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By Dr . Sharon Snider
This was a question posed to me recently by a young mother , and the answer is most definitely ‘ Yes ’.
20 / 20 vision alone is not enough to function successfully in school , sports , and eventually work . Five additional areas of visual performance are required and include eye teaming , focusing , tracking , visual perceptual skills and functioning ( kinetic ) visual fields .
Eye Teaming refers to the ability of the two eyes to work together and is accomplished by six muscles behind each eye operating properly . If the eyes misalign slightly , even a child with 20 / 20 vision can experience blurry vision . And depending on the amount of misalignment , reading-related symptoms such as perceived movement of the print , double vision , eyestrain , headaches , and stomachaches may occur .
Focusing , as a visual skill , is controlled by a muscle in the eye which changes the shape of the lens . If this muscle fails to function efficiently , visual tasks such as copying from the board to the book are tedious , taxing , or downright impossible , and this is true even for the child who has 20 / 20 acuity . Additional symptoms may include blurred vision , headaches , red / watery eyes , and avoidance of reading-related tasks .
Tracking refers to the ability of the eyes to move from target to target to target quickly and efficiently . Tracking is mediated by the eye teaming muscles , the focusing muscle , and the vestibular system . In a reading task , the task could be tracking letter-to-letter-to-letter to read a word , or word-to-word-to-word to read a sentence , or line-to-line-to-line in order to read a paragraph . For a sportsrelated tasks , following the flight of a ball rapidly moving towards one ’ s head would be a desired skill . However , many children - with 20 / 20 vision - are unable to read easily or to perform well in ball sports due to poor tracking skills .
Two final areas that most parents or professionals are unaware of are the areas of Visual Processing and Functioning Visual Fields both of which are brain-driven visual processing tasks . And again , a child may have 20 / 20 acuity yet score poorly if the brain is unable to correctly analyze the visual information coming from the eyes . Chronic ear infections / tubes , surgery with anesthesia , environmental toxins , and concussions to name a few may be contributing factors to impaired neurological function .
If an eye teaming or focusing problem is present , a child with 20 / 20 visual acuity can still experience blurry vision . When a tracking problem is present , copying from the board to the book is difficult or playing ball may be impossible – even in the presence of 20 / 20 vision . In the presence of visual processing deficits , handwriting may be sloppy , letters may be reversed , a child may read the same word five times and never recognize it was just read , and / or spelling may be impossible – even with 20 / 20 vision . Impaired functioning fields may produce tunnel vision causing a child with 20 / 20 vision to be unable to find the book ( or shoes , or keys , or …) right in front of them
The only way to fully assess a child ’ s visual status is through a test battery termed a Neuro-Visual Assessment ( NVA ). An NVA is designed to thoroughly evaluate each area of visual performance . When weaknesses are noted , appropriate treatment can then be provided to correct the problem . A child can only be successful when all the visual skills are functioning properly . You can contact Snider Therapy Centers at ( 205 ) 408-4414 to inquire about scheduling a NVA .