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Related Experiment Video

Updated: May 28, 2026

A Gaze-Contingent Display Framework for Perceptual Learning Research with Simulated Central Vision Loss

A Gaze-Contingent Display Framework for Perceptual Learning Research with Simulated Central Vision Loss

Published on: April 11, 2025

Illusory contours over pathological retinal scotomas.

Elisa De Stefani¹, Luisa Pinello, Gianluca Campana

¹Department of Neuroscience, University of Parma, Parma, Italy. elidestefani@gmail.com

|October 25, 2011

Summary

People with macular degeneration can perceive illusory contours, even in blind spots. This suggests the visual cortex can construct shapes using basic visual cues despite vision loss.

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Area of Science:

Neuroscience
Visual Perception
Ophthalmology

Background:

Visual perception is not solely driven by physical stimuli.
Illusory contours, like those in the Kanizsa figure, are perceived without physical borders.
Macular degeneration causes pathological retinal scotomas, impacting central vision.

Purpose of the Study:

To investigate the perception of illusory contours in pathological retinal scotomas.
To determine if curvature discrimination of illusory contours is possible in blind spots caused by macular degeneration.

Main Methods:

Examined curvature discrimination of Kanizsa figure illusory contours across retinal scotomas in patients with macular degeneration.
Compared results with previous studies on normal-sighted subjects and physiological scotomas.

Main Results:

Perfect discrimination of illusory contour curvature was demonstrated over pathological retinal scotomas.
This perception occurred despite significant scarring and reduced discrimination of inducer angles.
Low spatial frequency information from inducers was sufficient for contour perception.

Conclusions:

Subjective contours can be perceived within pathological retinal scotomas.
The visual cortex can utilize low-spatial frequency information to construct complex shapes even with absent bottom-up input.
This finding has implications for understanding visual processing in retinal diseases.