An awareness of the world about us
Visioncare optometry explains what behavioural/developmental Optometry is and its benefits.
A child is born with a pair of eyes but without a visual world.
Vision is learned and is built on experience. We know not to worry about a moving shadow and we know the taste of an orange but all this has to be learned, during infancy.Traditional Optometry ensures that the image lies in focus on the retina and that the eyes are healthy and point in the same direction.
However, vision (as opposed to sight) is far more complex. It is learned and interacts with other senses, building up an awareness of the world about us, enabling and guiding us through space. Anything that is learned can be taught.
There is more to reading than having clear text and this is summarised in the five F’s
Focus – When targets are at varying distances then the muscles around the lens alter the focus to keep it clear. This is a moving dynamic action which needs constant adjustment, in a moving world. Dysfunction in this area means that effort is required to try and keep the target clear at all times and at all distances. It is closely linked with convergence, which is the ability to bring the input from the two eyes together to form a single image
Following – The ability to track a moving object depends on eye control and this must be learned and can be taught. Dysfunction here results in students becoming lost on the page and will need a finger to keep the place. They are also nervous about movement and motion. This is closely linked to saccades, which is the ability to jump accurately from word to word. This uses the integration of central and peripheral vision to help forecast eye movements and increase the rate of reading by the more accurate positioning of the eyes.
Fixation – The eyes don’t tell the brain what to see, but the brain tells the eyes what to look for. The eyes then must search for their target. Dysfunction here means that the student cannot find his place, or relocate his place when copying from the board. This again must be learned.
Fusion – When the two eyes work well together they create stereopsis in the brain giving an idea of space and location in that space. This gives grounding and awareness of where I am, where it is and the distance between the two. Dysfunction in this department is demonstrated by children who choose to stay near the wall and who are unable to move freely in open spaces.
Functional field – Traditionally it is the bottom line or 20/20 (6/6) vision which is the ideal (what is it?). Behaviourally we ask – where is it, when is it and what can I tell you about it!? Do I understand what this means? So that a student who has a greater spread of attention and can find the start of a new line and scan the text, will read more easily. Dysfunction with the functional field is more to do with attention. A narrow area of attention results in tunnel concentration. This again is a learned skill.
Last of all, we need the brain to have a visual and working memory. If information cannot be comprehended and retained, there is no effective filing system for recall in the future and learning is impaired.
All the above issues steal the individual’s ability to concentrate, leaving less attention available for comprehension and learning.
Eye movements are classed as using ‘Fine Motor’ control. Sometimes we find that a child has no control over their Gross Motor movements of arms and legs. They cannot sit still or move one limb independently of others. These Gross Motor skills need to be addressed first. Trampette work, footwork as in skipping and hopscotch help to gain control in these areas whereupon we can move on to developing fine motor skills, used for eye movements and handwriting.
Originally written by: Ruth Perrot of Visioncare Optometry
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VisionCare Optometry is your local Independent Optometry practice in the Castleford and York areas. Providing timely and appropriate visual assessments and professional assistance to meet the visual needs of their patients.