When a bright light hits your eyes, your pupils constrict causing a sneeze. They say this reflex usually happens on initial exposure to the sun or a very bright light. If this is something that ...

Photic sneezing usually happens after exposure to a bright light such as sunlight and most often when moving from darkness to light, such as after turning on the lights in a dark room.

I sneeze every time I start chewing a piece of gum. It happens to other people whenever they look at a bright light or toward the sun, or even when they pluck their eyebrows or have sex.