So I understand we see things because light is reflecting off an object and that light is hitting our eye. It gets focused by our eye onto our retina. So it makes sense to me how someone can have bad eyesight, where everything goes equally out of focus. But how can a person be near-sighted, where light travelling a shorter distance (ie reflected from a closer object) is in focus but light travelling a farther distance is not in focus? And the reverse for far-sighted? How does the distance the light is traveling affect whether it can be in focus? It seems to me like everything should be able to be equally in focus, or equally out of focus
In: Biology
Nearsightedness (Myopia) and Farsightedness (Hyperopia) are both caused by the eye being misshaped.
With Myopia, the eye is elongated front-to-back, while with Hyperopia, the eye is squashed front-to-back. In each case, the issues with vision arise when the lens cannot focus the image on the retina properly because the retina, in effect sits outside the range the lens is capable of focusing in; in the case of Myopia, the image is focused in front of the retina, in Hyperopia, it’s focused behind the retina. The lens in effect is designed to focus the image in only one place, so if the retina isn’t where it’s supposed to be, there are problems.
Both Nearsightedness and Farsightedness can also be caused by the lens of the eye having too much (Myopia), or not enough (Hyperopia) curvature, which results in the same effect.
Each condition effects distance or close-up vision respectively.
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