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enter image description hereWhat is the relationship between near point and focal length of the eye?normally in a convex lens when the object is kept at 2f we get the same size image as shown . A healthy human eye can see objects without any trobles. Then is the near point of the eye, 2f of the eye lens? Im really confused about focal length of eye lens and near pont.

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As I recall, a relaxed lens of a healthy eye puts the image of nearby (but not close) objects on the retina of the eye. For distant objects, the muscles around the lens must make minor adjustments to the shape of the lens (unless you are far-sighted). For nearby objects, the muscles must work harder to shorten the focal length of the lens. When the object is brought in so close that it can no longer be kept in focus, it is inside of the near point.

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  • $\begingroup$ Correct - at least for young folks; as we get older, the lens stiffens, leading to "presbyopia" and the need for reading glasses because our eye can't change focal length. $\endgroup$ – Carl Witthoft Nov 24 '20 at 14:09

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