A definition
A child's vision is more than the ability to see the 20/20 line on the eye-chart.
"Vision is the process of deriving meaning from what is seen. It is more than the concept of visual acuity, clearness of sight, or 20/20 vision. Good vision also involves the ability to use the eyes for extended periods of time without discomfort, to analyze and interpret information and to respond to what is being seen. Vision is the learned ability to look for information and performance; it allows us to understand things that we cannot touch, taste, smell or hear. Vision is the process by which we percieve space as a whole. Good vision goes beyond 20/20 visual acuity, good optics and normal eye health. It involves normal binocular vision, ocular mobility and vision information processing skills, which allows us to respond to our environment."
Quoted from School Nurses Guide to Vision Screening.
The following
is a detailed definition of the vision skills needed for a child to be successful
in school and in life.
Tracking - while reading the eyes move across the page with saccadic movements which we normally percieve as a smooth flow across the printed line. Children with tracking problems tend to loose their place while reading, skip or transpose words. They are usually very slow readers as well since their eyes are jumping back and forth. In some cases the two eyes move independently making reading very difficult. Vision training is the most effective way to treat tracking problems.
Focusing - or accommodation refer to the ability to see clearly at all distances. Focusing also include the ability to shift focus from near to far and back.
Bilateral intergation - the visual input to the sense of spatial relationship. Good bilateral integration allow children to use their vision to monitor and adjust their bodies and maintain good balance and coordiantion. Mastering a scate board is a good example of bilateral integration. Children with poor bilateral integration may have difficulty learning to ride a bicycle and easily confuse left/right directions.
Visual motor integration - the visual input to the bodys finer motor suystem such as hand cordination. Children with poor visual to hand coordination may have poor handwriting and take longer time to complete written assignments. They usually become frustrated and lose concentration.
Visual spatial orientation - consistently knowing left from right either in relationship to their own bodies or the world around them. Many teachers consider letter reversal after age seven to be a symptom of dyslexia. Children with poor visual spatial processing have not developed adequate skills for spatial orientation (laterally and directionally).
Visual perception - the ability to interpret, analyze, and give meaning to what is seen. Visual perception skills consists of the following:
Visual discrimination - the ability to determine exact characteristics and distinctive features among similar objects or forms. While reading, this skill helps children distinguish between similar words, such as was/saw, then/when, on/one, run/ran, but/hot etc.
Visual memory - the ability to remember the characteristics of a given object or form. This skill helps children remember what they read and see by adequately processing information through their short term memory. And from there it is filtered out and transferred into long term memory. Children with poor visual memory may struggle with comprehension. They may have difficulty remembering what a word looks like, consequently they are poor spellers, and take longer time copying assignments because they must frequently review the text.
Visual spatial relations - the ability to distinguish deiffrences among similar objects. This skill helps children in understanding relationships and recognizing underlying concepts. This area is closely realted to problem solving and conceptual skills required for higher level science and mathematics.
Visualization - the ability tomentally manipulate forms and visualize the result. This skill helps children distinguish diffrences in size, shape, and orientation. Children with poor visualization (form-constancy) may frequently reverse letters and numbers.
Visual sequential memory - the ability to remember forms and characters in correct order. This skill is particularly important in spelling. They often subvocalize (wisper or speak aloud) as they write in an attempt to use their auditory sense to achieve the task. Recognizing pattern may also be a problem.
Visual closure - the ability to visualize a complete whole when given incomplete information or a partial picture. This skill helps children read and comprehend quickly. Their eyes don't have to individually process every letter in every word for them to quickly recognize the word by sight. This skill also help children recognize inferences and predict outcomes. Children with poor visual closure may have difficulty comprehending a thought. They also tend to confuse similar objects or words, especially words with similar beginning or ending.
Visual figure ground - the ability to percieve and locate a form or object within a busy field with a lot of visual stimuli. This helps children mastering details. Children with poor figure-ground skills are easily confused by too much print on the page. They may also have difficulty scanning text to locate specific information such as finding a word in the dictionary.
Good education develop all the above skills. All of the above skills are needed for a child to succeed in life. They are the fundamental building blocks upon which learning takes place.
