What is the primary benefit of using a red-light mode when checking devices during dark adaptation?

Red light minimally impacts the night vision adaptation process.

The process of achieving full visual sensitivity to low light levels—necessary for seeing most meteors—takes a significant amount of time, usually 20 to 30 minutes, as the rods in the eyes become fully activated. Exposure to bright light, especially from common screens like cell phones, resets this vital process. Red light is specifically recommended because it has the least disruptive effect on the photochemical processes occurring in the rod cells of the retina responsible for night vision. Exposure to longer wavelengths (red light) does not trigger the same level of bleaching or suppression of the light-sensitive pigments as shorter wavelengths (like blue or white light), thus allowing the observer to check necessary information while preserving the hard-won dark adaptation.