Understanding Cerebral Visual Impairment
Kia ora! my name is Fi and I work in Wellington, New Zealand as an RTV (Resource Teacher, Vision).
At present, quite a majority of my caseload are learners who have CVI (Cerebral Visual Impairment). This was an area in which I had very little knowledge when I came in to this career. It seemed large and intimidating, and I was not sure where to start when working with these learners. How could I assess their vision on a functional level? what strategies could I employ in order to assist them in developing their vision? Looking back, I must admit that I was at a bit of a loss as to how to proceed.
One of the most helpful things I learnt to begin with, was that learners with CVI display the following characteristics:
Colour preference: Learners with CVI have a strong preference for items of a particular colour. Warm colours, such as red and yellow are often preferred and are easier for learners with CVI to see.
Movement: Learners are visually attracted to objects that move, or have properties of movement. This may include the object having a shiny or reflective surface that simulates movement, or a light up toy.
Wait time: This is also known as visual latency. What it means is that there is a delayed response fro the time the object is presented to the time that it is visually regarded. Often the wait time will far exceed what is expected.
Complexity: Learners with CVI can have varying degrees of difficulty attending to something that is visually complex. This may include colours or patterns on an object, the number and placement of objects or even the complexity of competing sensory information.
Visual field preference: A learner may have a specific field preference or loss of part of their visual field which cannot be explained by an ocular condition. For example, a learner may only be able to view an item in their right field.
Light-gazing: This is common among learners with CVI. It is the tendancy to gaze at a light source or appearing to look 'through' or 'beyond' an object without focus. It can be known as 'non-purposeful gaze'.
Distance viewing: Difficulty viewing a target at a distance, beyond near space. Most learners with CVI find it easiest to view things when they are presented at a distance of no more than 30cm.
Visual reflexes: Visual blink and visual threat reflex are often absent or inconsistent.
Visual novelty: This refers to a difficulty looking at new or unfamiliar objects, and may present as not seeming to notice a new object or a complete avoidance of the object altogether by turning the eyes or the head away.
Visually guided reach: A learner with CVI may not look and reach for an item simultaneously. The learner may fix their gaze on the object, but as they reach for it, turn their head away.
At present, quite a majority of my caseload are learners who have CVI (Cerebral Visual Impairment). This was an area in which I had very little knowledge when I came in to this career. It seemed large and intimidating, and I was not sure where to start when working with these learners. How could I assess their vision on a functional level? what strategies could I employ in order to assist them in developing their vision? Looking back, I must admit that I was at a bit of a loss as to how to proceed.
One of the most helpful things I learnt to begin with, was that learners with CVI display the following characteristics:
Colour preference: Learners with CVI have a strong preference for items of a particular colour. Warm colours, such as red and yellow are often preferred and are easier for learners with CVI to see.
Movement: Learners are visually attracted to objects that move, or have properties of movement. This may include the object having a shiny or reflective surface that simulates movement, or a light up toy.
Wait time: This is also known as visual latency. What it means is that there is a delayed response fro the time the object is presented to the time that it is visually regarded. Often the wait time will far exceed what is expected.
Complexity: Learners with CVI can have varying degrees of difficulty attending to something that is visually complex. This may include colours or patterns on an object, the number and placement of objects or even the complexity of competing sensory information.
Visual field preference: A learner may have a specific field preference or loss of part of their visual field which cannot be explained by an ocular condition. For example, a learner may only be able to view an item in their right field.
Light-gazing: This is common among learners with CVI. It is the tendancy to gaze at a light source or appearing to look 'through' or 'beyond' an object without focus. It can be known as 'non-purposeful gaze'.
Distance viewing: Difficulty viewing a target at a distance, beyond near space. Most learners with CVI find it easiest to view things when they are presented at a distance of no more than 30cm.
Visual reflexes: Visual blink and visual threat reflex are often absent or inconsistent.
Visual novelty: This refers to a difficulty looking at new or unfamiliar objects, and may present as not seeming to notice a new object or a complete avoidance of the object altogether by turning the eyes or the head away.
Visually guided reach: A learner with CVI may not look and reach for an item simultaneously. The learner may fix their gaze on the object, but as they reach for it, turn their head away.
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