Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision, human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury. Some drugs have a photosensitizing effect. Properties of natural or artificial light that may abnormally affect people include: Conditions that may include sensitivity to light include vertigo and chronic fatigue syndrome. Controlled application of artificial light can be used in a program of light therapy to treat some disorders.

Sunlight

Sunlight, especially its ultraviolet radiation component, can cause increased or additional types of damage in predisposed individuals, such as those taking certain phototoxic drugs, or those with certain conditions associated with photosensitivity, including: Also, many conditions are aggravated by strong light, including:

Fluorescent and LED lamps

The Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008 reviewed the connections between light from fluorescent lamps, especially from compact fluorescent lamp, and numerous human diseases, with results including: