: To measure the microsaccade characteristics of MS patients to quantify the presence of SWJ 

MS is a neurodegenerative inflammatory disease of the CNS characterized by decline in neurological function that is partially ameliorated by existing therapies. Sensitive tools for tracking worsening are needed to help with the development of treatments to slow decline. Oculomotor deficits are common in MS and include disruption of normal fixation. The tracking scanning laser ophthalmoscope (TSLO), a high-resolution retinal eye-tracking device, can objectively quantify these deficits. 

We recorded three, 10-second scans of fixational eye motion in 71 MS patients (average EDSS 3 +/- 1.8, average disease duration 14.4 +/- 19.4 years) to quantify the presence of SWJs. Eye traces were manually labeled to flag SWJs, defined by having two, roughly equal microsaccades of opposite direction separated by an inter saccadic interval (ISI) ranging between 100-300ms. We classified 48 MS patients (67%) as “SWJ”, as they met our minimum threshold of 3 SWJs instances per scan in at least 50% of traces. We computed the average number of SWJs for each patient’s total traces and conducted exploratory correlation analyses between those averages and their disability (EDSS), fatigue (GFI), hand dexterity, and cognition (SDMT) scores. Finally, we compared if their SWJs were detected at bedside. 

TSLO can flag subclinical SWJ deficits in patients with MS which may contribute to visual dysfunction in MS patients. This documents a notable increase in the number of patients categorized with SWJs.