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Are You Over-Wearing Your
Contact Lenses?
Contact lenses are a wonderful vision
correction option/alternative for most patients. They allow, in many
cases, clearer vision and better peripheral vision than eyeglasses. In
fact, many patients rely on their contact lenses too much; minimizing the
wearing of eyeglasses, sometimes to the point of not wearing eyeglasses at
all.
First of all, the cornea (the clear structure of the eye in front of the
pupil that the contact lens covers) requires oxygen to remain vital and
healthy. In most of the body’s tissue, oxygen is supplied by red blood
cells by blood vessels. The cornea lacks blood vessels to deliver oxygen
as it absorbs its oxygen from the air, so when wearing contact lenses it
must “breathe through” your contact lens. But when oxygen is deprived to
the cornea, the body recognizes this and the eye creates new blood vessels
(a term called neovascularization) that encroach into the cornea to help
supplement oxygen to the oxygen-depleted cornea.
The U.S. Food & Drug Administration (F.D.A.) approve contact lenses as
being either “daily wear” or “extended wear.” I tell my patients that
“daily wear” means wearing your lenses no longer than 14 hours a day with
no napping or sleeping with them inserted. Extended wear, according to the
F.D.A. means longer wearing times, usually “up to” 7 continuous days, and
with the Ciba Vision Focus Night & Day lens, up to 30 days continuous of
wear.
Are you lenses approved for extended wear? Ask you eyecare professional
and he/she will tell you.
Even though the F.D.A. “approves” a contact lens for extended wear, it
doesn’t mean that the lens may be “safe and effective” for every patient.
The cornea’s oxygen demand is different for every individual; some
patients tolerate extended wear just fine, and others do not. How do you
know if your eyes do or don’t? Well, if you sleep with your lenses that
are approved for extended wear but your vision is “filmy” or “watery” for
the first half hour to hour of the morning after awakening… you are not a
good candidate for wearing your lenses overnight. This “watery” vision is
due to the cornea swelling with fluid, causing the cornea not to be clear;
and giving “watery” vision.
My recommendations to patients: 1) I do not recommend
extended wear for most patients even though a lens may be approved for
extended wear. 2) Live by the "Half Hour Rule"; wait to insert your
contact lenses until a half hour after awakening and remove them a half
hour before you go to bed, 3) if you do wear your lenses overnight, take
your lenses out if you should experience cloudy, filmy or watery vision
(and with extended wear, take at least one half or one day off a week from
your lenses), and 4) remove your lenses if you experience discomfort,
pain, a discharge (mucous) and/or redness and visit your eyecare
professional for care and treatment.
Please live by the "Half Hour Rule" if you do wear your lenses long
hours and you will greatly decrease your chances of having contact
lens-related problems. By doing this, it allows your cornea to “oxygenate”
itself before times of oxygen stress (wearing a contact lens or by having
to “breathe” oxygen through your eyelids while sleeping. If you live by
the "Half Hour Rule," you will decrease immensely the possibility
of having contact lens related problems, like eye infections, swollen
corneas and the growth of blood vessels in your corneas.
Why should you worry about new blood vessels growing in your corneas?
Well, if the blood vessel growth is significant, you won’t find a doctor
in the land that will fit you with contact lenses anymore. And if you
would consider LASIK refractive surgery for yourself now or down the road,
excessive blood vessel growth in the cornea can affect your candidacy for
LASIK surgery. Blood vessels located in the corneal area of the “flap” are
much more likely to create scar tissue and complicate LASIK surgery, and
in some advanced cases, makes the patient ineligible for LASIK surgery at
all.
BTW: I recommend that all my contact lens patients have backup
eyeglasses to use when taking breaks from their lenses and to have if the
need should arise during a contact lens complication, like an eye
infection. Please invest in a pair of eyeglasses, even if you don’t spend
a ton of money on them. All eyes need breaks from contact lenses.
The Bottom Line: wearing contact
lenses is a wonderful privilege and also carries a responsibility on the
part of your eyecare professional and yourself. Wear them smartly and
responsibly will hopefully reduce the likelihood of complications and
problems, but if you abuse the privilege, you may lose the ability to wear
them. ~RQ
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