Why does squinting help you to see more clearly? How does it work?

02 August 2009

Question

Why does squinting help you to see more clearly? How does it work

Answer

Dave - Okay. The way your eye works in the first place is it has a lens at the front - a lens in the cornea. They act together to focus light onto the back of your eye. Basically, a lens is a curved piece of transparent material. The light goes slightly slower in the lens than in the air so when light hits it at an angle it will slow down and go on the corner. A perfect lens is shaped so as it focuses all of the light from one point to outside your eye to one point on the back of your retina. The problem is as things get closer and further away, you need to change the focus. You need to change the distance. The way your eye does that is by changing the shape of your lens. The problem comes if you're short-sighted or long-sighted. Then your lens isn't the right shape for the length of your eye. And you can't adjust enough to help to see things so things look fuzzy. But the smaller the iris, the smaller an area of lens which light can get through, the less it can go wrong so the less fuzzy, the less the errors are so the less fuzzy the image is. So, basically, the main thing that squinting does is it reduces the area that light can get in through in the same way if you go out on a sunny day things look less fuzzy because your iris closes down. So if you squint you should close down your eye. You let light in through less of the lens and things look less fuzzy

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