Interocular Symmetry in Anterior Segment Parameters in Children With Intermittent Exotropia Observed by CASIA2 AS-OCT.

PURPOSE: To explore the interocular symmetry of the anterior segment parameters in subjects with intermittent exotropia (IXT) and compare it with that in the normal subjects.

METHODS

A total of 122 eyes of 61 subjects with IXT and 88 eyes of 44 normal subjects were enrolled. Central corneal thickness (CCT), the radii of curvature of the anterior and posterior lens (ALR and PLR), lens thickness (LT), lens equatorial diameter (DIA), anterior chamber depth (ACD), lens tilt, and decentration were measured with CASIA2 AS-OCT; the parameters in IXT were measured again after cycloplegia. T-tests, intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to compare binocular differences and quantify symmetry. We compared the binocular symmetry between normal subjects and the subjects with IXT and the symmetry in different refractive states.

RESULTS

The ICCs were high in CCT, ACD, ALR, and LT and moderate in PLR, DIA, lens tilt, and decentration in all subjects (p < 0.05). IXT after cycloplegia showed similar ICCs to those of normal subjects, while ICCs before cycloplegia were all below normal. In the Bland-Altman plot, the IXT group had a larger mean difference and more dispersed 95% confidence intervals than the normal group. The normal group had similar ICCs for different refractive states, but hyperopic subjects had smaller ICCs than myopic subjects in the IXT group.

CONCLUSIONS

IXT had lower binocular symmetry in the vision state than normal children, with the asymmetry being more pronounced in hyperopia. Binocular interocular asymmetry of children with IXT is of concern. Trial Registration: Chinese Clinical Trial Registry: ChiCTR2300075756.