Well, I've searched the forums, and I feel rest-assured this has not been posted before...so....
Here is the question: Do any of you sneeze (or have the urge to) when you look at bright light? (the sun, for example)
Evidently, it is a genetically inherited (autosomal [not sex linked] dominant, according to this guy) malformation of the nerves that run from your nose and eyes...they link together. If the retinal nerves are overstimulated (via bright light), it triggers the nerves in your nose. It could also be caused by the use of tobacco.
You can see the wiki article here, but you should read the primary sources, below, that wiki used.
Individual differences with respect to the sneezin...[Hum Hered. 1983] - PubMed Result
The photic sneeze reflex as a risk factor to comba...[Mil Med. 1993] - PubMed Result
Solar Sneeze Reflex
The photic sneeze response: a descriptive report o...[J Am Optom Assoc. 1995] - PubMed Result