Abstract
Purpose :
Atypical Parkinsonian syndrome (APS) describes a heterogeneous group of disorders mimicking the clinical presentation of Parkinson disease (PD) but with disparate natural history and pathophysiology. While retinal markers of PD are increasingly described, APS has been afforded less attention possibly owing to its lower prevalence. Here, we investigate retinal morphological differences in individuals with APS in a large real world cohort.
Methods :
We conducted a cross-sectional analysis of the AlzEye study, a retrospective cohort where ophthalmic data of individuals attending Moorfields Eye Hospital between January 2008 and March 31st 2018 (inclusive) has been linked with systemic disease data through national hospital admissions. Retinal features were extracted from macula-centered color fundus photography (CFP) and optical coherence tomography (OCT) and compared between individuals with APS and those unaffected. Individuals with idiopathic PD were excluded. Retinal neural and vascular features were measured using automated segmentation and analyzed with multivariable-adjusted regression models.
Results :
Among a cohort of 91,170 patients, there were 51 patients with APS and 91,119 controls. Individuals with APS were older and more likely to have hypertension and diabetes mellitus. After adjusting for age, sex, hypertension and diabetes melitus, individuals with APS had a thinner ganglion cell-inner plexiform layer (-3.95 microns, 95% CI: -7.53, -0.37, p = 0.031) but no difference in other retinoneural or retinovascular indices. Optic nerve cup-to-disc ratio was similar between groups.
Conclusions :
Our cross-sectional analysis of the AlzEye cohort reveals distinct retinal morphological characteristics in APS compared to healthy controls. The study notably identifies a thinner ganglion cell-inner plexiform layer in APS patients, without accompanying changes in the inner nuclear layer or significant alterations in retinovascular indices and optic nerve cup-disc ratio. These changes are distinct from those observed in PD, where thinning of the inner nuclear layer (INL) is a characteristic feature.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.