| Purpose. A concurrent cohort study was conducted to examine both the environmental and familial risks for the progression of myopia in Singapore children aged 6 to 12 years Methods. 311 Singapore children aged 6 to 12 years who were volunteers from different parts of the island were enrolled in a concurrent cohort study of the risk factors for the progression of myopia. Both a questionnaire and four 24 hour diaries were developed to quantify closeup work activity, family history of myopia, socioeconomic status, outdoor activities, and other risk factors, as wen as potential confounders. The change in refractive error was documented as changes in cycloplegic autorefraction, subjective refraction, axial length, anterior chamber depth, vitreous chamber depth, lens thickness and corneal curvature changes. Both univariate analysis and multivariate analysis (Generalized Estimating Equations) were conducted to estimate the effect of each risk factor.; Results. The reliability of closeup work activity as denoted by the intraclass correlation coefficient was 0.87 and when closeup work activity from a questionnaire was compared to four 24 hour diaries the correlation was 0.50. 311 children were actively followed up for an average of 11 months. The average increase per year in cycloplegic subjective refraction in the right and left eye were −0.62 and −0.57 Diopters per year respectively. The rate of progression of myopia was higher in younger children, females, and children with a higher degree of astigmatism at baseline. Children with a parental history of myopia, first degree relatives with myopia and higher family risk scores had a higher rate of progression of myopia. There was no significant correlation between the different types of closeup work activity and the progression of myopia.; Conclusions. Both a questionnaire and four 24 hour diaries were developed to quantify closeup work activity and other risk factors accurately. Family risk scores were associated with changes in cycloplegic subjective refraction. Overall, our studies support the hypothesis that hereditary factors are important not only in determining pre-myopic eye size or the onset of myopia, but also contribute in an important way in determining the progression rates of myopia in children. |
