Not all lights are created equal. Some are visible to the human eye as colors. Others, though not perceivable, produce long-lasting biological effects. For example, ultra-violet (UV) light (10-400 nm), which comes to us in the flavors of UVA, UV B, and UVC (though little of the latter reaches the earth), is well known to alter our skin cells at the genetic level, causing DNA damage. The result: aged, weathered skin; precancerous skin lesions known as actinic keratoses (AKs), and in the worst-case scenario, skin cancer. Yet there are other types of light that can help fight these problems. An emerging field of light-based technologies, known by names such as […]