One in four people worldwide suffers a series of chain sneezes, similar to those caused by an allergy, when suddenly exposed to sunlight. This is known as a solar sneeze reflex or photic sneeze. It is called a photic sneeze, and it happens to 15 to 25% of people. It may be due to congenital dysfunction in sending signals from the trigeminal nerve endings to the brain. The hypothesis is that the light overstimulation of the conjunctival and corneal ocular zones, in turn, stimulates the trigeminal nerve zone (responsible for the sensitivity of the region), causing the sneezing reflex. One of the theories about its origin attributes it to interference between stimuli conducted by the optic nerve (which transmits the visual stimuli that the retina captures) and the trigeminal nerve ( which has a motor and sensory functions in the face). Thus, when it arrives a lot of light to the retina, it overstimulates the trigeminal and makes those people make aches. In fact, it seems evident that there is a certain relationship between the eye and the nose, since the same act of sneezing includes a momentary closing of the eyes, while tears clean the nose through the tear duct. Most authors consider this type of sneeze to be hereditary.
One of the earliest references to the relationship between the sun and the sneeze can be found in Greek mythology. It is said that it was Prometheusthe one who introduced the sneeze into mortals, erecting a statue that he wished to bring to life, for which he stole a ray of light from the sun and so that Zeus did not discover his crime he hid the ray in his snuffbox. One day, having forgotten this, he went to inhale a bit of snuff powder and by accident the lightning struck his nose, causing him to sneeze violently.