If you happen to be in the market for a small artificial sun, you may be interested to know that for about $1300, you can get a tennis-ball-sized LED array that outputs 120,000 lumens.

Blue light is a high-energy part of visible light from the sun, screens, and light-emitting diode (LED) bulbs. Your cornea and lens don’t block blue light the way they block ultraviolet (UV) rays.

If you’ve been to a wedding or a downtown coffee shop in the last 10 years, you’ve probably seen those little lightboxes that are so popular these days. They consist of letters placed ...