APPEARANCE OF THE EYES

Since CVI is a brain-based vision loss, unless a coexisting eye condition is present, there are not many ocular abnormalities that are linked to it. However, a misalignment of the eyes is a common occurrence in children with CVI. Typically, a child will present a misalignment of the eyes (Strabismus is common in children 7 years and under, while Amblyopia is common in older children and adults (Lueck, Dutton, 2015)). In order for children and adults to use their vision optimally, the eyes need to work together to focus and send clear images to the brain. When there is a misalignment of the eyes, whether it is one eye turning inward (esotropia), outward (exotropia), downward (hypotropia), or upward (hypertropia), the eyes will not be able to see as clearly (Lueck, Dutton, 2015). Alternating eye alignment may also occur in certain tasks. This misalignment can be more pronounced when a child is tired, sick, or overwhelmed (Perkins School for the Blind, 2022).

MOVEMENT OF THE EYES

The ability to move one’s eyes in a smooth, coordinated fashion is commonly impacted in children with CVI. A disorder in the movement of the eyes can cause a child difficulty in fixing their gaze to gain visual attention and recognition (Lueck, Dutton, 2015). The ability to look at objects in the 3-dimensional world or 2-dimensional objects on a piece of paper involves carefully coordinated mechanisms of both eyes working together. An individual with CVI may have difficulty recognizing that the object in front of them is a 3-dimensional object because the inability of smooth movement of the eyes prohibits them from sustaining vision long enough to see depth. They may be unable to smoothly shift their eyes to follow moving objects or to read what is on a page in front of them. (Lueck, Dutton, 2015). Some children with CVI also have Nystagmus, an involuntary movement of the eyes. In children with Nystagmus, they may have a “null-point:” a place where they move their eyes to minimize the involuntary movement to see more clearly (Lueck, Dutton, 2015).

IMPACT OF COLOR

Color may play an important part in the lives of individuals with CVI. Color can assist these individuals in understanding and recognizing their near and distant world around them. Some individuals with CVI have one preferred color that allows them to visually attend better and may help with visual recognition of an object, while others prefer any bright, saturated color (TEACH CVI Screening). They may use color to help identify or find certain objects or to help recognize the people in their lives. Color coding (identifying an item by its color as opposed to its shape) is something that may occur to support their visual recognition and visual attention. When items are multicolored or against a multicolored background, visual attention, identification, and recognition may be impacted – these individuals may prefer items to be one color to be able to look at them as a whole, rather than individual parts. Color highlight around certain parts of objects or text on paper map help draw visual attention (Roman-Lantzy. 2018) to those specific parts/areas and support visual learning and understanding (Bennett, 2022).

IMPACT OF LIGHT

The use of light can serve as a support or a barrier in visual attention and recognition. Light can play an important role in individuals with CVI. It can be used as a way to gain visual attention and recognition. Some individuals require light to be able to visually access and recognize items. Materials that are presented with backlighting can reduce visual fatigue and assist the individual in gaining visual recognition, sustained gaze, and visual attention. Individuals with CVI may also be photophobic or have a sensitivity to light or a brightly lit environment. Signs of photophobia include avoiding light, squinting, keeping their head down, and difficult with dark-light transitions (Bennett 2022). Light gazing is an involuntary and sometimes uncomfortable action that occurs when an individual is visually drawn to light (TEACH CVI Screening) (overhead, doors, windows), and it may be difficult to get them to disengage (CVI Scotland 2022). Light gazing may occur when the child is tired or stressed (Roman-Lantzy. 2018)

IMPACT OF MOTION (ATTENTION TO MOVEMENT/ IMPAIRED PERCEPTION OF MOVEMENT)

Motion can have supporting effects or act as an obstacle for individuals with CVI. Individuals with CVI can use motion as a way to gain visual attention. However, in an environment with constant movement in the periphery, motion could cause the individual to become distracted from the visual target, or it could draw their visual attention to it making it hard to disengage (Bennett, 2022). Some individuals with CVI have trouble with the perception of motion (TEACH CVI Screening). They may be unable to see an object unless it’s moving or has a shiny quality to it (the light reflecting from the object resembles movement) (Roman-Lantzy, 2018), and they may have difficulty judging speed, distance, and direction of motion. This can be a cause of stress when these individuals are traveling throughout their environment. This difficulty understanding of motion can lead to “looming behavior” in which the object moving around them is unable to correctly be judged, causing the individual to pull away from a person or objects if approaching too quickly (CVI Scotland, n.d.). Individuals with CVI may also have difficulty seeing an object if it is moving (Lueck, Dutton, 2015).

