AIM: To investigate the epidemiological status of refractive state among school-age children of 5 to 12 years in Chengguan district of Lanzhou city, and to analyze the correlation with axial length(AL), horizontal and vertical corneal refractive power(K1, K2), anterior chamber depth(ACD)and corneal diameter(W-W).

METHODS: The value of AL, K1, K2, ACD and W-W of 813 school-age children(1626 eyes)aged 8.46±2.30 years old(5-12 years)were measured by IOL-Master, refractive error was measured by computer refractor. The eyes were divided into 5 groups according to different mean spherical equivalent(SE)diopter: high myopia, moderate myopia, low myopia, emmetropia and hyperopia. The correlation between diopter and different refractive parameters of different ages and different diopter groups were analyzed respectively, the SPSS 19.0 was used for the statistical analysis.

RESULTS: There were statistically significant difference(P<0.05)in uncorrected visual acuity and refractive state among the different groups of 5-12 years school-age children, the prevalence of myopia tended to increase with the age. There were statistically significant difference in AL and ACD among the different age groups(P<0.05), AL and ACD increased with the age. There were statistically significant difference in AL among three myopic groups(P<0.05). There were statistically significant difference in ACD between low myopia and moderate myopia, low myopia and high myopia(P<0.05). There were statistically significant difference in corneal refractive power and corneal diameter between low myopia and high myopia, moderate myopia and high myopia(P<0.05). SE was negatively correlated with AL(r=-0.764, P<0.01)and ACD(r=-0.498, P<0.01), but had week correlation with corneal refractive power or corneal diameter.

CONCLUSION: The increase of AL plays an important role in the changes of refractive among school-age children of 5-12 years, AL is the main morphological variable related to myopia. Meanwhile, refractive changes may be affected by corneal refractive power(K1, K2), ACD and corneal diameter(W-W). 7-8 years old can be regarded as the main phase from emmetropization to myopization of school-age children.