Analysis of factors related to the development of ocular biometric parameters in Chinese children aged 6-10 years: a cross-sectional study

Abstract

Objectives: Emmetropia depends on the precise coordination of ocular biometry, including axial length (AL), corneal curvature, lens thickness and anterior chamber depth (ACD). Disruption of this coordination leads to refractive errors such as myopia. This article aimed to determine the factors affecting ocular biometry and myopia development in young children.

Design: A cross-sectional study.

Setting: This study was conducted in a primary school in the Yanqing district of Beijing, China.

Participants: 792 students in grades 1-3 without hyperopia (>+2.00 D), strabismus, or amblyopia were selected.

Exclusions: students had conditions affecting best corrected visual acuity and whose guardians refused to provide informed consent. Ocular biometric measurements and non-cycloplegia autorefraction were performed. The questionnaire addressed factors such as perinatal factors and environmental factors.

Interventions: None.

Primary and secondary outcomes: Ocular biometry and myopia.

Results: According to the multivariate logistic regression analysis, electronic screen use >2 hours/day (OR=2.175, p=0.013), paternal myopia (OR=1.761, p=0.002), maternal myopia (OR=1.718, p=0.005), taller height (OR=1.071, p<0.001), maternal education (OR=0.631, p=0.012) and maternal gestational hypertension (OR=0.330, p=0.042) were associated with myopia. AL was affected by female sex (OR=0.295, p<0.001), older age (OR=1.272, p=0.002) and taller height (OR=1.045, p<0.001). Female sex (OR=0.509, p<0.001), taller height (OR=1.046, p<0.001), use of electronic screens >2 hours each day (OR=3.596, p<0.001) and time spent outdoors >2 hours each day (OR=0.431, p=0.001) influenced ACD incidence. Central corneal thickness (CCT) was associated with older age (OR=1.113, p=0.008), paternal education (OR=1.474, p=0.007), premature birth (OR=0.494, p=0.031), history of blue light therapy in infancy (OR=0.636, p=0.041) and history of incubator therapy in infancy (OR=0.263, p=0.009). Only sex influenced corneal curvature.

Conclusions: The factors associated with myopia were partly related to ACD and AL, and perinatal factors were associated with myopia and CCT.

Trial registration number: ChiCTR2200065398.

Keywords: Adolescent; China; Factor Analysis, Statistical; Paediatric ophthalmology.

Figure 1

Age and sex distributions of myopia incidence and biological parameters. K is the average K of corneal curvature. ACD, anterior chamber depth; AL, axial length; CCT, central corneal thickness.

Figure 2

Results of multivariate logistic regression analysis. (A) Independent factors related to myopia. (B) Independent factors affect axial length. (C) Independent factors influencing anterior chamber depth. (D) Independent factors associated with central corneal thickness: **Age, paternal education, preterm birth and history of blue light therapy in infancy were incorporated into the model, and all four factors were correlated with central corneal thickness. *Age, paternal education, history of incubator therapy in infancy and history of blue light therapy in infancy were incorporated into the model, excluding the history of blue light treatment. The remaining three factors were associated with CCT. Electronic screen use=electronic screen use >2 hours each day; outdoor time=outdoor time >2 hours each day. ACD, anterior chamber depth; AL, axial length; CCT, central corneal thickness.