Correlation of optic nerve on magnetic resonance imaging with visual acuity in children with cerebral visual impairment.

Aim: The aim of the study was to correlate the optic nerve dimensions at various locations on magnetic resonance imaging (MRI) with the visual acuity of children with cerebral visual impairment (CVI).

Materials and methods: A 1-year cross-sectional study was conducted in a tertiary care hospital involving 60 children aged 1 to 12 years diagnosed with CVI but without ocular pathologies. Visual acuity was evaluated using teller acuity cards (TACs). MRI of the brain and orbit was performed using three-dimensional high-resolution, volumetric heavily T2-weighted sequences to screen for brain pathologies and measure optic nerve dimensions at two locations. The correlation between visual acuity and optic nerve dimensions was analyzed. The Chi-square test was employed to assess significance using SPSS software.

Results: In our study, 64% (n = 38) of the participants were children under 3 years of age. The severity and characteristics of CVI influenced visual functioning at different ages. As children with CVI grew older and moved from Phase I to Phase III, the proportion with very low visual acuity significantly decreased from 85.2% in Phase I to 22.2% in Phase III and from 63.2% in the <3-year age group to 18.2% in more than 5-year age group. No direct correlation was found between optic nerve dimensions and visual acuity but optic disc changes such as optic disc pallor significantly correlated with low visual acuity.

Conclusion: Our findings suggest that there may not be a direct correlation between optic nerve dimensions and visual acuity in children with CVI. However, optic disc changes do correlate with visual acuity, but optic disc changes alone are not a criterion for assessing visual function. Additionally, our study highlights the significance of a combined assessment by a neuro- ophthalmologist and neuro-pedaitrician in children with CVI.