Cortical visual impairment (CVI) is a term that describes visual impairment as a result of brain damage. This is different from other types of visual impairment, known as ocular impairments, which occur because of physical problems with the eyes. With CVI, the eyes can see, but the brain has a hard time making sense of what the eyes can see.
Typical characteristics of CVI:
There are ten common characteristics of CVI. Knowing these can help you determine if a child has CVI.
Preference for a specific colour.
Many children will respond best to particular colours more than others. Bright red and yellow are often favourites, but some children prefer other highly saturated colours such as bright blue, green, or pink.
Need or preference for movement.
Children with CVI often need movement in order to see an object. For example, it may be easier for them to look at a ceiling fan or a swaying balloon.
Delayed response when looking at objects (visual latency).
Children with CVI typically need a lot of time before they will look at an object. Often they will look briefly and look away before looking again. For this reason it is important to give the child enough time when presenting an object.
Difficulty with visual complexity.
Simplicity is crucial for those with CVI. First, it is important that the object itself is simple. For example, a stuffed animal with only one colour, like Elmo or Big Bird, is better than one with multiple colours. Additionally, the background and environment also need to be visually simple. Putting a solid black cloth or board behind a single coloured toy can reduce visual clutter in the background. You can make the environment simpler by eliminating noise or any other competing sensory input.
Light-gazing and non-purposeful gazing.
It is common for children with CVI to stare at light. You may notice the child is frequently distracted by a nearby window or staring up at a ceiling light. They might also appear to look at things that are not there, or look at things without intent.
Visual field preferences.
A child with CVI may see an object better when it is presented in their periphery, or they may turn their head in order to better see an object. You can help the child by presenting objects in different areas of the visual field and make note of where the child seems to see best.
Distance vision impaired.
It may be difficult for a child with CVI to see things that are too far away. This is related to the preference for visual simplicity. Objects far away, sometimes even more than a foot or two, may easily get lost in visual clutter.
Visual blink reflex is absent or impaired.
Children with CVI may have an absent or delayed protective blink response if an object comes too close to the eyes, or touches the bridge of the nose.
Preference for familiar objects.
Although neurotypical children will usually prefer novelty, children with CVI usually prefer objects they are familiar with. It is difficult for them to process what they see, but familiar objects will have been previously processed by the brain and therefore easier to see. The more familiar, the easier.
Impaired visually guided reach.
A child with CVI may have a hard time reaching for an object while looking at it. Commonly, they will look and then look away while reaching.
There is hope!
Cortical visual impairment is very often undiagnosed or misdiagnosed. Ophthalmologists may not recognize it because it is not an eye condition. Neurologists may not recognize it because they don’t view vision problems as their territory. Unfortunately, parents are often told their children are blind or that there is nothing they can do. But there is hope! What we’ve learned is that CVI can, and often does, get better with appropriate intervention. A study conducted by CVI expert, Dr. Roman-Lantzy, found that, in a group of children with CVI who had highly motivated parents, 97% went from Phase I to Phase III in an average of 3.7 years. To learn more about the three phases of CVI, check out Little Bear Sees’ What is CVI page.
Some vision specialists or teachers of the visually impaired (TVI) are very knowledgeable about CVI and can help with assessment and intervention strategies. Even without the assistance of vision specialists there is so much that parents can do. To learn more about CVI and how you can help, visit us at www.LittleBearSees.org.