LED Street Lights: Good for the Environment, Bad for Night Vision? Karl Citek, OD, PhD, of the AOA, Sheds Light on the Topic

—The emission of blue light from these new technologies has raised some concern. Get tips to help patients who struggle while driving at night.

As communities and car manufacturers turn to more efficient, longer-lasting light sources for streetlights and headlights, the health effects of each have spurred debate. The emission of blue light from newer technologies is the main point of controversy—some have speculated if it affects age-related macular degeneration or cataracts. Little data is available at present; the American Optometric Association has encouraged further research to assess the impact of blue light on eyesight. In the meantime, Karl Citek, OD, PhD, chair of the American Optometric Association’s Commission on Ophthalmic Standards, offers his point of view and suggestions to physicians on how they can help their patients cope with seeing in a new light.

“White” LED streetlights emit more short visible wavelengths (ie, blue light) than incandescent or sodium light sources. Short wavelengths can scatter more easily in an optical medium that may not be perfectly clear, such as nighttime fog or rain, or in an eye with early cataract formation. As such, light sources (eg, streetlights, high-intensity discharge [HID] headlights) can appear to have halos, be blurry, or cause glare. In addition, many people will perceive the light to be more “harsh” or “stark.”

There are no proven health problems for most people; the actual amount of blue light emitted is significantly less than that present on a sunny day. The only individuals who would remotely be susceptible to retinal damage are children under age 2—they have very clear eyes—and patients who have had cataracts removed, either without a replacement intraocular lens (IOL) or with an IOL that does not include ultraviolet absorbers.

However, there is some evidence that even low doses of blue light exposure can affect melatonin output and thus disrupt sleep cycles—but is it not a good idea that drivers are awake when driving at night?!?

How might LED lights change a driver’s perception compared with traditional streetlights?

Because there is more blue in the light source, objects that reflect blue should more easily be identified as the correct color. But, overall, the light may appear harsher than other sources.

What is your opinion about the use of LED at eye-level (headlights) vs overhead (streetlights)? Is there a difference between the two?

LED and HID headlights may be more efficient at illuminating the roadway for the driver of the vehicle, but a driver in an oncoming vehicle has a more difficult time looking away from the headlights. The safest strategy for a driver in an oncoming vehicle is to ease off the gas and look down and to the side of the road until they pass. Streetlights would only pose the same issue if they were low, on a hilly street, or in the vicinity of something of interest, such as a street sign.

What advice can you give to physicians to help patients who might be affected by LED streetlights?

LED streetlights—and HID headlights—are not going to go away. Anti-reflection coatings on spectacle lenses can help to reduce some of the glare and halos that patients might experience. But the best strategy is avoidance. Patients should be advised not to look directly at these lights if at all possible, and, if necessary, to slow down and take extra time to drive through or past such environments.

Published: March 01, 2017

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