Here’s Why Purple LED Holiday Lights Make Some People Sick

Light has profound effects on our health and mood. We light our homes to create feelings of warmth, and use lamps to combat depression. Movies and video games even have warnings about lights and seizures. Clearly, lighting and our brains have a deep relationship.

It’s no wonder, then, that Christmas lights, with their twinkling and flashing and sheer ubiquity during the holiday season, can create problems for people with LED light sensitivity.

Why are some people affected by LED lights? Michael Meiser, lighting expert at Lumilum, says it’s because LED lights are brighter than incandescent or fluorescent lighting, and they emit blue light (more on that below). What’s more, with energy efficiency top of mind, we’re exposed to LED lights everywhere now.

Meiser says that time of year plays a part, too. “As people spend considerable time surrounded by bright, flashing Christmas lights, this will likely exacerbate symptoms of light sensitivity,” he says.

How Do LED Lights Work?

LED stands for light-emitting diode. “LED bulbs produce light by passing electric current through a semiconducting material [the diode],” Meiser says. When the the electrons in the diode are excited by the current, their movement releases energy called photons — aka light — through a phenomenon called electroluminescence.

In traditional incandescent lightbulbs, electricity heats up a tungsten filament — the spring-like metal piece inside the glass — which glows hot and emits light. One drawback? They emit a ton of heat, up to 90 percent of the energy consumed.

LEDs, by contrast, convert much more energy to useable light. Meiser says LED lights are 90 percent more efficient than regular incandescent, and 80 percent more than a halogen bulb. That means they’re cheaper to run and much more environmentally friendly than traditional lighting sources.

“Their energy efficiency is such that an LED bulb using five watts of power does the same job as a filament bulb using 40 watts,” Meiser says.

What’s the Problem with Purple LED Lights?

Purple LED lights aren’t really purple, but rather red and blue combined. Studies show blue lights interrupt our circadian rhythm, affecting sleep by suppressing melatonin production. Meiser says blue lights contribute to migraines and visual fatigue, too.

And while red light shows promise for medical use, particularly in dermatology, Meiser says “combining it with blue light triggers the photoreceptors in the eye linked to the part of the brain that controls alertness, causing people to strain their eyes.”

Then there’s the flicker. Our homes run on alternating current (AC). That means the electricity in your wiring constantly travels back and forth from the source (your electrical panel, and before that, the transformer and the utility) to the outlets in your home. This fluctuation causes all lights, not just LEDs, to continually dim or shut off with the frequency of the current.

LED lights employ drivers to provide a constant source of voltage and prevent flicker, but some people are more photosensitive than others. “The flickering from purple LED Christmas lights might trigger people with light sensitivity more than other colors,” Meiser says.

What Are the Symptoms?

If you’re sensitive to LED lights, you may experience headache, nausea, dizziness, eye pain and inflammation, along with burning, watery or dry eyes.

What Can You Do?

Meiser says you can reduce LED light sensitivity at Christmas, or any time of year, by taking the following steps:

• Avoid flashing Christmas lights. If your lights have two settings, keep them on static.
• Put lights on a timer so they won’t shine in your eyes all day.
• Switch lights off at least an hour before bed.
• Invest in blue light glasses, which block blue light before it reaches your eyes.
• Boost ambient light indoors to create a more balanced environment.