An accuracy study of the AL/CR ratio in assessing different degrees of hyperopia in children aged 3-6 years

Abstract

Purpose: To assess the association between different hyperopia levels and the axial length/radius of corneal curvature (AL/CR) ratio and check if hyperopia levels can be assessed by the AL/CR ratio, and provide a basis for hyperopia screening in preschool children. Methods: The spherical equivalent refraction (SER), axial length (AL), and corneal refractive power (K) were obtained through cycloplegia optometry, IOL-Master on children aged 3-6 years, and the AL/CR ratio was calculated. They were categorized into four groups based on the SER: physiological, mild, moderate, and high hyperopia. The data were analyzed utilizing SPSS 23.0. Results: The AL/CR ratio in the high hyperopia group (2.60 ± 0.08) compared to the moderate hyperopia group (2.72 ± 0.08), and the mild hyperopia group (2.83 ± 0.07) was statistically significant (F = 508.125, P = 0.000). The association between SER and AL/CR ratio was higher than the AL and the CR (R = -0.873, R = -0.738, R = 0.374, P = 0.000), and it became greater with the increasing degree of hyperopia (R = -0.284, R = -0.478, R = -0.401, R = -0.637, P = 0.000), with a mild negative correlation in the physiological hyperopia group and a moderate negative correlation in the mild, moderate and high hyperopia groups. The linear regression equation showed that for every 0.1 unit decrease in AL/CR ratio, the SER changed by approximately 1.68 D in the hyperopic direction (R2 = 0.762, P = 0.000). In children aged 3-6 years, when the AL/CR ratio was ≤ 2.80, this suggested SER of approximately ≥ +4.0D. Conclusions: The AL/CR ratio can be utilized to assess different degrees of hyperopia and as an objective indicator of hyperopia. The AL/CR ratio ≤ 2.80 indicates moderate hyperopia in preschool children.