Objective: We compared the pupillary findings of drug-naïve Parkinson’s disease (PD) patients and controls to investigate the characteristics of pupillary light reflexes (PLR) in PD patients and whether they can be used as a supportive diagnostic tool.

Background: An automated pupillometer already being used to determine the condition of patients with neurologically critical illness and predict the prognosis.[1] In neurodegenerative diseases such as Alzheimer’s dementia and PD, there have been reports of studies that the PLR result is different from normal, but it has not been widely used in neurodegenerative diseases.[2-4] In this study, we compared pupillometer parameter between the control group and drug naive PD patients to find out whether it is possible to broaden the use of the pupillometer in PD patients.

Method: The parameters related to the PLR were collected using an automated pupilometer from 42 patients newly diagnosed with PD (age=67.1±10.5, M:F=15:27) and 57 control group (age=66.6±9.4, M:F=18:39). The eight parameters were measured in both eyes with a pupilometer. To find the asymmetry of the results measured in both eyes, we calculated the asymmetry index (AI) as follows: (|Left-Right|/(Left+Right))*100. We compared the pupillometric parameters between PD patients and controls using R software version 4.0.3.  All P-values were two-tailed, and variables were considered significant at P < 0.05.

Results: In the PD patient group, the mean HY stage was 1.57±0.80, and the average UPDRS part III score was 20.5±11.5. There were no statistically significant differences in the age and gender ratio between the two groups. However, the average rate of change in pupil size of both eyes (28.5±6.4% VS. 31.0±5.3%, p=0.041), constriction velocity (CV) (2.1±0.7mm/sec VS. 2.4±0.6 mm/sec, p=0.028), and maximum constriction velocity (MCV) (3.1±1.0 mm/sec VS. 3.5±0.8 mm/sec, p=0.039) were significantly lower in the PD patient group than in the control group. As a result of obtaining the asymmetry index, the AI of CV (11.7±10.2 mm/sec VS. 7.1±5.0 mm/sec, p=0.010) and MCV (11.2±10.5 mm/sec VS. 6.4±5.5 mm/sec, p=0.010) was significantly increased in PD patients.

Conclusion: This suggests that the autonomic nervous system is accompanied by abnormalities from the early stage of PD, and also suggests that the asymmetric dopaminergic neuronal degeneration observed in PD may affect the pupil light reflex.

References: [1] Lussier BL, Olson DM, Aiyagari V (2019) Automated Pupillometry in Neurocritical Care: Research and Practice. Curr Neurol Neurosci Rep 19, 71. [2] Frost S, Robinson L, Rowe CC, Ames D, Masters CL, Taddei K, Rainey-Smith SR, Martins RN, Kanagasingam Y (2017) Evaluation of Cholinergic Deficiency in Preclinical Alzheimer’s Disease Using Pupillometry. Journal of ophthalmology 2017, 7935406-7935406. [3] Hall CA, Chilcott RP (2018) Eyeing up the Future of the Pupillary Light Reflex in Neurodiagnostics. Diagnostics (Basel) 8. [4] Giza E, Fotiou D, Bostantjopoulou S, Katsarou Z, Karlovasitou A (2011) Pupil light reflex in Parkinson’s disease: evaluation with pupillometry. Int J Neurosci 121, 37-43.

« Back to MDS Virtual Congress 2021

MDS Abstracts - https://www.mdsabstracts.org/abstract/comparison-and-analysis-of-pupillometer-parameters-between-patients-with-drug-naive-parkinsons-disease-and-controls/