OCT-based retinal biomarkers forecast central nervous system structural decline in Parkinson's disease: A...

Parkinson's disease (PD) is among the most prevalent progressive neurodegenerative disorders, impacting both the central and peripheral nervous systems.This longitudinal study investigates whether structural changes in the retina, due to its developmental and structural similarities with the brain, can act as early indicators of brain alterations in patients with PD.

Data from 29 PD patients and 25 healthy controls were analyzed. After a mean interval of 2.7 years after retina imaging, all participants underwent a 1.5T magnetic resonance imaging (MRI) Scan. Image processing was performed using 3D Slicer and the CAT12 toolbox, while statistical analyses were conducted with R software.

In healthy controls, a significant positive correlation was observed between gray and white matter volumes and peripapillary retinal nerve fiber layer (pRNFL) thickness (r = 0.5, p < 0.05) and (r = 0.4, p < 0.05). In contrast, PD patients showed a significant association between increased CSF volume and reduced pRNFL thickness and optic nerve rim volume (r = -0.50 to -0.40; p < 0.05) and (r = -0.50; p < 0.05), respectively. Moreover, neuromelanin signal intensity in the substantia nigra correlated positively and significantly with pRNFL thickness in nasal and superior sectors exclusively in the PD group (r = 0.40 to 0.60; p < 0.05).

Retinal alterations in PD are closely aligned with concurrent brain neurodegeneration and may serve as predictive biomarkers. These findings suggest that OCT, when combined with MRI, may support a non-invasive strategy for early risk stratification and longitudinal monitoring of PD.