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L. Hyman, J. Gwiazda, M. Hussein, T.T. Norton, Y. Wang, W. Marsh–Tootle, D. Everett, COMET Group; Relationship of Baseline Age, Gender and Ethnicity with 3–Year Myopia Progression and Axial Elongation in the Correction of Myopia Evaluation Trial (COMET) . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2734.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To identify the baseline factors independently related to 3–year myopia progression and axial elongation in COMET. Methods:COMET enrolled 469 children who were randomly assigned to progressive addition lenses (PALs) with a +2.0 addition or single vision lenses (SVLs) and followed for 3 yrs. Eligible children were 6–11 yrs, ethnically diverse, with spherical equivalent myopia of –1.25 to –4.50D in both eyes. The primary and secondary outcomes, myopia progression by cycloplegic autorefraction and axial elongation, measured by A–scan ultrasonography, were measured annually. Analyses were child–based and used the average of the eyes. Multivariate analyses used multiple linear regression to adjust for covariates and control for the treatment effect of PALs vs SVLs. Results: Younger age, female gender and African–American (A–A) vs white ethnicity were independently associated with more 3–year progression and did not interact with treatment. Progression decreased with each increasing year of age from 6–7 through 11 yrs (p < 0.0001). Thus, the youngest children had the highest 3–year progression (–2.31D), which was over twice as high as the oldest children (–0.96D). In addition, although younger children (6–7 and 8 yrs) had less baseline myopia, their 3–yr myopia was higher than the myopia of the children 10 and 11 years old (–4.58D and –3.80D vs –3.53D and –3.38D). A–A children had the least progression among all ethnic groups and on average they progressed less than white children by an adjusted difference of 0.29D (p=0.0003). Progression was also higher in females than males by 0.17D (p=0.008). These factors were also significantly associated with progression at 1 and 2 yrs. Findings for axial elongation were similar to those for progression. One diopter of myopia progression equaled 0.5mm increase in axial length. Conclusions:COMET children with the highest risk of progression were younger at baseline, female and of white (vs A–A) ethnicity. The higher progression among the youngest children (6–7 yrs) raises the possibility that their myopia may be a different type than found in older children. The 2:1 ratio of myopia progression to increase in axial length is different from the 3:1 ratio, referenced more frequently.
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