Significant Axial Elongation with Minimal Change in Refraction in 3- to 6-Year-Old Chinese Preschoolers: The Shenzhen Kindergarten Eye Study.
Ophthalmology
; 124(12): 1826-1838, 2017 12.
Article
in En
| MEDLINE
| ID: mdl-28711218
ABSTRACT
PURPOSE:
To document the distribution of ocular biometry and to evaluate its associations with refraction in a group of Chinese preschoolers.DESIGN:
Population-based cross-sectional study.PARTICIPANTS:
A total of 1133 preschoolers 3 to 6 years of age from 8 representative kindergartens.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. MAIN OUTCOMEMEASURES:
Ocular biometric distributions and their relationships to refraction.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.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.
Full text:
1
Database:
MEDLINE
Main subject:
Refraction, Ocular
/
Cornea
/
Axial Length, Eye
/
Hyperopia
/
Myopia
Type of study:
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Limits:
Child
/
Child, preschool
/
Female
/
Humans
/
Male
Country/Region as subject:
Asia
Language:
En
Year:
2017
Type:
Article