Photophobia: When Light Hurts, a Review.

PURPOSE OF REVIEW: To provide an updated overview of Photophobia with a particular focus on photophobia related to migraine.

RECENT FINDINGS: Melanopsin-containing photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs) have been identified in the retina and explain the rational for photophobia in individuals who are blind. Photophobia, a sensory disturbance provoked by light, is a common neurological and ophthalmological symptom. Migraine, a common neurological condition, is pathognomonic of photophobia; however, other primary headache conditions, traumatic brain injury, and impairment of the optic pathway can cause photophobia. In addition, anterior and posterior segment ocular pathology, medications, and psychiatric conditions can result in photophobia. At least 2 (possibly three) distinct neural pathways are involved in photophobia. Some of the basic science regarding these pathways is discussed in this review including the role of calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide. Management of photophobia includes treatment of the underlying etiology and conservative strategies such as wearing sunglasses.