RESPONSE INTERVAL (DELAY FOR LOOKING/DELAY FOR UNDERSTANDING/VISUAL FATIGUE)

Response intervals are the length of time between when an individual is presented with an item and when the individual realizes there is an item in front of them, visually attends to that item, and recognizes that item (Perkins School for the Blind, 2022). Individuals with CVI often have a delay in response when presented with materials. This interval can vary, depending on time of day, alertness, visual fatigue levels of the individual, and how accessible the materials presented to them are (lack of visual clutter and crowding – both around the item and environmentally) (Perkins School for the Blind, 2022). Response intervals are unique to individuals and may decrease as the individual becomes more familiar with an item, the environment, or the task expected from them (Roman-Lantzy, 2018).

Signs of Visual Fatigue can include, but are not limited to:

• Vocalizing
• Putting head down
• Staring off into space
• Rubbing eyes
• Turning away
• Laughing
• Trying to socially engage
• Showing lack of visual regard
• Appearing sleepy
• Showing frustration behaviors (crying)
• Looking unfocused
• Avoids looking
• Looks down more
• Gets silly
• Gets fussy
• Doesn’t pay attention
• Starts rejecting things
• May start scratching or yelling

VISUAL FIELD FUNCTIONING

Visual fields are the entire area that individuals can see when they look straight ahead. Staring straight ahead, objects are seen clearly through central visual fields, while objects in the periphery are not as detailed. An individual with CVI may have a preferred visual field (Roman-Lantzy, 2018), or they may have reduced visual fields depending on where the damage in the brain is (Perkins School for the Blind 2022). They may demonstrate visual neglect in a specific visual field and this loss follows their head and eye movements (CVI Scotland). They may tilt their head to look at something (TEACH CVI Screening). Individuals with CVI may be unable to be visually aware of, visually attend to, or visually recognize items when they are not presented in their visual fields. Individuals may have difficulty in their lower visual fields, making it difficult to negotiate stairs, curbs, items on the ground, or various floor boundaries/surfaces (Lueck, Dutton, 2015). Some individuals may have difficulty viewing an object when it appears in multiple visual fields because they lack the ability to focus on an entire scene – they can only look at one thing at a time. This is known as Simultanagnosia (CVI Scotland). The following factors can affect an individual’s ability to use their visual fields: fatigue, competing sensory stimuli, clutter, movement, auditory distractions and noisy places, and crowded environments (Perkins School for the Blind, 2022)

ACCESS TO PEOPLE

An individual with CVI may be unable to make eye contact while speaking to others (TEACH CVI Screening). They may not look toward the faces of individuals talking to them, and if they do, they may look “past” them or not recognize them at all (Bennett, 2022). This may be because they have a general disregard of faces (Roman-Lantzy). They may not be able to identify other people in crowds or photographs and may mistake strangers for people they know (Lueck, Dutton, 2015). Facial expressions, body posture, and other gestures may be difficult for these individuals to decipher (Lueck, Dutton, 2015), leading to potentially inappropriate responses in social gatherings and situations (Bennett, 2022). Individuals who lack facial recognition skills may use a variety of compensatory strategies to improve their ability to remember people. Some of these strategies may include relying on hair color/pattern, the sound of others’ voices, the context they are in, etc. (Bennett, 2022). Looking at faces requires visual attention, and if a child with CVI has difficulties in visual attention, they will have difficulties looking at faces and understanding facial expressions.

