Comparision of Pupil size in Pediatric Migraine patients with photophobia versus healthy controls and its correlation to the severity of headache

Migraine is one of the oldest reported diseases and the second most disabling disease worldwide. It affects almost 1.1 billion people worldwide and is a major cause of morbidity and disability specially in the young population. The ICHD-3 defines migraine as a primary headache disorder with attacks lasting 4-72 hours, typically unilateral, pulsating, moderate-to-severe, worsened by activity, and associated with nausea/vomiting and/or light/sound sensitivity (photophobia/phonophobia). Pediatric migraine is the most severe primary headache in children leading to decreased quality of life. The new ICHD-3 has increased the time window of childhood headaches for a diagnosis of primary migraine to 2–72 hours. ICHD-3 also takes cognizance of some factors unique to this condition, such as shorter pain durations and unilateral as well as bilateral pain locations. In 80 % of migraine attacks, photophobia or light sensitivity is a core component.  The exact cause of photophobia in migraine is not yet known and a number of causes have been postulated like cortical hypersensitivity to light, altered ocular parasympathetic outflow, and intrinsically photosensitive retinal ganglion cell pathways acting on dura-sensitive thalamocortical neurons which in turn can influence pupillary light reflexes. In a recent study we reported that the patients of migraine with photophobia have a larger pupil size as compared to patients with no history of migraine and that the severity of headache correlates with a larger pupil size. In this study we want to check the pupil sizes in patients of pediatric migraine with photophobia and whether it has any influence on the Migraine Disability Assessment (MIDAS) scores.