Altough few ophtamologist are well
versed in this particular aspect of medical toxicology, it seems that
progress has been made in the treatment and care of dysfunctional tear
syndromes as far as preserved eye drops are concerned. Obviously, it
depends on the ophthamlmology service and how many dry eye and ocular
surface patients they treat. In these situations, the deleterious
effects of preservatives are evident soon enough to establish a
causative effect very quickly. Some teams, like the one of the
Quinze-Vingts in Paris, are even specialised in preservative
consequences related publications. But many other medical services who
treat less fragile ocular surfaces still continue to prescribe one or
several preserved drops in higher concentrations that the maximum
recommend by pharmaceutical companies (usually less than 4 drops a day).
Actually one might argue that "drops" don't mean anything since a drop
containing a percentage of 0.005 is not the same as one containing 0.01
of the same preservative. And what about a different preservative? what
about the combination of two different preservatives?. The other
important question is: for how long? Let's remind them that dry eyes and
glaucoma are lifetime diseases. However, it's also obvious to our
members and delegations abroad that some progress has been made, even if
for most of our membres finding preservative-free treatments is still a
dilema. Let's not forget that doctors are also confronted to this lack
of choice and probably why so many preserved drops are still being
prescribed currently. But little by little, they are beginning to have a
choice for dry eyes, glaucoma and allergies, even though the choice is
still insufficient and the preservative-free prescritpion reflex is not
always there.
Let's see examine a few examples of
eye care practionners involved in the "fight against preservatives"
worldwide:
Probably more than toxicity, it's the
severe allergic reactions and intolerance that practionners take into
account. Thus some specialised teams prescribe more and more single use
vials and other unpreseved bottles to dry eye and allergy sufferers. But
in a meeting on ocular allergies, it was stated that " benzalkonium
represents 4 to 11% of "sensitisations" and mercurial derivatives 13 to
37 %, but more than that, they have a toxic effect" [1].
In August 2005, a team of ocular surface experts
convened in Chicago to discuss the latest
information on treating dry eye syndrome and real-world issues in
artificial tear therapy, including preservative use. The
group stated that ocular surface health should always remain a
top priority and that Preferred Practice Pattern
Dry Eye Syndrome Medical Treatment guidelines should be modified to
recommend the use of preservative-free formula artificial tear products
for all levels of dry eye conditions in consideration of the medical
benefit they offer to dry eye syndrome sufferers. The
Dry eye consensus group recommended increased use of
preservative-free artificial tear formulations as first-line therapy
[2].
The Hong Kong Association of
Private Eye Surgeons (HKAPES) warned that frequent
use of eye-drops could damage eyes and might even cause loss of vision.
HKAPES said most eye-drops contained preservatives that were
harmful to eyes. A study made by the University of Hong
Kong stated that most users were ignorant of the risk. Nearly 70
percent of the 518 polled (aged between 20 and 50) knew preservatives in
eye-drops were harmful but had no idea that they were contained in most
eye-drops. HKAPES President John Chang said preservatives, especially
detergent, could lead to blurred vision and lengthen the period of
recovery after an eye surgery. Contact-lens users could also be at
risk because the lenses act as a reservoir for the chemicals.
This problem is all the more important since only
a few of the respondents (17 percent) used eye-drops after consulting an
ophthalmologist. Most preferred buying it in pharmacies
[3].
Thus, even if medical awareness
increases regarding preservatives, a new questions arises related to
pharmacies and users' awareness when these purchase drops without a
prescription.
1 Association pour la promotion de l’allergologie en Aquitaine
(APALA), by Bruno Mortemousque
Bordeaux Hospital, notes taken by Dr H. Masson, Novembre 2003.
2. Increasing importance of dry eye
syndrome and the ideal artificial tear: consensus views from a
roundtable discussion, Asbell, Penny A ,
Current Medical Research and Opinion, Volume 22, Number 11,
November 2006 , pp. 2149-2157(9).
3. Eye
drops might cause blindness, www.chinaview.cn,
2005-08-04 09:37:47
