Photophobia is a fear, aversion or sensitivity to light.
During a Migraine
Photophobia is a common symptom of migraine, most commonly during the "headache" phase, though it may arise in any of the other phases as well. Some migraineurs experience an increased sensitivity to both natural and artificial light. A migraineur may find even normal levels of light unpleasant, even painful. Exposure to light may also induce nausea in a migraine sufferer. Migraineurs may wear sunglasses or seek dark environments to avoid these symptoms.
As a Trigger
Some migraineurs may generally experience photophobia even when they are not having a migraine. Exposure to high levels of lighting, particularly artificial, may trigger migraines in those who are especially sensitive.
A study regarding the effects on different colors/wavelengths of light found that narrow-band green light did not cause the same negative symptoms in migraineurs as ever other spectrum. It may even reduce symptoms, but more research is needed to confirm this discovery.
- Oxford University Press. "A narrow band of green light could improve migraines: Findings show that pure green light is least likely to exacerbate migraine." ScienceDaily. ScienceDaily, 17 May 2016.  December 18, 2016.