Brain structure in children with congenital visual disorders and visual impairment

Abstract

AimTo examine if congenital visual impairment is associated with differences in brain anatomy in children.MethodTen children (8–12y) with congenital disorders of the peripheral visual system with severe visual impairment (SVI; >0.8 logMAR) or mild‐to‐moderate visual impairment (MVI; 0.6–0.8 logMAR) were compared to 21 typically sighted comparison (TSC) children. Thalamus volume, grey matter density, white matter microstructure, and integrity of visual tracts were investigated in SVI, MVI, and TSC groups with anatomical and diffusion‐weighted magnetic resonance imaging.ResultsCompared to the TSC group, the SVI group had lower white matter integrity in tracts of the visual system (optic radiations: SVI 0.35±0.015, TSC 0.39±0.007 [p=0.022]; posterior corpus callosum: SVI 0.37±0.019; TSC 0.42±0.009 [p=0.033]) and lower left thalamus volume (SVI 4.37±0.087; TSC 4.99±0.339 [p=0.015]). Neuroanatomical differences were greater in the SVI group, while no consistent differences between the MVI and TSC group were observed.InterpretationPosterior tracts of the visual system are compromised in children with congenital visual impairment versus those who are typically sighted. The severity of visual input appears to have affected neuroanatomical development as significant reductions were only found in the SVI group.What this paper adds Severe visual impairment in mid‐childhood is associated with reduced integrity of visual pathways and reduced thalamus volume.

Visual Neuropsychology in Development: Anatomo-Functional Brain Mechanisms of Action/Perception Binding in Health and Disease

“…At the neural level, a relatively early detection of CVI is based on the analysis of visual evoked potentials which, already at 6 months of age, can appear abnormal and therefore suggest the presence of CVI (Mercuri et al, 1997b), further depending on the size (Mercuri et al, 1998) and location (Mercuri et al, 1997a) of the brain lesion. In particular, the basal ganglia seem to play a central role in coordinating the information exchanges between the eyes and the visual cortex, as well as in facilitating neural plasticity at the cortical level (Mikellidou et al, 2019), possibly resulting in aberrant patterns of anatomo-functional connectivity between different brain regions (Muñoz-Moreno et al, 2016;Bathelt et al, 2020). It is anyways important to note that CVI can impair a full range of competences at different levels, including purely visual skills (visual field, motion sensitivity, visual exploration) as well as attention, memory, and visuo-motor coordination (Lueck et al, 2019).…”

Association of Visual Impairment with Brain Structure

“…To the best of our knowledge, this is the first study to date to report the association of VI with brain structure in the middle-aged and elderly participants. A previous study investigated the effects of congenital VI on brain structure in children 23 . They found defects in the development of the posterior tracts of the visual system and reduced volume of the thalamus in children with congenital VI.…”

Ocular and Cerebral Causes and A New Scoring System to Evaluate Visual Function in Young Children with Visual Impairment

“…Finally, cranial MRI ndings were evaluated and classi ed according to the previous reports. [3][4][5] Low vision etiopathogenesis were divided into three periods as prenatal, natal, and postnatal periods, according to the duration in which the injury developed. After the neurological and ophthalmological examinations of the patients were completed, the etiologies were classi ed into three groups as an ocular pathology, cerebral visual impairment (CVI) and combined group with ocular pathology and CVI together.…”