Yearly changes in cases of acute acquired comitant esotropia during a 12-year period

PURPOSE: The number of patients with acute acquired comitant esotropia (AACE) has been increasing in Japan. The purpose of this study was to investigate the changes in the number and characteristics of patients with AACE examined in our institution during a 12-year period. METHODS: We retrospectively reviewed the medical records of patients with AACE aged < 30 years who suddenly developed diplopia or esotropia and were examined in Hyogo College of Medicine Hospital from January 2008 to December 2021. We investigated the association of the yearly changes in the number of patients with the age category, refractive error category, AACE type, esotropia type, and use or nonuse of smartphones. RESULTS: The total number of patients with AACE was 171, and this number significantly increased each year (Pearson correlation coefficient, 0.9450; p < 0.0001). Significant increases were found among students in junior high school and beyond, patients with myopia, patients with Bielschowsky type AACE, and patients with basic esotropia (p < 0.0001 for all). We compared two age groups, elementary school students and below versus junior high school students and above, and found that the rate of increase was significantly higher in the junior high school students and above (estimate, 1.951; p < 0.0001), and the non-myopia group and myopia group and found that the rate of increase was significantly higher in the myopia group (estimate, 1.891; p < 0.0001). Excessive use of smartphones was confirmed in 82 of 133 patients, and the rate of the increase in the number of patients with AACE was significantly greater among patients with than without excessive use of smartphones (estimate, 1.098; p = 0.0009). CONCLUSION: This study confirmed a significant increase in the number of patients with AACE in recent years. The excessive use of smartphones may be associated with the increase in AACE.