Abstract
PurposeTo examine the prevalence of refractive errors in children aged 3–6 years in China.MethodsChildren were recruited for a trial of a home-based amblyopia screening kit in Guangzhou preschools, during which cycloplegic refractions were measured in both eyes of 2480 children. Cycloplegic refraction (from 3 to 4 drops of 1% cyclopentolate to ensure abolition of the light reflex) was measured by both autorefraction and retinoscopy. Refractive errors were defined as followed: myopia (at least −0.50 D in the worse eye), hyperopia (at least +2.00 D in the worse eye) and astigmatism (at least 1.50 D in the worse eye). Different definitions, as specified in the text, were also used to facilitate comparison with other studies.ResultsThe mean spherical equivalent refractive error was at least +1.22 D for all ages and both genders. The prevalence of myopia for any definition at any age was at most 2.5%, and lower in most cases. In contrast, the prevalence of hyperopia was generally over 20%, and declined slightly with age. The prevalence of astigmatism was between 6% and 11%. There was very little change in refractive error with age over this age range.ConclusionsPrevious reports of less hyperopic mean spherical equivalent refractive error, and more myopia and less hyperopia in children of this age may be due to problems with achieving adequate cycloplegia in children with dark irises. Using up to 4 drops of 1% cyclopentolate may be necessary to accurately measure refractive error in paediatric studies of such children. Our results suggest that children from all ethnic groups may follow a similar pattern of early refractive development, with little myopia and a hyperopic mean spherical equivalent over +1.00 D up to the age of 5–6 yearsin most conditions.
Highlights
The conventional picture of neonatal refractive development is derived from small studies on children of predominantly European ancestry in Europe [1,2,3] and the United States [4,5,6]
The prevalence of myopia is very low, of the order of 1–2% at most. These changes in distribution appear to result from a process in which the axial length (AL) of the eye is matched to the corneal radius of curvature (CR), since by the age of 5–6, the ratio of the AL to the CR, in addition to spherical equivalent refractive error (SE), shows increased kurtosis7
A total of 3,300 children in the randomly selected 10 kindergartens were invited to participate in the study, representing approximately 1% of the total population of 3–6 year-old children and 0.7% of the kindergartens in Guangzhou
Summary
The conventional picture of neonatal refractive development is derived from small studies on children of predominantly European ancestry in Europe [1,2,3] and the United States [4,5,6] It suggests that children are born with a normal distribution of refractive error, with a significantly hyperopic mean refractive error. Over the first year or two after birth, this distribution is sharpened by a reduction in the relatively rare myopic refractive errors, and a reduction in hyperopic errors, leading to a narrower distribution of spherical equivalent refractive error (SE) characterised by significant kurtosis, but with the peak in the hyperopic, rather than emmetropic, range At this age, the prevalence of myopia is very low, of the order of 1–2% at most.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