FORM ACCESSIBILITY

Form, or how items are presented (3-dimensional, 2-dimensional, real object, abstract images etc.), preferences can vary between individuals with CVI, and it is best practice to provide literacy materials in various forms. Individuals with CVI may have better access to literacy materials if they are presented as 3-dimensional, real objects rather than printed on paper (Roman-Lantzy, 2018). Some individuals may be able to recognize a 3-dimensional object, yet unable to recognize that same object if it was printed on a flat piece of paper. These individuals may be unable to recognize a cartoon or drawing of an object (abstract), or more complex drawings (pictures of a situation) (TEACH CVI Screening) but may be able to recognize the real object printed on a 2-dimensional piece of paper. Real-form color images may be able to be recognized as opposed to black and white real-form images. They may use compensatory strategies to decipher an image (color coding, environmental context), however, if the image is not in the preferred form for best visual attention and recognition, it will not be accessible to the individual (Bennett, 2022).

VISUAL GUIDANCE OF UPPER LIMBS

An individual with CVI may present a lack of visually guided reach, or an inability to use their eyes and upper limbs (arms/hands) simultaneously (Roman-Lantzy, 2018). They may have to look at an object to locate where it is, look away, and then reach for the object without looking (TEACH CVI Screening). Lack of this visuo-motor coordination may be due to lack of visual access of their environments. This lack of visually guided upper limbs can lead individuals with CVI to over/under reach for an item, display an inappropriate grip while reaching for an item (Lueck, Dutton, 2015), have difficulty placing items on shelves or tables (alone or in relation to other items – next to, behind, etc.), or displaying a wide sweep of the area to locate an object because they are unsure exactly where it is in space (Bennett, 2022). All of these are characteristics of their visual brain not processing where an item is in relation to their body. This lack of visual guidance to the upper limbs also translates to the activity of writing, leading to inaccurately spacing words and letters and inappropriately holding the writing utensil (Bennett, 2022). It is important to note that visual complexity, background clutter, amount/lack of light, and how complex/simple the environment is all contribute to success or lack of visuo-motor skills (Bennett, 2022).

VISUAL GUIDANCE OF LOWER LIMBS

Eye-leg/foot coordination, or visual guidance of lower limbs, is the ability to connect what is in the visual environment enough to navigate through it safely on foot. Individuals with CVI may not have, or have reduced, visual attention to their legs and feet, making it difficult to walk on uneven ground or different types of floor boundaries (e.g., carpet to wood) (Dutton Inventory). They may struggle with putting their shoes on or stepping off a curb (Bennet, 2022). Lack of visual guidance of the lower limbs could cause individuals to trip over objects and furniture on the ground (Bennett, 2022, TEACH CVI Screening)). A fixed environment (no furniture changes) in which the floor is clutter free and the walls/rooms are removed of crowding and complexity will have a positive effect on these individuals in relation to their visual guidance of lower limbs. An environment that is constantly changing with objects on the floor, and the room seems overall crowded and cluttered will have an impact on how an individual with CVI uses their lower limbs to navigate.

SENSORY INTEGRATION WHILE USING VISION

Sensory integration is the ability to take in, process, and organize all environmental and biological stimuli in everyday life (Perkins School for the Blind, 2022). Visual attention may be hard to obtain or maintain when there is competing sensory stimuli around an individual with CVI – especially auditory stimuli (Roman-Lantzy, 2018). Visual attention may be impacted by familiar and unfamiliar sounds. Sounds may cause an individual to lose focus to turn to explore the sound, or they may startle the student (TEACH CVI Screening). Movement, whether it’s being physically moved, touching a moving object, or objects moving around them in their environment, may be too much to visually attend to a task. Individuals with CVI may not be able to use multiple senses at the same time and will only succeed when one sensory modality is being challenged at a time (Perkins School for the Blind, 2022).

IMPACT OF CLUTTER AND CROWDING: IMPACT OF SPACING AND OBJECT ARRANGEMENT

Some individuals with CVI prefer items to be presented on a solid color background, reducing crowding and clutter. If items are placed too close together (crowding) or there are many different items in the individual’s view (clutter), the individual may struggle with visual attention and recognition. Visual attention and recognition may also be impacted if the items are not in a predictable order or place (Bennett 2022). The individual may also have a difficult time looking at all of the items – they may only be able to see one item at a time (simultanagnosia). When items are presented with crowding and clutter, it can be upsetting to them. Some individuals may not be able to find a certain toy when it is surrounded by other toys of similar size, shape, and color (TEACH CVI Screening). 2-dimensional worksheets/pictures, 3-dimensional real objects, crowded environments (Lueck, Dutton, 2015), classroom with too many items on the walls, floors, surfaces, etc. can all be considered cluttered and crowded if presented a certain way (Bennett, 2022).

