Why does looking at a bright light or sunlight sometimes make people sneeze?

Discover ^ | January 2002 | Louis Ptacek

[Oxylus]

Question:
Why does looking at a bright light or sunlight sometimes make people sneeze?

Carl Owens,
Corcoran, California

Louis Ptacek of the University of Utah's Howard Hughes Medical Institute replies:

Sneezing provoked by sudden exposure to intensely bright light is known as the photic sneeze reflex. It is not uncommon'about one in 10 people are photic sneezers. Some studies suggest it may be due to an accidental crossing of nerve signals involved in normal sneezing and pupil dilation. But the photic sneeze reflex occurs only after someone has been adapted to the dark for at least five minutes. Even photic sneezers' pupils will adjust normally (without triggering a sneeze) if they go in and out of bright light for short periods of time, so the real mystery is why an extended period of darkness makes a difference. The reflex is not troublesome to most people, but it is of considerable interest to scientists. The trait travels in families'approximately 50 percent of children born to photic sneezers are photic sneezers themselves'so it should be possible to identify one or more genes that are responsible. The photic sneeze reflex may also relate to other reflex phenomena. For example, people with epilepsy frequently have seizures induced by strobe lights, and visual stimuli can precipitate headaches in many migraine patients. Studying the photic sneeze reflex is likely to improve our understanding of sensory pathways in the nervous system, as well as the circuitry of the sneezing reflex.

[Texas_Jarhead]

Hey what-do-ya-know, I'm a photic sneezer. Don't I qualify for some taxpayer money under the ADA?

FReegards

[Romulus]

Surely more than one in ten. From my school days, I recall coming out of church after Friday Mass, into the brilliant noonday sun, with whole ranks and files of children sneezing in unison, me included.

[mykdsmom]

I wasn't aware of this phenomenon but I wanna know why yawning is catching.

I even yawn when someone I'm talking to on the phone yawns........WHY?

Anyone, Anyone?

MKM

[inflorida]

Finally, some information about this.
My husband always sneezes a few times after he catches some glimpses of the sun (usually after getting out of the car).
All of his siblings do this as well and to think that all of this time I thought it was just in his head...

[aomagrat]

So that's why I sneeze my head off in bright light. Not just the sun either. I can sneeze by looking at a light bulb or even a flash light.

[Servant of the Nine]

Hey what-do-ya-know, I'm a photic sneezer. Don't I qualify for some taxpayer money under the ADA?

We can probably get you sterilized for free.

So9

[messenger4]

That is funny!!!

[demkicker]

I've never notice that exposure to light makes me sneeze. OTOH, when I feel a sneeze coming on but am tortured because it won't materialize, I was taught to look at a bright light or the sun to bring the sneeze on. Sure enought, it works every time!

[inflorida]

I wasn't aware of this phenomenon but I wanna know why yawning is catching.
I even yawn when someone I'm talking to on the phone yawns........WHY?

I am also waiting for the day that this is explained.

[GOPmember]

I recall hearing of a teleological explanation for this. As cave dwellers emerged from their caves, some would clear potentially harmful fungi from their upper respiratory tract (blastomycosis, histoplasmosis, coccidiodomycosis, etc.) by sneezing, triggered by exposure to sunlight. Those who did not exhibit this reflex may have been more prone to potentially fatal pneumonias and other infections due to these organism and, therefore, were less likely to procreate.

Whether true or not, it seems like a reasonable theory.

[alloysteel]

The post-coital phase of orgasm sometime causes me to sneeze....

[Texas_Jarhead]

Well isn't that a polite and thoughtful sentiment.

[linemann]

dang...this is a first. I yawned by READING the word Yawn!?!

[is_is]

I'm pretty sure that Moose's and cheese are involved somehow.

[Aggie Mama]

Maybe someone can explain why I sneeze after eating a mint (the red and white kind), or chocolate, or after taking a sip of dry white wine. I thought that the yawning was a psychological response of a pack mentality i.e. all of us need to stay awake to protect our tribe from whatever evil lurks outside, so I'm going to yawn too. Could be total hogwash, but it sounds good!

[citizen]

It's from a certain trigger caused by the blue light spectrum. I was surprised, I sort of assumed it was the red spectrum.

And it's great, if I "need to sneeze" I just look at a light, any light, and get usually relief.

[I am still Casey]

This one is easy.....do it all the time.

If you feel like you need to sneeze, instead of struggling with it, just look at a bright light, and presto!

Stimulation of the optic nerve. Works every time.

[blackbart.223]

"So that's why I sneeze my head off in bright light. Not just the sun either. I can sneeze by looking at a light bulb or even a flash light."

I get the urge to puke every time I see Bill and The Sea Hag on TV. I wonder if there is a link between the two phenomena?