Did you know that the visual system has two jobs? I KNOW! Its first job is to make sure we can see the world clearly both near and far (this is called eyesight). Its second job, visual processing, is much more complex and we'll be diving into that in this post!
Visual processing (will now be referred to as just 'vision') is what the brain does to make sense of what we see in the world around us. It's a combination of many 'skills' including: visual fixation (attention), tracking, perception, eye teaming (convergence/divergence), focusing, and visual motor integration.
Fun facts about vision:
At birth, a newborns vision is very unclear and develops gradually; they can only see about 8-15 inches from their face (just far enough to see who is holding/feeding them).
Infants are also born color blind (but can process movement) and don't develop color vision until about 6-7 months old
Our peripheral vision processes movement and 'where' objects are in space
Our central vision processes color and 'what' an object is
The eyes are not developmentally ready to read until around age 7-8 years old
Vision is often the sense that becomes dominant
Our vision guides our movement and assists with problem solving regarding safety and survival
As most as 80% of learning is accomplished through the eyes!
There are over 15 visual functions critical to reading and learning.. WOW!
The brain is not wired to read; this is a skill we have to be taught
When reading, the right eye maintains our place on the line and the left eye reads the actual word.
Shocking statistics:
Only about 5% of vision difficulties are identified by the Snellen Eye Chart vision screening tool
1 out of 4 children have an undiagnosed vision problem that interferes with their ability to read and learn
According to the CDC, just 36.3% of children under 6 have had their vision tested
Only 7.4% children have been seen by an eye care provider during the previous year
25% of children ages 5-12 have vision problems that could be impacting learning
60% of children with diagnosed learning disabilities also have an undiagnosed vision problem
So.. do you think vision is important? WE THINK SO! Let's learn more.
Now that we have a better understanding on the two jobs of our visual system's, let's take a quick look (pun intended) at each skill that makes up vision - tracking, perception, teaming, focusing, and visual-motor integration. Children who have adequate vision skills will demonstrate a strong urge to learn to read, be excited to go to school, want to participate in sports, and will seek out new experiences.
There are 3 basic types of eye movements: fixation, quick shift saccades, and visual pursuits. Fixation is the eyes ability to hold a steady gaze without moving off target. Saccades are the eyes ability to make accurate jumps or shifts as we change targets. Pursuits are the eyes ability to follow a moving target. These three skills make up our tracking skills (or oculomotor skills) - the ability to control where we aim our eyes, and are essential for all aspects of learning.
What poor tracking skills might show up as:
Letters, words, and numbers appear blurry
Poor reading comprehension as the eyes jump off or around the page
Frequently loses place while reading
Skips or switches words, or omits complete lines of text altogether
The head has to move in order to follow a moving target or across the page of a book
Your child used his/her finger to maintain their place on the line while reading
Difficulty catching a ball
Visual perception is the brains ability to interpret, analyze, and give meaning to what we see. It's the skill we use to understand; not just see. Perception is further broken down into sub skills based on their function. These skills include visual discrimination, visual memory, visual-spatial relations, visual figure ground, visual closure, and visual form consistency. Visual perceptual skills help us recognize words we've already seen, tell the difference between p/q and b/d, sequence letters for spelling, scan a busy worksheet, mentally manipulate objects for math, and determine right from left.
Visual Discrimination - Our ability to discern between exact characteristics and differences between similar items/objects.
Visual Memory - Our ability to hold visual information for immediate recall.
Visual Sequential Memory - Our ability to remember visual information in the correct order.
Visual-Spatial Relations - Our ability to perceive the position of objects in space, in both relation to each other and to one's self.
Visual Figure Ground - Our ability to perceive and locate an object in a busy environment without getting confused by the background or surrounding images.
Visual Closure - Our ability to visualize a complete whole when given a partial picture or incomplete information.
Visual Form Consistency - Our ability to mentally manipulate forms and visualize the result.
Whew - that's a lot of things the brain needs to be able to do with what the eyes see!
What poor visual perception skills might show up as:
Significant difficulties with reading comprehension
Will often confuse similar words such as was/saw or then/when
May need to re aloud to self to remember what has been read
May omit, add, switch, or reverse letters within words when spelling
Have difficulty knowing right and left sides of own body (laterality) as well as right and left sides of other objects/people (directionality)
Demonstrate poor spacing between letters or words
May write at an angle or have poor awareness of lines on the paper
Eye teaming (also called binocular vision) is how we aim both of our eyes to one point in
space at the same time. This allows the brain to take two images (one from each eye) and create a single image with depth perception. There are two ways we 'team' our eyes: convergence and divergence.
Our ability to turn the eyes inward towards an object up close, while maintaining single vision, is called convergence.
Our ability to aim the eyes outward towards a distant object, while maintaining single vision, is called divergence.
Being able to create one image for the brain to process is critical for learning; especially reading. Children who have poor eye teaming skills are quick to fatigue, which results in frequent breaks from reading to rest the eyes. This often comes across as 'attention' difficulties, but it's really a clue that something is going on with the eyes.
What poor eye teaming skills might show up as:
Frequent eye rubbing and blinking
Poor attention at school; highly distracted
Frequent protests for practicing reading skills
Often say "reading is boring" - but it's just really hard
May have an eye that 'wanders' or turns out
Focusing is yet another essential skill for learning. We use focusing, also known as accommodation, to help us adjust our vision from near to far, and far to near; much like when copying from the board or shifting our visual attention from one object to another. Focusing happens when the muscles of the eye contract and relax to change the shape of the lens when shifting attention near and far. Difficulties with focusing and accommodation can only be detected and treated by an eye care provider. If you suspect your child might have difficulty focusing please contact your pediatrician or eye care provider for an examination.
Visual-motor Integration, is exactly what you think it is - using our vision to produce a motor action. The Visual Learning Center defines visual-motor integration as "... the ability to correctly perceive visual information, process it, and move our hands or body accordingly". Children who have good visual-motor integration often appear coordinated, have age appropriate hand-eye coordination skills, can manually manipulate a variety of objects (big or small), and usually don't have difficulty with handwriting.
What poor visual-motor integration skills might show up as:
Clumsiness
Poor hand-eye coordination
Dislike or have difficulty participating in sports
Have sloppy handwriting
Demonstrate a weak or poor pencil grasp
Difficulty writing or coloring inside the lines
Can't or really struggles to tie shoes
That was a TON of information that can often be overwhelming. However, our hope is that with this information you are better equip to spot visual difficulties your child may be experiencing that will or may already be impacting their learning. With school back in full swing, feel free to share this post with mom friends, teacher friends, or others who work with kids. Vision difficulties can be hard to detect especially now with distance/virtual learning. So, the more people to have this information the better the chance we have to get those kids the necessary help they need!
If you're wondering how OT's can help improve your child's visual processing skills, please reach out! We could talk about vision all day!
Play on friends,
Amy & Cassie
Sources:
College of Optometrists in Vision Development (http://www.covd.org)
Eye Can Learn (http://www.eyecanlearn.com)
American Academy of Opthamology (https://www.aao.org)
American Academy of Optometry (https://www.aaopt.org)
The Center for Vision Development (https://www.thecenterforvision.com)
Visual Learning Center (http://www.visuallearningcenter.com)
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