Sensory
LINKS
Visual System
What is the Visual System?
The visual system relies on the use of your eyes as well as your brain. Light bounces off objects into our eyes through the pupil. The light passes through the lens and back towards the retina. At the retina, the light is then transformed into an electrical signal that is sent through the optic nerve and to our brains where we can recognise the object we’re looking at. The visual system works closely with many other systems including the vestibular, tactile and auditory systems in order to help us navigate our world to keep us safe and participate in everyday activities like reading and writing, locating objects, hitting and catching a ball. ​
[National Eye Institute, NIH, 2016]
What is Visual Processing?
Visual processing disorder refers to the reduced ability to make sense of the information that we receive from the eyes. This is not to get confused with difficulties with vision as a student who has 20/20 vision may still have difficulties interpreting and processing visual information. Visual processing disorders can affect individuals in different ways and take many kinds of forms including: ​​
[Neuroscientifically Challenged, 2015]
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Form Discrimination ​
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The ability to discriminate and differentiate the positional aspects of objects. Form discrimination allows the differentiation between different shapes and letters, i.e. the difference between the letter 'b' and the letter 'd'. This is a basic skill necessary in order to read and write.
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Visual Discrimination
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The ability to discriminate differences and similarities within shapes, patterns, colours, size. Visual discrimination disorders can affect a student's ability to read, recognise objects and scanning pictures for information.
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Visual Memory
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The ability to ​recognise, remember and recall visual information. This skill is important when reading and writing as a student would have to recall the formation of parts of a letter from memory.​​
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Visual Pursuit and Tracking
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The ability to tack movements with your eyes in a smooth and fluid motion ​
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Signs of Dysfunction
Hypersensitivity to Input
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Sensitive to lights and bright reflective objects
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Squints and covers eyes to certain lighting
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Easily distracted by visual stimuli (movement around the room, decorations, doors, windows etc.)
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Has difficulty in rooms that are too bright, colorful or dimly lit
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Has difficulty looking at TV, computer, and/or iPad screens for extended periods of time
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avoids eye contact
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looks down frequently
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enjoys playing in the dark
Hyposensitivity to Input
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Has difficulty telling the difference between similar letters (i.e. b + d and p + q)
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Frequently looses place when writing, reading or copying work from the chalkboard
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Difficulties with spacing between letters and words when writing
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Confuses left and right
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Difficulties discriminating differences between shapes, pictures, words symbols and objects
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Has difficulty locating items among other items (i.e. toys in bed, papers on desk and clothes within drawer)
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Poor body and spatial awareness