Flicker-defined form stimuli are minimally affected by centre-surround lateral contrast interactions

Area of Science:

• Visual perception
• Ophthalmology
• Neuroscience

Background:

• Flicker-defined form (FDF) stimuli are increasingly used in visual field testing.
• Unlike traditional methods, FDF displays feature a flickering background.
• Understanding lateral interactions is crucial for FDF stimulus perception.

Purpose of the Study:

• To investigate if lateral interactions beyond the stimulus border influence FDF perception in healthy young adults.
• To assess the impact of surround size and retinal eccentricity on FDF detection.
• To examine the role of temporal phase differences on FDF stimulus contrast.

Main Methods:

• Experiment 1: Measured FDF contour detection across varying surround sizes (20°, 30°, 40°) and retinal eccentricities (0°, 10°, 20°).
• Experiment 2: Assessed apparent temporal contrast using target-surround phase differences (0°-180°) for FDF and solid-field stimuli.
• Collected psychometric functions to quantify detection and contrast perception.

Main Results:

• A mild surround-suppression effect was observed for FDF stimuli, irrespective of surround size.
• The magnitude of FDF surround suppression correlated with reduced temporal contrast energy compared to solid-field stimuli.
• Surround size and retinal eccentricity did not significantly alter the surround-suppression effect.

Conclusions:

• Lateral interactions beyond the FDF stimulus border are unlikely to significantly impact visual field testing results.
• Mild surround suppression of contrast occurs in FDF stimuli due to background-target interactions.
• Perceptual effects related to center-surround interactions may influence FDF outcomes under certain conditions.