RESUMEN
PURPOSE: To detect the long-term changes in the ratio of exotropia to esotropia in Japanese patients. METHODS: The published annual reports of 3 children's hospitals in Japan were reviewed with respect to the number of new patients diagnosed with either exotropia or esotropia. The yearly ratios of exotropia to esotropia were calculated from the past 30-year data. The ratios were analyzed by using regression analysis to determine the long-term variability. RESULTS: The ratio of exotropia to esotropia has increased in a parallel manner from less than 1.0 to nearly 2.0 in each of the 3 hospitals. CONCLUSIONS: This gradual increase in the ratio might be attributed to the increasing number of exotropic children who consult a doctor according to the level of development in health care, or might be the result of declining occurrence of accommodative esotropia along with the decreasing number of hyperopic children. Further studies are required to determine the reason for this tendency.