Functional-structural correlations in the afferent visual pathway in pediatric demyelination

Abstract

Objective: We evaluated the relationship of optical coherence tomography (OCT)-measured ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness to other functional measures of afferent visual pathway competence including high-contrast visual acuity (HCVA) and lowcontrast visual acuity (LCVA), visual field sensitivity, and color vision perception in a pediatric population with demyelinating disorders. Methods: This was a cross-sectional evaluation of 37 children, aged 8-18 years, with pediatric demyelinating disorders (n = 74 eyes), and 18 healthy controls (n = 36 eyes), who were recruited from the University of Toronto, Hospital for Sick Children and the University of Calgary, Alberta Children's Hospital, Canada. A standardized visual battery, including spectral-domain OCT, visual fields, LCVA, and HCVA, was performed in all subjects. Results: Mean RNFL thickness was 26 μm (25.6%) lower in patients with demyelination (76.2μm [3.7]) compared to controls (102.4μm [2.1]) (p < 0.0001). Mean GCL thickness was 20% lower in patients as compared to controls (p <0.0001). Mean GCL and RNFL thickness were strongly correlated (r = 0.89; p < 0.0001), yet in contrast to RNFL thickness, no differences in GCL thickness were noted between optic neuritis (ON) eyes and non-ON eyes of patients. HCVA and LCVA and visual field mean deviation scores decreased linearly with lower RNFL thickness. Conclusion: GCL thickness was decreased in patients regardless of history of ON. The retina may be a site of primary neuronal injury in pediatric demyelination.