The Prevalence of Ptosis and Nystagmus in Rural Population

PURPOSE: To determine the prevalence of ptosis and nystagmus in the general rural population in Iran. METHODS: Two villages were selected from the north and southwest of Iran using a multi-stage cluster sampling approach. After selection of the participants and inviting them to a complete eye exam, they all had vision tests and an ophthalmic examination. Vision tests included measurement of visual acuity, refraction, and the cover test. Then the slit-lamp exam was performed, and the diagnosis of ptosis and nystagmus was determined by an ophthalmologist. RESULTS: Of the 3851 invitees, 3314 people participated in the study. The prevalence of ptosis in this study was 2.23% [95% confidence interval (CI): 1.73-2.74], and 45.3% of the cases were bilateral ptosis. The prevalence of ptosis was lowest in the 21-30 year (0.2%) and the under 5 year (0.8%) age groups, and the highest prevalence was observed in people over 70 years of age (6.7%) (P < 0.001). The prevalence of ptosis was higher in illiterate people than those with an academic education level (P = 0.012). The prevalence of astigmatism was 62.8% in those with ptosis and 34.2% in those without ptosis (P < 0.001). The prevalence of nystagmus was 0.39% (13 cases). CONCLUSIONS: This study found that the prevalence of ptosis is relatively high in the general rural population in Iran, and the prevalence increases with age. Astigmatism is significantly high among cases with ptosis, and its prevalence has an inverse relation with the level of education. Nystagmus also had a high prevalence in this population.