Abstract
Abstract: :
Purpose: The Orinda Longitudinal Study of Myopia was designed primarily to predict the onset of myopia in school–aged children, but its 12 years of data lend themselves well to the prediction of rapid myopia progression in children who developed myopia during the course of the study. Methods: Two hundred nineteen myopic children were identified (myopia between –0.75 D and –4.00 D in both meridians with astigmatism </= 1.00 D at any examination, as measured by cycloplegic autorefraction). Children were excluded if their first myopic visit was during the last year of data collection (n=20) or if they were diagnosed with myopia and then had no subsequent follow–up visits (n=34). Rapid myopia progression was defined as an average myopia progression of at least –0.75 D. Logistic regression was used to model the association of rapid progression with various factors. Results: Factors investigated for association with rapid myopia progression were age at myopia onset, amount of myopia at the first myopic visit, refractive error status of the mother and father, number of myopic parents, and years of follow–up. Only the child’s age at the first myopic visit and the number of years of follow–up were significantly associated with rapid myopic progression after onset. The mean (+/– standard deviation) age of onset of the rapid progressors was 9.7 +/– 1.7 years compared to 11.4 +/– 1.2 years for the slow progressors (p<0.0001). The rapid progressors had 3.4 +/– 1.7 years of follow–up in the study compared to 1.7 +/– 0.9 years of follow–up (p<0.0001), but this is most likely related to the older age at which the myopia presented in the slow progressors and the continuation of the study only through the eighth grade. When controlling for the number of years of follow–up in a multivariate analysis, only age at myopia onset was significantly related to rapid myopia progression. For every year older at myopia onset, the risk of rapid progression decreased by 33% (p=0.0268). Conclusions: Age at initial myopia onset for juvenile myopia is related to rapid myopic progression between the ages of 6 and 14 years, with younger myopia onset being associated with more rapid progression.
Keywords: myopia • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: risk factor assessment