Objective: To characterize longitudinal changes in pupillometric parameters in de novo Parkinson’s disease and explore their associations with clinical severity and disease progression.
Background: Automated pupillometry provides objective measures of autonomic pupillary function and has been proposed as a potential biomarker for Parkinson’s disease (PD). However, longitudinal changes in pupillometric parameters in de novo PD and their relationships with clinical severity and disease progression remain unclear.
Method: This longitudinal observational study included patients with de novo PD enrolled between 2019 and 2026 who underwent automated pupillometry at two predefined time points. The primary endpoint was longitudinal change in pupillometric parameters, including the Neurological Pupil Index (NPI), constriction velocity (CV), maximum constriction velocity (MCV), latency (LAT), and dilation velocity (DV), calculated using binocularly averaged values. Secondary analyses assessed longitudinal changes in the side-specific progression of motor laterality, asymmetric indices, and their associations with clinical severity and progression measures, including Hoehn & Yahr stage, the Movement Disorder Society-Unified PD Rating Scale Parts III and levodopa equivalent daily dose.
Results: The NPI decreased and LAT increased significantly over a mean follow-up of 5.3 ± 0.6 years, whereas CV, MCV, and DV showed no significant changes. Similar changes were observed in pupils ipsilateral to both the more and less affected sides, with no significant inter-side differences. Asymmetric indices remained unchanged, and longitudinal changes in NPI were not correlated with clinical severity or progression measures.
Conclusion: In de novo PD, pupillary dysfunction progresses bilaterally and symmetrically over time. Automated pupillometry may be a useful tool for monitoring of autonomic pupillary dysfunction in PD; however, its utility as a marker of clinical progression requires further validation.
To cite this abstract in AMA style:
JSL. Lee, SY. You. Longitudinal Changes and Clinical utility of the Neurological Pupillary Index in De Novo Parkinson’s Disease [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/longitudinal-changes-and-clinical-utility-of-the-neurological-pupillary-index-in-de-novo-parkinsons-disease/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/longitudinal-changes-and-clinical-utility-of-the-neurological-pupillary-index-in-de-novo-parkinsons-disease/