Systematic arcminute-scale fixational offsets in patients with early visual cortex damage.

Area of Science:

• Neuroscience
• Ophthalmology
• Visual Science

Background:

• Cortically induced blindness (CB) from stroke damages the visual cortex, causing significant visual field deficits.
• CB is known to impact large-scale oculomotor behavior, but its effect on fine-tuned fixation is less understood.

Purpose of the Study:

• To investigate subtle alterations in fixational oculomotor behavior in patients with Cortically induced blindness (CB).
• To determine if oculomotor dynamics and fixation precision are affected by early visual cortex damage.

Main Methods:

• Employed high-precision eye tracking to monitor gaze behavior in CB patients and age-matched controls.
• Assessed fixational oculomotor behavior during passive fixation and a high-acuity central task.

Main Results:

• CB patients exhibited a consistent, small gaze offset toward their blind field during passive fixation.
• This offset vanished during a high-acuity central task, indicating context-dependent control.
• Fixation precision and underlying oculomotor dynamics (microsaccades, ocular drift) were comparable between CB patients and controls.

Conclusions:

• The adult oculomotor system dynamically adapts to asymmetric visual input following cortical damage.
• Fixational gaze offsets in CB may represent attentional shifts or compensatory rebalancing.
• Early visual cortex damage does not preclude context-dependent control of fixation in adulthood.