Calling all sneezers: scientists try to unpick mystery of 'photosneezia'

Thought to affect a quarter of Britons, photic sneezing is a curiosity but can have serious consequences Scientists are attempting to unpick the mystery of the "photic sneeze" - a bizarre reflex that causes people to sternutate (sneeze) in response to bright light - and they need your help. Also known as "photosneezia", the phenomenon is thought to affect about a quarter of the UK population, although the mechanism that triggers it is unknown.