Our ancestors had hunter’s eyes for survival in the wilderness: their vision was designed for spotting game and enemies at a distance.
It is only in the last 100 years that we have been forced to deal with sustained, near visual tasks, and the resulting stress on the visual system has produced many symptoms and problems.
If you experience headaches, blurred vision, tired, itchy or watery eyes or other vision linked problems, you may already know how uncomfortable sustained visual stress can feel. Your discomfort may be related to the heavy visual load of working at near distances – when reading or using computers.
If you are a student, you may read almost three times the number of textbooks your grandparents did! If you are employed in an office, you probably use your visual system for hours of close work. If you work with computers you may spend much of your day looking at a computer screen. These tasks can all contribute to visual stress.
Even if you have 20/20 eyesight (in the UK referred to as ’6/6′) you may have difficulty working at close tasks. The term 20/20 simply means you see well at distances of 20 feet (6 metres) or more, it does not usually refer to how well you see at 30-50 cms (12-16 inches), the distance at which you do most of your close work.
Vision is much more than simply seeing clearly
It is the entire process whereby an individual understands what he or she sees. Here the word ‘see’ is used in a broad context. Not only is vision the understanding of what is seen, but it is also the ability to direct one’s own actions and motor activities accurately and efficiently with a minimum expenditure of effort and energy.
For example, when driving a car, vision is much more than reading the number plate clearly at the legally required distance. It is the total process whereby the spatial relationships between the cars, lorries and other objects 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 pedestrians, other cars, junctions and other hazards. Vision is what directs the cricket player to swing the bat at just the right moment and at exactly the right point in space to make contact with the ball. Vision is what is used by students to understand what they have read and to write things accurately on the line of a page.
It has been said that the most complex organ in the known universe is the brain and the most complex activity that the brain does is vision. 87% of all learning is done through vision, 6% through hearing and 7% from the rest of the body. Vision is therefore the dominant process in the human species. Fortunately, it is also the most accessible to improvement through the use of Behavioural Vision Care with lenses and vision training.