Safe driving depends largely on proper eyesight. In fact, safe driving relies on several different visual capabilities including being able to see both far ahead as well as your immediate surroundings, side or peripheral vision, seeing at night and color vision, plus many others.
Strong distance vision is very important because it helps you to observe the road in front of you and see any dangerous things that might appear. This gives you the opportunity to respond quickly and prevent any accidents that might have otherwise taken place. Alternatively, if your distance vision is poor then there's a chance you may not be able to see the hazards in time to stop an accident.
Distance vision is also directly related to the maintenance of your windshield and glasses (including sunglasses), so ensure both are kept very clean and free of both dust and scratches which can reduce your vision, mostly at night and on bright days.
You also need peripheral or side vision, which allows you see either side of your vehicle, which is necessary to be aware of other cars, animals and pedestrians without needing to even glance away from the road ahead. Being able to see peripherally is also important for changing lanes and turning. Maximize use of both your rearview and side mirrors. Make sure they're angled properly, to assist your view of the road to your sides and back.
Road safety is also highly dependent on good depth perception. It helps you evaluate distances properly in crowded driving conditions, change lanes and overtake other cars on the road. Strong depth perception requires adequate functioning in both of your eyes. If you've lost visual acuity in one eye, it's essential to consult with your eye doctor to determine whether it is safe for you to get behind the wheel. It may be suggested that you stop driving until a solution is found to correct your vision.
Accommodation also comes into use on the road. If you're unfamiliar with the term accommodating, it is the ability to move your focus from a view far to something close, for example, from the distance ahead of you to the speedometer. For those 45 or older it's common for you to have trouble with near vision, and it's normal to require glasses or another corrective device to make it easier to see objects up close. Call your optometrist to discuss the options.
Color vision is also pretty important in the car. Drivers need to be able to instantly see traffic lights, road signs and hazard signals. For those with color blindness, response time could be a little slower than people with regular vision. If this sounds familiar, it's best not to wear medium or dark colored sunglasses, as these can seriously interfere with the ability to discern colors.
It's best not to wait until you renew or apply for your driver's license to have an eye exam. You don't want to risk your own life or those of other people on the road! If you feel your eyesight isn't up to par, visit your optometrist, and get a proper eye exam sooner rather than later.