Photophobia is a
symptom of abnormal intolerance to visual perception of
light. As a medical symptom, photophobia is not a morbid fear or
phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational
fear of light such as
heliophobia. The term
photophobia comes from the
Greek φῶς (
phōs), meaning "light", and φόβος (
phobos), meaning "fear".