VISUAL ATTENTION

Visual attention is the ability to locate and fixate on a target, and it is something that individuals with CVI sometimes struggle with (TEACH CVI Screening). It is important to note that just because an individual with CVI can look at something, does not mean they know what they are looking at. Looking and understanding/recognizing are fundamentally different. There are multiple factors that will impact an individual with CVI’s visual attention. These factors are described in detail in this report, but in summary, they are: light (environmental/backlit), motion, color, how far away the item is (Roman-Lantzy, 2018), how familiar the item is to the individual, if the item presented matches the form that is most accessible to them, the context the item is presented in, if the item is presented in their preferred visual field, and if the item is presented with or without crowding and clutter. How the individual is feeling (happy, sad tired) is also a factor that will impact visual attention. It is important to create an optimal environment. A quiet environment without competing sensory stimuli will benefit the individual’s visual attention. If any of these factors are present, visual attention may take longer, may not be as sustained, or may not happen at all (Perkins School for the Blind 2022) (Lueck, Dutton, 2015).

VISUAL CURIOSITY

Incidental learning is learning that occurs unconsciously due to individuals interacting and observing the world around them. Due to visual limitations and inability to process an entire visual scene, individuals with CVI may have incidental learning that is stunted and limited. Because of this limited exposure to incidental learning, individuals with CVI may struggle to understand what is around them. They may have less interest in exploring environments and may find it difficult to discern how their environment relates to themselves, struggle with finding interest in objects and people around them and be unable to interact with (or recognize) individuals and items are various distances away. Because of these visual curiosity limitations, information that would otherwise be learned incidentally must be directly taught. A multi-sensory learning approach which incorporates the individual’s compensatory strategies may improve their visual curiosity (Perkins School for the Bind, 2022).

VISUAL RECOGNITION: DIFFICULTIES IN NEW ENVIRONMENTS/DIFFICULTY WITH VISUAL RECOGNITION OF NEW ITEMS

Visual recognition occurs on a daily basis for everybody, and it entails sorting through a catalog of images and concepts learned in the past from the brain to determine if what is being looked at is understood, and if it is similar to items and concepts seen or learned about before. This is an area that individuals with CVI may struggle with, due to their limitations in visual attention and understanding. Because of this, new and unfamiliar places may cause stress and anxiety (TEACH CVI Screening). The visual recognition of an individual with CVI can range from now knowing what the item is at all, to knowing what the item is based on certain contextual clues in specific environments, and it includes categories such as objects, animals, people, or facial expressions. It may be difficult for an individual to form visual memories that can later assist in visual recognition (Lueck, Dutton, 2015) due, in part, to the individual not being able to see the entirety of the object (impacted visual fields or simultanagnosia), lack of opportunities to see and interact with the object, and inability to generalize about an item or store it into visual memory. An individual may be able to visually recognize highly familiar items (like their own cup) that they interact with and use often throughout their day, but novel items (other cups of various shapes and sizes) and environments may be more difficult for the individual to recognize due to lack of visual experience with them (Roman-Lantzy, 2018). They may be able to visually recognize items that are in predictable places or contexts, and they may use their other senses as a compensatory skill to assist in recognition. These visual recognition difficulties depend on how often they are exposed to the items in 3-dimensional and 2-dimensional forms, how far or close the item is to the individual, and what the environment or context surrounding the item is (Perkins School for the Blind 2022).

COMPENSATORY SKILLS

Compensatory skills can incorporate any of the senses: sound (from the object itself or auditory cues), touch (tactile exploration), and proprioception. They can also incorporate the use of color supports and color coding, memory, context clues, prediction skills, and the use of expressive and receptive language (Perkins School for the Blind, 2022).