Saccades during visual search in macular degeneration

Area of Science:

• Ophthalmology
• Neuroscience
• Vision Science

Background:

• Macular degeneration (MD) causes central vision loss, impacting high-acuity vision and eye movements.
• Individuals with MD develop a preferred retinal locus (PRL) to compensate for scotoma (blind spot).
• Understanding visual search strategies in binocular MD is crucial for rehabilitation.

Purpose of the Study:

• To investigate eye movement strategies during visual search in individuals with bilateral MD.
• To compare search patterns between individuals with binocular scotomata, monocular scotomata, and controls.
• To explore the role of backward saccades in visual search for those with MD.

Main Methods:

• Participants (5 binocular MD, 3 monocular MD, 6 controls) underwent scotoma mapping using an eyetracker.
• A visual search task involved identifying targets in natural scenes within a 10-second timeframe.
• Saccade characteristics, including direction and amplitude, were analyzed.

Main Results:

• Individuals with binocular scotomata exhibited more saccades towards their scotoma compared to controls.
• Saccades into the scotoma were short and did not fully reveal the blind region.
• Participants frequently made backward saccades to re-examine recently uncovered areas.

Conclusions:

• Backward saccades in binocular MD may aid in inspecting regions near the scotoma, similar to regressive saccades in reading.
• The increased prevalence of backward saccades might be linked to the PRL's proximity to the scotoma.
• These findings offer insights into adaptive visual search strategies in MD.