A 6-year longitudinal optometric study of the refractive trend in school-aged children.

This report describes the analysis of the refractive data of optometric patients examined annually between the ages of 7 and 13 years. The results indicate a declining hypermetropic/increasing myopic refractive trend in 73% of the 41 individuals who attended over the entire 6 years of the investigation: overall, there was a mean rate of change of -0.09 D pa. Annual myopic incidence values of between 3.5 and 12% were found, resulting in a rise in myopic prevalence in this clinical population from 5 to nearly 40% over the course of the study. For the refractive classification adopted here, the juvenile myopic patients emerged from a pool of previously emmetropic subjects: the proportion of hypermetropic patients remained approximately stable over the 6 years reviewed. The age-related annual rates of myopic prevalence are approximately a factor of two greater in this self-selected clinical population compared to those reported for investigations in a general population. The inference is that children who were classed as emmetropic at age 7 should continue to be reviewed annually by the optometrist who should be alert to the possibility of clinically significant degrees of myopia emerging later.