Fixation Preference for Visual and Auditory Targets in Monkeys with Strabismus.

Area of Science:

• Neuroscience
• Ophthalmology
• Vision Science

Background:

• Strabismus, a condition characterized by eye misalignment, often leads to altered visual processing.
• In strabismic individuals, eye fixation choice can depend on the target's location on the retina.

Purpose of the Study:

• To investigate eye choice behavior in strabismic subjects when responding to both visual and non-visual (auditory) targets.
• To compare how visual and auditory stimuli influence fixation preference in strabismic monkeys.

Main Methods:

• Eye movements of two exotropic strabismic monkeys were recorded during a saccadic task.
• Monkeys were presented with visual or auditory targets in a dark room under monocular or binocular viewing conditions.
• Fixation preference was quantified by the frequency of using a specific eye to acquire targets at various locations.

Main Results:

• Both monkeys exhibited spatial patterns of fixation preference for visual and auditory targets, with rightward targets favored by the right eye and leftward targets by the left eye.
• The boundary for switching fixation preference shifted significantly between visual and auditory tasks.
• During monocular viewing, fixation switching was limited to target extremities for visual stimuli but not for auditory stimuli.

Conclusions:

• Fixation preference for target location is maintained even with invisible auditory targets.
• These findings suggest that visual suppression mechanisms can modulate innate eye-choice behaviors that are fundamentally independent of visual input.