Chen D, Li R, Li X, et al. - Researchers conducted this population-based cohort study to assess the prevalence, incidence and associated risk factors of strabismus among preschool children in China. Children born between September 2011 and August 2012 in Yuhuatai District of Nanjing have been invited to take part in the Nanjing Eye Study for an annual comprehensive eye examination since 2015. From 2015 to 2017, the data provided in this paper were collected, as these children grew from 3 to 5 years old. Using univariable and multivariable logistic regression models, risk factors were evaluated for prevalent and incident strabismus. In 2015, a total of 2018 children of 2,300 eligible preschoolers finished the baseline eye examination when they were 3 years old. The authors observed a higher incidence of strabismus and a higher exotropia:esotropia ratio than previous studies in preschool children. Parental strabismus history and prematurity have been linked to a higher risk for both prevalent and incident strabismus.