Fixational Microsaccades in Patients With Parkinson Disease

Area of Science:

• Ophthalmology
• Neuroscience
• Biomarkers

Background:

• Fixational microsaccades (FM) are small, involuntary eye movements essential for visual stability.
• Altered FM patterns are linked to central nervous system disorders, including multiple sclerosis.
• This study investigates FM characteristics in Parkinson disease (PD) patients.

Purpose of the Study:

• To characterize fixational microsaccades (FM) in individuals with Parkinson disease (PD).
• To explore the relationship between FM parameters and PD severity.

Main Methods:

• Retinal motion traces were recorded from 14 PD patients and 17 controls using a tracking scanning laser ophthalmoscope (TSLO).
• Key FM metrics measured included number, amplitude, velocity, peak velocity, and frequency.
• Correlation analysis was performed between FM measures and the MDS UPDRS III motor subscale and Hoehn and Yahr Stage.

Main Results:

• PD patients displayed significantly higher numbers, larger amplitudes, and increased velocities and frequencies of FM compared to controls (P < 0.05).
• Average FM amplitude, velocity, and peak velocity strongly correlated with PD severity as assessed by UPDRS III and Hoehn and Yahr Stage (r = 0.56–0.62, P < 0.05).

Conclusions:

• This is the first study to characterize FM in PD patients using TSLO.
• TSLO demonstrated high precision for detailed retinal imaging with minimal motion artifact.
• Impaired FM in PD correlates with disease severity, indicating potential as a biomarker for progression and treatment response.