In this International Year of Light, it is particularly appropriate to review the historical concept of what is light and the controversies surrounding the extent of the visible spectrum. Today we ...

What is blue light? “All the light we see is made up of different wavelengths of light,” says Vivienne Sinh Hau, MD, an ophthalmologist at Kaiser Permanente in Riverside, California. “Certain ...

Classically, light can be thought of in two ways: either as a particle or a wave. But what is it really? Well, the ‘observer effect’ makes that question kind of difficult to answer. So before we get ...

Blue light usually comes from the sun but also from digital screens and LED lights. Some experts believe artificial sources may be causing eye damage in humans, but animal studies are inconclusive.

Women's Health may earn commission from the links on this page, but we only feature products we believe in. Why Trust Us? At the simplest level, different colors of light have different wavelengths.

Ultraviolet light is a type of electromagnetic radiation that makes black-light posters glow, and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging ...

If your social media feed is full of glowing red face masks and crimson saunas, you're not alone. Lately, it seems like everyone is obsessed with red light therapy and hailing it for its various ...

We independently review everything we recommend. We may get paid to link out to retailer sites, and when you buy through our links, we may earn a commission. Learn more› By Nancy Redd Shifts in the ...

Light-years make measuring astronomical distances much more manageable. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. A light-year is a ...

Red light therapy (RLT) is a therapeutic technique that uses low-level wavelengths of red light to help treat skin conditions such as wrinkles and psoriasis. Though the treatment seems promising, more ...

One of the most common questions I get asked as a beauty editor is what at-home beauty treatments are actually worth it. My answer? Red light therapy. There’s a reason you’ll find red light devices in ...