The Visual Process
Just about everyone knows what 20/20 is, or at least they think they do. Either way, this is what most people think of when they hear the word vision. Most eye doctors spend most of their time helping people get 20/20, often referred to as 20/20 vision. You may not realize this but 20/20 is nothing more than average eyesight. It is the ability to see a certain size letter at a certain distance. Some people can see better than 20/20, some cannot see 20/20 even with what are referred to as “corrective lenses.”
The funny thing is, the lenses we know as corrective are really not corrective at all. They are actually compensating lenses - crutches. Obviously some people need these crutches in order to see well enough to get around easily. These lenses do little more than mask an outward symptom – the inability to see clearly at some distance. Compensating lenses ignore any underlying reasons for the symptom they cover up. In fact they typically cause the underlying conditions, and the very symptoms they were intended to eliminate, to worsen as a result of wearing them as recommended.
There is much more to vision than just seeing clearly. That is why I avoid the word vision and use visual process when communicating with people. The visual process is a dynamic process that occurs in the brain, not in the eye. The retina (the inner back surface of the eye, which processes light) is in fact part of the brain. The visual process develops, and continues to do so throughout our lives. The visual process is primarily purposes with deriving meaning in order to direct our actions. The visual process is learned and therefore trainable at any age. People can also experience visual difficulties at any age. Behavioral optometrists are trained to analyze, diagnose and treat every type of functional visual condition for people of all ages.
So there should be much more to an eye exam that just trying to see smaller letters across the room. The much more thorough visual evaluation performed by behavioral optometrists is much more than that. We evaluate the ability to smoothly and accurately track a moving target, how efficiently a person is able to shift their eyes from one target to another, how consistently and accurately the brain is integrating the input from the two eyes and how stable and flexible the focusing ability is.
Here is the issue in a nutshell.
Vision, or something akin to it has evolved from some of the simplest creatures in the history of our planet, all the way up to what some consider the most highly evolved, most intelligent creatures in our planet’s history – dolphins, I mean human beings. Different creatures have different types of eyes for different reasons. Different types of eyes provide different types of advantages. For example, flies have compound eyes to provide maximum awareness of their surroundings to avoid being swatted by creatures that have, to their way of thinking inferior, simple eyes. However, I don’t think that, even if they were able to reach the gas pedal, their compound eyes would ever enable them to operate a motor vehicle. Those compound eyes provide a very different visual experience from our simple eyes. Other creatures, like lizards, have eyes on the sides of their heads to give them the ability to keep track of more of their surroundings.
Some creatures have their eyes stuck right on the front of their face, pointing straight ahead. The greatest advantage provided by this set-up is the ability to judge space and depth with a great deal of precision. This was initially helpful in tracking and catching moving prey. It is much easier to gauge distances with this type of equipment. This means you can eat, and live to attempt swatting flies for another day. In ALL creatures vision provides not only information, but also the ability to perform some activity that involves movement.
Nowhere in creation have eyes evolved for the task of reading, nor for staring endlessly at a computer screen. There are two important factors that make these tasks stressful for a visual system that is designed as ours is. First, these activities are two-dimensional. Second, they involve very little movement other than a few fingers stumbling around a keyboard, or lips moving to read a few difficult passages. For a visual system designed for action and three-dimensional seeing, the constant, prolonged encounter with a two-dimensional surface is like walking into a brick wall. We are all happier to be able to walk around in any direction we would like. Walking straight into a solid wall for hours on end, day after day would cause not only extreme boredom, but severe frustration, stress and fatigue. This is similar to what is happening to our visual systems when we subject them to prolonged exposure to two-dimensional tasks.
Visual behavior without movement presents a similarly bad situation. Our eyes are in constant motion. If not for the fact of these constant microscopic eye movements, we would not see. Period. Experiments have been done that simulated a situation where the eyes were perfectly still. They showed that if an image was projected to the exact same spot on the back of the eye it would fade from conscious awareness in a matter of seconds. This constant wiggling of the eyes keeps this from happening. The point here is that, from the bottom up, vision is intimately involved with movement. However, we are more concerned here with movement of the body. Our visual systems are best suited to activities that involve our moving around in some way.
I hope you can see that the visual process is so much more than just sitting in a chair reading letters on a wall. It is complex, elegant and pervasive in human behavior. Don’t settle for an eye exam; have your visual process evaluated as soon as possible. All children should receive a thorough visual evaluation before entering school because most visual problems go undetected without the input from a behavioral optometrist.
There is much more to vision than just seeing clearly.
Contact Dr. Gallop for more information about behavioral optometry, vision therapy or any other questions you have about your own visual process.