Let there be small amounts of light!

Apparently dilated pupils are attractive. If you want to be more attractive - try rubbing cocaine in your eyes!

I once read a life hack advice column, with stupid suggestions on how to be more efficient at life. Some of them of course were really good, the others were trash. One of the best suggestions was to keep one eye closed when you wake up at night, so that after you've flicked the light on then off again your night vision will be retained in the closed eye. Brilliant! No more walking in to furniture on the way back from the bathroom right?

I always thought this was because the pupil of the closed eye would remain dilated, allowing more light in when the darkness returns. It turns out that's not the case. As neurology has taught me, in a normal person shining a light in one eye causes the pupils of both eyes to constrict (The consensual response.) If that's not happening, you should get yourself to a doctor because you've probably got some sort of brain lesion.

With regard to the night vision it actually turns out it's the cells at the back of your eye that make the detector for light. In the absence of light they become more sensitive to smaller and smaller amounts of light. By covering your eye in the light, the sensitivity is retained*.


And now you know another useless fact.

*Yes this has something to do with carrots, as carrots contain carotine, which is converted to Rhodopsin, which is used to signal to the brain when light hits the back of the eye. In the dark you get more Rhodopsin building up, so the cells are more likely to signal in lower light. So eat your veggies!