Tribya: About twenty-five percent of the population sneeze when they are exposed to light.

The photic sneeze reflex (also known as photoptarmosis, Autosomal Dominant Compelling Helio-Ophthalmic Outburst Syndrome (ACHOO) colloquially known as sun sneezing. It is a condition of uncontrollable sneezing in response to numerous stimuli, such as looking at bright lights or periocular (surrounding the eyeball) injection. The Photic Sneeze Effect has been documented for many centuries. The Greek philosopher Aristotle was one of the first to contemplate this strange phenomenon in 350 BCE, exploring why looking at the sun causes a person to sneeze in The Book of Problems: “Why does the heat of the sun provoke sneezing?”