Foster Grant® Kramer Rectangle Blue Light Reading Glasses help reduce blue-violet light.* Our blue light glasses and reading glasses are perfect for use indoors and outdoors. While, even indoors, the sun is the largest source of blue light, blue light is also found in the LEDs of our domestic lighting and our screens, but the illumination levels are lower. *Filters at least an average of 30% of blue-violet light (between 400 and 455nm as stated by ISO TR 20772:2018) as measured in 5 nm increments. Covered under U.S. Pat. No. 8,360,574. Other U.S. and foreign patents pending.