Interocular Choroidal Thickness Differences Noted in Children With Monocular Exotropia

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Children with alternating exotropia did not exhibit these significant interocular differences in subfoveal choroidal thickness.

Children with monocular intermittent exotropia without anisometropia or amblyopia  have a significantly greater subfoveal choroidal thickness (SFCT) in their nondominant eye, according to findings published in the Journal of American Association for Pediatric Ophthalmology and Strabismus. Children with alternating exotropia did not have significant interocular SFCT differences.

Researchers conducted a retrospective analysis of 81 children with intermittent exotropia presenting to a single center between 2018 and 2020. The cohort consisted of patients with (n=46, mean age 6.5±1.6 years, 24 boys) and without fixation preference (n=35, mean age 6.9±1.7 years, 15 boys).  The team performed optical coherence tomography (OCT) imaging and obtained SFCT and central foveal thickness (CFT) measurements over the course of 3 consecutive visits. 

Researchers determined that SFCT was significantly higher in the nondominant eye for patients with a fixation preference (mean, 300.9±47.1 vs 289.9±45.4 μm) and CFT was not significantly different (mean, 213.9 vs 213.4 μm) compared with the dominant eye. For eyes with alternating fixation, the right and left eyes had both similar SFCT (mean, 307.6±53.8 vs 306.4±51.0 μm) and CFT (mean, 210.3±12.2 vs 211.1±11.7 μm). This resulted in SFCT interocular differences of −11.0±18.0 μm and 1.9±22.2 μm between children with monocular and alternating exotropia, respectively, revealing a statistically significant difference between the groups (P =.005). 

“In patients with intermittent exotropia without amblyopia, the difference in subfoveal choroidal thickness between the eyes in the monocular group was significantly greater than that between eyes in the alternating group,” according to the investigators. “These findings suggest the presence or absence of fixation preference may affect subfoveal choroidal thickness.”

Study limitations include a small sample size, the absence of a control group, and the use of manual OCT measurements.


Na JH, Lee SJ. Interocular differences in subfoveal choroidal thickness in monocular intermittent exotropia. J AAPOS. Published online May 4, 2022. doi:10.1016/j.jaapos.2021.12.011