Do you know anyone who drives a car? Do you drive a car yourself? If you are a driver you may recall that in order to get your driver’s license you had to pass one test having to do with your visual ability. You had to read the letters on the wall or in a fancy box to measure your eyesight or visual acuity. Passing that eye test meant that you could see at least 20/40 (in most states), which means being able to see a 2/3” tall letter at a distance of twenty feet (20/20 means being able to see a letter half that size at the same distance). There are no other visual requirements for normally sighted people to get a driver’s license.
It’s entirely possible that I felt compelled to write about this particular topic at this moment in time because my daughter recently got her driver’s permit soon to be a license. And these days for those living without easy access to public transportation, as we do, a car is as much standard equipment for today’s teen as a smart-phone…or so I’m told. In any event, the visual process is critical for driving, as it is for so much of what we do.
Clear distance eyesight actually has little to do with either effective or safe driving. Obviously the human visual system was not designed for traveling in small boxes at unnaturally high speeds. The human visual process evolved for walking, running, hunting, gathering, crafting tools and clothing, preparing and eating food and playing games of one kind or another. We rely on good peripheral awareness, accurate eye movements, stable and flexible eye teaming and focusing skills to achieve good results in all these time honored pursuits. It turns out that all of these abilities also come in very handy for driving though they are all but ignored when determining someone’s capacity to safely and effectively operate a motor vehicle. I would say that focusing skills are the least important of these and I will include acuity is in this category.
Safe, effective driving requires good peripheral awareness in order to anticipate and respond quickly and appropriately to the movements of other vehicles, which cannot be counted on to do what we might want or hope they will do at any given moment. Peripheral awareness is our early warning system. It can and should alert us to changes in our surroundings before we are consciously aware of these changes. Unsurprisingly, the sooner we are aware of something the better our chances of responding quickly and appropriately. This can be a matter of life and death especially when driving on busy roads.
The other basic visual skills, aiming our eyes and using the two eyes in an integrated fashion are also critical for safe and effective driving. Good depth perception depends on being able to point both eyes at the same place at the same time. Driving requires good depth perception in order to accurately judge the distance between your car and all the others near you whether you are navigating an intersection, a crowded street or highway or placing your care between two others in a parking lot or curbside. Good peripheral awareness and depth perception are also critical for judging time. We must assess the time it will take for oncoming vehicles to approach whenever we try to merge or turn onto a road. As far as I can tell, many drivers have less than optimal ability to make these judgments. This is probably why so many of us feel that another driver has cut us off, causing us to slam on our brakes and think bad thoughts.
I firmly believe, based on my years of experience both as a provider of vision therapy and as a vision therapy patient, that our roads would be immeasurably safer if every new driver was required to participate in a vision therapy program designed to enhance peripheral awareness, eye movements, eye teaming and focusing abilities.
Next time: Parents, Be Sure To Look Both Ways Before Uncrossing Your Child’s Eyes