An estimated one third of the population will often sneeze when looking at the sun or a bright source of light; this is due to a genetic quirk known as the photic sneeze reflex; a condition described by neurologists as having to do with crossed wires in the brain.
It’s impossible to sneeze in your sleep.
You can’t sneeze with your eyes open.
Looking at the Sun can trigger a sneeze. For some people, bright lights mean big sneezes.