Lens Distance From Eye
The overall size of the lens is controlled by how far the lens is positioned away from the eyes. A closer distance allows for a smaller lens, but there is a limit on how close eyeglass lenses in a frame can be to the eye, imposed by the eyelashes and eyelid.
Contact lenses placed directly on the cornea are physically larger than the pupillary region, and have a ring of extra unused material around the outer perimeter that simply helps to center the lens on the cornea.
Eyeglass lenses need to be larger the further away they are from the eye. Very large lenses in a double-bridge frame do not necessarily provide greater peripheral vision, due to the nose rest holding the lenses slightly further away from the eyes than with smaller lens frames.
Read more about this topic: Corrective Lens
Famous quotes containing the words distance and/or eye:
“Though there were numerous vessels at this great distance in the horizon on every side, yet the vast spaces between them, like the spaces between the stars,—far as they were distant from us, so were they from one another,—nay, some were twice as far from each other as from us,—impressed us with a sense of the immensity of the ocean, the “unfruitful ocean,” as it has been called, and we could see what proportion man and his works bear to the globe.”
—Henry David Thoreau (1817–1862)
“A good metaphor is something even the police should keep an eye on.”
—G.C. (Georg Christoph)