Rigid Gas Permeable (or RGP) contacts represent the latest in hard contact lens
technology. As indicated by the name, RGP lenses are composed of a rigid silicone
material that allows gas exchange to take place through the lens. This important
characteristic allows oxygen to reach the
cornea, which is vital to ocular health. Unlike the hard lenses
of the past, RGP lenses provide a much healthier and more comfortable fit for wearer's.
RGP vs. Soft Contacts
RGP lenses differ from soft contacts in several ways. Because RGPs are rigid and
maintain their shape and position on the cornea, they often provide superior visual
clarity to soft contacts. They also tend to be easier to handle (they won't fold
over or turn inside out) and the fact that they do not contain water, means that
they do not accumulate protein deposits to the degree seen in soft lenses (the proteins
and lipids that are present in tears are hydrophilic and are attracted to water).
Given proper care and maintenance, RGPs also tend to be more durable than soft contacts
and may last for several years. These lenses may even be polished to extend the
period of use.
Even though RGP contacts may provide superior vision and durability when compared
to soft lenses, they are not for everyone. RGPs require a significant period of
adjustment due to the way the lens tends to reshape the cornea to a certain degree.
One must also wear them daily because any lengthy lapse in wear will result in another
period of adjustment. Price and comfort are often reasons for choosing soft contacts
over RGPs.
Who can wear RGP lenses?
RGP contacts may be worn by individuals with standard spherical, toric, or bifocal/multifocal
prescriptions. They may also be prescribed to patients with a condition known as
keratoconus, which causes the cornea to become cone-shaped and results in impaired
vision. The shaping properties of this type of lens may help to reduce the affects
of such a condition.
