Mapping the binocular scotoma in macular degeneration

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Macular degeneration (MD) can cause binocular scotoma, obstructing vision and leading to missed information.
• Current methods for mapping scotoma are often limited, particularly for binocular cases.

Purpose of the Study:

• To develop and validate an iterative eye-tracker method for precise mapping of binocular scotoma in individuals with MD.
• To compare the accuracy of eye-tracker perimetry with existing scanning laser ophthalmoscope/optical coherence tomography (SLO/OCT) methods.

Main Methods:

• Nine individuals with MD and four controls underwent monocular scotoma measurement using SLO/OCT.
• Monocular and binocular scotomata were precisely mapped using an eye tracker, monitoring fixation.
• Participants detected flashed dots on a grid, with points refined manually to map scotoma boundaries.

Main Results:

• Eye-tracker measurements of monocular scotomata closely matched SLO/OCT findings, validating the eye-tracking technique.
• Participants utilized clustered fixation patterns centered on their preferred locus.
• For binocular scotomata, the eye-tracker map correlated with the overlap of monocular scotoma profiles from SLO.

Conclusions:

• Eye-tracker-based perimetry is a reliable and sensitive tool for mapping both monocular and binocular scotomata.
• This method offers advantages over SLO/OCT, which is restricted to monocular viewing, for comprehensive scotoma assessment in MD.