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Significant Axial Elongation with Minimal Change in Refraction in 3- to 6-Year-Old Chinese Preschoolers: The Shenzhen Kindergarten Eye Study.
- Source :
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Ophthalmology [Ophthalmology] 2017 Dec; Vol. 124 (12), pp. 1826-1838. Date of Electronic Publication: 2017 Jul 13. - Publication Year :
- 2017
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Abstract
- Purpose: To document the distribution of ocular biometry and to evaluate its associations with refraction in a group of Chinese preschoolers.<br />Design: Population-based cross-sectional study.<br />Participants: A total of 1133 preschoolers 3 to 6 years of age from 8 representative kindergartens.<br />Methods: Biometric measurements including axial length (AL), anterior chamber depth (ACD), and corneal radius of curvature (CR) were obtained from partial-coherence laser interferometry (IOL Master; Carl Zeiss Meditec, Oberkochen, Germany) before cycloplegia. Lens power (LP) and AL-to-CR ratio were calculated. Cycloplegic refraction (3 drops of 1% cyclopentolate) was measured using an autorefractor (KR8800; Topcon Corp., Tokyo, Japan), and spherical equivalent refraction (SER) was calculated. Biometric and refractive parameters were assessed as a function of age and gender. Multiple regression analysis was performed to explore the associations between refraction and ocular biometry.<br />Main Outcome Measures: Ocular biometric distributions and their relationships to refraction.<br />Results: Among the 1127 children (99.5%) with successful cycloplegic refraction, mean SER was 1.37±0.63 diopters (D). Prevalence of myopia increased from 0% at 3 years of age to 3.7% (95% confidence interval, 1.0%-6.5%) at 6 years of age. Biometric parameters followed Gaussian distributions with means of 22.39±0.68 mm for AL, 7.79±0.25 mm for CR, and 24.61±1.42 D for calculated LP; and non-Gaussian distributions with means of 3.34±0.24 mm for ACD and 2.88±0.06 for AL-to-CR ratio. Axial length, ACD, and AL-to-CR ratio increased from 3 to 6 years of age, CR remained stable, whereas LP declined. Overall, SER declined slightly. For the SER variance, AL explained 18.6% and AL-to-CR ratio explained 39.8%, whereas AL, CR, and LP accounted for 80.0% after adjusting for age and gender.<br />Conclusions: Young Chinese children are predominantly mildly hyperopic, with a low prevalence of myopia by the age of 6 years. An increase of 1 mm in AL was associated with only 0.45 D of myopic change. Decreases in LP reduce the myopic shifts that normally would be associated with increases in AL, and thus play a key role in refractive development in this age group.<br /> (Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)
- Subjects :
- Anterior Chamber
Asian People ethnology
Biometry
Child
Child, Preschool
China epidemiology
Cross-Sectional Studies
Cyclopentolate administration & dosage
Female
Humans
Hyperopia ethnology
Interferometry
Light
Male
Mydriatics administration & dosage
Myopia ethnology
Pupil drug effects
Vision Tests
Axial Length, Eye physiopathology
Cornea physiopathology
Hyperopia physiopathology
Myopia physiopathology
Refraction, Ocular physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1549-4713
- Volume :
- 124
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Ophthalmology
- Publication Type :
- Academic Journal
- Accession number :
- 28711218
- Full Text :
- https://doi.org/10.1016/j.ophtha.2017.05.030