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 especially 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 viscosity increasing agent
a vehicle by which all the above ingredients are
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)
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.)
Studies have shown preservative-free preparations are safe to use in
patients, especially 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.