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What is CVI?


A wooden background with leaves and branches to the left.  The title test says "AAC Branches: What is CVI".  The footer contains the AACcessible logo and web address:  www.aaccessible.org.

The AAC Branches series was created to help AAC partners learn about "the other stuff" involved in effective AAC learning, outside of language and communication skills. In this series, we'll explore topics related to motor skills, sensory regulation, vision, mental health, and more.


This week, we're launching a series on CVI. If you are breathing anywhere near the AAC space, you've likely heard of CVI. You may even have a more than basic understanding of what CVI is. Just in case this isn't you, I thought we'd kick off CVI Awareness Month with a refresher.

CVI is the #1 Cause of Pediatric Visual Impairment

Cerebral visual impairment, also referred to as cortical visual impairment, is a brain-based visual impairment that results from injury to the visual pathways of the brain. CVI is the leading cause of visual impairment in children residing in the developed world. According to the Pediatric CVI Society, between 33% and 58% of kids with a diagnosis of cerebral palsy, hydrocephaly, and/or periventricular white matter injury present with CVI. Contrary to popular understanding, visual processing takes place in areas of the brain within and outside of the occipital lobe of the brain. With over 60% of the brain’s pathways dedicated to visual processing, significant injury to the brain of any kind and in any location places, a child at risk for CVI.

Although largely considered a “pediatric” disorder, CVI is a life-long condition that persists into adulthood for many affected learners. Given the neuroplasticity of the brain, CVI changes with time, teaching, and environmental support, but may not entirely resolve for significantly impacted individuals.


Header at top says: There's more to vision than meets the eye.  THe image is a drawn graphic of a light beam entering the side profile of an eye ball.  The eyeball graphic is then connected to an optic nerve which is next to an image of a brain.  This image i smeant to show the pathway of sight from eye to nerve to brain.
The Vision Path (click to enlarge)

CVI is Not Related to "Eye Sight"

To understand what CVI is, it is helpful to first understand what CVI is not. Visual impairment can result from disruptions at any point in the vision pathway. When disruption to vision occurs due to differences or disorder in the parts and processes of the eye itself, the impairment is referred to as “ocular". In ocular impairments, something is hindering the eye's ability to receive and transmit the visual information presented in the environment. Ocular impairments range in severity and affect the quality (acuity) of what a child sees. Ocular impairments may also impact the way a child's eyes move and work together. Some common ocular impairments present in children with complex communication needs include refractive errors (e.g., nearsightedness, farsightedness), nystagmus (i.e., involuntary eye movements), and strabismus (i.e., eyes that are not typically aligned).

Vision impairment resulting from disruption of the visual processing areas of the brain are termed "cortical" or "cerebral" visual impairments. In cortical visual impairment, the eye is able to receive visual information from the environment, and transmit that visual information to the brain, but the brain is not able to, or has limited ability to interpret the information it receives. CVI is a condition that impacts a child's ability to make sense of what they see, not necessarily their ability to see it in the first place. Matt Tietjen said it well when he shared that educators and partners supporting children with CVI shouldn't be asking- "Can you see it?" but rather "What do you see?”


CVI Can Exist Alone, or With

Multiple Special Needs

For some children, CVI may present as the only or the most significant learning challenge. For others, CVI may be one component of a complex profile of special learning needs. As AAC partners, we often encounter children who fit best in that second group, making the recognition of and appropriate responses to CVI risk and presence all the more challenging. CVI may also present in some children who have co-occurring ocular impairments, which may further complicate appropriate and timely diagnosis.



The Ten Characteristics of CVI

As with any complex learning need, a comprehensive assessment by a qualified professional is essential in properly identifying the presence and profile of CVI. However, any partners supporting children with complex communication needs must be aware of the warning signs of CVI in order to effectively support the needs of these complex learners.

Experts in the field of CVI have developed a list of ten, key characteristics that are frequently observed in children with CVI. Not all children will demonstrate all of these visual behaviors, making appropriate assessment essential to not only diagnosis, but also to the implementation of the most appropriate support and teaching strategies for each learner’s individual, vision profile. Children who are impacted by CVI may be described in terms of “phases” and within each phase, a continuum of visual behaviors may be noted. Understanding CVI phases and the changing characteristics that evolve as a child lays down new visual pathways, is an important part of adapting strategies and materials to most effectively facilitate communication and learning. The graphic to the right outlines a brief description of the ten, key characteristics of CVI. This graphic can be downloaded in PDF for free on our tools page. You will also find an accessible version of the graphic linked in the description on our tools page.


Learn More about CVI from the Experts

Anyone serving children and adults with complex communication needs must obtain a basic understanding of CVI and other vision challenges in order to adjust their

strategies and effectively collaborate with essential team members.


If you are looking for great online resources to learn more about the nature of CVI, as well as how you can adjust your assessment and intervention perspective to consider vision needs, check out our AAC and Vision section at the Stacks!


AACcessible offers courses related to CVI and AAC on our AAC Academy platform. These courses are comprehensive and appropriate for various professionals, as well as caregivers. Whether you are working with a child with known CVI, or with a learner whom you suspect has been impacted by this brain-based vision challenge, ongoing learning on this topic is sure to increase your confidence and improve the efficacy of your support strategies.


Visit the Loop throughout the month to learn more about CVI and connect with some amazing resources!


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