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Rafael Iribarren, Ian G. Morgan, Yiong H. Chan, Xiaoyu Lin, Seang M. Saw; Changes in Lens Power in Singapore Chinese Children During Refractive Development. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4450.
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© ARVO (1962-2015); The Authors (2016-present)
To examine changes in lens power during refractive development in Singapore Chinese children.
Children aged 6-9 years from three Singapore schools were invited to participate in the SCORM (Singapore Cohort study Of the Risk factors for Myopia) study. Yearly eye examinations involving cycloplegic refraction and biometry measures were performed in the schools over a five-year period. Children were classified into one of five refractive error groups: persistent hyperopia, emmetropizing hyperopia, persistent emmetropia, newly developed myopia, or persistent myopia. The power of the crystalline lens was calculated using Bennett’s formula, based on cycloplegic refractions and biometry. The rate of change per year across the refractive groups was studied age-gender adjusted using General Linear Model. Mixed model analysis was performed to compare the groups taking into account all visits.
There were 1747 children with at least three visits available for lens power calculations and 887 (50,8%) were males. At baseline, persistent myopes and newly developed myopes had significantly lower lens power than emmetropes (24.50 D and 25.07 D vs 25.42 D respectively, p<0.001). At follow up, the newly developed myopes and the persistent myopes showed the largest increase in axial length. The changes in lens power and lens thickness at follow-up were similar in all refractive groups, except for the newly developed myopes, who showed significantly greater decreases in lens power (0.36 D/ year vs. 0.29 D/years, p<0.001) and lens thickness (0.015 mm/year vs. 0.0003 mm/year, p<0.001) than the persistent emmetropic group.
Lens power decreases similarly with age in all refractive groups during school years, except that newly developed myopes showed a greater decrease in lens power. The major differences between refractive groups were in axial elongation, but the lower lens power in myopic children at baseline and a greater loss of lens power in newly developed myopes, suggests some regulation of lens power relative to axial elongation.
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