What is light sensitivity?

Light sensitivity, also known as photophobia, refers to a heightened sensitivity to light which can lead to discomfort or pain in the eyes when exposed to light. Andrew Huberman discussed that certain people are more sensitive to light, and even small amounts of artificial light at night can significantly shift their circadian clock, thereby affecting their sleep and alertness levels. He mentions that light sensitivity can differ greatly among individuals, with some people being able to tolerate intense light without discomfort, while others may find even moderate levels of light painful or bothersome 1.