I drive a truck with LED headlights and I like how much better I can see the road at night (we live in the country). I keep hearing that LED headlights are blinding to other drivers. More cars have brighter headlights now, but it’s not usually a big problem for me. Could these lights be causing long-term eye damage that I’m not aware of? – Matt, Smiths Falls, Ont.
When it comes to the health of your eyes, there’s no known dark side to LED headlights.
“I don’t think there is any evidence that headlights produce enough light to cause damage to the eyes,” Dr. Chryssa McAlister, director of community practice for the Canadian Ophthalmological Society, said in an email. “We see that only with very high intensity light, such as the sun, which most definitely can damage the retina.“
Glare from headlights is “not harmful” to your eyes, even if it feels painful, McAlister said.
“At night, our pupils dilate to allow more light in, which gives that feeling of discomfort and glare with headlights,” she said. “If you stare at a bright light, your eye temporarily struggles to adapt back to the dark conditions.”
Research into glare divides it into two types: discomfort glare, which is annoying or even painful, and disability glare, which makes it harder to see.
While headlight glare can feel blinding, it shouldn’t actually be disabling for most drivers, McAlister said.
But it can be a problem for older drivers, especially if they have cataracts, which cloud the lens in the eye, she said.
“As light bounces off the cataract, it causes the light to scatter,” McAlister said. “This can make you feel temporarily blinded [but] it should resolve quite quickly [within a few seconds] after the light passes.”
Dim view of LEDs?
Vancouver and Victoria city councils recently called on Transport Canada to update federal safety rules to limit glare.
Transport Canada told us late last year that it’s not keeping track of the exact number of glare complaints but plans to conduct a survey later this year.
So why is glare suddenly in the spotlight?
Headlights are getting brighter over all and more new vehicles have LED headlights, which look more glaring to other drivers than older technologies, such as halogen, Daniel Stern, a Vancouver-based automotive lighting consultant, said in an email.
The problem isn’t the LED technology itself, but that car companies are using it to make headlights smaller and bluer, which makes glare worse, Stern said.
While there’s no peer-reviewed research showing that LED light is uniquely harmful to your eyes, bluer light can feel a lot harsher than yellow light, McAlister said.
“We are used to the yellow of a halogen, which is nicer and warmer,” she said.
If you compare two lights of the exact same brightness – one more blue and the other more yellow – the blue light will look brighter and more glaring, Stern said.
That bluer light from LEDs can feel especially glaring to older drivers, McAlister said.
“As we age, the eye’s natural lens gradually yellows, which increases the scattering of [blue] light,” she said.
But LED headlights don’t actually need to be blue – blue light doesn’t make it any easier to see the road than yellower light, Stern said. That means car companies could switch to warmer LEDs that light the road just as well but aren’t as glaring.
There are plenty of ways Transport Canada could change the rules to make headlights less glaring, including requiring that new LEDs emit warmer light, Stern said.
Sunglasses at night?
While newer, brighter headlights might irk others on the road, they make it easier for drivers to see at night, McAlister said.
Still, if you’re finding it tougher to drive at night because of headlight glare, it’s a good idea to get your eyes checked, she said.
“For younger patients without eye disease, a common cause of difficulty with night vision and glare could be an uncorrected need for glasses,” McAlister said.
If you do need glasses, you can also get anti-glare coatings for them that “may help” without blocking light, she said.
But McAlister doesn’t recommend tinted or polarized glasses that are marketed specifically for driving at night.
There’s no evidence they help and, because they block light, they make it harder to see at night, she said.
“Probably the best advice is to keep your focus on the road ahead and not on the lights of oncoming cars,” McAlister said.
Have a driving question? Send it to globedrive@globeandmail.com and put ‘Driving Concerns’ in your subject line. E-mails without the correct subject line may not be answered. Canada’s a big place, so let us know where you are so we can find the answer for your city and province.