Cerebral Visual Impairment or CVI is an umbrella term for brain-related problems with vision
Children with brain-related visual impairment, also known as CVI, have difficulty seeing the world around them and this can cause avoidable mental health problems like anxiety and low self-esteem. CVI can manifest in many ways –like being unable to: find things in a cluttered page; or avoid bumping into people; or copy; or change eye position effectively to keep focused on a task. In a primary school –aged child this can appear as failure to understand; as clumsiness or inattention, or as social and communication difficulties. The visual impairment underlying these problems may be hidden as the child may appear to be able to see objects normally. Therefore their behaviour is put down to other causes and may elicit punishment, or to being set back academically.
Which children have CVI?
Several groups of children are known to be at increased risk of CVI. In children born prematurely (approximately 7% of births) many studies report CVI in sometimes as many as 86%. Similarly children with learning difficulties, cerebral palsy, autism, or with other developmental disorders may have CVI with varying frequencies. The available population data are based on visual acuity: for example, a population-based survey estimated that 5.9 per 10,000 children in the UK were registered as blind or visually impaired, of whom half have CVI. However using visual acuity as the diagnostic marker misses many children with CVI, whose acuity is normal or near-normal (they can read down a chart). Over half of the 1.55 million (19%) children with special educational needs (SEN) in 2013 had diagnoses that put them at excess risk of CVI. If 1 in 20 of these has CVI then the population prevalence would be 1% but there are no robust data to provide a true figure. The diagnosis of CVI requires multidisciplinary input, for example for paediatrics and ophthalmology, to establish whether the child’s vision is or is not as expected for their age and level of development.