The focal length of the eye length increases when ciliary muscles is most relaxed

Dear Student

​​​​​​When ciliary muscles are relaxed, lens becomes thin and the interior of the lens become least rounded so it has more focal length.
To view distant objects, the ciliary muscles relax making the lens of the eyes flattened. The thin, flattened lens increases the focal length of the object and focuses it on the retina so that we can see objects from long distance.

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