Visual Processing Examination
What is Visual Processing?
Visual processing is a broad term used to describe how the brain interprets and responds to what the eyes see.
Sometimes patients can have normal visual acuity (20/20 vision), eye health and eye coordination and still have trouble with reading, writing, orientating themselves in space (clumsy), or making sense of visual information in visually crowded areas or contexts.
How does visual processing work in the brain?
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When the eyes "see" an object in front of them - the light image of the object gets transmitted from the front of the eye to the back of the eye (retina). The photoreceptors at the back of the eye take the light signal and make a chemical signal and sends down the optic nerve, through the brain to the occipital lobe.
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The occipital lobe sorts the information based on size, shape, orientation, and location. It visually processes the "image" your eyes see to make a representation of it in the brain using visual discrimination
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The occipital lobe then sends the visual image to the parietal lobe to visually process where the image is in relation to the person - Is it on the right or the left? Is it in front of or behind this other object? This is called visual processing of laterality, directionality, and spatial orientation. How the parietal lobe decides to move the body in response to the visual image is called spatial planning.
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Simultaneously, the occipital lobe sends the visual image to the temporal lobe to visually process what exactly the image is - Is it a letter or word? What does the word mean? Have we seen it before? This requires not only visual discrimination, but also visual memory and language skills.
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The frontal lobe then takes that spatial and object recognition information and puts it together, it decides what we want to do with the visual information and then sends signals down to the brainstem and cerebellum to make the eyes respond to the information
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The more objects we have to look at (like a grocery store aisle) or the more complicated the cognitive task (reading a book) the more visual processing skills are needed. So patients with visual processing problems may have difficulty with visual crowding, distraction, inattention and overwhelm
What is a visual processing exam?
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The visual processing examination evaluates each individual visual processing skill and identifies relative strengths and weaknesses for the patient
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A patient may have a weakness in one of these areas due to a recent brain injury or stroke, or they may have had it since childhood due to a developmental issue.
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By identifying the relative strengths and weaknesses, we can advocate for adaptations in the home, school or work environment(s) and recommend rehabilitation methods to strengthen these perceptual skills.
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Dr Theis has extensive training and experience in visual processing evaluations in patients with brain injury as well as developmental (pediatrics) cases.
What to Expect with a Visual Processing Exam
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In order for the brain to accurately visually process, it must have normal visual acuity, eye health and eye coordination.
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Therefore, a visual processing examination can only be completed after a comprehensive neuro-optometric evaluation, to ensure that the difficulty with visual processing is truly a higher-order (cognitive) dysfunction and not due to a lower-order (eye/eye-coordination) dysfunction. Visual processing skills emerge as a result of proper eye teaming skills.
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The visual processing examination is done on a separate day after the neuro-optometric evaluation. It requires multiple tests and can take up to 1-3+ hours for testing depending on the cognitive level of the patient. After testing, the results will be evaluated by Dr. Theis and she will provide a summary letter and discussion with the patient in a subsequent follow up visit.
