What is CVI?

What is Vision?

Vision is a complex system that takes years to develop! When you are born and open your eyes for the first time you are set off on a path to gather and develop vision. Part of your vision includes what your eyes see, but it also includes what you hear, feel, taste, smell and remember. When the visual system works well, all these elements come together creating a picture of your world for your brain to interpret and analyze.

If you are born with perfect eyes, it will still take years of your brain analyzing all the information coming in from your eyes to create vision. The brain looks at a perfect picture coming from your eyes, interprets the light reflection and the shadows. It then adds in all the other information like memory, touch, taste, hearing and smell to really create a fantastic picture of your world! This takes years of development.

If you are born without eyes, you can still use your visual system to envision your world. You might use a cane to see how far away things are or measure how big they are. You might smell your food or your pencil to help see it with your brain. You can touch and taste an apple to “see” it with your “mind’s eye.” You might remember where you left your shoes so you can find them again. It may take some time, but you will create vision.

If you are born with eyes that don’t see well, you might need glasses to see better or maybe even need surgery to remove cataracts or fix a muscle issue. There are many things that can be done to help facilitate your eyes to “see” well. Your well seeing eyes will then send a clear picture to the brain and it will learn to process the information along with the other information creating vision!

This is called Visual Function and we are pretty good at assessing visual function with equipment in eye doctor’s offices, pediatricians and even in our classrooms through vision screenings.

But what if you are born with a brain that doesn’t process visual information well? This is called Cortical / Cerebral Visual Impairment and it is often hard to diagnose. It’s a neurological condition that makes the visual world difficult to recognize and make sense of. The brain's inability or insufficiency in processing information results in a visual picture that is hard to navigate. It makes an otherwise passive function of vision become something that is active work and strenuous for the child. Vision suffers as the brain fatigues. The ability of the brain and the brain's pathways to process and USE the information is called “Functional Vision”

Assessing “Functional Vision” is a bit more difficult and professionals are really just beginning to understand how.

The good news is there is an answer to why so many kids can see well or have normal “Visual Function” but have abnormal “Functional Vision”. We now know that the cause often lies within the neurological system and the brain's ability to process this information. We are beginning to understand what represents “clutter” to the brain Impacted by CVI. Just like you and I have a hard time concentrating when there are too many distractions, it’s the same for vision if you have CVI. Cortical / Cerebral Visual Impairment is a lifelong condition and one of the leading causes of blindness in children, however if a child is diagnosed early there are many things that can be done to help children learn to access their world.

Clutter is what makes the visual pathways get confused and overwhelmed. Clutter might look like a busy background. Clutter might look like a pile of toys on the floor. Clutter can also be auditory overstimulation. Remember our visual system includes things like hearing, taste, smell and touch! A strong smelling perfume can even cause a distraction to the child dealing with CVI and working hard to interpret their visual picture of the world around them.

The first thing that can help is to bring your vision concerns to your eye doctor, therapists and other medical professionals. Write down what is going on at the times you notice your child isn’t “seeing” well or functioning well with their vision. Maybe your child seems distracted or unable to focus on what you are asking them to look at. Take note of what all is going on, then communicate this to your doctor.

The second thing we need to do is listen to and observe our kids. Encourage kids who are verbal to express their visual difficulty and then listen. Be observant to kids who may not have the verbal skills to express themselves. By observing their behavior and ability to focus you can determine what situations may need to be altered to help your child process their visual world. If they feel uncomfortable in their surroundings, help reduce the clutter for them. Think about all that is going into the visual picture and begin to lessen it. Maybe it’s turning down music or removing some items from around them. It could be the lights need to be brighter or maybe the lights are too bright and need to be darker. Kids with CVI need to know that they are believed! They need to know that it is ok to feel like they need a white cane in a particular situation. Perhaps walking down the hall with a group of noisy kids navigating a stairway past a bunch of noisy classrooms at the end of the day is too much for them and they need to be able to communicate that without skepticism.

Studies and Resources

CVI is something that we are still learning about, but we know a lot more today than we did even 5 years ago and that’s great! If you think your child may be having difficulty processing their vision, ask your eye doctor about CVI. There are many helpful resources out there like the ones at www.CVINow.org and the CVI Center at the Perkins School for the Blind.

• The Assessment of Visual Function and Functional Vision, Merabet study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761988/
• Visual Behaviors page: https://www.perkins.org/understanding-cvi-visual-behaviors/
• How to advocate & get a diagnosis, our Dr Kran interview: https://www.perkins.org/how-to-better-advocate-for-your-cvi-child-and-get-a-diagnosis-advice-from-dr-barry-kran/