What Are The Different Types of Contact Lenses?

Millions of people today wear contact lenses to help them see clearly. If you need
prescription lenses, you could be one of them. With all the lens choices available now,
most people can find contacts that give them sharp, comfortable vision without
compromising eye health.

Pasadena Eye Associates’ Contact Lens Service is dedicated to providing the highest
quality contact lens care. We offer a complete range of lenses, from the simplest cosmetic
contacts to the most sophisticated bifocal lenses.

As the area innovator and utilizer of corneal topography, our EyeSys Computerized
Corneal Topography System allows us to measure and describe the specific contours and
numerical curvature of the cornea. In addition, a computerized autorefractor and
keratometer as well as a highly trained Contact Lens staff allow us to obtain a level of
accuracy in determining the specifics of your cornea previously unattainable.

Types of lenses


Our expertise enables us to fit patients who are new to wearing contact lenses, as well as
those who have previously failed with contact lenses. Contact lenses can be divided into
several classifications:

  • By material characteristics: soft (cellophane-like) or rigid (formed flexible plastic).
  • By wear schedule: Daily Wear or Overnight Wear (also called "Extended Wear", a
    modality which has fallen into disfavor because of the high incidence of
    complications).
  • By life-span of the lens: Disposable (1 day or 2 week), Planned Replacement (1
    month, 3 month or 6 month), or Conventional year or 2 year).
  • By correction modality: Spherical, Toric or Astigmatic, or Bifocal

 

Lens Type Advantages Disadvantages
Rigid gas-permeable (RGP)
hard lenses are made of slightly
flexible plastics that allow oxygen
to pass through to the eyes.
They provide excellent vision,
a short adaptation period,
they are comfortable to wear,
correct most vision problerns,
are easy to put on and to care for,
are durable with a relatively long
life... available in tints (for
handling purpose ) and bifocals.
Require consistent wear to
maintain adaptation... can slip
off center of eye more easily
than other types.
Daily-wear soft lenses
Made of soft, flexible
plastics that allow oxygen to
pass through to the eyes.
Very short adaptation
period ... more comfortable
and more difficult to
dislodge than RGP lenses...
Available in tints and
bifocals... great for active
lifestyles.
Do not correct all vision
problems... vision may not be
as sharp as with RGP lenses
... require careful cleaning
and care... need replacement
at least annually.
Extended-wear
Available for overnight wear
in soft or RGP lenses.
Can usually be worn up to
seven days without
removal.
Do not correct all vision
problems... require regular
office visits for follow-up
care... must be replaced at
least annually.
Extended-wear disposable
Soft lenses worn for an
extended period of time, from
one to six nights, and then
discarded.
Require little or no
cleaning... minimal risk of
eye infection if wearing
instructions are followed...
available in tints and
bifocals... spare lenses
available.
Vision may not be as sharp as
RGP lenses...do not correct all
vision problems... handling
may be more difficult.
Planned replacement
Soft daily wear lenses that
are replaced on a planned
schedule, most often either
every two weeks, monthly or
quarterly.
Require simplified
cleaning and disinfection...
good for eye health...
available in most
prescriptions.
Vision may not be as sharp as
RGP lenses. .. do not I correct
all vision problems... handling
may be more difficult.

 

Contact lenses can be used in almost any optical correction. This includes patients who
are nearsighted (myopic), farsighted (hyperopic), astigmatic and those who require
bifocals (presbyopic). They can be colored to either enhance or highlight the natural eye
color or radically change the eye color, say from dark brown to light blue or grey or to
mask cornea or iris malformations.

We offer the following cosmetic contact lenses:

  • Soft daily wear lenses
  • Disposable lenses
  • Planned replacement lenses
  • Colored lenses
  • Enhancement tinted lenses
  • Astigmatic lenses (toric)
  • Bifocal lenses
  • Extended wear lenses

Contact Lens Evaluation and Fitting

A comprehensive eye exam is required within one year prior to contact lens evaluation.
At your contact lens evaluation you will be examined to see if you are a candidate for
contact lens wear. This will include an updated eyeglass prescription, the measurement of
the corneal curvature (using a computerized corneal topographer or an autokeratometer),
a modified health assessment of the eye, and an in-office trial with diagnostic lenses. The
contact lens evaluation and the lenses are usually not covered by insurance. However, to
determine your exact benefits, please contact your member services representative at your
insurance provider.

