In visual perception, the far point is the farthest point at which an object can be placed (along the optical axis of the eye) for its image to be focused on the retina within the eye's accommodation.
It is sometimes described as the farthest point from the eye at which images are clear.
See visual acuity or Snellen chart for details about 6/6 (m) or 20/20 (ft) vision.
Sometimes far point is given in diopters, the inverse of the distance in meters (see Simple myopia).
A corrective lens can be used to correct myopia by imaging an object at infinity onto a virtual image at the patient's far point.
According to the thin lens formula the required optical power P is
This calculation can be improved by taking into account the distance between the spectacle lens and the human eye, which is usually about 1.5 cm: