Prevalence of anisometropia and associated factors in Shandong school-aged children

Abstract

ObjectiveTo investigate anisometropia's prevalence and associated factors in school-aged children.MethodsA cross-sectional school-based study was conducted in Shandong Province, China, including children aged 4 to 17 from 9 schools. Anisometropia was defined as the differences between the two eyes in spherical equivalent (SE) or cylinder degree of 1.00 diopter (D) or more [SE or cylindrical (CYL) difference ≥ 1.00 D] after cycloplegic autorefraction. The Generalized Linear Model (GLM) was used to analyze the effects of ocular parameters [the differences between eyes in axial length (AL), habitual visual acuity (HVA), and corneal astigmatism (CA)] and lifestyle parameters (time spent indoor near work and outdoor activities) on anisometropia.ResultsTotal 4,198 (93.4%) of the 4,494 children were included in the statistical analysis. The mean difference in inter-eye SE was 0.42 ± 0.61 D. The prevalence of anisometropia was 13.2% (95%CI: 12.1 to 14.2%) (SE anisometropia's prevalence:10.3%; CYL anisometropia's prevalence: 4.1%), increased with older age (OR = 1.10, P = 0.002), the worse myopic eye (myopia vs. premyopia, OR = 1.87, P = 0.002), the worse hyperopic eye (hyperopia vs. premyopia, OR = 1.77, P = 0.013), larger difference in inter-eye AL (0.1–0.3 vs. ≤ 0.1, OR = 1.67, P = 0.008; >0.3 vs. ≤ 0.1, OR = 28.61, P < 0.001), HVA (>0.2 vs. ≤ 0.2, OR = 3.01, P < 0.001), CA (OR = 6.24, P < 0.001), the worse stereoacuity (>100 vs. ≤ 100, OR = 1.59, P = 0.001), longer indoor near work time per day on weekends (4–8 vs. <4, OR = 1.41, P = 0.038; ≥8 vs. <4, OR = 1.40, P = 0.131), and shorter outdoor activity time per day on weekdays (≥1 vs. <1, OR = 0.75, P = 0.046) in multivariable analysis. In the SE anisometropia group, the difference in inter-eye AL (>0.3 vs. ≤ 0.1, β: 0.556, 95%CI: 0.050 to 1.063), HVA (>0.2 vs. ≤ 0.2, β: 0.511, 95%CI: 0.312 to 0.710), and CA (β: 0.488, 95%CI: 0.289 to 0.688), stereoacuity (>100 vs. ≤ 100, β: 0.299, 95%CI: 0.110 to 0.488) had a positive impact on the difference in inter-eye SE.ConclusionsOcular parameters and lifestyle parameters are associated with the occurrence of anisometropia in children aged 4 to 17 years, including the difference in inter-eye AL, HVA, CA, stereoacuity, indoor near work time, and outdoor activity time. Preventing myopia and early treating anisometropic amblyopia may be effective ways to reduce the prevalence of anisometropia.

Prevalence of anisometropia and influencing factors among school-age children in Nantong, China: a cross-sectional study

“…Compared with previous studies, such a high prevalence of anisometropia is rare. In fact, compared to previous studies ( 5 , 35 , 37 ), there is not much difference in the prevalence of anisometropia between 7 to 9 years of age. The sharp increase in the prevalence of anisometropia is worth noting.…”

“…In 2016, a school-based study conducted in Shandong, China ( 5 ) found that 7.0% of 6,025 school children aged 4–17 years had refractive anisometropia. In 2022, in another epidemiological survey of students 4–17 years of age in Shandong, China ( 37 ), the prevalence rose to 13.2%. In the current study, we found that the prevalence of anisometropia was relatively low in early school age children (7–9 years of age) (7.8–9.0%), but it increased to 16.0% at 10 years of age, and even to 39.0% at 19 years of age.…”

Is refractive error a factor affecting scoliosis?

“…The prevalence of hyperopia tended to decrease with age (Ptrend<0.001). These results were similar to previous studies [ 44 – 46 ]. In particular, the prevalence of myopia increased from 30.3% in the age group of 7−8 years to 94.3% in the age group of 19−20 years, indicating the severe need for myopia prevention and control in Chinese school-age children.…”

Prevalence and risk factors for astigmatism in 7 to 19-year-old students in Xinjiang, China: a cross-sectional study

“…Students with hyperopia ( > + 0.5 D) were 3.437 times more likely to develop astigmatism than those with emmetropia (-0.50 D to ≤ + 0.50 D), while individuals with low myopia (-3.00 D to <-0.50 D), medium myopia (-6.00 D to ≤ -3.00 D) and high myopia (SE ≤ -6.00 D) were 1.296 times, 2.695 times and 6.391 times more likely to develop astigmatism, respectively, compared with emmetropia cases. This corroborated previous studies conducted in Yiwu, China [ 32 ] and Anyang, China [ 14 ], as well as a study conducted by the MEPEDS [ 25 ] and the US VIP multicenter study [ 6 ]. We can conclude that children with refractive errors are more likely to develop astigmatism than those without refractive errors.…”