The Best Red Vs Blue Light In Glass Ideas. Red light has a wavelength larger than blue. When applied to a lens, these glasses filter out blue light rays, reducing the risk of injury to your eyes.
The greater the wavelength, the greater the speed, causing a difference in the refractive index. Considering this fact red light travels faster in crown glass as compared to blue. My text book gives $v/c$=refractive index as 1 of the formulas to calculate.
