Unlike most blindness and visual impairments, cortical visual impairment (CVI) is caused by the brain rather than the eye.
Of course, this doesn’t mean there aren’t any problems with the eye. More often than not, CVI exists alongside ocular vision loss, which is a direct eye problem.
The most common causes of cortical visual impairment are:
- Lack of sufficient oxygen in blood cells (hypoxia)
- Not enough blood supply to the brain (ischemia)
- Developmental brain defects
- Head injuries
- Infections of the central nervous system
The first two are the most major causes, and may occur during the birth process. This is why children born with CVI may appear fully blind at first. However; vision normally improves over time (most progress is made 2 years after diagnosis).
It is rare that someone will recover completely from CVI, but significant help can be provided for children who do suffer from it.
There are certain characteristics of CVI that are different to visual impairments caused by the eye.
CVI can cause a person to have an inefficient visual sense. Their vision can fluctuate and change from one day to the next, or even from minute to minute. This is usually brought on by fatigue or tiredness, and can be reduced but not eliminated.
Another common characteristic of CVI is that children may find their peripheral vision to be more effective than their central vision. This could also be related to the fact that discerning foreground and background items is difficult, and becomes worse in a situation where the visual field is crowded.
Depth perception can be a big problem for children with CVI. There is usually some amount of perception – rarely will a child with CVI have zero.
Debunking Common Myths
– Contrary to popular belief, having CVI does not mean that a child will have cognitive deficits.
– Likewise, children with CVI are not usually visually inattentive, and are NOT poorly motivated.
– CVI is a true visual impairment, despite it being a neurological problem rather than a direct eye impairment.
– Children with CVI are not totally blind, though it can be a possibility.
Dealing with CVI in Children
There are certain tips and methods for teaching or working with children that have CVI, but one thing that must be taken into account is that each case is unique, and while some methods may appear to work for some children, they won’t work on others.
It takes a lot more energy for someone with CVI to process information visually and often causes them to tire easily. This is something to take into account – receiving information in audio form is a lot more efficient.
Keep space uncluttered as possible. It’s hard for children with CVI to discern between different objects when there is such a variety in their field of vision. Keep things simple and in place. Providing familiarity and simplicity aids perception.
Color over black and white wherever possible. Children with CVI can often perceive color a lot better than dull, or non-bright colors.
Do you have someone suffering from CVI in your family? Maybe you do yourself? Whatever the case, take a look at our range of products for those with blindness and low vision.
Disclaimer: This information is intended for your general knowledge only and is not a substitute for medical advice or treatment for specific medical conditions. We cannot and do not give you medical advice. You should seek prompt medical care for any specific health issues and consult your physician.