Optical coherence tomography angiography assessment of macular and peripapillary microvasculature in Parkinson’s disease

Parkinson’s disease (PD) involves retinal dopaminergic dysfunction and is accompanied by various visual abnormalities. Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality used to evaluate retinal microvascular structures. This study aimed to assess macular and peripapillary microvascular characteristics in patients with PD. This prospective cross-sectional study included 62 patients with clinically confirmed PD with different disease severities and 62 age-matched healthy controls. OCTA imaging was performed using the AngioVue RTVue XR Avanti system. Vessel density (VD) was measured in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and peripapillary capillary plexus. Foveal avascular zone (FAZ) area and perimeter were quantified. Disease severity was assessed using the Hoehn and Yahr scale. Associations between OCTA parameters and disease severity were also analyzed. The VD values measured from both the SCP and DCP were lower in patients with PD than in healthy controls (SCP, p = 0.035; DCP, p < 0.001). Furthermore, peripapillary VD was lower, and FAZ area was larger in the PD group (p = 0.002 and p = 0.026, respectively). Disease stage had moderate negative correlations with VDs in the SCP and DCP and a positive correlation with FAZ area (p < 0.05 for all). Reduced macular and peripapillary VDs together with FAZ enlargement were observed in PD. The moderate correlations of these OCTA findings with disease severity suggests that rather than directly indicating disease progression, OCTA may provide complementary information on retinal neurovascular involvement when interpreted alongside clinical assessment.