Previous: The Truth About 'Truth Serum'
Next: Alan Turing and The Imitation Game



View count:542,518
Last sync:2023-01-27 21:45
Night blindness is real, and it can be caused by any number of things that affect the complicated mechanics of your vision.

Hosted by: Michael Aranda
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:

Or help support us by subscribing to our page on Subbable:
Looking for SciShow elsewhere on the internet?

Thanks Tank Tumblr:

(SciShow Quick Questions music)

Michael Aranda: Night blindness might sound like an exaggerated condition; I mean, it's kind of hard for anyone to see in the dark, but it's real, and it can be cause by any number of things that reflect the complex mechanics of your vision.
The inside surface of your eye is the retina. It's mostly made up of two kinds of sensory cells, rods and cones. Rods simply detect light, allowing you to see in shades of grey, while cones work together to provide color vision. Night blindness, officially known as nyctalopia, is any condition that interferes with the functioning of your rods, which makes it difficult for your eyes to detect light. (0:32)
In most cases of nyctalopia, a person's vision is pretty normal is pretty normal in bright or moderate conditions, but in low light, their vision is so weak that it approaches actual blindness. (0:40)
But night blindness isn't considered a disorder on its own. It's a symptom of other conditions, that either hinder light from reaching the rods or impair their function. For example, cataracts, cloudy areas that form in the lens of the eye, can block or bend light, preventing the rods from detecting it properly. (0:54)
And because rods are mostly found around the edge of the retina, anything that changes the shape of the eye or the direction of the light entering it can effect night vision. (1:01) This includes certain forms of nearsightedness, or the effects of some vision correcting surgery, or medications or disorders that affect the pupil of the eye. Also, your rods only work because they contain the light-sensitive protein called rhodopsin, and your body can't make rhodopsin without Vitamin A, so night blindness can also be caused by a Vitamin A deficiency. (1:17)
Many orange foods, like carrots and cantaloupe, and dark greens, such as kale or spinach, are very rich in Vitamin A, so treatment for nyctalopia can range from either improving your nutrition to getting prescription eye glasses to surgery.
So, as you can see, night blindness is for realsies. (1:30)
Thanks for asking, and thanks especially to our Subbable subscribers who keep these answers coming. If you have a Quick Question, let us know on Facebook, Twitter, Tumblr, or in the comments below, and don't forget to go to and subscribe.
(SciShow Theme music plays)