Neurovascular Changes in the Retina of Parkinson's Disease Patients: A Comprehensive Study on Disease Severity,...

This study aims to investigate retinal neuronal and vascular structural alterations in Parkinson's disease (PD) patients concerning disease duration and severity, levodopa dosage, and stroke risk.

This retrospective study included 40 PD patients and 40 age- and sex-matched controls. Retinal parameters, including central foveal thickness (CFT), macular thickness (MT), retinal nerve fiber layer (RNFL), and retinal vascular density, were measured using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Disease severity was assessed using the Hoehn & Yahr (H&Y) scale, and stroke risk was evaluated using the Stroke Risk Assessment (SRA) tool.

PD patients demonstrated significantly reduced MT in the temporal quadrant and reduced vascular density in both the superficial (SCP) and deep (DCP) capillary plexuses compared to controls. Additionally, the superficial and deep foveal avascular zone (FAZ) areas showed notable enlargement. A negative correlation between disease duration and both the temporal and nasal quadrants of the SCP and a positive correlation between disease severity and deep FAZ area was observed, while disease severity exhibited negative correlations with temporal MT, average and superior quadrant RNFL. Levodopa dosage was inversely correlated with inferior and temporal MT and temporal SCP and DCP and positively correlated with the deep FAZ area. No significant correlation was found between the SRA score and retinal vascular changes.

This study is the first to evaluate retinal neuronal and vascular changes in PD regarding stroke risk assessment. Our findings suggest that retinal changes are associated with disease severity and duration in PD patients. Further prospective studies with larger sample sizes are needed to validate these findings and explore the potential role of OCTA in early detection and stroke prevention in PD.