Contact Lenses
Contact lenses are thin, clear, disks of plastic that float on the tear film that coats the cornea,
the clear front window of the eye. Contact lenses are used to correct the same conditions that
eyeglasses correct:
• Myopia (nearsightedness);
• Hyperopia (farsightedness);
• Astigmatism
• Presbyopia
•
Hard Contact Lenses
Most kinds of hard contact lenses are rarely used today. However, rigid gas-permeable (RPG)
lenses, which hold their shape, yet allow the free flow of oxygen through the lens to the cornea,
are easier to adjust to and more comfortable to wear than the older kinds of hard lenses.These
lenses may be the best choice in cases where the cornea has enough astigmatism (that is,
shaped like an egg instead of an orange) that a soft lens will not provide sharp vision. They may
also be preferable for people with allergies or who tend to form an excess of protein deposits on
their lenses.
Soft Contact Lenses
Soft contact lenses are the choice of most contact lens wearers for their comfort as well as for
the many options available today. These options include:
• Daily-wear lenses. These lenses are the least expensive, are removed and cleaned
nightly, and are replaced on an individualized schedule. They should not be used as an
extended-wear lens.
• Extended-wear lenses. These lenses are worn overnight and are removed at least
weekly for thorough cleaning and disinfection. They are being recommended less
frequently, since there is a greater risk of corneal infection with any overnight wear of
contact lenses. The decision to accept the risks and benefits of extended-wear lenses
requires a process of evaluation between you and your ophthalmologist (Eye M.D.).
Once you have been carefully fitted for your contact lenses, it is important to have follow-
up examinations with your ophthalmologist to ensure continuing eye health. As with any
contact lenses, extended-wear lenses should be removed at the first sign of redness or
discomfort.
• Disposable-wear lenses. These lenses a