Is It OK to Drive at Night With Glaucoma?by Jennifer Nelson
If you have glaucoma, you probably still need a car to get around. (Even to see your eye doctor!) But this condition can mess with your sight—and your ability to drive. Fluid buildup in the eyes increases eye pressures, leading to vision problems including blind spots and halos. And while treatments can improve symptoms, some people with this condition find that night vision in particular declines, making driving safely an even tougher task. Find out how glaucoma can interfere with your road time—and if you should make the call to hand over your keys.
Glaucoma Affects Your Peripheral Vision
Driving goes hand in hand with independence. And most people with mild to moderate glaucoma can drive just fine, according to Yuna Rapoport, M.D., assistant clinical professor of ophthalmology at Icahn School of Medicine at Mount Sinai in NYC. However, the disease usually affects peripheral vision first, narrowing your visual field so you don’t see much more than what’s straight ahead. “Our peripheral vision is important at all times, but especially at night,” she adds, when even perfect-sighted people have more difficulty making out other vehicles and pedestrians in the darkness.
Peripheral Vision Loss Can Go Unnoticed
Many people don’t notice peripheral vision loss until glaucoma has already progressed—which is why regular eye exams are so important to catch this major symptom early on. You can have 20/20 vision centrally with glaucoma, even with a peripheral visual field that’s been constricted by as much as 80%, says Dr. Rapoport. That means you can be legally blind in some states and still pass a driver’s vision test, where you are typically only tested on central vision. An eye care provider might be the better judge of who should be allowed to start their engines!
You May See Light and Color Differently
“Glaucoma reduces sensitivity to light,” says Jason Bacharach, M.D., a glaucoma specialist at the North Bay Eye Associates at Pacific Vision Eye Institute in San Francisco, CA. You may find it difficult to distinguish colors or identify items from less vivid backgrounds. Colors may also appear dull—all of which can affect how well you respond to traffic lights, brake lights, and road signs. These symptoms may only occur in advanced stages of glaucoma. “You can imagine how a combination of a narrow visual field, washed out colors, and faded imagery lead to challenges when behind the wheel,” he says. After dark, all the more so.
Glare Is a Concern, Too
When pressure builds up in the cornea, retina, or optic nerve (as happens with glaucoma), low-light conditions can trigger blurry vision with a halo effect. Halogen lights, like those in today’s car headlights, can cause terrible glare and trigger such symptoms—a true safety risk. In fact, a 2019 meta-analysis found that people with glaucoma were more likely to be involved in car accidents—with glare, processing speed, sharpness of vision, and peripheral vision loss all major factors, suggesting a driver’s license vision test may not be an adequate assessment for safe driving.
Testing Your All-Around Night Vision Is Key
But, wait—can you take a test for decreasing night vision? If your eye doc suspects that yours might be a safety issue, you may be asked to take a night vision assessment using the Pelli-Robson Contrast Sensitivity Chart. It‘s similar to the eye charts used during regular eye exams, just with letters in different shades of grey. This test measures your ability to see contrast between white and grey shapes. In addition, you doc might suggest you try a driving simulator, which can help assess your vision during different simulated driving conditions.
You Can (Slightly) Improve Night Vision
There isn’t a magic Rx to improve night vision, but ask your eye care provider about glasses that have an anti-reflective coating, which allows 100% of visible light into your eye for better vision. Certain tints such as amber or yellow can improve nighttime vision as well. Also, some people with glaucoma use prescription eye drops to constrict their pupils. Pupils dilate at night, and this can actually make some people more nearsighted than they are in bright light conditions, explains Dr. Rapoport. Constricted pupils also help you see better when more blue light is present at night, which has a shorter wavelength.
How to Reduce the Effects of Glare
If you’ve been having issues with road glare—and your eye doctor has given you the go-ahead to keep driving after dark—there are a few ways to combat this problem. Anti-reflective coatings on your eyeglasses may reduce glare from light sources (such as oncoming traffic). In addition, people with glaucoma can benefit from occupational therapy to learn how to maximize their visual field, as well as how to adjust their body position in the car to deal with glare. Be sure to keep headlights condensation-free and your windshields clean, too.
Should You Stop or Limit Your Night Driving?
If you find night driving difficult, trust your judgment—hop out of the driver’s seat, or at least limit your evening outings. If you have visual field loss you may be slower to anticipate and respond to changing road conditions, have trouble matching speed when changing lanes, and have difficulty staying in your lane around curves. Peripheral vision loss can cause a blind spot you didn’t know you had. “That can be dangerous for patients who don’t know they have glaucoma and miss something coming from the side, like a car,” says Dr. Rapoport.
Get the Green Light From Your Eye Doctor
Anyone with vision loss from glaucoma should consider opting out of driving in poor weather, at higher speeds, and at night when it’s tough to make out what’s ahead—and to the sides—of your vehicle. Keep eyeglass prescriptions up to date, follow your treatment routine, and talk to your doctor about driving. You might also benefit from driving training courses through rehabilitation centers to improve techniques. Most important? Get regular eye exams to discern the degree of your vision loss, says Dr. Rapoport, which can keep you—and others—safe on the road.