People with photophobia experience intense pain when they're exposed to bright light. Photophobia is a common symptom of a migraine headache.
Although its main definition is "extreme light sensitivity," photophobia can also be an irrational fear of light. Its Greek roots are phōs, "light," and phobos, "fear." Many medical conditions can cause people to have eye or head pain when they're exposed to light, including TMJ, traumatic brain injury, cataracts, and eye injuries. If the midday sunshine sends you blinking painfully back into your dark house, you're either a vampire or you're suffering from photophobia.