Photic sneeze reflex: My mother and I have this!
Photic sneeze reflex is an autosomal dominant hereditary trait which causes sneezing (due to naso-ocular reflex ) when suddenly exposed to bright light, possibly many times consecutively. The condition affects 18-35% of the human population.
The probable cause is a congenital malfunction in nerve signals in the trigeminal nerve nuclei. The fifth cranial nerve, called the trigeminal nerve, is apparently responsible for sneezes. Research suggests that some people have an association between this nerve and the nerve that transmits visual impulses to the brain. Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex.
This sneeze reflex can also be brought on by sudden inhalation of cold air or exposure to strong flavors. This implies an overstimulation of any nerve close to the trigeminal nerve can cause the sneeze reflex