The biometric parameters of aniso-astigmatism and its risk factor in Chinese preschool children: the Nanjing Eye Study

Abstract

BackgroundsTo determine the biometric components of aniso-astigmatism and associated maternal risk factors in Chinese preschool children.MethodsIn the population-based, cohort Nanjing Eye Study, children were measured for noncycloplegic refractive error using an autorefractor and for biometric parameters using an optical low-coherent reflectometry. The difference of total astigmatism (TA) between both eyes was calculated using cylinder power (non-vectorial aniso-TA was defined as ≥ 1.00 Dioptre Cylinder [DC] between both eyes) and by vector analysis (vectorial aniso-TA was defined as a difference of ≥ 0.5 in J0 or J45 between both eyes which is equivalent to 1.00 DC). The prevalence of aniso-TA was presented. Interocular biometric parameters were compared between with vs. without aniso-astigmatism group. In addition, risk factors were determined using multivariate logistic regression model.ResultsOf 1131 children (66.90 ± 3.38 months, 53.31% male), the prevalence of non-vectorial aniso-TA was 1.95% (95% Confidence Interval (CI) = 1.14%-2.75%), while the prevalence of vectorial aniso-TA was twice as common as non-vectorial aniso-TA, neither varying with sex or age. With aniso-TA eyes were more asymmetric in axial length and corneal curvature radius than without aniso-TA eyes. In multivariate logistic regression model, 5-min apgar score less than 7 was significantly associated with higher risk of aniso-TA (vectorial aniso-TA: Odds Ratio (OR) = 6.42, 95%CI = 2.63–15.69, P < 0.001; non-vectorial aniso-TA: OR = 4.92, 95%CI = 1.41–17.68, P = 0.01). Being twin or triple was significantly associated with higher risk of vectorial aniso-CA (OR = 2.43, 95%CI = 1.05–5.60, P = 0.38). Pre-term delivery (OR = 2.60, 95%CI = 1.09–6.15, P = 0.03) and post-term delivery (OR = 3.61, 95%CI = 1.31–9.96, P = 0.01) were significantly associated with higher risk of vectorial aniso-CA.ConclusionsBoth corneal curvature radius and axial length asymmetry were correlated with aniso-TA. Children with 5-min apgar score < 7 were more likely to have aniso-TA, while twin or triple, pre-term or post-term delivery were risk factors for vectorial aniso-CA.