Abstract
Purpose :
To investigate the effects of binocular visual function in different refractive states on myopic refraction and axial growth in 6- to 10-year-old children.
Methods :
Prospective cohort study. A total of 4,764 students in grades 1-4 (6 to 10 years old) were examined in November 2021 and completed a 1-year follow-up examination. They were divided into the myopia group (SE < -0.75D), emmetropia group (-0.75D ≤ SE ≤ 0.50D), and hyperopia group (SE > 0.50D) according to the spherical equivalent (SE). Ophthalmologic examination, including objective optometry, axial length (AL), measurement of phoria in the distance (3m) and near (40cm) using the Maddox rod method, the amplitude of accommodation (AMP), and near stereopsis.
Results :
A total of 4370 (91.73%) were used for the analysis. The 1-year △AL for the myopic (n=1520), emmetropia (n=2331), and hyperopia (n=539) groups were 0.34±0.20 mm, 0.30±0.20 mm, and 0.23±0.17 mm, respectively. Stereopsis ≤60″ was recorded as the normal group, and the difference in △ SE of between the normal and abnormal stereopsis groups in the emmetropia group was statistically significant (t=1.983, P=0.047). Children with distal phoria < -6PD were defined as the exophoria group, those with distal phoria > 0PD were defined as the esophoria group, and others were defined as the normal group. After adjusting for age, baseline SE, and AL, △AL was negatively correlated with baseline far phoria and near phoria in the myopic group (r=-0.078, P=0.003; r=-0.068, P=0.011), positively correlated with NPC (r=0.056, P=0.035), and negatively correlated with changes in distant phoria (r=-0.111, P < 0.001). △AL was negatively correlated with near phoria (r=-0.058, P=0.006) and far phoria (r=-0.069, P=0.001) in the emmetropia group. In the hyperopia group, △AL was negatively correlated with near phoria (r=-0.088, P=0.050) and changes in far phoria (r=-0.111, P=0.013).
Conclusions :
Axial elongation in children with different refractive states is related to the outward movement trend of the far eye position. The axial length of myopic exophoria grows faster than that of normal or esophoria. For children with emmetropia, poor stereopsis may be a risk factor for refractive growth.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.