For optics such as binoculars or a rifle scope, eye relief is the distance from the eyepiece to the viewers eye which matches the eyepiece exit pupil to the eye's entrance pupil. Short eye relief requires the observer to press his or her eye close to the eyepiece in order to see an unvignetted image. For a shooter, eye relief is an important safety consideration. An optic with too short an eye relief can cause a skin cut at the contact point between the optic and the eyebrow of the shooter due to recoil.