Cerebral / Cortical Visual Impairment (CVI)
Cerebral visual impairment (CVI) is the most common cause of visual impairment in children in the developed world, yet often goes unrecognised and is little understood.
In addition to our eyes, a large part of the brain is involved in “seeing”. So conditions which affect the structure or function of the brain often influence how a person “sees” and responds.
Common features of CVI
CVI affects each child uniquely and to differing degrees. An affected child may also have an eye condition causing visual impairment, but many people affected by CVI may have “healthy eyes”, yet function as if severely visually impaired. It is vital that difficulties are identified and appropriate strategies are put in place to support the child. Here are some of the ways that CVI might affect a child:
- Vision seems variable; the child can appear to see less well when tired or ill
- Difficulty finding the beginning of a line or the next word when reading, or misses pictures or words on one side of a page
- Reaching beyond or around the object when picking it up, perhaps grasping it incorrectly, missing or knocking it over
- Uncoordinated movements
- Gets lost, anxious or distressed in visually complex places such as crowded places, supermarket, or busy swimming pool, or cinema
- Regularly bumps into things when walking while talking
- Sits closer than 30 cm to the television
- Difficulty concentrating in visually busy environments, especially if noisy too
- Inability to fix on objects for any length of time
- Difficulty selecting a toy from a full box or clothing from a pile or full drawer
- Lack of, or slow response to objects on a “busy” background which the child may respond to against a plain, contrasting surface
- Eye movements not made independently of head movements, or not very regular and “smooth”
- Difficulty recognising familiar people or objects such as their car or classroom door
- Reacts angrily when distracted from a task
- Lack of response to faces or facial expressions
- Profound difficulty copying down information.