Night Light Pollution and Ocular Fatigue

Abstract

Environmental brightness is an important factor in synchronizing human circadian rhythms to solar light-dark cycles. Therefore, disruption of the environmental light-dark cycle can cause abnormal circadian rhythm and may result in various psychological or physiological human dysfunctions. It is a fact that civilization makes the night brighter; in addition to streetlights and car lights, smart pads, cell phones, computers, and TVs further increase urban night illumination. As a result, undesired environmental alteration called ‘light pollution’ spreads widely across the world with the constant growth of human civilization.1 In contrast to natural solar light, artificial light sources emit more blue light (a short wavelength of light with a range of 460–500 nm). Notably, constant or excessive exposure to blue light can cause inadvertent retinal damage by oxidative stress.2