CVI stands for Cortical Visual Impairment/Cerebral Visual Impairment. CVI is a brain-based visual impairment caused by damage to the visual pathways or visual processing areas of the brain. Learners struggle with visual attention and visual recognition resulting in a lack of access for understanding the world around them. CVI is known to be the leading cause of visual impairment in children in the United States. With CVI, the eye’s connection to and in the brain doesn’t work correctly. You should know that CVI is common, and many effective educational programming strategies can help provide access and set the stage for improvements in visual functioning.
Understanding Cortical Visual Impairment/Cerebral Visual Impairment (CVI)
Often, people associate blindness with ocular — or eye — impairment. However, CVI is neurological. It’s a brain-based visual impairment wherein the impairment involves the brain’s visual system. Many kids with CVI often have completely healthy eyes. They simply have trouble processing what those healthy eyes are seeing. CVI refers to a type of visual impairment caused by injury to the brain’s visual pathways and visual processing centers.
5 Facts to Know About CVI
- It is the most common cause of visual impairment in children.
- It is the leading cause of congenital blindness (vision loss at birth) in the United States.
- It causes children with healthy eyes to have difficulty processing what they see.
- It causes children to display some unique visual behaviors commonly seen when there is damage to the brain's visual system.
- It is typically diagnosed when abnormal visual responses can’t be attributed to just to the eyes.
Children and adults with CVI have different severity levels of visual impairment. There’s no one-size-fits-all model, and each child is unique.
"If you've met one child with CVI, you've met one child with CVI." - Dr. Gordon Dutton
Some kids see the world as a swirling kaleidoscope of color and light. While those with better visual attention can exhibit some focus, they still struggle to understand what they see. They become overwhelmed by so much meaningless visual stimulation because their brain has trouble perceiving it. This overstimulation often causes children with CVI to avoid looking at objects and the people around them. They may stare at light and appear very visually impaired. If they do attend to objects and people in the world, they might struggle to recognize those objects and people. Other kids with CVI look at objects but lack understanding of what they see. They might appear to have learning difficulties or become anxious in new environments. Many have CVI meltdowns due to fatigue or challenges with sensory integration.
Because of those symptoms, CVI is sometimes misdiagnosed as an emotional or psychological disorder. Common misdiagnoses include ADHD, autism spectrum disorder, delayed visual maturation or learning disabilities. However, CVI is its own diagnosis. Once accurately diagnosed, your child might improve her visual attention and visual recognition through targeted evaluation and instruction.
CVI is often one piece of a child’s complex diagnosis and commonly found among kids with other types of brain involvement or metabolic issues such as cerebral palsy, autism and Rett Syndrome, to name a few.
Approaches to CVI
There isn’t a cure for CVI, but your child’s ability to use his or her vision has the possibility to improve with the right assessment and educational programming. The good news is that there are many effective practices that help children build visual attention and visual recognition.
Dr. Gordon Dutton and Dr. Christine Roman, Matt Tietjen as well as the creators of TEACH CVI Screening Materials, are notable theorists in the CVI field. They’ve also developed ways to look at the functional vision of children with CVI and create accessibility for children with CVI. Perkins draws from their work, among others, to inform our education.
Dr. Gordon Dutton
Dutton originated a Visual Skills Inventory at the Royal Hospital for Sick Children in Glasgow, Scotland. These inventories assess children’s visual behavior and identify any problematic areas of visual functioning. Dr. Dutton’s research focuses on the role the brain plays in processing vision. Much of his work focuses on the ventral and dorsal streams. Think of the ventral stream as the “what” system that identifies objects, shapes and words. The dorsal stream helps you understand where things are — a ball heading toward you on a field, an arm outstretched to shake your hand. These two streams of the brain need to work together.
Dutton’s work classifies kids with CVI into three groups: those with profound visual impairment; those who have some useful functional vision alongside additional cognitive or other disabilities; and those who have enough useful vision to work at close to full capacity.
Dr. Christine Roman
Roman developed the CVI Range, which is an assessment of several aspects of functional vision. This should never be used as a tool to diagnose CVI but to look at several functional visual skills of children with CVI. Dr. Roman's CVI Range places some of the children's visual behaviors on a severity continuum of 0 to 10. Some visual skills can be measured using the CVI range, but it doesn’t mean that all visual skills are included in this assessment.
