Night Vision and Driving:
How Safe Are Older Motorists?
Fading night vision can be a serious traffic hazard, particularly among older motorists who drive after dark.
Because people now in their 50s and older will likely maintain active lifestyles during the next few decades, a record number of senior drivers will be on roadways in the years ahead.
Unfortunately, lax vision screening requirements for driver's license renewals in many states mean significant numbers of drivers in this age group may not be seeing their optometrist or ophthalmologist frequently enough to insure their vision is adequate for safe driving.
To make matters worse, age-related eye problems such as cataracts can develop so slowly that older drivers may be unaware that their vision is declining.
Accidents and Older Drivers
While older drivers generally may be more at risk of having accidents, U.S. Centers for Disease Control (CDC) statistics show that young motorists are more likely to be involved in traffic accidents causing death.
But an American Medical Association (AMA) statement notes that the large number of senior drivers is a public health issue, because of age-related declines in vision, cognition and motor function.
According to the AMA, these factors make older drivers "vulnerable to crashes in complex situations that require good visual perception, attention and rapid response."
The American Automobile Association (AAA) says a typical driver makes 20 decisions per mile and has less than a half second to react quickly enough to avoid a traffic accident. Age affects the three essential steps involved in that reaction process: sensing, deciding and acting.
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The National Highway Traffic Safety Administration says 6,512 Americans who died in automobile accidents in 2005 15 percent of all fatalities on the road that year were 65 or older. That percentage is expected to keep climbing as the number of older Americans increases.
Motor vehicle crashes also are the leading cause of injury in adults between 65 and 75 years old, and the second leading cause of injury to those 75 or older, according to the CDC.
Two other noteworthy facts:
- When measured by crashes per mile driven, data show a substantial rise in crashes by drivers over age 70, according to the American Association of Retired Persons.
- The National Safety Council says traffic death rates are three times greater at night than during the day. As aging Baby Boomers continue to take to the roads at night in greater numbers than their parents, the risk of fatal crashes is expected to increase substantially.
Why Is Aging and Night Driving a Problem?
As we age, our eyes usually begin to fail long before we notice it. For example:
Driving at night, especially when it's raining, can be particularly hazardous when older drivers have vision problems.
- Pupils shrink and don't dilate as much in the dark as we age, reducing the amount of light entering the eye. Various reports indicate that the retina of an 80-year-old receives far less light than the retina of a 20-year-old. This can make older drivers function as though they are wearing dark sunglasses at night.
- The aging cornea and lens in the eye become less clear as we age, causing light to scatter inside the eye, which increases glare. These changes also reduce contrast sensitivity the ability to discern subtle differences in brightness making it harder to see objects on the roadway at night.
- An older person may test well in the eye doctor's office but still struggle to focus on the road at night, where lighting is poor and more complex visual tasks are required. According to the National Traffic Highway Safety Administration, advancing years decrease our ability to see stationary and moving objects, including cars or pedestrians that might cross the road in front of us. Our ability to resist glare and see reflective road signs and markings also decreases with age.
- Many people's eyes have optical imperfections called higher-order aberrations that can't be corrected with eyeglasses or contact lenses. These aberrations increase with age and reduce vision, especially when the pupil dilates at night, according to 1999 research published in Investigative Ophthalmology and Visual Science.
- Age-related macular degeneration, glaucoma, diabetic retinopathy or cataracts affect 33 percent of all people age 40 and older the same percentage who have nearsightedness, farsightedness and other refractive errors, according to The Vision Council. So even if you are lucky enough not to have a refractive error, you still are at significant risk of developing other common diseases affecting older eyes.
These problems, combined or in isolation, "may cause such a gradual decline in vision that a driver doesn't realize he has become visually impaired," says ophthalmologist Elaine G. Hathaway, MD, speaking on behalf of The Vision Council.
|Cataract||- Cloudy or blurry vision
- Faded colors
- Headlights, lamps, or sunlight that appear too bright
- Halos around lights
- Poor night vision
- Double vision or multiple images in one eye
- Frequent changes in your eyeglasses or contact lens prescription
|Diabetic retinopathy||- Severe vision loss, even with no initial symptoms
- Blurred vision
- Specks of retinal blood, or spots, affecting your vision; spots may clear without treatment, only to be followed by severely blurred vision, severe vision loss and blindness
|Glaucoma||- No symptoms initially
- Gradual decrease of peripheral vision
- Eventual loss of peripheral vision and blindness
|Dry macular degeneration||- Blurred vision, which is a common early sign
- Inability to see details clearly at a short distance as disease progresses
- Small, growing blind spot in central vision
|Wet macular degeneration||- Straight lines appear crooked
- Loss of central vision
|Source: National Eye Institute, U.S. National Institutes of Health|
Ironically, high beams, auxiliary lights and fog lights designed to help you see better at night can put you at risk for an accident due to the glare you may experience when oncoming vehicles have these features.
Finally, some motorists who have undergone laser vision correction such as LASIK may experience increased glare from oncoming headlights due to corneal higher-order aberrations caused by their surgery.
Many Older Americans Ignore Need for Eye Exams
Despite these ample reasons for concern, many states have lax vision screening requirements for drivers renewing their licenses.
According to a Vision Council report released in the fall of 2006, the 10 states with the highest rate of fatal crashes include four that require no vision screening for license renewal and four that only require screenings at intervals of eight or more years. The Vision Council also reports that only 20 states require more frequent vision screenings for older drivers.
|Below are the key points of a 2006 state-by-state analysis of driver's license vision screening requirements conducted by The Vision Council.|
|Vision Screening Requirements for License Renewal||States|
|No vision screening required||Alabama, Connecticut, Kentucky, Mississippi, New Jersey, Oklahoma, Tennessee, Vermont|
|Vision screening required for older drivers only||Georgia, Maine, Oregon, Pennsylvania|
|Visual screening required for all renewal applicants, but more frequent screenings not required for older drivers||Alaska, Arkansas, Delaware, District of Columbia, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New York, North Carolina, North Dakota, Ohio, South Dakota, Texas, Washington, Wisconsin, Wyoming, West Virginia*|
|Vision screening required for renewal applicants; more frequent screenings required for older drivers||Arizona, California, Colorado, Florida, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Maryland, Missouri, Montana, Nevada, New Mexico, Rhode Island, South Carolina, Utah, Virginia|
|Source: "Keeping Our Eyes on the Road," Vision Council of America, 2006. (The organization is now named The Vision Council.) |
*Since The Vision Council survey was taken, West Virginia enacted a state law requiring vision screening for driver's licenses beginning in early 2009.
Taking responsibility for your eyes by having regular eye exams the best way to ensure you have the visual abilities needed for safe driving as you get older.
However, the CDC has found what it describes as "an alarming lack of concern" for preventive eye care among Americans age 50 and older. About 45 percent of adults in this category have never had a dilated eye examination, according to the CDC.
Gary Heiting, OD, reviewed this article.
[Page updated May 2014]
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