You may have read the recent New York Times article about how the New York state Department of Motor Vehicles considered dropping the eye exam requirement for driver's license renewals. Well, it only took a week for the New York state Department of Motor Vehicles to reinstate that briefly dropped requirement. Evidently, vision is important while driving. Who knew?
Well, in Pennsylvania, if a person can see at least 20/40 vision combined with both eyes together without glasses, that person is legal to drive without any optical correction. If the vision is worse than 20/40, then it must be corrected by glasses and/or contacts to the best vision possible. If a person has an eye condition that limits the best corrected vision to only 20/40 or 20/70, restrictions are imposed on the driver (ie. driving only during the day and more timely vision evaluations). If a person cannot see better than 20/100 with both eyes, it is illegal for them to drive, for their own safety and the safety of other drivers and pedestrians.
In addition, a person's horizontal peripheral vision must be intact, at least 120 degrees. Someone with sight in only one eye may still meet the vision requirements, having a restriction that requires additional mirrors while driving.
The vision can change from one year to the next. With conditions such as cataracts and macular degeneration, sometimes the vision change is so gradual, that no decrease in visual acuity is perceived by the patient until they get their eyes examined. I have personally had patients that claim to see just fine, and then when it's time to read the vision chart, they struggle to see the "Big E." The "Big E" is 20/400 vision...not legal to drive in any state.
This is why the vision requirement for driver's licenses is important: it keeps the drivers honest about their vision. The Pennsylvania Department of Transportation randomly sends out a vision examination form to be filled out by an eye doctor to ensure the driver's vision is where it should be. Some people don't get their eyes examined every 1-2 years like they should; to check for vision changes and ocular diseases such as glaucoma.
I also have patients that have a complaint of glare and light sensitivity when driving at night or when it is raining. Many times, it is because they are "only" seeing 20/40. Even though they are legal to drive without glasses, and 20/40 is decent vision, getting a mild eyeglasses prescription to clear the vision to 20/20 or better eliminates that glare and light sensitivity complaint. Seeing more clearly would also allow that person to see signs further down the road than what they are used to, and possibly improve their reaction time as well.
(The above is NOT likely to occur with excellent vision and improved reaction time)
I'm due for my driver's license renewal this November, and just checked each eye on the vision chart (20/15 in each eye with glasses...excellent). I know that I need glasses or contact in order to see when I drive, and I don't try to "just get by." If you think you should be seeing better when you drive, get your eyes checked out. You may be surprised to see what you've been missing.