Functional Connectivity Density Abnormalities Observed in Brain Regions of Children With Strabismus and Amblyopia

Children with strabismus and amblyopia (SA) appear to have functional connectivity abnormalities in various brain regions, particularly in areas with visual, cognitive, and emotion-related pathways, according to research published in BMC Ophthalmology. 

Investigators included 26 children with SA (14 boys and 12 girls) and 26 healthy controls (14 boys and 12 girls) in the study. The mean age of both groups was approximately 8 years. Mean OD best-corrected visual acuity (BCVA) in the SA and control groups were 0.20±0.05 D and 1.00±0.15 logMAR, respectively, (P =.012). OS BCVA was 0.50±0.15 and 1.10±0.10 logMAR in the SA and control group, respectively (P =.007).

The researchers compared functional connectivity density (FCD) values of brain areas based on blood oxygen level-dependent (BOLD) signals in the children with SA and healthy controls and matched for age, sex, education level, and socioeconomic background. They evaluated all participants with functional magnetic resonance imaging (fMRI), and calculated global FCD (gFCD) and local FCD (lFCD) values.

Researchers used area under the curve (AUC) in the receiver operating characteristics (ROC) curve for analysis, and noted those with SA had significantly lower gFCD values for the right cerebellum, right temporal inferior gyrus, and left putamen (AUC, 0.787, 0.836, and 0.800, respectively; P ≤.001 for all) compared with the control arm. They revealed significantly higher gFCD values for the right angular gyrus, left angular gyrus, left middle cingulate gyrus, right medial frontal gyrus, and right superior parietal gyrus (AUC, 0.840, 0.741, 0.796, and 0.767, respectively; P ≤.002 for all) compared with healthy controls. 

They also reported SA patients had lower lFCD values for the middle right temporal pole (AUC, 0.800; P =.0001), right cerebellum (AUC, 0.787; P =.005), left putamen (AUC, 0.792; P =.0001), left hippocampus (AUC, 0.760; P =.0003), right hippocampus (AUC, 0.881; P =.053), left thalamus (AUC, 0.767; P =.073), and left cerebellum (AUC, 0.800; P =.0001), and significantly higher IFCD values for the right superior parietal gyrus (0.846; P =.0001) compared with the control arm.

Investigators report that understanding these connectivity abnormalities is crucial because “detailing such connectivity aberrations is useful in exploring the pathophysiology of SA and providing useful information for future clinical management.”

Study limitations include a small sample size and single center design. 

Reference

Shi Y, Ge Q, Lin Q, et al. Functional connectivity density alterations in children with strabismus and amblyopia based on resting-state functional magnetic resonance imaging (fMRI). BMC Ophthalmology. Published online February 2, 2022. doi:10.1186/s12886-021-02228-3