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Updated: Sep 14, 2025
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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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Asymmetries in Foveal Vision
Samantha K Jenks1,2, Marisa Carrasco3,4, Martina Poletti5,2,6
1Department of Brain and Cognitive Sciences, University of Rochester, Rochester, New York 14627.
Summary
Foveolar vision, despite assumptions, shows perceptual asymmetries. Humans exhibit higher sensitivity along the horizontal meridian and a reversed vertical meridian asymmetry in the foveola, impacting visual perception.
Area of Science:
- Neuroscience
- Visual Perception
- Human Vision
Background:
- Visual perception exhibits known asymmetries, with higher sensitivity along the horizontal meridian and lower sensitivity along the upper vertical meridian.
- These visual field asymmetries are generally understood to decrease with proximity to the center of gaze, leading to the assumption of their absence in the foveola.
Purpose of the Study:
- To investigate fine visual discrimination at isoeccentric locations within the foveola and parafovea.
- To determine if perceptual asymmetries persist in the foveola, the high-resolution region of the retina.
Main Methods:
- Employed high-precision eyetracking and a gaze-contingent display to precisely control stimulated foveolar locations.
- Assessed fine visual discrimination in 12 human observers at various eccentricities across the foveola and parafovea.
Main Results:
- Confirmed that visual sensitivity remains higher along the horizontal meridian compared to the vertical meridian, even within the foveola.
- Observed a reduced magnitude of horizontal asymmetry but a reversed vertical asymmetry in the foveola, with stimuli slightly above the center being more easily discerned than those below.
- Demonstrated that foveolar perceptual asymmetries differ in magnitude and direction from those in the immediately adjacent parafovea.
Conclusions:
- Foveolar vision is not uniform and is characterized by distinct perceptual asymmetries.
- These findings challenge the assumption of uniform foveolar vision and highlight differences between foveal and extrafoveal perceptual fields.
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