What vision is the vision that helps a person see direct objects?

Having a good vision is absolutely necessary in order to drive a car. I know what you're thinking -- le duh -- but that’s why you're required to pass vision screenings at the DMV when you go get a learner permit or driver license or even a CDL (commercial driver's license). If you can’t see road signs, signals and other cars, then you shouldn’t be driving. Let’s take a look-see at some of the important ways that your vision can assist you while driving.

Central Vision

Central vision is what you see out your front windshield when looking straight ahead. It’s where you’ll see lovely sights like highway litter, gas station signs, and billboards.

Your central vision field is where the majority of visual information you receive while driving comes from. For example, central vision lets you know when cars in front of you have braked, when there’s a stoplight, when the speed limit decreases or when you should exit the interstate. All very important things.

Peripheral Vision

Peripheral vision is a little less obvious, but it’s super important for driving. Basically, peripheral vision is what you see out of the corner of your eye when looking straight ahead. Peripheral vision lets you see when other cars are passing you, while still allowing you to focus on what’s in front of you. Do you see what I mean? (Note: Peripheral vision is not a substitute for checking your blind spot!)

Peripheral vision complements central vision to help you make informed driving decisions -- like when it’s safe to move over a lane, when there’s a pedestrian trying to cross or when you need to go to the car wash because a bird just pooped on your window (ugh, the worst). Peripheral visions lets you see potential hazards before they enter your central vision. Together, the two types of vision help make you a smarter driver. Pretty cool, right?

And that’s what central and peripheral vision looks like!

Corrective Eyewear

Older drivers aren't the only ones who need to practice good vision care. As a new driver about to go through driving school, you're going to be required to take an eye exam and pass some vision requirements before you get your learner permit or driver license. If you don't have perfect eyes with 20/20 vision, you'll need to wear some eyeglasses or corrective lenses. Having visual acuity is so important when you're behind the wheel. If you can't see what's going on around you, you'll end up in some gnarly crashes. If you ever experience vision loss, low vision quality, or a vision condition that impairs your ability to driver safety, pull over immediately and call a ride. In most states, if you wear glasses or corrective lenses the driver licensing department will place a note on the back of your license ID noting this.

Make sure to check out the rest of our safe driving videos for more tips to keep you in control on the road!

"eyes don't tell people what to see..........people tell eyes what to look for"

Unfortunately we over-rely on one sense, a sense that does have limitations. The human body has never evolved to be able to drive a car. As such we still have the eyes and other senses of primitive man. The following sections outline the different limitations of human vision:

VISUAL FIELD

We have the widest range of vision (largest visual field) when stationary. Typically our primary vision is within 10° - 12° of our line of sight. But objects can be detected outside of this in our peripheral vision, 90° to the left and right, 60° above and 70° below our line of sight. This means when stationary we have a 180° horizontal visual field and a 130° vertical visual field.

At speed however our vision focuses automatically further ahead and thus the visual field reduces in all directions. At 100 km/h our horizontal visual field is only 40° (20° to the left and right of our line of sight).

Outside of the visual field we need stimulus to make us turn our head and look in that direction. A good stimulus could be movement relative to the background or a flashing or pulsating light or some other bright light.

This is one reason why our indicator lights flash, so they can be noticed and seen by other drivers even outside of their field of vision.

This is also a good case for the use of daytime running lights on vehicles, especially when driving at high speeds to make sure your being seen by other drivers.

RAPID EYE MOVEMENT (REM)

The maximum movement rate for a human eye is 4 fixations per second and can only be sustained for a short term.

An alert, busy and skilled driver, giving their full attention to driving is capable of 2 fixations per second. This information then must be processed.

Therefore at 100km/h (28m/s) an alert driver is not physically capable of seeing something, comprehending it and making an appropriate response or decision unless the hazards/objects are spaced at least 20 metres apart. Inputs received faster than this lead to information overload and concentration is diverted from driving to process this additional information.

Under normal driving conditions most drivers achieve 1-1.5 fixations per second whilst;

• talking on the mobile phone and/or
• talking to passengers and/or
• tuning the radio, changing cassettes or compact discs and/or
• not watching where they are going.

If you are like me, at some time you have driven through an intersection and then asked yourself, "Gee I hope that light was green", a quick check in the rear vision mirror confirms if vehicles behind followed you through the intersection. What is happening is our mind is processing other information instead of concentrating on the driving task, eye fixations and comprehension of what we see has been reduced. Driving in a daydream!

