preprint
Abstract: ABSTRACT Purpose In fully-sighted individuals, pursuit and saccadic eye movements work together to foveate moving targets; pursuit attempts to match target velocity, while catch-up saccades re-align the fovea to the target if it deviates during pursuit. Although saccade-pursuit interactions are well understood in healthy individuals, less is known about how these mechanisms adapt in the presence of central vision loss. Methods We simulated central vision loss in healthy young adults to examine plasticity in saccade-pursuit mechanisms, investigating whether and how catch-up saccades adapted over five days of visual tracking. 25 fully-sighted participants performed a task where they pursued a moving target that stepped position randomly (designed to elicit catch-up saccades) while viewing with a gaze-contingent central scotoma. The scotoma was shaped like a bitten cookie to encourage use of a specific preferred retinal locus (PRL) corresponding to the peripheral location with the highest acuity. Results After five days of repetition, most participants’ catch-up saccade endpoints shifted towards the PRL rather than the fovea. On average, endpoints shifted 0.5° towards the PRL between days 1 and 5 (0.3°-1.5°), with significant shifts in 13/25 participants. Adaptation was asymmetric; shifts were largest when the target moved towards the PRL (into the scotoma; towards cartesian quadrant 1) and smallest away from the PRL (out of the scotoma; towards cartesian quadrant 3). Conclusions In summary, we observed adaptation of saccade-pursuit interactive mechanisms through re-referencing of catch-up saccades from fovea to PRL. These results provide a promising avenue for rehabilitation in central vision loss aimed at improving eye movements and encouraging PRL use. Ultimately, such an approach may enhance residual visual function and quality of life. Significance Statement Individuals with central vision loss can shift their oculomotor reference from the fovea to a preferred retinal locus (PRL) during saccades to stationary targets. Whether this extends to moving targets remains unclear. Our findings demonstrate catch-up saccade adaptation to a PRL after 5 hours of training. Our results support rehabilitation strategies promoting efficient PRL use, allowing individuals with central vision loss to optimize their residual vision.
Institutions: Queen's University, Université de Montréal
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7220445046