Common visual behaviors of CVI recognized by major theorists in the field
Every child’s visual journey with CVI is unique, and a diagnosis is often made by ruling out other causes. However, there are common CVI visual behaviors, or characteristics, associated with CVI. They are:
Appearance of the Eyes: This is an assessment of alignment and eye preference. We assess whether both of your child’s eyes are pointed straight or whether one eye is turned in with the other turning out. Does your child favor or use one eye over the other? Does she alternate?
Movement of the Eyes: This is an assessment of ocular (eye-related) motor skills. We look at the way both of your child’s eyes move in different directions: horizontally, vertically, and diagonally. We analyze shift and gaze and how she responds to a moving target.
Visual Attention: This is an assessment of your child’s ability to look and sustain gaze for recognition. For example, your child might focus on only one small area while unable to process or understand other items. We consider her ability to maintain gaze in cluttered and un-adapted environments, as well as her ability to maintain gaze while ill or tired.
Access to People: Your child might have difficulty looking at faces and difficulty with facial recognition. Some kids have trouble interpreting facial expressions. For example, you might smile, and she won’t smile back or look into your eyes. Many parents describe their child looking “through” them or past them.
Response Interval: This is an assessment of her degree of delay in visual attention and delay in visual recognition. Your child might take a long time to look at an object and a long time to understand what she’s seeing.
Upper Limb Precision: This is an assessment of reaching while maintaining visual attention, reaching accuracy, and looking while exploring an object. Your child might hold something in her hands but can’t look at it, or she might gaze off into the distance while playing with an object. Or she might over- or underestimate her reach or reach tentatively.
Lower Limb Precision: This is an assessment of her ability to step accurately or to place her foot accurately, such as into a shoe.
Sensory Integration: This is an assessment of the impact of competing sensory input on her vision use. Your child might not be able to listen or feel a vibration while busy looking.
Visual Field Abilities: This is an assessment of visual field awareness and abilities to recognize materials in all fields. Your child might not respond to items in a particular visual field, such as peripheral, left and right, upper and lower. Or she might pay more attention to one side, with a visual deficit in another.
Impact of Motion: This is an assessment of her need for motion to gain visual attention; the distraction of environmental motion; the inability to follow fast-moving items; impaired perception of motion (speed, distance or direction of motion); and a phenomenon called blindsight (the ability to avoid objects while moving, without awareness of the obstacle). Your child might need an object to move to know it’s there. Or she might have trouble assessing distance and speed, such as a ball or car coming toward them.
Impact of Spacing/Object Arrangement/Clutter: This is an assessment of the number of objects your child can tolerate in a display. Sometimes spacing items out improves kids’ visual attention and visual recognition. Your child might have trouble with visual clutter — when too many things are in an environment, they might blend together. Or she might be able to identify items in a predictable line but not scattered on a table, because it’s too visually complex.
Form Accessibility: This is an assessment of the “accessible form.” Think about a common figure, like Donald Duck: Even though it’s a cartoon, we know it’s a duck. A child with CVI might have trouble making that distinction. Your child might see three-dimensional items but have trouble with photos, for example. Or she might see color but struggle with black and white or drawings.
Impact of Color: This is an assessment of how your child reacts to different colors and black and white, how she uses color for visual attention and object recognition and how she uses it as an overall strategy function. Many kids with CVI prefer one color over another. We try to see how color helps her understand the world.
Impact of Light: This is an assessment of the distraction of light, need for light, light sensitivity, attraction to light and need for backlighting. Your child might be so impacted by light that it’s just a visual target; other kids benefit from lighted objects.
Visual Recognition: This is an assessment of your child’s abilities to visually recognize known items or known classes of items. Your child might immediately recognize her favorite toy or cup but might not recognize a similar, unfamiliar object.
Visual Curiosity: Think about going to the grocery store. A child is constantly learning about shapes and objects as she watches mom or dad load up the conveyor belt from her perch in the carriage. A child with CVI might not absorb those incidental life lessons. This is an assessment of the accessibility of “incidental learning” for distance materials and events with and without compensatory supports and for all visual fields.
If your child is diagnosed with CVI, you might feel worried and overwhelmed. Keep in mind that CVI research and treatment are continually growing and improving, and help is available.
For additional information, support and resources regarding CVI, get involved with our Facebook Group.