Analysis of lens power and its influencing factors in children aged 3-12 years

Objective

To understand the changing trend and influencing factors of lens power (LP) in children aged 3-12 in Jing’an District, Shanghai.

Methods

A cross-sectional study was conducted.One hundred and thirty-one eyes of 131 patients with refractive errors were included in the Optometry Clinic of Shanghai Eye Hospital from October 2019 to January 2020.The 1% atropine sulfate was employed to dilate pupils for children aged 6 years or younger, and 0.5% topiramate for children older than 6 years.The axial length, mean keratometry (Km), anterior chamber depth (ACD), lens thickness (LT) and central corneal thickness (CCT) were measured using an IOL Master.The spherical equivalent (SE) and best corrected visual acuity (BCVA) were measured after cycloplegia using autorefractor and phoropter, and the LP was calculated using the Bennett formula.The patients were divided into different age groups, including 3-4 years group (16 eyes), 5-6 years group (20 eyes), 7-8 years group (25 eyes), 9-10 years group (33 eyes) and 11-12 years group (37 eyes). There were 57 eyes in the male group and 74 eyes in the female group.The patients were also divided into different refractive groups, including mild myopia group (38 eyes), moderate myopia group (12 eyes), high myopia group (25 eyes), emmetropia group (11 eyes), mild hyperopia group (9 eyes), moderate hyperopia group (13 eyes), and high hyperopia group (23 eyes). The differences in ocular biological parameter measurements between different age groups, different gender groups and different refractive groups were compared and the correlations between age, eye parameters and LP were analyzed using Pearson correlation analysis.The contribution of multiple influencing factors to LP was analyzed by multiple linear regression models.The study protocol followed the Declaration of Helsinki and was approved by an Ethics Committee of Shanghai General Hospital, Shanghai Jiao Tong University Hospital (No.2020KY018). Written informed consent was obtained from each guardian of the subject.

Results

The average LP of children in the 3-4 years group, 5-6 years group, 7-8 years group, 9-10 years group and 11-12 years group were (27.35±1.88), (24.71±1.92), (22.92±1.87), (21.49±1.54) and (21.25±1.55) D, respectively.With the increase of age, the LP value was decreased gradually.There were significant differences between 3-4 years group and 5-6 years group, 5-6 years group and 7-8 years group, 7-8 years group and 9-10 years group (all at P<0.05). The average LP value of girls was obviously higher than that of boys (t=-3.38, P<0.01). The LP value of the high myopia group was significantly lower than that of the emmetropia group, and the LP values of the moderate myopia and the low myopia group were significantly lower than that of the hyperopia group, and the LP values of the low hyperopia group and the moderate hyperopia group were significantly higher than that of the emmetropia group (all at P<0.05). The LP value was negatively correlated with age, AL, ACD and CCT (r=-0.76, -0.79, -0.38, -0.18; all at P<0.05), and was positively correlated with SE and LT (r=0.62, P<0.05; r=0.68, P<0.01). There was no obvious correlation between Km and LP (r=0.07, P=0.45). The independent influencing factors of LP were analyzed through multiple linear regression equations, showing that LP=-0.430×AL+ 0.329×LT-0.267×age-0.108×gender-0.084×CCT (male=1, female=0). The standardized coefficients of each factor arranged in descending order were AL, LT, age, gender and CCT (all at P<0.05).

Conclusions

The LP of children aged 3-12 in Jing’an District of Shanghai decreases with age and increases with SE.LP values of girls are higher than those of boys.