Why can looking at a bright light make you sneeze?

Monday 18th July 2011
Submitted by hashworth1

The technical wording for this is the photic sneeze reflex. Its exact cause is not known but it’s been found to run in families. One theory is that photic sneezers are unusually sensitive to light. The irritation caused by emerging out of the dark into the light or staring towards the Sun causes a similar reaction to that from pollen, leading to the sneezing reflex.

GOT A QUESTION?

Scratching your head over a burning scientific conundrum? Submit your question and we'll get our esteemed panel of experts to answer it for you.

 

Why do onions make you cry?
previous qanda Article
Why do you get hungry when you're drunk?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Viagra is the brand name for sildenafil citrate, a drug that was originally studied for use in patients with high blood pressure or heart disease. It works by blocking the action of an enzyme...

It depends on how high (or low) you set the bar of fluency. Ziad Fazah, born in Liberia, brought up in Beirut and now living in Brazil, claims to be the world's greatest living polyglot, with...

Astronomer Fred Hoyle was the first to point out that if you could drive a car upwards at 95km/h (60mph), it would only take about an hour to get into space. To get to the Moon would take a little...

For most people, a single unit of alcohol takes around two hours to metabolise. For ordinary-strength beer, the legal limit is approximately two pints, so you would need four hours to metabolise...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...