RESUMO
PURPOSE: To investigate potential risk factors for the progression of myopia. METHODS: Prospective study. Myopic progression was evaluated by cycloplegic autorefraction and axial length (AL) every 6 months in children 6 to 15 years old. Univariate analysis and multiple logistic regression were applied. RESULTS: Around 82 children with median age of 10.3±2.3 years. Myopia progressed by -0.816±0.6 D over 18 months. Increased myopic spherical equivalent refraction (SER) was correlated with increase in AL (P<0.001). Univariate analysis found SER to be significantly associated with: age, especially between 6 and 9.4 years old (P=0.001), parental myopia (P=0.028), and less time spent outdoors (P=0.009). There was a significantly greater increase in SER during months with the least daylight hours (P<0.001). CONCLUSION: Outdoor activities and daylight have a protective effect against increased AL and progression of myopia. Younger children with significant myopia should be monitored closely, especially those around 6 years old with myopic parents.