What do you do if you run out of gas while driving at night in African bush country? Do you curse because your cell phone has no signal? Do you wait until the AM? If you chose to leave your vehicle to find help (not recommended), your peripheral vision may be  really useful because it can see better in the dark than your central vision and is good at detecting motion, like a snake lunging at your from an overhead branch. Awareness of vision at the edge of sight is a practiced skill of jugglers. In urban jungles, the car that changes into your lane unpredictably and threatens to crash into you triggers your peripheral vision first.

Most of us focus (pun) on the color, 3D, and detailed vision that is generated from the central part of our retina, called the fovea. Peripheral events often trigger us to  bring the image into our central awareness. In many ways, central and peripheral vision complement each other. Vision can also complement other senses too, like the sense of touch. This is needed for hand eye coordination and can be evaluated during a neurological exam with  finger to nose tests. This examines the integration of different parts of brain involved in coordination, vision, spatial awareness, and sensory and motor abilities.

The lack of coordination of movement is called dysmetria and can be tested with the nose-finger-nose exam. Here is how it is done.  You put a finger on your nose and then as quickly as you can touch the doctor’s finger in front of you before returning your finger back to your nose. This is done quickly and repeatedly. It depends on one’s central vision and a target your finger can feel to know that you have reached the target. Think of your finger as a rocket blasting off from your nose, going through space, and landing on the lunar surface of the doctor’s finger before returning to your terrestrial nose.

Now consider what you would experience if the exam was modified. What if you did not have the sense of touch (alternatively, what if the doctor’s finger was a hologram). In this case, you would have to compensate with vision to be sure that your finger reach its target and did not overshoot or undershoot. This would take a lot of concentration. Accuracy and speed of this exercise would reasonably be expected to be worse.

In another scenario, what if you did this exercise using your peripheral vision instead of your central vision. Peripheral vision is not as detailed as central vision and sacrifices depth perception. The finger to nose test would be harder still, and even harder if the sense of touch was also absent.

This information is useful for understanding how vision and touch enhance each other when you are driving and selecting controls on the dashboard or elsewhere in the cabin. To prove this, consider a game called “Touch the Penny”. To do this, take a blank sheet of white paper and put a penny in its center. Trace the periphery of the penny so that is outline remains and fills the circle with brown color. Place the sheet on a table to the side of your dominant hand and hold a pen between your thumb and second finger and place your third finger on your nose. Now without looking down, and keeping your eyes straight ahead, use your peripheral vision to guide your third finger to the drawing of the penny and then mark the center of thepenny with an “x”. After that, bring your finger back to your nose, and repeat the cycle ten times, moving back and forth as fast as you can. Now repeat the entire exercise, but this time stick the actual penny on the sheet. Again, your third finger is used to guide its landing into the middle of the penny, one that you can actually feel it. Like the finger to nose test, speed and accuracy are better with a recognizable tactile target.

When it comes to driving, the ideal is “eyes on the road all the time”. It would be helpful if it was never necessary to divert one’s gaze off the road to operate cabin controls. This couldhappen with heads up displays that project menus onto the windshield without significantly obstructing the view. Another way this can be achieved is by adding distinct tactile qualities to the controls in the cabin so that the driver need not look away from the road to recognize the control. If the control is viewed using peripheral vision, the sense of touch can improve selection accuracy and confidence.

There are times when buttons and controls in a car’s cabin are difficult to see. Perhaps it is night or the controls are hidden, perhaps because of novel positioning underneath the rim of the steering wheel. When vision is challenged, the benefits of Braille for the blind should not be unseen by the sighted. In sum,  1) many senses can be combined to improve our interactions with our machines and 2) make sure your vehicle is well equipped when driving into the wilderness, urban or otherwise.

Source of the image of the eye: Hans-Werner Hunziker. Hans-Werner34. https://upload.wikimedia.org/wikipedia/commons/3/39/Double_system_e.jpg