[Andrew Norton]

Andrew Norton  asked the Naked Scientists:
   
Hi Chris

Why when you sneeze in the dark(after opening your eyes) as it is nigh impossible to sneeze with them open do I see white speckles in front of my eyes?

Kind regards

ANDREW NORTON   

What do you think?

[Eldar]

I think the speckles are appearing because the preassure the sneeze creates in the sinuses.

A sneeze accelerate the air in your lungs up to 200 km/h, and that creates preassure to your blood vessels in your eyes, forcing the blood out of your eyes, and "black-out" the light-sensitive cells for a split-second.

You will get the same effect if you are boxing and gets a hard face/head hit from your opponent.

[Chemistry4me]

I think yor_on has the answer from this thread:

Anyway, if you close your eyes and press on them with your fingers you will be able to see both shapes and colours, not because there is light coming to them, just because that pressure you are applying on your eyes will be interpreted by the brain as having both shape and colour.

Like Eldar said, the pressure is caused in this case by the sneeze.

[thedoc]

Listen to the answer to this question on our podcast.

[jen]

so interesting! I see little dots or shapes like music notes when I sneeze. started recently. its scattered and fades towards the right side..... so glad I read this article

[PAUL MCKNOCKITER]

I THINK YOU MEAN ITS IMPOSSIBLE FOR YOU TO SNEEZE WITH YOUR EYES OPEN CHRIS YOU cuddling  IDIOT