At times i will say to parents of children that I
have assessed that they are not seeing
properly. The child all the while doesn't know
any different, thinking that seeing double
is normal or they have been labeled with
inattentiveness but are unaware that their
eyes aren't seeing properly. The parents
often will tell me that they have just seen an optometrist who said that their child has 20/20 vision, with good visual acuity. However seeing and vision are not the same. Vision deals with the part of sight that receives the image on the retina to be processed. Having 20/20 vision does not necessarily mean you have perfect vision. 20/20 vision only indicates the sharpness or clarity of vision at a distance. Seeing however is the physical process of sight, how well can we steer and control our eye muscles to see. It's made up of four elements: focus, teaming, fixation, and eye tracking. Together, this is what is called "eye fitness".
Focus: is the ability to see clearly and automatically whenever the eyes move from one focal point to another. It develops gradually over the first year of life.
Teaming: is binocular vision, or the ability of both eyes to see as one. With the eyes teamed up, depth perception kicks in. Depth perception is our ability to see the world in 3-D, which is critical to understanding that space has dimension:near/far, shallow/deep, and so forth. without depth perception, even the simplest things - like catching a ball, going down stairs, or steering a bike - would be impossible. Teaming is needed for convergence and divergence. Convergence brings the eyes together to see something up close. Divergence keeps the eyes parallel to each other to see things far away.
Fixation: is the ability to keep the eyes deliberately set on a single object or location without wandering. This is important because focus and comprehension require looking at a subject long enough for the brain to recognize and interpret it. Fixation is also an essential precursor to eye tracking.
Eye Tracking: is the ability to follow a moving object with your eyes while keeping your head still. Mature eye tracking has the appearance of smooth eye movement, but in fact, it is actually a series of instantaneous eye fixations, much like a motion picture camera.
This is where when parents and teachers are excited to start a child on the road to reading, need to stop and consider if he or she are ready or not. Not just cognitively, but physically. Reading requires a high level of eye fitness which depends on the type and amount of activity the eyes get in the early years.
Gill Connell and Cheryl McCarthy in their book A Moving Child is a Learning Child, explains :
by activity, it is not time spent in front of a screen. Screen play occurs on a flat, 2-D plane, which has limited value for developing 3-D eye fitness. focusing near and far is impossible on a screen. Furthermore, small screens (especially smartphones and tablets) do not let the eyes sweep widely to strengthen the muscles and fine-tune eye tracking. In Fact, these mesmerizing, confined images create conditions for ocular lock, a frozen stare with no awareness or cognition of what's being seen.
They go on to explain what happens if you start teaching a child to read, but her eyes just aren't ready ? While reading, she may:
If you want a child to love reading, there are two simple, powerful things you can do:
Other visual difficulties that could affect your child's readiness for reading and learning:
Irlen Syndrome (also referred to at times as Meares-Irlen Syndrome, Scotopic Sensitivity Syndrome, and Visual Stress) is a perceptual processing disorder. It is not an optical problem. It is not the issue of how well the external image lands on the retina but It is a problem with the brain's ability to receive and process the visual information coming from the retina along the optic nerve. This problem tends to run in families and is not currently identified by other standardized educational or medical tests. The use of tinted lenses or colored overlays are used to accommodate Irlen Syndrome. Also seeing an Optometrist who specializes in Behavioral or Developmental Optometry can help.
To learn more visit Irlen Syndrome.
Eye fitness is how well one can control and move there eyes while keeping the head still however the Vestibulo-Ocular Reflex (VOR) is about how well the eyes can stay still/fixed when the head moves. The Vestibulo-Ocular Reflex is very important to proper learning, reading, and writing. With this function, the brain receives sensory input when the head moves. In an instant, the Vestibulo- Ocular Reflex senses the movement and triggers the eye muscles to move the eyes in the opposite direction at the same speed to compensate for the head movement to keep the visual field stable. The Vestibulo-Ocular reflex needs to be fast. Clear vision requires immediate eye compensation to any head movement. This eye movement is necessary for the eyes to stay focused on an object while the head or body is moving even slightly.
If we didn’t have this reflex, our eyes would move with our head, causing bouncy and blurry vision. The head is constantly moving ever so slightly, even when sitting at a desk. Therefore, it would be almost impossible to focus on anything without the Vestibulo-Ocular Reflex. This is a problem that is not tagged at a regular vision check. The child doesn’t know anything different, so they won’t mention it, but react by avoiding schoolwork and reading. The child gets misdiagnosed as Dyslexic, Dysgraphia, Dyscalculia or ADD. Their eyes look away from the page they are supposed to be concentrating on because it blurs with slight movements. Movements like the slight turn of the head to read along a line.
Eye doctors don’t routinely test the VOR unless the dysfunction is severe enough to be noticed. A sensitivity on one side means there will be undersensitivity on the other. The undersensitive side can make a child clumsy and bang into things. If overactive, the child will get dizzy and may get motion sick.
Vestibulo-Ocular Reflex Test:
Have the child sit opposite you in a stationary chair. Hold up your index finger about 18 inches from the front of her nose. Have the child focus both eyes on your finger and tell her to slowly turn her head to one side only as far and as fast as she can while she can still see your finger, then ask her to turn her head back to the middle and stop. Do this ten times to the same side without stopping. The child should be able to keep her eyes fixed on your finger he whole time. If her eyes turn away toward her head motion, this is abnormal. Count how many times the eyes turned away from your finger and toward the direction of the head movement.
The more the eyes turn away from the finger, the more the reflex is underactive. If the child is able to maintain contact with the finger but gets dizzy afterward, it is a sign that the reflex is overactive on that side. The underactive reflex will be on the opposite side of the underactive hemisphere.
If your child tests positive for the VOR chances are there are other eye functioning challenges such as eye fitness difficulties and/or visual processing difficulties. But good news is that all these challenges can be helped though vision therapy, colored overlays, tinted glasses
and /or simple exercises you could do at home. At Nimble Kids eye fitness and VOR can be assessed and an initial Irlen Screening test can be conducted to check if your child's visual developement is progressing well.