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Rigid contact lens are generally hard in nature while
the cosmetic lenses are usually the colored lenses used to correct
vision disorder or to change the eye color. Lets know about these two
types of contact lenses in detail:
Rigid gas
permeable contact lenses
These lenses were introduced in 1979 and
are considered as hard lenses but they are not like the past hard lenses
which were manufactured using polymethylacrylate (PMMA). Instead they
are made from a flexible material called silicone as silicone allows
more oxygen to enter the eye than the other soft lenses. The material
called PMMA used in the past in hard lenses did not allow oxygen to
reach the eye resulting in an unhealthy condition, also they were
uncomfortable and and were not easy to get used to. Gas permeable lenses
are very durable and they provide resistance to the deposition of
materials on the lenses to avoid any ill-effects on the eye. These
lenses provide their patients superior visual acuity. These lenses are,
easy to clean, not very expensive, and can be used for a long period of
time. Because of the rigid material present in these lenses, the lenses
keep their shape while blinking thus providing you crisp vision.
However, you should consider some points regarding these lenses:
A) There is greater risk of having corneal ulcers which could damage your
vision.
B) The cornea may take an undesirable shape.
C) Contacts if worn during sleep, may decrease the flow of oxygen to the
cornea.
D) These lenses are hard to adapt as a person needs time to get used to
them.
These lenses are also called oxygen permeable lenses.
Cosmetic
lenses
Cosmetic lenses have a special color layer within the lens
which allows color to blend with your own natural eye color by never
touching your eye. This color layer allows you to change or enhance your
eye color. Colored contact lenses come in varying colors which can
enhance the color of your eye by using an enhancement tint which is
translucent.
Color contact lenses come in
various types like hard, soft, and novelty. Color contacts for changing
the color of your eye use opaque tints which are made of patterns and
solid colors. For wearing these lenses, you don't necessarily be
suffering from some vision disorder. Even people with great eyesight can
use them too.
They also come in the form of disposable lenses to provide
the users, an opportunity to change their eye color regularly.
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