Objective: Saccadic eye movement is highly involved in the neural network through basal ganglia (BG), which would contribute to the control and abnormalities of eye movement. However, given the complexity of BG circuit, the mechanism of how saccade is affected in Parkinson’s disease (PD) is uncertain. Therefore, this study was aim to analyze the characteristics and the correlation between saccades and disease progression by monitoring the saccadic eye movement in early PD patients.

Methods: Thirty patients with primary early PD were followed up for 180 days to monitor their activities of daily living, PD-related clinical function, neuropsychological cognitive function and saccadic eye movement function. Differences were compared between baseline and 180-day follow-up, including saccadic latency, duration, amplitude, peak velocity and antisaccadic error rate, in order to evaluate the relationship between saccade features and disease progression.

Results: During 180-day follow-up, patients performed better at prosaccade (PS) tasks than at baseline with a slight larger saccade (10.35±1.00 vs 9.94±0.35 degrees, P=0.037). They also had a shorter saccadic duration during antisaccade tasks (62.93±22.91 vs 71.13±28.51 ms, P=0.027). Antisaccadic latency was positively associated with motor disability, independent of cognitive performance (r=0.609, P<0.001).

Conclusion: Saccadic eye movement is probably affected in PD patients at early stage, with increased prosaccadic amplitude and decreased antisaccadic duration. With the development of disease, longer antisaccadic latency is positively associated with more serious motor disability.