Refractive-state-specific acute ocular structural changes induced by full-spectrum light in children with intermittent exotropia.

PURPOSE: To investigate the acute effects of short-term exposure to full-spectrum light on ocular biometric parameters in children with intermittent exotropia (IXT) across different refractive states.

METHODS

Children with IXT were recruited and categorized into myopia, emmetropia, and hyperopia groups based on their baseline refractive status. All participants underwent a single 4-hour session of exposure to full-spectrum light (illuminance: ≈ 500 lux; correlated color temperature: ≈ 4000 K). Axial length (AL), subfoveal choroidal thickness (SFCT), and crystalline lens thickness (LT) were measured before and after the intervention using optical biometry and optical coherence tomography. Changes in ocular parameters were analyzed using linear mixed models and partial correlation analyzes.

RESULTS

The ocular response to full-spectrum light exhibited significant refractive-state specificity. The myopia group exhibited significant acute axial shortening (ΔAL = -0.008 ± 0.003 mm; p < 0.05) and a negative correlation between axial length and choroidal thickness changes (p = 0.013), in the absence of significant choroidal thickening at the group level. In contrast, emmetropic eyes showed physiological axial elongation with inferior choroidal thickening, while hyperopic eyes maintained structural stability.

CONCLUSIONS

Short-term exposure to full-spectrum light induces distinct, refraction-dependent ocular structural responses in children with IXT. While emmetropic eyes maintain normal circadian growth patterns, myopic eyes exhibit acute axial shortening. The dissociation between axial shortening and choroidal thickening in myopic eyes suggests the involvement of alternative posterior segment regulatory mechanisms. These findings suggest good short-term biocompatibility of full-spectrum lighting and provide insight into refraction-dependent light-eye interactions in children with intermittent exotropia; however, longitudinal studies are needed to determine whether these acute effects translate into sustained ocular changes and to assess potential rebound effects.