I guess I'm in the one third group.

In theory, some people should have an orgasm or at leat a tingling.

obviously something to do with an overload of the senses when lookin at extreme brightness ie: the sun

When I know a sneeze is near, a bright light is usually all it takes. Three or four very powerful sneezes are my norm, sometimes even more.

I only sneeze from my seasonal allergies, *LOL*

Yup, light gets me every time.

To sneeze, I mean.

It gets me every time.

Bless you!
i remember going to see an eye-ear-nose-throat (EENT) doctor when i was young for something else not the sneezing thing.
But i guess they ( EENT ) must be more inter-connected than we think.