What are contact lenses?
Contact lenses are small visual devices made with curved pieces
of plastic shaped in a way to conform directly to the wearer’s
eye. They provide an artificial refracting surface to the human
eye and are used to correct vision problems like myopia and hypermetropia.
Contact lenses aid in eye focusing in the same manner as spectacles
do. Apart from these corrective measures, contact lenses can also
be used for cosmetic and therapeutic reasons.
There have been many modifications and improvements to the original
idea of contact lenses, conceptualized first by Leonardo Da Vinci,
through centuries. About 35 million people in the U.S. wear contact
Features of Contact Lenses
The lenses are made from different types of materials – soft
and rigid – and come in a variety of designs and colors.
These include disposable, colored, astigmatic, aphakic, presbyopic
and keratoconic lenses. The initial fitting and follow up care
are important parts of contact lens usage to give maximum benefits
of vision, appearance, comfort and tissue integrity.
Advantages of Contact Lenses
Contact lenses are capable of correcting most of the problems
that spectacles can as well as some additional ones that glasses
People not satisfied with their appearance using glasses can
opt to use contact lenses for improved appearance. Contact lenses
are not in the danger of slipping off, getting wet, or fogging
up, which can easily happen with spectacles.
Extremely hypermetropiac people or those who have had cataracts
removed, feel better wearing contact lenses as compared to spectacles,
which in these cases produce uneven vision. Moreover, contact
lenses give improved vision for people with damaged corneas due
to disease or injury. Also for sportsmen, wearing contact lenses
prove to be more practical as in the case of those where wearing
spectacles pose a problem in their jobs. In addition to all these,
contact lenses provide better side vision compared to glasses.
Uses of Contact Lens
The primary use of contact lenses is to correct myopia (short
sightedness). They can also be used to rectify hyperopia, astigmatism,
presbyopia and aphakia. Rigid lenses are used to correct irregular
trauma. Soft lenses are used as bandages for conditions like bullous
keratopathy, recurring corneal erosion as well as to increase
comfort, vision and postoperative wound healing.
Main Types of Contact Lenses
There are two principal types of contact lenses in use today.
Soft contact lenses are those that are made of hydrophilic plastics
and absorb liquid and must be kept moist for softness and easier
moulding to the corneal surface. They are extremely comfortable
and are used by majority of contact lens users. The other type
in use is the gas permeable (RPG) or rigid contact lenses, which
are composed of durable and flexible plastics, which permit oxygen
to pass through to the cornea and are easier to maintain. The
original hard lenses, or PMMAs, used earlier did not allow oxygen
to pass to the eye and have been replaced by the RPGs.
If a person desires to use contact lenses, he or she should do
so only after consultation with an ophthalmologist. He/she will
advise whether contact lenses would be suitable for a person to
use or which kind of lenses, soft or gas permeable, should be
used in a particular case. It is imperative that a yearly examination
be done after the initial use of contact lenses.
The Adverse Effects of Contact Lenses
People have difficulty in using contact lenses if they have eye
irritations due to allergies or dust and chemicals. Overactive
thyroid gland, severe diabetes or extreme arthritis in the hands,
dry eyes related to pregnancy, contraceptives, diuretics, antihistamines
and decongestants and eye disease prevents a person form using
The usage of contact lenses may give rise to problems like eye
infections, allergic reactions to lens care solutions and deposit
on lenses, redness of the eyes, scratched corneas, alteration
in corneal shape and structure and abnormal blood vessels growing
in the apparently clear cornea. You should consult your eye specialist
without delay if there is burning, extreme sensitivity or hazy
vision or pain.
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