Corneal Topography demonstrating "With the Rule Astigmatism"

Contact Lens Wearers Frequently Asked Questions

Can I store contact lenses in tap water?


No. Soft lenses must be stored in a disinfecting solution. Temporary storage in saline is
allowed, but the lenses will have to be disinfected prior to the next use. RGP lenses can be
stored in tap water in an emergency, but will need to be cleaned and conditioned by
soaking in an appropriate disinfecting solution prior to use.

Can I lose a lens behind my eye?

No. There is no where for it to go. The conjunctiva, the fine, thin membrane that covers the
sclera (white part) and inside of your eyelids is well attached to the side walls of the eye
socket. Although you can not lose a lens, it can find its way up and under the upper lid
and be pretty hard to locate. A soft lens can roll up and likewise be hard to find. Either
way, if you flush your eye with water or saline, the lens should float out. In rare instances,
a RGP lens may adhere by suction to the conjunctiva. First apply wetting solution to the
lens and wait about a minute. Then try to move the lens while gently pressing on one
edge. If that doesn't work, you can try to very gently lift up under one edge to break the
seal. Or go see your eye doctor. If a contact lens adheres repeatedly, it is not fitted
correctly and should be replaced.

How can I tell if I have the lens in the wrong eye?

Alternately cover each eye with your hand. Do not simply squeeze your lids closed.
Compare the vision. If one eye is noticeably better or worse, switch them and try again.

How can I tell if a soft lens is inside out?

Here are three methods, however, not all work for all lenses. (1) Place the lens on the tip
of your finger facing upward, like a bowl. If when viewed from the side the edges of the
bowl flare outward, it's inside out. (2) Add saline, drop by drop to fill the bowl. If the
edges begin to curl inwards, it's the correct way. (3) Place the lens on the crease in your
hand just below your pinkie. This is sometimes called the "life line or heart line). Make
sure the lens is centered over the crease. As you curl your fingers inward to close your
hand, the edges of the lens should roll inwards to form a "soft taco". This is the correct
position.

My lens has a very small chip or tear in the edge but it doesn't seem to bother me.
Should I replace it anyway?

Absolutely. Never, ever wear a lens that is obviously damaged, even if it feels all right. It
could be causing damage to your eyes that might not be immediately apparent. And never
wear a lens which is uncomfortable, causes pain or leaves your vision hazy or distorted.

How do I know when to dispose my disposable lenses?
They seem to be OK longer than I expected.


As a basic rule, never sleep in lenses more than one week, or less, as prescribed by your
doctor. Dispose of them as recommended. Daily wear users should replace their lenses as
recommended by their eye care practitioner. Wearing your lenses past the recommended
replacement interval may result in serious complications affecting your eye health and
vision. Disposable lenses are meant to be discarded at regular intervals.

My eyes get dry. What kind of eye drops can I use?

You should use products specifically designed for use with type of lens you are wearing.
Saline solution can be used with any contact lens. The re-wetting drops for RGP lenses
are far more effective than saline and special soft lens lubricating drops also work well.
Drink more water to help with increasing your natural tear production. Unless directed to
do so by your eye doctor, do not use medicated eye drops, including "get the red out"
brands with contact lenses. Soft lenses may concentrate the drug and alter the effect. The
lens itself may be damaged.

I used to make my own saline. Is there a problem with that?

Yes. Home prepared saline is not sterile and there is the risk of bacterial or parasitic
contamination. Although extremely rare, the resulting infection can be so damaging that
it simply is not worth the risk.

There are so many solutions out there, how do I know which is best?

Rule one: do not "mix and match" contact lens products. The chemicals used within any
one care system are designed to be compatible. Using alternative products could create
chemical reactions which could damage or discolor the lenses, irritate your eyes, or
reduce the desired effect of the product. Unless you're a chemist, don't do it.

Rule two: When it comes to saline, you have a choice between unpreserved and preserved
products. Unpreserved is preferable, and if your system requires unpreserved, that's what
you use. Within each of those categories (preserved or unpreserved), choose the least
expensive. Saline is saline: salt in sterile, distilled water with a few buffers added.

Note: Be careful to keep your lens care products clean. Do not touch the tip of the bottles
to any surface. If you do, quickly discard the next few drops. Always close the container
with the original top immediately after use.

If you have any further questions in regard to Contact Lenses please feel free to contact us.



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