RANGE OF EYE MOVEMENT

With our head stationary our eyes can scan 50° of our visual field.

However as we have evolved from hunter gatherers with technology, we don't utilize this range of eye movement.

Instead we turn our heads to focus in other directions. As such we limit eye movement to only 15° left and right.

Only leading sports professionals have trained themselves to better use their eyes and their visual field.

ILLUMINATION

The human visual system is capable of operating over an enormous range of illumination, due to 2 factors;

The pupil of the eye can contract or dilate to let in more or less light.

After a period of darkness, receptor cells in the retina of the eye begin to regenerate. As such after 30 minutes of darkness our night vision can improve up to 10,000,000 times.

The pupil's rapid contraction or dilation maintains vision in sudden change in light condition. However the pupil's diameter can reduce (contract) 6 times faster to sudden brightness after darkness, than exposure to darkness after brightness.

As such entry to an undercover carpark, building, garage, tunnel or canopy of trees should be done with extreme caution since their is a period of reduced vision as our eyes adjust to the darkness.

Glare from headlights or street lights can also reduce our vision. When driving a night care must be taken to ensure headlights are not left on high beam when a vehicle approaches, as you are somewhat blinding the driver.

If a vehicle approaches you with their high beam on, look to the edge of the road on your side, to reduce the glare until they have passed. If they are approaching from a long way off, a brief flash of your high beam might notify them of their mistake. Remember flashing your lights at them constantly is only blinding them.

VELOCITATION

Velocitation is caused by long periods of high speed travel. The eyes become fatigued in the horizontal plane to images streaming through the windscreen. Velocitation can be noticed when entering built-up areas after long periods of country driving. The speed drop from 100 km/hr to 60 km/hr makes the driver think the car is going much slower (maybe walking pace). The eyes can no longer judge horizontal velocity correctly and as such cannot judge safe following distances. The only remedy is to stop the images streaming through the windscreen, to do this stop and park for several minutes to allow the eyes to rest.

It is for this reason, a driver on the highway may catch up to you and then follow close behind making no attempt to pass. The driver subconsciously has found it very relaxing to stare at the rear of your vehicle rather than scan the road ahead. In this situation you are now essentially steering both cars.

Your safest option would be to slow gradually and force the other driver to pass. Also check that you are not lowering your concentration by staring aimlessly at the vehicle in front of you.

VEHICLE BLIND SPOTS

The blindspots in a hatchback are very small, its the blind spots the driver has that are the big worry. The cars mirrors should be checked and adjusted correctly before driving. Unfortunately you see many drivers on the road with mirrors missing or aiming down at the road.

Its another sign of a driver ignorant to the risks, who persists in driving even though the passengers mirror is poorly aligned. Would you make the effort to stop and adjust the mirror or just take the attitude "It’ll be all right".

Lets take a look at the blindspots a driver has.

With the drivers head and eyes positioned straight ahead, none of the sections are visible in the drivers vision.

Firstly there is a small blindspot created by both A-pillars, for a tall driver the rear-view mirror can create a distant blind-spot.

Outside of the drivers peripheral vision a blindspot extends around to what the side mirrors cover. This area is larger on the passengers side. These limitations of human vision create blindspots large enough to park a truck in.

As such it is imperative to adjust your mirrors correctly. Adjust the middle rear vision mirror so that from your correctly adjusted seating position you just cannot see the top of rear windscreen in the top of the mirror. Aim this mirror up from the road immediately behind your car.

Don’t be afraid to USE your centre rear vision mirror, the mirror may also have an anti-glare adjustment for night driving.

Some drivers sub-consciously believe it is a sign of weakness to acknowledge the car behind or worse still make eye contact with the following driver. These are the drivers who daily fight for every bit of bitumen they can and will try anything not let another car pass. Using your mirrors keeps you aware of those fools around you; allowing you time to make the right decision when required.

In a car adjust the electric side mirrors out, so that the inside of the mirror just cannot see the side of your vehicle. Don’t waste mirror by looking at the side of your car, it won’t fall off and know one should ever overtake you that close.

Now there will always still be blindspots, so be prepared to look around the A-pillar when cornering and shoulder check blindspots before leaving a parking spot, indicating, merging and change lanes. Look out too for motorcyclists in your blindspots.