Chorioretinal structural and microvascular alterations as biomarkers for the diagnosis of Parkinson's disease

To evaluate the structural and microvascular chorioretinal characteristics in patients with Parkinson's disease (PD) and to investigate their association with the severity of disability in PD.

This prospective study included 35 patients with PD and 30 healthy, age- and sex-matched control subjects. All participants underwent both optical coherence tomography (OCT) and OCT angiography (OCTA) with enhanced depth imaging (EDI). Outcome measures included: Best corrected visual acuity (BCVA), superficial capillary plexus vessel density (VD), perfusion density (PFD), foveal avascular zone area (FAZ), central macular thickness (CMT), and subfoveal choroidal thickness (SFCT). The severity of the patients' disability was assessed using the Movement Disorder Society Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III).

Compared to control subjects, PD patients showed significantly lower macular VD (16.5 ± 2.7 vs. 18.0 ± 1.3 mm/mm², p = 0.03), lower macular PFD (39.5 ± 7.0 % vs 43.6 ± 2.6 %, p = 0.03) and higher SFCT (297 ± 69 vs. 246 ± 56, p = 0.002). The MDS-UPDRS-III showed a significant inverse correlation with BCVA and SFCT. No correlation was observed between PD duration and study measures.

This study found lower macular perfusion density and increased choroidal thickness in patients with Parkinson's disease compared to healthy controls, suggesting altered retinal vascular status in PD. Additionally, better visual acuity and greater subfoveal choroidal thickness were associated with better clinical performance. These findings indicate a potential association between OCT and OCT-A metrics and disease characteristics in PD.