English abstract
Purpose: The purpose of this study is to evaluate the changing trends in myopia over an 11-year period among Omani schoolchildren. Methods: This retrospective study took place from January to June 2012. National vision screening data from 1999 to 2010 were reviewed for information concerning all children in the fourth, seventh, and tenth grades of Omani public schools. Changes in the rate of myopia by gender, grade, severity, and governorate were evaluated. Results: Among 397,430 fourth-grade students, the prevalence of myopia was 2.44%. In contrast, the prevalence of myopia among 533,003 and 461,307 children in the seventh and tenth grades, respectively, was 4.41% and 7.36%. Compared to 2002, the rate of myopia in 2010 was 1.43% higher for fourth-grade students (P < 0.001). Myopia prevalence rates among seventh-grade students increased by (5.36-3.36 = 2.0) 1.11% between 1999 and 2010, but declined by 7.62% versus 6.34% = 1.28% between 1999 and 2010 for seventh- and tenth-grade students, respectively (P < 0.010 and <0.001, respectively). The risk of myopia in the fourth, seventh, and tenth grades was significantly higher for females in 2002 and 2010 (P < 0.001). The regional variation of myopia was also significant (χ2 = 495; P < 0.001). Among seventh- and tenth-grade students in 2010, the ratio of children with mild-to-moderate/severe myopia was 1.5:1 and 1:2.7, respectively. Conclusion: Although the rate of myopia increased with grade, the trend over time suggests that myopia affected more children at a younger age. Female students had a significantly higher risk of myopia.
