METHODS: Cross sectional study, 816 cases(1632 eyes)aged 3-16 years old suspected ametropia were selected in the Affiliated Eye Hospital of Nanjing Medical University from December 2017 to December 2018. Uncorrected visual acuity(UCVA), mean AL and mean CR were tested. Autorefraction was performed after cycloplegia, which was measured as the spherical equivalent(SE).

RESULTS: Among 816 cases of children and adolescents aged 3-16, 773 were ametropia, accounting for 94.7%, with the highest proportion aged 7-14. The difference(one eye)in the mean AL, and AL/CR ratio of different refractive groups were statistically significant(P<0.05). In different refractive states, the mean AL and AL/CR ratio showed a low correlation with SE in emmetropes and low hyperopes but higher correlation in moderately hyperopic and myopic children. The mean AL, AL/CR ratio were higher correlation with SE increased with age. Sensitivity was 0.880, specificity was 0.916, and accuracy was 89.2%. The area under ROC curve was 0.954.

CONCLUSION: The proportion of myopia among children and adolescents gradually increases and shows a large increase after 7 years old. The AL and AL/CR ratio showed higher correlation in moderate hyperopes, myopes and older ages. The AL/CR ratio is highly accurate in the diagnosis of myopia in adolescents and children.