What Is Cortical Vision Impairment?
Whew! Trying to find information on this topic has been the hardest thing! This is partially due to the fact that different doctors may label this condition with a different name. Neurological vision impairment, cortically blind, delayed visual maturation and cortical vision impairment (hereafter referred to as CVI) are often used interchangeably.
Just for further clarification, neurological vision impairment is now the preferred term and the other three are labels depending on where in the brain the damage has been done. A neurological vision impairment refers to the condition where the occipital lobe, the area of the brain that controls vision, is injured. When that part of the brain is damaged, visual images are not received.
The actual physical condition of the eye can be normal, and yet the child cannot see or is visually impaired. This damage can be mild to severe, temporary or permanent, depending on the amount and exact location of the damage. Hypoxia is, of course, one of the top causes of this condition.
Take Care of Your Eyes
Children with Vision Impairment
Children with CVI usually have other optical conditions. All of these conditions may also fluctuate depending on several factors such as fatigue, illness and medications. The most common of these are:
* Esotropia (also known as strabismus)óone or both eyes turn inward
* Exotropia (also known as strabismus)óone or both eyes turn outward
* Nystagmusórapid or jerky eye movement (jumping eyes)
* Optic Nerve Atrophyóthe nerves that carry the images to the brain may be atrophied (this is irreversible)
Binocular vision impairment is a condition due to strabismus that means loss of binocular depth perception. This is very common in children with cerebral palsy. The eyes do not aim in the same direction with this condition.
This is also referred to as spatial confusion. For example, lets say a child has this binocular vision impairment, but is able to move. He or she can see the chair, but can't get in it, they might sit on the floor instead.
Fluctuating vision is common in CVI. Children may see one day and not the next. They may see one hour and not the next. It is very unpredictable. Some seizure medications, such as Dilantin, Tegretol, and Phenobarbitol can cause this fluctuation in sight or make it worse. It seems that most kids with CVI may have better peripheral vision than they do central vision.
They appear to be looking to the side of you, when really, they are looking right at you. One eye may be stronger than the other eye, as well. It is so hard as a parent, when a child is labeled cortically blind, to figure out if or what your baby is actually seeing.
Surgery, drugs, and therapy may help some of the conditions. In terms of specialists, ophthalmologists are trained in surgery and eye diseases, so their opinion would lean more toward surgery. Optometrists tend towards therapy. Surgery being rather drastic, therapy should be considered first.
Surgery would help exotropia and endotropia only, not the other conditions. I was not able to find much about what drugs might be used or in what way they would work. One interesting idea from a research study is the use of Botox for esotropia and exotropia.
Therapy for vision is also called by many names: visual therapy, vision therapy, optometric visual therapy, vision training, neuro-optometric visual therapy, behavioral optometry, orthoptic therapy, and developmental optometry.
Regardless of what it is called the idea is that vision is a learned skill and can be rehabilitated to a certain degree. It is believed that most children with CVI will show at least some recovery. The brain can be trained to better control eye alignment, focusing abilities and eye teamwork (depth perception).
For the therapy to be effective for your child, you must do it daily in real life situations, not just in scheduled therapy sessions. For Rachel we received one half hour of services per week, through the Maryland School for the Blind, included in her IFSP, which would not be enough to be effective in and of itself.
Peripheral Vision Exercises
10 Quick Visual Impairment Tips
It seems only natural that children with CVI prefer to learn by touch and activities that involve touch and are visually inattentive. Here is a great list of tips that I found on the web.
1) Use high contrast colors to stimulate vision. For example, red and white, rather than red and orange. Don't overstimulate with lots of colors when working on this.
2) Use bright lighting.
3) Give lots of time to respond to the object. Don't put it away or give up quickly because it seems as if your baby is not responding.
4) Yellow and red are the easiest colors to see.
5) Use a multisensory approach. A toy with bright contrasting colors and an interesting texture would be good, for example.
6) Repetition and routine are essential to fostering visual development.
7) Reduce fatigue. People with CVI who are tired out see less clearly than they usually do.
8) Reduce outside noise and other stimulation that would distract the child from the visual stimulation.
9) Objects are easier to see if they are moving.
10) Keep in mind the positioning of your child, and this goes with the fatigue issue. If they are using all of their energy to hold themselves up on their arms or in some other way, then they will not have as much energy to see.