The purpose of this study was to investigate the role of α-synuclein in Parkinson's disease and its molecular mechanism, and to establish an evaluation model for corneal nerve fiber injury. The function and mechanism of α-synuclein in Parkinson's disease were studied. The expression level of α-synuclein in corneal tissues of Parkinson's disease patients and normal control group was detected by immunohistochemistry and Western blot. At the same time, the morphological changes of corneal nerve fibers were observed by confocal microscopy, and the degree of corneal nerve injury was evaluated by corneal synesthetic nerve function test. The results showed that the expression level of α-synuclein in the corneal tissue of patients with Parkinson's disease was significantly increased, and the morphology and function of corneal nerve fibers were significantly abnormal. Corneal synesthetic nerve function test results also showed that the corneal sensory nerve conduction speed slowed down and sensitivity decreased in patients with Parkinson's disease.