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Updated: Jun 23, 2026
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A Gaze-Contingent Display Framework for Perceptual Learning Research with Simulated Central Vision Loss
Published on: April 11, 2025
Perceptual distortion in homonymous paracentral scotomas
Nikolaos A Mavrakanas1, Nathalie P L Dang-Burgener, Erika N Lorincz
1Department of Clinical Neurosciences, University of Geneva Hospitals, Geneva, Switzerland.
Summary
Cortical remapping can cause visual field distortions even far from a scotoma. Patients with visual field defects perceived lines as shorter, with distortion increasing further from the defect.
Area of Science:
- Neuroscience
- Visual Perception
- Neuroplasticity
Background:
- Investigates cortical remapping's effect on visual perception beyond scotoma areas.
- Examines spatial distortion in patients with homonymous paracentral scotoma.
Observation:
- Two patients with right inferior homonymous paracentral scotoma observed.
- Perceptual spatial distortion assessed using isometric vertical lines and a shifting fixation point.
- Time for distortion manifestation and line perception recorded.
Findings:
- Subjects perceived the line within the scotoma as shorter than the other.
- Perceptual shortening magnitude increased with fixation point distance from the line's end.
- Distortion appeared after 5-10 seconds of fixation and varied over time.
- The line appeared uninterrupted or blurred within the scotoma.
Implications:
- Suggests long-range cortical reorganization following brain damage.
- Larger receptive fields in visual map periphery may explain increased distortion with eccentricity.
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