Photic sneeze reflex
The photic sneeze reflex (also known as ACHOO syndrome, a contrived acronym for Autosomal-dominant Compelling Helio-Ophthalmic Outburst) is an inherited and congenital autosomal dominant reflex condition that causes sneezing in response to numerous stimuli, such as looking at bright lights or periocular (surrounding the eyeball) injection. The condition affects 18 to 35% of the world's population, but its exact mechanism of action is not well understood.