Damage to the brain is the commonest cause of visual impairment in children in developed countries.¹ Improved survival of premature infants has increased the prevalence of periventricular leucomalacia, and greater success in managing profoundly ill children has led to increased survival of children with meningitis, encephalitis, and hypoxic ischaemic encephalopathy. Hydrocephalus is now also successfully treated, while congenital disorders of the brain add to the prevalence of brain dysfunction.² On the other hand, early treatment of cataract, the successful management of glaucoma, screening for retinoblastoma, and effective immunisation for rubella have all decreased the prevalence of blindness in children as a result of eye disorders.

A large proportion of the brain serves visual function. The cerebral cortex, underlying white matter, and (during early visual development) the basal ganglia³ all play a major part. The classic view is that the visual system comprises the anterior visual pathways, the lateral geniculate bodies, the optic radiations, and the occipital cortices wherein the process of “vision” takes place. Disruption of these pathways may result in restricted visual fields and impairment in visual acuity. The article by Lowery et al in this issue (p 960)⁴ highlights the importance of having a high index of suspicion when a child presents with undiagnosed poor visual function. Cerebral …