Macular degeneration affects eye movement behavior during visual search.

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Perception

Background:

• Patients with central vision loss, such as from macular degeneration (MD), often utilize a preferred retinal locus (PRL) for viewing.
• The impact of PRL-based viewing on eye movement metrics during visual search tasks remains unclear.

Purpose of the Study:

• To investigate whether eye movement metrics are modulated by peripheral viewing with a PRL during a visual search paradigm.
• To compare visual search performance in MD patients with healthy controls and controls using a simulated scotoma.

Main Methods:

• A visual search paradigm with two conditions: serial search (unfilled circle target among C-shaped distractors) and pop-out search (filled circle target).
• Tested four MD patients, a healthy control group, and a healthy control group with a simulated scotoma.
• Analyzed saccadic search latencies, target selection sensitivity, saccade amplitude, intersaccadic interval, and number of eye movements.

Main Results:

• MD patients showed significantly longer saccadic search latencies in both conditions compared to control groups.
• This difference was not attributable to target selection sensitivity.
• MD patients exhibited smaller saccade amplitudes, increased intersaccadic intervals, and more eye movements, with some characteristics mirrored in the simulated scotoma group.

Conclusions:

• Altered visual search behavior in MD patients is explained by the combination of central scotoma and peripheral viewing.
• Peripheral viewing itself, not necessarily a reorganized visual system, contributes to these behavioral changes.
• Switching from foveal to PRL-based vision impairs visual search efficiency.