(Roman-Lantzy, 2007, 2018)
- Color preferences (often red, yellow, saturated)
- Need for movement (to elicit/sustain attention)
- Visual latency (processing time)
- Visual field preferences
- Difficulty with visual complexity (array, target/object, multisensory, faces)
- Need for/attraction to light
- Difficulty with distance viewing
- Atypical visual reflexes
- Difficulty with visual novelty (easier with familiar objects, people, settings)
- Difficulty with visually guided reach (looking and reaching at the same time)
- Individuals with CVI notice color preferentially and sometimes, it may have a specific color such as red or yellow.
- My child seems to notice the red balloon; it’s like the green, blue, and purple ones don’t exist”, “My daughter loves Big Bird but never seems interested in the other Sesame Street characters”.
- High contrast, black & white materials are not helpful.
- Color is both a dorsal (“where”) and ventral (“what”) stream characteristic
- Individuals with CVI are attracted to sources of movement including shiny surfaces.
- “My daughter is always moving. She pushes tabletop activities away.” , “My son doesn’t look at himself in the mirror, but he loves to hold it to his face.”, “My child isn’t able to pay attention in class when the children or adults are moving around”.
- Movement can help attract attention and be a source of distraction.
- Movement is a dorsal stream characteristic and thus, can help establish and maintain visual attention.
- Visual latency is a delay between the time a target is presented and the time it takes for the individual to visually attend.
- “My son doesn’t always notice things right away. It seems like he needs extra time.”, “When my child is tired, she is really slow to see what I am showing her.”
- Latency can sometimes be misinterpreted as inattention.
4. Visual Fields
- There can be preferences for viewing targets in a particular field and, difficulties in others. Lower field losses are very common.
- “My daughter turns her head when she is really working to see something.”, “I constantly worry that my son will fall when we are near a curb outside.” ,“She constantly has bruises on her legs from tripping over things on the floor.”
- Visual field differences are common even when the eye exam is normal.
5. Visual Complexity
- Individuals with CVI may perceive the world as a “kaleidoscope” of meaningless color and pattern. This characteristic is associated with difficulties locating a target/element within complex arrays, with highly patterned objects, in noisy/busy areas, and in interpretating details of the human face.
- “She knows her family members but only glances toward their faces.”, “Our son loves when we read to him but rarely looks at the pictures on the pages”., “Our daughter’s teacher tells us that she seems to sleep much of the day in her special education classroom.” , “Our son is using auditory scanning for communication because he struggled to learn the symbols on the 64-choice visual array.”
- Complexity is a ventral stream characteristic
- Individuals with CVI may be attracted to sources of light and require specific light supports for activities at near.
- “Her favorite thing to look at is light.” , “When our son looks at books, he scoots over to the big living room window.”
- Even after light gazing wans, the need for light, especially backlighting, will remain. Properly implemented methods using light can help reduce visual fatigue.”
- Light is a dorsal stream function
- Despite the normal or near-normal eye exam, most individuals with CVI have difficulty perceiving targets at expected distances.
- “She mostly pays attention to things within reach.”, “He’s not able to see the animals when we go to the zoo.”
- There is a great reduction in incidental learning due to difficulties with distance viewing.
- The individual with CVI may fail to blink when touched at the bridge of the nose or in response to the visual threat.
9. Visual Novelty
- Individuals with CVI are able to see the visual world but are not able to interpret what is seen. As a result, they may prefer to engage with familiar objects, remain in familiar places, or show little curiosity in new settings.
- “My daughter wasn’t interested in the gifts she was given for her birthday. She cried until I let her watch her favorite video”, “The field trip to the museum didn’t seem like fun for our boy. We asked him what he saw or did and only mentioned eating lunch.”, “I thought she knew what a horse looked like but when we showed her a new book about animals, she said the horse was a dog”.
- This characteristic requires intensive instruction in salient visual features and comparative thought.
- This is primarily a dorsal stream characteristic
10. Visual Motor
- Individuals with CVI often use an unusual pattern of look and reach. They look toward a target, look away, then reach without looking.
- “No matter how much we remind him, our son seems to spill his drink when he reaches for it at mealtime.”, “Our daughter really struggles to stack blocks. She keeps knocking them over before she gets the block on top of the tower”.
- This characteristic may reflect the lack of integration of the dorsal and ventral streams of visual processing.
The Pediatric Cortical Visual Impairment Society (PCVIS) has done a wonderful job illustrating through photos of how these characteristics present in children who have CVI. I encourage you to visit that page.