How Do Bifocal Contact Lenses Work?
With bifocal eyeglasses, the method works because the lenses always stay in place, even as your pupils shift downward or upward. Contact lenses, especially soft ones generally **** with your pupils somewhat – so how do alternating bifocal contact lenses work? The answer is simple. Most alternating bifocal contact lenses are gas permeable lenses. Gas permeable lenses are smaller in diameter than soft contact lenses and they ride up on your eye in order to rest on or above your lower eyelid. Because of this, when your pupil shifts downward, the lens stays put so that you can see through the lower half of the lens where the near vision correction strength is.
