On light-induced sneezing

Purpose To investigate whether the tickling inside the nose before a light-induced sneeze in susceptible individuals is correlated to a recordable local activity or not. Methods Seven healthy volunteers, three with a history of light-induced sneezing, were stimulated with stroboscopic light or a strong halogen lamp. Recording was done with an evoked potential averaging technique via intranasal electrodes placed in such a way that they substantially reduced the strong electrical response from the retina. Results Despite an adequate light stimulus, no reproducible electrical activity could be recorded from any of the members in any experiment. Conclusion Light-induced sneezing is presumably a central phenomenon. The electrical activity travels through the optic pathways straight to the trigeminal nucleus and the tickling is a referred sensation. A genetic variation in the distance between the optic pathways (colliculus superior) and the mesencephalic part of the trigeminal nucleus may explain why light-induced sneezing is more common in certain families and races. Eye (2009) 23, 2112-2114; doi:10.1038/eye.2009.165; published online 3 July 2009