Wednesday, April 21, 2010

It's a Vision Thing

How well your child performs in school depends a great deal on his ability to process visual information.

When we think of getting our eyes checked, we envision sitting behind the machine with all of the lenses, and the eye doctor turning them and changing them until we can read the small letters on the eye chart easily from a distance. That is called visual acuity; it is the ability of the eyes to see objects clearly.

Vision, on the other hand, encompasses a complex set of skills, and refers to how you interpret and act on your environment, based on what you're seeing. This ability to process visual information in turn is determined not only by your visual acuity, but by the fine motor coordination in the eyes, and the ability of the brain to perceive and interpret that information correctly. Do you ever wonder why some people are terrific drivers, responding immediately and efficiently to changing traffic conditions, demonstrating easy awareness of everything going on around them, keeping the proper distance away from other cars, merging into traffic without a second thought, fitting effortlessly into tight parking places -- while other people just don't have that innate skill? It's because the good drivers have such strong visual processing skills and can coordinate their responses so easily.

When I evaluate a child, I spend quite a lot of time looking at different aspects of the child's vision. I evaluate visual perception, visual motor coordination, and screen for weaknesses in the fine motor movements of the eyes. So much of our functioning depends on having reliable vision. I would venture to guess that most, if not all children who need occupational therapy have some impairment in their visual skills. This is because low trunk tone and poorly integrated postural reflexes affect the fine motor coordination of the eyes. They don't have a stable base of support from which to work.

The muscles of the eyes have certain specific jobs they have to do well in order for a child to be able to read and write:

Convergence is the ability of the eyes to pull in for close work.

Saccades are the movements of the eyes necessary for reading. The eyes must fix at the left side of the page, scan across the correct line of text, jump down to the next line, and fix again at the left.

Accomodation is the ability of the eyes to converge and diverge quickly for copying from the board. They pull in to write, then release out quickly as the child scans the board, then pull back in again as the child looks down at his paper.

If the child's eye muscles are weak and these things are difficult for him, a whole host of problems can result. The first problem is the child's attention for close work. If you're straining to see what you're doing, this is frustrating and exhausting. Your sitting tolerance and attention span are going to be shortened as a result.

Another problem caused by weak eye muscles is reading comprehension. When we first learn a skill, we use the frontal cortex, which is responsible for voluntary control, judgment, and reasoning, to power the muscles involved, until a lower part of the brain, one used for automatic skills, takes over. {Remember learning to type, and laboriously hitting the keys over and over while muttering "QWER UIOP" until all of a sudden, your fingers started to fly and you didn't have to think about it anymore? All that repetition drove it downward, out of the frontal cortex and into the cerebellum.} When the muscles in the eyes are weak and their coordination is poor, the frontal cortex continues to do the work of controlling them, but that is the part of the brain that is supposed to be comprehending, remembering, and synthesizing what is being read. So the child's ability to understand and analyze what he reads is limited, and he is going to find the activity of reading physically and mentally tiring.

If a child does not have the ability to fixate his gaze, not only is he going to have a hard time with reading and writing, he's going to be visually distractible, because any ambient noise or movement is going to cause his eyes to lose their fragile focus.

Children with convergence issues have a tough time on the playground. Many of the boys I treat can throw a ball like Roger Clemens, but they can't catch one to save their lives. Their eyes just don't pull close enough in to keep visual track of a ball as it comes towards them, and sometimes they see two balls and can't decide which one to try to catch.

A child who can't make visual sense of what is going on around him is going to be in a flight or fight state in a chaotic atmosphere, like on the playground or in the cafeteria. He can't figure out what's coming towards him, and so he can't figure out how respond to it. Couple this with tactile defensiveness, a condition that causes the child's nervous system to interpret people coming into his personal space as a threat, and you've got a child who either lashes out and becomes disorganized, or tries to remain invisible, in gym class or on the playground.

If your child complains of headaches, rubs his eyes a lot when it's time to copy from the board or do a lot of sustained close work, turns his head to one side in order to read or write, loses his place when he reads, has a hard time playing games involving fast moving balls or objects, has a short attention span for close work or resists writing or reading, it may be that he's got a vision problem stemming from lack of fine motor control in the eyes.

If I detect motor weakness in the child's eyes on evaluation, I will talk about it with the child's parents, but will not necessarily request that they follow up immediately with another professional. Sometimes a year of work in the sensory gym, strengthening the trunk and doing lots of activities that work the eyes while the child is moving his body against gravity in a variety of positions, is all that is needed to strengthen the eye muscles and improve reading and attention. If the child is still having issues after a course of treatment, then I recommend that he be evaluated by a neurobehavioral optometrist for vision therapy. I do, however, occasionally encounter a child who tells me "I see double all the time," and these children get referred immediately.

A good way to make sure that a developing child's eyes get what they need in order to function optimally is to provide the child with plenty of movement experiences and to make sure that the child spends a lot of time working his head and neck muscles against gravity. This includes lots of tummy time, being carried on a hip or in a backpack, minimal time in front of a television or computer, and lots of time spent outdoors. Craft activities and manipulatives work the hands and eyes together. Bubbles, whistles, and blow toys are also great for synchronizing the eyes, hands, and breath. Playing games like balloon tennis encourage tracking, and tag and hide and go seek encourage the child to scan the environment. I also like books like Where's Waldo, and old fashioned games like Concentration and Memory.


Paula said...

Wow, you are good! You've just described my child: she loses her place while reading and complains about her eyes itching and watering when she's looking at the smartboard in class. She's awful at anything involving a fast-moving object, but just last week played balloon badminton in PE successfully. Thanks for all the good suggestions!

Anonymous said...

Thanks, you are great!!!! Very helpful.