Far point

See also: Farpoint

In visual perception, the far point is the point at which an object must be placed along the optical axis for its image to be focused on the retina when the eye is not accommodating. It is sometimes described as the farthest point from the eye at which images are clear.

For an object to be imaged on the retina of an unaccommodated myopic eye it must be brought nearer until it occupies a position conjugate to the retina. This point is called the far point of the eye. For a hypermetropic eye, incident light must be converging before entering the eye so as to focus on the retina. In this case the far point is behind the eye in virtual space, rather than in front of the eye. For an emmetropic eye, the far point is at infinity, but for the sake of practicality, infinity is considered to be approximately 6m or greater since the vergence change from 6m to actual infinity is negligible.

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