Fixational eye movements as active sensation for high visual acuity.

Area of Science:

• Neuroscience
• Computational Vision
• Ophthalmology

Background:

• Perception and action are interconnected, with self-motion influencing our worldview.
• Fixational eye movements (FEM), though involuntary, create retinal jitter, potentially impairing neural coding.
• Empirical evidence suggests FEM may benefit, not harm, fine detail perception, creating a paradox.

Purpose of the Study:

• To resolve the paradox of how fixational eye movements (FEM) affect human visual perception.
• To determine the conditions under which FEM improve or impair retinal coding and visual acuity.
• To model the relationship between FEM, retinal coding, and visual acuity.

Main Methods:

• Developed a computational model using an ideal Bayesian classifier on simulated retinal activity with FEM.
• Compared model predictions directly against human subject performance in a visual acuity task.
• Utilized high-resolution eye-tracking with an adaptive optics scanning laser ophthalmoscope to monitor empirical FEM.

Main Results:

• The model quantitatively predicted experimental observations, demonstrating how FEM can facilitate retinal information encoding.
• FEM introduce variability but also preprocess visual inputs, enhancing retinal ganglion cell activity.
• Human subjects' FEM amplitude remained within a near-optimal range, maximizing visual acuity benefits.

Conclusions:

• Perception benefits from action, even at the scale of fixational eye movements.
• FEM play a crucial role in optimizing visual acuity by modulating retinal input.
• Understanding the interplay between action (FEM) and perception is key to explaining visual processing.