[The vision distribution and causes of blindness in elderly population in Doumen county].
J Xu, M He, K Wu, S Li
Zhonghua Yan Ke Za Zhi | Published : 1999
OBJECTIVE: To investigate the vision distribution and the leading cause of blindness in farmer aged >or= 50 years in Doumen county. METHODS: Cluster sampling size was estimated within an error bound of 0.35% with 95% confidence limit, 1.25 design effect and 85% response rate. Presenting visual acuity was measured by ETDRS (early treatment diabetic retinopathy study) tumbling chart. Eye examinations of external eye, anterior chamber, lens, fundus and intraocular pressure were carried out by ophthalmologists. A diagnosis of the principal cause for all the eyes with presenting visual acuity less than 0.3 was made as well. The field survey was conducted by two teams after pilot agreement testing..View full abstract