Category: Parkinson's Disease: Non-Motor Symptoms
Objective: To characterize the focal intrinsic and extrinsic light responses in intrinsically photosensitive retinal ganglion cells (ipRGCs) at central and peripheral retina in patients with Parkinson disease (PD).
Background: There is high prevalence of circadian and sleep disruption in people with PD, however the underlying mechanisms of these symptoms are not clear. Melanopsin- ipRGC transmit light signals to brain areas controlling circadian rhythms and the pupil light reflex (PLR).
Method: PD patients [according to the Movement Disorders Society (MDS) diagnostic criteria] and healthy controls (HC) underwent ophthalmologic assessment including best-corrected visual acuity, color vision, Humphrey 24-2 perimetry, and SD-OCT. The PLR for small (0.43°) red and blue light stimuli presented at central (4.2°) and peripheral (21°) visual field locations were measured using a chromatic pupilloperimeter under mesopic light adaptation conditions. PD patients were rated with the MDS-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Montreal Cognitive Assessment (MoCA) and had a sleep evaluation according to PD sleep scale (PDSS-2).
Results: Seventeen PD patients (mean age ± standard deviation: 61.29 ± 11.54 years, PD duration: 4.29± 3.25 years) and 26 age-similar HC (65.07 ± 11.22 years, p=0.29) were enrolled. The rod-mediated maximal percentage of pupil contraction (PPC) was significantly lower at central and peripheral retinal locations in PD patients compared with HC (all p<0.04). Cone-mediated PPC was less affected. The sustained, intrinsic melanopsin-mediated pupil response recovery (PRP) in the central retina was significantly faster in PD compared to HC (p=0.01)
Conclusion: The intrinsic and extrinsic light responses in ipRGCs are differentially affected at central and peripheral retinal locations in PD patients. Correlation with PD motor and nonmotor symptoms will be explored. Chromatic pupilloperimetry is a useful and noninvasive method for exploration of PLR alterations in PD and may prove to be useful for diagnosis and monitoring disease progression.
To cite this abstract in AMA style:
T. Fay-Karmon, D. Jaber, I. Sher, S. Zorani, A. Bleterman, Y. Rotenstreich, S. Hassin-Baer. Mapping intrinsically photosensitive retinal ganglion cells (ipRGCs) dysfunction in patients with Parkinson disease using Chromatic pupilloperimetry [abstract]. Mov Disord. 2021; 36 (suppl 1). https://www.mdsabstracts.org/abstract/mapping-intrinsically-photosensitive-retinal-ganglion-cells-iprgcs-dysfunction-in-patients-with-parkinson-disease-using-chromatic-pupilloperimetry/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2021
MDS Abstracts - https://www.mdsabstracts.org/abstract/mapping-intrinsically-photosensitive-retinal-ganglion-cells-iprgcs-dysfunction-in-patients-with-parkinson-disease-using-chromatic-pupilloperimetry/