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The Importance of Eye
Lubrication:
Tears and Tear Film
Good vision starts with a good tear film that must
constantly be produced and spread over our eyes to keep
them moist.
Tear film:
Bathes, refreshes and protects the surface of the eye
from the irritating effects of dirt, dust, and other
airborne particles
Protects from infection
Helps to create a smooth surface so vision stays clear
and undistorted
Keeps eyes lubricated and comfortable
If you have an abnormal or deficient tear film, the
quality of your vision may be diminished.
Tears are made
up of 3 components: lipid, aqueous and mucins. and they must be in balance to create the moisture
that keeps our eyes comfortable. If any
is missing or damaged, the tear film is
compromised and the eye moisture will be depleted
causing the eyes to feel dry and irritated. |
Chronic dry eye can occur when the tear glands don’t produce the
right quantity/quality of tears to keep the eyes lubricated and
protected.
Chronic Dry Eye
Blinking spreads the tear film over the eye. If the tear film is
inadequate, dry spots can occur causing discomfort and damage to the
corneal cells on the surface of the eye. You may not know that you
have damaged corneal cells but your eyes may feel dry with a burning
sensation. Your eye care expert will be able to see the surface
damage during an eye exam.
Corneal cells can heal quickly if they are diagnosed early and
treated with a dry eye lubricant that protects the cells and allows
moisture to remain on the surface longer.
Common Causes of Dry Eye
There are many causes of Dry Eye. These can be attributed to a
number of different factors:
Aging: As we grow older, our eyes produce tears that have less
natural oil in them.
Menopause: Females entering menopause are among the most prone to
dry eye.
Autoimmune Disorders: Diseases such as rheumatoid arthritis, lupus,
multiple sclerosis, thyroid and Sjogren's syndrome can cause
inflammation in the tear-producing lacrimal gland.
Environment: Excessive heat or air conditioning, fans, dry or windy
climates, smoke, airplanes, and lack of sleep can all cause dry eye.
Work Environment: Outside wind, dust, heat, or smog can cause dry
eye. Focusing on a computer screen for extended periods is also a
common cause.
Medications: Numerous medications can cause dry eye. Be sure to tell
your eye care expert about all the medications you are taking.
Eye Medications: Preservatives in artificial tears and anti-glaucoma
drops may be toxic to the cells on the surface of the eye and
contribute to dry eye.
Contact Lens Wear: Wearing contact lenses can contribute to dry eye. |
WHY PRESERVATIVE FREE
Several television ad campaigns encourage patients to inform their
doctors and pharmacists about all the medications they are taking in
order to avoid harmful drug interactions. This is good advice for
patients on artificial tears as well.
An ocular medication is much more than just the active drug it
contains. Its other components may present difficulties for some
patients. This is true for patients who are using
artificial tear products, suffer chronic eye diseases like dry eye
or glaucoma, or require post-surgery dosing of medication drops.
Eye drops are composed of unique mixtures of:
the active drug and its drug delivery system
a preservative
a viscosity increasing agent
a vehicle by which all the above ingredients are
"carried"
Of these, it’s the preservative that is most often considered to be
the culprit in damaging the top layer of .the cornea leading to
disruption when drops are used often. This sequence leaves the
surface of the eye unable to keep the tear film in place and can
lead to ocular surface disease. If you are using certain medication
drops or wear contact lenses it is even more important to have tears
that are preservative free.
Common chemical preservatives found in ophthalmic drops are:
Benzalkonium chloride (BAK)
Disodium EDTA
BAK is the most prevalent and its cytotoxicity is well-documented.
Reports have shown that BAK can accumulate in ocular tissue and can
cause different types of cell death with frequent dosing. It’s
thought that patients at greatest risk for BAK-induced adverse
effects are those suffering from dry eyes. Because of the lack of
natural tears in these patients, the BAK in each eye drop is not as
diluted as it would be in a patient with normal tear formation. This
may damage the corneal epithelium (top layer of the eye)
contributing to ocular surface disease. (Using more than 4 – 6 drops
per day increases the likelihood of BAK-induced adverse effects.)
Non-preserved Drops
Studies have shown preservative-free preparations are safe to use in
patients, with frequent dosing.
Non-preserved artificial tears have an extra advantage over
preserved ones. They may be the best choice for patients immediately
following eye surgery (LASIK) due to increased viscosity and pH
buffering, which makes the drops more comfortable to use.
Preservative-free Oasis TEARS™ and Oasis TEARS™ PLUS eliminate the
source of toxic irritation caused by preservatives. |