Each time drivers in the United States renew their driver’s license, a vision test is part of the drill, right? Wrong. Surprisingly, regular vision tests aren’t required everywhere. Depending on the state, drivers may go without a vision screening their entire adult life after their initial license application, according to the Vision Council of America.
That’s alarming, because some of those drivers are likely to be among the 3 million Americans over the age of 40 who have some form of vision difficulty, such as glaucoma, diabetic retinopathy, or cataracts.
Frequently, eye diseases associated with age can narrow your range of vision, cause your eyes to become more sensitive to light and glare, and/or require you to need more light to see clearly. All of those symptoms may interfere with your ability to drive safely.
A driver’s ability to see and respond to pedestrians after dark is degraded by modestly blurred vision (caused by failure to wear optimal corrective lenses) and by cataracts. The danger applies even when drivers have passed the required vision test.
To better understand the perils of nighttime driving, Australian investigators enlisted 28 young adult licensed drivers to drive at night on a closed road circuit, wearing lenses that simulated refractive blur and cataracts. Pedestrians wearing a mixture of dark and reflective clothing were also part of the trial.
Drivers with simulated blurred vision recognized a pedestrian 52 percent of the time, while those with simulated cataracts did so only 30 percent of the time, according to the 2012 study, published in Investigative Ophthalmology & Visual Science. Moreover, drivers with normal vision recognized pedestrians at distances an average of 3.6 times farther than drivers with blurred vision, and 5.5 times longer than drivers with cataracts.
Fortunately, you can take steps to make driving safer for yourself and for other drivers on the road.
Learn the requirements
Vision requirements for licensing and relicensing vary from state to state. According to the Vision Council of America, all states require that applicants for a new license have at least 20/40 best-corrected vision (the best vision possible with glasses or contacts, as needed).
Many states also have a minimum requirement for your field of vision (the extent of peripheral or side vision you have when looking straight ahead). Others require that you have the ability to see the color of traffic lights. To find out the requirements for your state, contact your motor vehicles department.
Many states permit the use of bioptics, a specialized lens system for people who are unable to see clearly even with the use of traditional corrective lenses or surgery—a condition commonly known as low vision. With this system, miniature telescopes are attached to regular glasses, enabling the driver—after required training—to see pedestrians, road signs, traffic lights, and any other distant objects by glancing intermittently into the telescope.
Get your eyes checked
The American Academy of Ophthalmology (AAO) recommends that adults with no signs or risk factors for eye disease get a baseline eye disease screening at age 40—the time when early signs of disease and changes in vision may start to occur.
Based on the results of the initial screening, an ophthalmologist will prescribe the necessary intervals for your follow-up exams. The AAO recommends a complete eye exam every year or two after age 65 to check for eye diseases such as age-related macular degeneration, diabetic retinopathy, glaucoma, and cataracts.
If you’re at risk for eye problems—something your eye doctor will discuss with you—it may be wise to have an exam more than once a year (and of course if you do have problems, get checked as often as your doctor recommends). Between checkups, if your vision changes or you have trouble driving at night, let your eye doctor know right away so he or she can determine if any change in your ocular health has occurred.
Ursula Schell is a New York City-based medical writer who specializes in articles about eye health and has compiled data for the U.S. Food and Drug Administration. In her spare time she enjoys playing in a variety of musical groups.