When you renew your driver's license at the Department of Motor Vehicles, you'll probably be required to do a vision screening. As long as you can read the smallest letters on the eye chart, you're good to go -- even if you have to squint.
But doctors caution that's no way to determine whether your peepers are up to the challenge of spotting dangers and helping you stay safe on the road.
"A vision screening at the DMV's office is not a substitute for an eye exam, because it cannot detect all vision problems," says Dr. W. Lee Ball Jr., chair of the Better Vision Institute at the Vision Council.
In most cases, the DMV requires only that drivers have their eyes tested once every eight years or more, and a lot can change with your vision in that time.
"Even the slightest vision-related scenario can impact your safety by making it hard to judge distance or see clearly," says Dr. Sandy Feldman, an eye surgeon at ClearView Eye and Laser Medical Center in San Diego.
A proper eye exam might run you anywhere from $39 to $100. But an accident you literally didn't see coming could cost you much more -- so, in the long run, good vision could save you hundreds of dollars in accident-related car repairs and medical bills.
"Depending on how many claims or tickets you have, an accident that results from poor or impaired vision could also lead to (insurance) rates going up," Allstate agent Jennifer Nelson says.
Protecting your peepers
Even if you can read the DMV eye chart, Ball says, regular eye exams can uncover changes in the eye caused by glaucoma, age-related macular degeneration or diabetes.
"Some of these diseases have no symptoms in the early stages, but if detected, can be treated," Ball says.
According to Feldman, those who are age 20 to 40 should have an eye exam every two years -- unless they notice changes in their vision or have concerns. Once the candles atop your birthday cake reach 40, annual eye examinations are recommended.
Road signs that something is wrong
If you're experiencing any of these warning signs, you need to get your eyes checked, experts say.
Difficulty seeing street signs. "If you develop a cataract or your prescription for glasses changes, one of the earliest signs might be a reduction of distance vision," Feldman says. "This might make you miss exits on the highway or signs on the road that warn of impending construction."
Trouble seeing at dusk or dawn. Ball says that even if you have 20/20 vision, it may be tough to see clearly in low-contrast lighting conditions, such as dusk or dawn. "However, something like a cataract might make seeing at these times much more difficult," Ball says.
Feldman adds that if you've never worn glasses, trouble seeing at dawn and dusk could be a sign that you need them now, at least when you're driving.
Difficulty reading the dashboard or GPS screen. Feldman says that sometimes, as people age into their 40s, "near vision" fades and prescription lenses are required to see things within arm's reach.
Glare or haloes appear around lights at night. If you see rays of light or a "starburst" emanating from streetlights at night, you should have your eyes checked. Ball says this could be a sign of glaucoma or cataracts, or that you need anti-reflective lenses to reduce glare. Anti-reflective lenses improve vision by increasing the amount of light that reaches the eye and by reducing harmful glare.
Frequent blinking, or burning or tired eyes. These are symptoms of dry eyes, which may cause irregular or poor vision. Treatment is relatively easy. Ball says remedies include eye drops, drinking more fluids and cleaning or flushing your eyelids. Prescription medications are available if necessary.
At-home eye tests
Feldman suggests using these at-home tests to determine whether an eye exam is in order:
- The distance test. Stand about 5 feet from the television and make sure you can read the small print at the bottom of the TV screen. Cover one eye, and check each eye separately. Then step back to 10 feet from the television and check both eyes. If there is blurriness or any visual differences between your eyes, you should have them checked.
- The close-up test. Are you having trouble putting on makeup or reading menus in dimly lit restaurants? Difficulty seeing during these activities (which usually happens at about age 40) might indicate the need for reading glasses.