There were 1,652 boys and 1,518 girls aged 3-6 years included in the analysis and 551 children were excluded owing to incompletion of the study (n=548), true entropion (n=1) and external hordeolum (n=2). There was no statistical difference in age between boys (4.10 ± 0.75 yrs) and girls (4.08 ± 0.76 yrs) of all included subjects (Independent-samples t-test; p = 0.46). Overall, 26.2% (830 out of 3,170) children had lower eyelid epiblepharon, which could be further grouped into mild (54.3%), moderate (29.6%) and severe (16.1%) classes based on the severity of skin-fold height and cilia-corneal touch (Table 1).
Table 2 summarizes the general profile of all included children. Statistically significant differences were detected in the gender, age, SE, CYL, astigmatism type (Chi-square tests; p = < 0.001, < 0.001, < 0.001, < 0.001, and 0.022, respectively) and BMI (Independent-samples t-test; p = 0.018) between epiblepharon and non-epiblepharon children (Table 2); no significant differences were identified in either height or weight between these two groups (Independent-samples t-test; p = 0.303 and 0.413, respectively) (Table 2).
Differentiated by ages, the prevalence of lower eyelid epiblepharon was 30.6%, 28.0%, 15.0%, and 14.3% for 3, 4, 5, and 6 year-old children, respectively (Table 2). Figure 2 further illustrated the age-specific prevalence of lower eyelid epiblepharon by its severity according to criteria based on skin-fold height only (Figure 2A), cilia-cornea touching area only (Figure 2B), and criteria established by both (Figure 2C). At different degrees of severity, the younger roughly demonstrated higher prevalence of epiblepharon than the older (Figure 2).
Lower Eyelid Epiblepharon Associated Risk Factors
As statistically significant differences in age, gender and BMI were detected between children with and without lower eyelid epiblepharon (Table 2), multivariable logistic regression analysis was performed to further evaluate the association between lower eyelid epiblepharon and these three variables to screen for the risk factors of this eyelid disorder (Table 3). After adjustment of potential confounders including age, gender and BMI, epiblepharon was significantly associated with gender and age. Specifically, boys were more likely to have epiblepharon than girls (OR = 1.41 with p < 0.001); younger children at 3-, 4-, and 5- year-old demonstrated higher possibilities of having epiblepharon with reference to the older (6-year-old), although no statistically significant difference was identified between 5- and 6-year-old children (OR = 3.68, 2.95, and 1.24 with p = < 0.001, < 0.001 and 0.402, respectively). Whereas, adjusted for gender and age, the association between BMI and epiblepharon was no longer statistically significant (p = 0.062).
Relation between lower eyelid epiblepharon and refractive errors
Astigmatism (CYL ≥ 1.5 D) was identified in 307 children (9.68%) and 157 of them had epiblepharon. Statistically significantly higher prevalence of astigmatism was detected in epiblepharon children than non-epiblepharon children (18.9% vs 6.4%) (Chi-square test; p < 0.001). Meanwhile, in both populations, the astigmatism type was largely WTR (80.9% for epiblepharon vs 74.7% for non-epiblepharon).
Myopia (SE ≤ -0.5 D) was recognized in 39 children (1.23%) with 22 of them having epiblepharon; hyperopia (SE ≥ 2 D) was found in 277 children (8.74%) with 95 of them being epiblepharon-positive. Higher prevalence of myopia (2.7% vs 0.7%) and hyperopia (11.4% vs 7.8%) were identified in epiblepharon children than non-epiblepharon children (Chi-square tests; p = < 0.01 and 0.002, respectively). To further evaluate the association between lower eyelid epiblepharon and refractive errors, multivariable logistic regression analysis was performed where age and gender were adjusted for (Table 4). Overall, epiblepharon children presented an increased risk of astigmatism relative to nonepiblepharon children (OR = 3.41; 95%CI, (2.68, 4.33)), and epiblepharon preschoolers had higher risk of having myopia (OR = 3.55; 95%CI, (1.86, 6.76)) and hyperopia (OR = 1.53 95%CI, (1.18, 1.99)) than non-epiblepharon children.