AIM: To evaluate the value of the ratio of axial length to corneal radius of curvature(AL/CR)in the diagnosis of myopia in children and adolescents.METHODS: The refraction and ocular biometric parameters of 2 182 cases of children and adolescents(4 364 eyes)who initially visited the optometry clinic of the Second People's Hospital of Beihai from January 2022 to December 2023 were collected and analyzed.RESULTS: The receiver operating characteristic curve(ROC curve)showed that AL/CR had a higher area under the curve(AUC=0.925, 95%CI: 0.917-0.933)in diagnosing myopia. When AL/CR was 3.053, the Youden index was the largest. As the threshold of AL/CR decreased, the sensitivity of myopia diagnosis increased, while the specificity decreased. Compared with screening myopia, the sensitivity of AL/CR=3.053 in diagnosing myopia was low, but the specificity was high, especially in the cases of hyperopia and pre-myopia.CONCLUSION: The accuracy of AL/CR in diagnosing myopia is superior to that of axial length and average corneal curvature, with higher specificity. As the threshold of AL/CR decreases, the sensitivity of diagnosing myopia increases, but the specificity decreases. In cases of hyperopia and pre-myopia, the specificity of AL/CR in diagnosing myopia is higher than that of screening myopia.