Interocular difference in refraction and ocular biometry in children with anisometropia

To examine the association between interocular difference in refraction and ocular biometry in children with anisometropia. This analysis included 91 children aged 6-16 years with anisometropia, identified from a cross-sectional, school-based study of 765 children. All children underwent a comprehensive ophthalmic examination, including cycloplegic biometry and refractometry. The refractive lens power (RLP) was calculated using Bennett's equation. The mean interocular difference in SE was 2.24 ± 1.48D. Compared to the contralateral eye, the more myopic eye or less hyperopic eye exhibited a significantly longer axial length (AL), deeper anterior chamber depth (ACD), thinner lens thickness (LT) and deeper vitreous chamber depth (VCD) (all P < 0.05). No significant interocular differences were observed for corneal curvature radius (CCR), central corneal thickness (CCT) and RLP between the two eyes (all P > 0.05). When exploratory analyzing by anisometropia type, the more myopic eye or less hyperopic eye had a significantly thinner LT and less RLP than the contralateral eye in the antimetropia group. In univariate analysis, interocular difference in SE was significantly associated with interocular difference in AL (β=-0.822, P < 0.001), ACD (β=-0.401, P < 0.001 ) and VCD (β=-0.831, P < 0.001). In the multivariate regression analysis, interocular difference in SE was significantly associated with age (β = 0.144, P = 0.002), interocular difference in AL (β=-1.024, P < 0.001) and RLP (β=-0.421, P < 0.001). Interocular difference in the parameters of AL and crystalline lens are significant factors associated with anisometropia, whereas corneal parameters show no significant interocular difference between the two eyes. The role of lenticular parameters appears to be type-dependent. Exploratory analysis further revealed that the interocular difference in a compensatory lenticular pattern to axial elongation varies among different types of anisometropia.