Abstract: Objective  To explore the distribution of etiology and clinical characteristics of patients with ptosis. Design Retrospective case series. Participants 537 patients presenting with ptosis from January to December 2023 in the Department of Neurology, Beijing Tongren Hospital. Methods Clinical data were collected for etiological classification and statistical analysis. Main Outcome Measures The average age of onset, disease duration, gender, bilateral involvement, and the presence of major clinical symptoms such as pain, diplopia, and pupillary involvement in different etiological subgroups. Results Among the 537 patients, 251 were male with an average age of (58.1±19.4) years. Bilateral ptosis was observed in 375 cases, and unilateral ptosis in 162 cases. The etiology distribution was as follows: myogenic ptosis in 177 cases (33.0%), of which 165 cases (30.7%) were due to myasthenia gravis; neurogenic ptosis in 90 cases (16.8%), mainly due to oculomotor nerve paralysis in 86 cases (16.0%); pseudoptosis in 233 cases (43.4%), with eyelid spasm in 197 cases (36.7%); and undetermined causes in 37 cases (6.9%). Among patients with myasthenia gravis, 82.4% had bilateral eye involvement, 95.8% exhibited fluctuating symptoms of worsening in the evening, 78.8% had diplopia or eye movement disorders, 89.1% showed varying degrees of compensatory frontalis muscle activation, 64.8% had disappearance of the burying eyelashes sign after forceful eyelid closure, and 57.8% had symptoms of systemic skeletal muscle involvement. Patients with eyelid spasm did not have eye movement disorders and typically had a longer disease course. 38.9% of patients with unilateral facial spasm experienced paroxysmal vertigo and/or tinnitus. Patients with oculomotor nerve paralysis typically had eye movement disorders and pain, with some cases involving pupil impairment and generally a shorter disease duration. Conclusion Myasthenia gravis is the most common cause of myogenic ptosis, while eyelid spasm predominates in pseudoptosis, and oculomotor nerve paralysis is an important cause of neurogenic ptosis. Clinical features differ significantly among different etiologies of ptosis, necessitating comprehensive judgment to optimize individualized diagnostic and treatment processes. (Ophthalmol CHN, 2024, 33: 424-428)

Key words: ptosis, myasthenia gravis, blepharospasm, pseudoptosis