Behavioural Optometry
Understanding Sight and Vision
Optometrists define SIGHT as the ability of the eyes and pathways to discriminate and resolve small likenesses and differences (detail) critical to identification or determining what an object is.
But VISION describes a more dynamic and interactive process, essentially a whole INFORMATION PROCESSING SYSTEM developed through experience to gain understanding of the external visual space world, in order to extract meaning and make sense of a visual situation or event, enabling us to direct or co-ordinate PURPOSEFUL action in response. Vision is a learned process from which emerges an understanding of what is seen, where it is and how to react to it. Vision is much more than simply seeing clearly. It is the entire process whereby an individual understands what he sees. Not only is vision the understanding of that which is seen, but it is also the ability to use this information to direct one's own actions and motor activities (such as reaching out to pick up a glass or jumping over a stream) accurately and efficiently with a minimum expenditure of effort and energy.
For example, in a person driving a car, vision is much more than reading license plates clearly at two hundred feet: it is the total process whereby the spatial relationships between the cars and trucks and other things around are taken in and processed by the driver to guide the car properly to its destination without an accident and with minimum stress on the driver. Vision judges the relative speeds of the other cars, and alerts the driver to a pedestrian or another car in an intersection, or a door opening rom a parked car. Vision is what directs the baseball player to swing the bat at exactly the right moment at exactly the right place in space to make contact and hit a home run. Vision is what is used by students to understand what they read and to direct the pencil across the page to answer an essay test or fill in the blanks on a quiz.