I will sneeze every time, and if I need to egg the
sneeze on, I will look right at the light until I
sneeze. If I feel a sneeze coming on, I will either look at the sun or a bright light in a room. I rarely sneeze in a low light situation.
My doctor thinks I am nuts, as does my opthamologist. However, my Mom did this (but not my Dad) and both of my daughters do it too. My Mom says that her Mom did it as well. It's very strong reflex and completely uncontrollable.