Non-Invasive Fundus Retinal Detection Technology for Early Diagnosis of Parkinson's Disease

The objective of this observational study is to investigate whether non-invasive fundus retinal detection technology can be used for the early diagnosis of parkinson's disease (PD). It aims to answer the following primary questions: the sensitivity and specificity of non-invasive fundus retinal detection technology in the early diagnosis of PD; and whether this technology offers advantages over dopamine transporter positron emission tomography (DAT-PET), a conventional screening method for PD. The researchers will analyze the diagnostic performance of this technology for early-stage PD patients among cohorts including early parkinson's disease, parkinson's syndromes, essential tremor patients, and healthy individuals. Furthermore, in PD patients who concurrently undergo DAT-PET imaging, the study will compare the diagnostic value of non-invasive retinal imaging against that of DAT-PET.