Trends in the prevalence of vision impairment among the oldest-old Chinese population from 1998 to 2018.

Background: Vision impairment has become a prominent public health issue worldwide. However, little is known about vision impairment prevalence trends among the oldest-old adults in China. This study aimed to examine 20-year trends in the prevalence of vision impairment among the oldest-old Chinese adults and explore the contributions of sociodemographic variables, health behaviours, and chronic conditions to the trends.