Objective: To investigate the prevalence of heterophoria among urban and rural students in Shantou
City of Guangdong Province, China. Methods: Cluster sampling was used in randomly selecting 7 537
students from 9 schools in Shantou City. Ocular alignment was assessed by using the Hirschberg light
reflex and cover test. Cover testing was performed by using fixation targets at both distance (6 m) and near
(30 cm). Statistical analyses were performed using SPSS statistical software to investigate the association of
age, grades and schools and different types of strabismus. Results: A total of 7 464 students were examined (participation rate was 99.03%), including 3 928 boys and 3 536 girls, mean age 11 years. The prevalence of
esophoria and exophoria were3.08% and 60.65%. Esophoria prevalence of primary school students have the
signiffcant difference (P<0.001) contrast with middle school students and high school students. And prevalence
of exophoria was highest in high school students and significantly higher than middle and primary school
students respectively (P<0.001). Heterophoria was more prevalent in rural school students than urban school
students(P<0.05). Multivariate logistic regression model indicated that the prevalence of heterophoria had no
significant correlation with grades and ages. Conclusion: This survey first reported the prevalence of heterophoria
in China. The prevalence of esophoria appears to be higher in primary students and exophoria was highest in high
school students; Prevalence of Heterophoria in the population of this survey generally showed higher in rural
school students than urban areas. These may be associated with refraction in Chinese students.