How do glasses correct your vision? I know it has something to do with the retina but what exactly does it do?
In: 1
When light bounces off an object, it scatters in different directions. Some of these rays will be able to go through your pupil and hit your retina. But, if that’s all that happened, your vision would be blurry. Instead, you have a lens which can bend these rays together so that all the rays coming from a particular point in space hit the same point on your retina. This means there is a picture projected onto the back of your eye.
But, different distances will require different amounts of bending. Imagine two people standing a meter apart. If you’re a covid-safe 2m away from them and try to point to one with one arm and one with the other, there’s an angle between your arms. This is like the angle between light going through the top of your pupil and the bottom of your pupil. Now say you’re at the opposite end of a football field from them (whichever version of football) and you point your arms at them. Your arms are basically pointing in the same direction. This is the difference between the light from near and far objects.
The lens in the eye adjusts how much bending it does by changing shape. But, because of reasons, it might not be able to do it enough, meaning nearby objects appear blurry. In this case, glasses have a convex (bulging) lens that does some of the bending. Or, your eyes might be stuck bending light too much, meaning far objects are blurry. Then, glasses have concave lenses that actually bend the light outwards, meaning the extra inward bend your eyes do is now the right amount.
Latest Answers