Can someone explain night vision to me?



So if I have to go pee at night, I don’t turn on lights in the house but I do use the bathroom light. Before I turn on bathroom light, I keep one eye closed.

Afterwards, when I leave the bathroom, the formerly-closed eye can see in the dark well but the eye that got light is a bit terrible.

So I use the formerly-closed eye to navigate back to bed.

So how does night vision work?

In: Biology

Pupils dilate to allow in a certain amount of light, each eyes pupils are at different dilation.

There are two types of cell in the human eye responsible for eyesight.

* *Cone* cells, responsible for color vision, work best in bright light
* *Rod* cells, more sensitive than cone cells, operate best at low light, responsible for peripheral vision and night vision

The rod cells get overwhelmed in bright light and cease functioning, requiring time to re-adapt to darkness; this is why you temporarily can’t see after you switch off the light.

Covering one eye prevents its complement of rod cells from being deactivated, allowing them to provide you with night vision.

Fun side fact; that’s why pirates wore eye patches, not because they lost an eye, but so they could transfer the patch from eye to eye when they went back and forth between above deck and below deck, so they wouldn’t have to wait for their eyes to adjust to the dark