Sight and Perception

posted in: Vision Impairment

The ability to see is clearly a critical factor when it comes to safe driving. Having trained many legally blind (20/200) people to drive, I have witnessed firsthand, however, that “seeing” has more to do with perception than visual acuity. 20/40 visual acuity is the commonly used threshold used by most licensing agencies throughout the county to determine whether or not a person is fit to drive. Standards are also established for minimum “fringe” vision requirements, otherwise referred to as “visual field”. The International Council of Ophthalmology recommends a binocular field of at least 120° horizontal and 40° vertical.

A person with low vision is capable, however, of seeing better than a person with 20/20 vision. This is due to the fact that eyesight is composed of various physiological components making up the “visual system”. The act of seeing starts when the lens of the eye focuses an image of its surroundings onto a light-sensitive membrane in the back of the eye, called the retina. The retina is actually part of the brain that converts patterns of light into neuronal signals. From there, the brain may, or may not process the data into useful information. When an image is projected onto the retina “screen” but not consciously processed the brain, the scene has not been perceived. I have found that lack of attention on the driving task is the primary cause of perceptual deficits.

The astonishing lack of attention we pay to our surroundings has been highlighted by research conducted by Dr Daniel Simons of the University of Illinois. Experience the phenomenon firsthand by watching the surprising video at You will see two teams (one with white t-shirts and another one with black) passing a basketball and moving around. It is very important for you to pay attention and count the times that the white team members pass the ball between them. Be careful! Only count passes between the white team. The experiment will be only valid if you watch the movie one time. Once you have watched the video, compare your results with the correct answer below*.

With professional training to hone perceptual skills low vision drivers have proven to have better driving records than the average driver. They learn to use their sight more effectively by focusing their attention on the critical components of the driving task. Imagine how much safer the roads would be if everyone learned effective perceptual skills and kept their eyes on the road.

*The white team passed the ball 14 times. Nevertheless, that is irrelevant in this test. The question is: Did you see the gorilla? Don’t believe there was a gorilla in the video? Watch it again without counting passes…

Mr. Crites is an educator, business owner, and industry leader. Don holds an MBA from George Fox University, is an ODOT certified Trainer-of-Trainers, and serves on the Transportation Safety Division Driver Education Advisory Committee. He was also the first to be certified by the DMV as a Rehabilitation Training Specialist. As the President and CEO of Oregon Driver Education Center, Inc. since 2001, Don and his wife, Paula, have led ODEC to become the largest, and one of the most respected driving schools in the industry. His mission is to reduce injury and fatal collisions through education and training.

Article Source: