Retinopathy in Parkinson's disease: A potential biomarker for early diagnosis and clinical assessment

Parkinson's disease (PD) is a prevalent neurodegenerative disorder caused by degeneration of dopaminergic neurons, originating from the substantia nigra pars compacta, and characterized by motor symptoms such as bradykinesia, muscle rigidity, resting tremor, and postural instability, as well as non-motor symptoms such as anxiety, depression, reduced sense of smell, cognitive impairment, and visual dysfunction. Emerging evidence highlights the retina as a promising site for non-invasive exploration of PD pathology, due to its shared embryonic origin with the central nervous system. In recent years, with the development of ophthalmic technology, the acquisition of retinal-related function and structure has gradually become mature. PD-related retinal changes have become a research hotspot for non-motor symptoms of PD. This review provides a comprehensive synthesis of retinal dysfunctions in PD, focusing on structural and functional changes as potential biomarkers for early diagnosis and clinical assessment. By integrating findings from advanced imaging and electrophysiological studies, this review introduces novel perspectives on the correlation between retinal changes and PD pathophysiology, offering innovative approaches for early detection, disease progression monitoring, and therapeutic stratification.