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Services > Contact
Lens
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What
Are Contact Lenses?
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Contact
Lenses (CL) are small, thin, curved transparent discs that
are designed to rest on the cornea, the clear front surface
of the eye. Contacts cling to the film of tears over the
cornea because of surface tension, the same force that
causes a drop of water to cling to the side of a glass.
Contact lenses are mostly used to correct near-sightedness,
far-sightedness and astigmatism. Contacts provide a safe
and effective way to correct vision when used with care
and proper supervision. They can offer a good alternative
to eyeglasses, depending on your eyes and your lifestyle.
However, one must remember, they are health devices, not
commodities or beauty aids, and not everyone can wear them.
Also, their use can affect the well being of your eyes
and only an optometrist or an ophthalmologist (eye surgeon)
is qualified to assess the health of your eye. Your healthy
vision is the first priority.
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What
are the advantages and disadvantages of each type of
contact lens?
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RGP
(Semi-soft) lenses: RGP lenses are made of special,
firm plastics combined with other materials, such as
silicone and fluoropolymers, which allow oxygen in the
air to pass directly through the lens. These lenses are
very durable and typically last longer than soft lenses.
RGP lenses provide excellent quality of vision, have
a long life, and can correct astigmatism as well as uneven
curvature of the cornea. The disadvantages are that these
may take a little longer to get used to, it is easier
for dust to get behind RGP lenses, causing irritation
and discomfort, and one can't switch back and forth with
glasses as easily. However, regular wearers find them
comfortable and the visual acuity outstanding.
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Soft
lenses are made of flexible water-absorbent (hydrophilic)
material having water content between 30-80%. These lenses
are comfortable the moment they are inserted in the eye.
They are less likely to dislodge and can be worn for
longer periods. However, their biggest disadvantage is
that they cannot correct higher degrees of astigmatism.
They also need to be changed more frequently.
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Which
type of contact lens is best for me?
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Each
individual is different, although there are some broad
guidelines that may be followed. If you are interested
in initial comfort, soft contact lenses may suit you better
than rigid gas permeable (RGP) lenses. On the other hand,
RGP lenses tend to last longer. A soft (hydrophilic) lens
is more appropriate for occasional wear (at most once or
twice a week).
Not
everyone can wear both types. Only after thoroughly examining
your eyes and vision, can one advise whether you can wear
RGP lenses, soft lenses or both. In your initial consultation,
a number of tests and measurements will be performed, usually
following a full, general visual examination. This evaluation
will determine the optimum contact lenses for your specific
needs. Additionally any other factors that determine your
ability to wear lenses successfully will be explained to
you.
Various
general health factors, including medication, ocular, medical
and family history will be assessed. A number of prescription
medications, drugs and allergic factors can influence the
ability to wear contact lenses successfully. Additionally
your work and social environments can affect lens choice
for example air-conditioning, computer use, dusty environments
and so forth will affect the lens choice. |
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