A few examples of Contact lenses are:
The shortest replacement schedule is single use (daily disposable)
lenses, which are disposed of each night. These may be best for patients
with ocular allergies or other conditions, because it limits deposits of
antigens and protein. Single use lenses are also useful for people who
use contacts infrequently, or for purposes (e.g. swimming or other
sporting activities) where losing a lens is likely.
Two-week Replacement Disposables
The main advantage of wearing disposable lenses is that you put a fresh
pair of lenses in your eyes every two weeks. Another advantage is ease
of care with multipurpose solutions.
One-month Replacement Disposables
Similar to two-week replacement lenses but you throw them out every 30
Conventional Contact Lenses
These are the original soft contact lenses. It is recommended these
lenses be replaced on a yearly basis. Conventional lenses are more care
intensive than disposable lenses.
Certain soft contact lenses come in colors to either enhance your eye
color or completely change it.
Toric lenses are made from the same materials as regular contact lenses
but have a few extra characteristics:
• They correct for both spherical and cylindrical aberration.
• They may have a specific 'top' and 'bottom', as they are not
symmetrical around their center and must not be rotated. Lenses must be
designed to maintain their orientation regardless of eye movement. Often
lenses are thicker at the bottom and this thicker zone is pushed down by
the upper eyelid during blinking to allow the lens to rotate into the
correct position (with this thicker zone at the 6 o'clock position on
the eye). Toric lenses are usually marked with tiny striations to assist
• They are usually more expensive to produce than non-toric lenses
Bifocal Contact Lenses
Multifocal soft contact lenses are more complex to
manufacture and require more skill to fit. All soft bifocal
contact lenses are considered "simultaneous vision" because
both far and near vision corrections are presented
simultaneously to the retina, regardless of the position of
the eye. Of course, only one correction is correct, the
incorrect correction causes blur. Commonly these are
designed with distance correction in the center of the lens
and near correction in the periphery, or vice versa..