Abstract
Abstract: :
Purpose: To examine the risk factors for variations in ocular biometry parameters in Singapore Chinese children, a population with a known high prevalence rate of myopia at an early age. Methods:Axial length, vitreous chamber depth, lens thickness and anterior chamber depth were determined by Nidek US-800 A-scan biometry measures of Chinese children aged 7 to 9 years (n=1453). Cycloplegic autorefraction and corneal radius of curvature measures were made using the Canon RK-5 autokeratorefractometer. We asked about number of books read per week, parental myopia and other risk factors. Results: In multivariate linear regression models, axial lengths were longer and vitreous chambers deeper in children who were older, male, who read more than 2 books per week, were taller and who had at least 1 parent who was myopic, after controlling for several factors. In these models, children who read more than 2 books per week had axial lengths that were 0.17 mm longer and vitreous chambers 0.15 mm deeper compared with children who read 2 or fewer books per week. Anterior chambers were deeper in males and taller children, while corneal curvature was steeper in females, older and shorter children. Conclusion: Both greater axial length and vitreous cavity depth were associated with older age, being male, reading more than 2 books per week, increased height and parental myopia. Anterior chamber depth, corneal curvature or lens thickness, however, were not associated with reading or parental myopia. These findings confirm that conventional risk factors for myopia are associated with the vitreous cavity, but suggest that anterior segment parameters such as corneal curvature and lens thickness may be subject to different postnatal growth control mechanisms.
Keywords: 481 myopia • 355 clinical (human) or epidemiologic studies: risk factor assessment • 543 refractive error development