Contact Lenses are thin clear plastic discs that sit on the cornea of the eye. Contact lenses can correct:
Myopia (nearsightedness)
Hyperopia (farsightedness)
Astigmatism
Presbyopia
Millions of people around the world wear contact lenses. Depending on your lifestyle, your motivation and the
health of your eyes, contact lenses may provide a safe and effective alternative to eyeglasses when used with proper
care and maintenance.
What are the different types of contact lenses?
Mainly 2 types: hard and soft.
Soft lenses are known for their comfort as well as their high and low water content. There are many
categories:
Monthly wear. Worn daily and can be used for a month.
Daily Disposable wear. These lenses are more expensive, are removed
nightly and are replaced daily. They should not be used as a monthly
wear lens. They are recommended for people with allergies and for
those who tend to form deposits on their lenses.
Colored contacts. Change the appearance of your eye color to varying degrees.
Also can correct any refractive error.
Toric contacts. Can correct astigmatism, although sometimes not as well as the
rigid gas-permeable (RGP) lenses. More expensive.
Bifocal contacts. Correct presbyopia.
Hard lenses include the rigid gas-permeable (RGP) contacts. These lenses may be the best choice when the
cornea has astigmatism that cannot be corrected by a soft lens. They may also be
preferable when a person has allergies or tends to form protein deposits on his or her
contacts.
Presbyopia can be corrected in one of three ways:
Wear your distance correction in the contacts, and wear reading glasses when needed;
Wear one contact for distance vision, and one for near vision. This is called “monovision,” and it works well
for many people but not for everyone. You may need a trial period to decide if monovision is for you;
Wear bifocal contacts, which are designed to allow both distance and near vision. These lenses are
somewhat more expensive to fit and may not provide satisfactory vision for all people.
Special uses for contact lenses include “bandage” lenses to cover the corneal surface and provide comfort after
injury or surgery; lenses for infants; special RGP lenses (Rose K or Clear-Cone) for people with irregular corneas due
to injury or Keratoconus; and painted contact lenses to change appearance or reduce glare after eye trauma.
How is contact lens fitting done (Topography)?
Corneal topography is necessary for fitting contact lenses. Your contact lenses should fit your eyes as well as
possible, and knowing the exact shape of your cornea is extremely important. Every patient has a specific Corneal
Curvature (BC). Topography of the cornea is the test that measures this specific curvature. Soft contact lenses are
pre-manufactured according to power, curvature and diameter (each brand having 2-3 BC). Before wearing a contact
lens a topography exam should be done to match the right contact lens BC to the patient’s cornea curvature. Failing
to do so can lead to serious problems (intolerance, vessels, warpage). Contact lenses that are too tight may constrict
normal tear flow, creating an unhealthy environment for normal cell function. On the other hand, fitting a lens that
is too loose may allow for excess movement of the lens on your eye, causing discomfort and possibly damage to the
epithelial cells.
What are the risks of wearing contact lenses?
Lenses that are not properly cleaned and disinfected increase the risk of eye infection. Lenses that are old or not
properly fitted may scratch the eye or induce blood vessels to grow into the cornea. Because a lens can warp over
time, and the cornea can change shape, the fit of the contact lens and the power should be re-evaluated on a regular
basis with Topography testing.
Episodes of eye redness while wearing a contact lens should not be trivialized
because they may be the sign of corneal infection. Every time there is eye
redness, the contact lens should be removed and the eye examined by Dr. Farah.
Contact lenses are well known to induce or worsen eye dryness. Preservative-
free wetting drops alone may be used while wearing your contact lenses. In case
of tear dryness, discuss with Dr. Farah a better option which is preserving your
own tears (Punctal Plugs).
What is proper care of contact lenses?
Any lens that is removed from the eye needs to be cleaned and disinfected at least 6 hours before it is reinserted. Dr.
Farah will discuss the best type of cleansing solution for you.
Care of contact lenses includes cleaning their case, since it is a potential source of infection. The case should be
rinsed with water, wiped and allowed to air-dry.
Daily wear lenses should not be worn while sleeping. Tap water or homemade saline (salt water) solutions have been
linked to serious corneal infections and should not be used. Contact lenses should not be worn in the pool.
A certified technician will teach you how to put and remove
your contact lenses and will give you the required instructions.
Who should not wear contact lenses?
You may not be a good candidate for contacts if you have:
Frequent eye infections
Severe allergies
Dry eye that is resistant to treatment
A very dusty or dirty work environment
An inability to handle and care for the lenses