Hi, I'm Craig, and this is Mental Floss on YouTube. Today I'm going to answer Amar Jerath's Big Question: Why do you see better when you squint? Let's get started.

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In order to answer this question, I'm going to have to talk a little about how the eye works. Just in case you weren't paying attention in science class. So the whole reason we can see is thanks to our good friend light. While you're looking at something, light is entering the pupil.

The lens in your eye lives right behind the pupil, and that focuses light on the retina. The retina is a layer of tissue containing photo-sensitive cells known as rods and cones. That's where the image of what you see is created, and then that image gets sent to the optic nerve in the brain. In the retina there's something called fovea which is part of the eye that makes sharp central vision, aka detail-oriented vision possible. We need that type of vision so we can do stuff like read and drive.

When you look at an object and it appears blurry, that's usually because of light, too. The lens doesn't properly focus the light onto the retina, unless you have another eye condition like cataracts causing this to happen. When you squint, two things change to help you see better: the shape of your eye and the amount of light entering it. And a third thing: you look like Gilbert Gottfried. If you know who that is. 

First, there's the shape. When a person squints, the new shape of the eye makes it so that the light coming into the eye can be focused directly on the fovea, and since the fovea is the best at getting visual details that helps us see more clearly.

Second, there's the amount of light entering the eye. When someone squints, less light is let into the eye. Blocking out a bunch of unnecessary, excess light makes it easier for the eye to focus because it's trying to focus on less all at once. 

This can really help when you're in a bind, but it's probably worth mentioning that if you're frequently squinting in order to see, you might need glasses. Or, if you already have them, you need to stop forgetting to wear them. You go get your glasses!

But, contrary to popular belief, squinting isn't gonna damage your vision. It might give you a headache, but that's because of the muscle contraction in your face. It might also give you these things. Angel tears? Something? Crows feet.
 
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Thanks for watching Mental Floss on YouTube, which is made with the help of all these foveas. If you have a Big Question of your own that you'd like answered, leave it below in the comments. See - see you next week.