New Contacts, Old Infections. Warning for extended wear contacts!

The newest extended-wear contact lenses have a similar risk of eye
infections as older soft lenses worn for fewer nights.

That news is reported in Ophthalmology. It comes from postmarketing
studies funded by CIBA Vision, which makes the silicone hydrogel
lenses, marketed as Night & Day.

The researchers included Oliver Schein, MD, MPH, of Johns Hopkins
University's medical school.

Lenses' History

The FDA approved the silicone hydrogel lenses in 2001 for continuous
wear for up to 30 nights.

Older generations of extended-wear contacts had been associated with
rare cases of vision loss and eye infections. That prompted the FDA's
1989 decision to cut extended wear to seven days.

Years later, silicone hydrogel lenses were developed. Compared with
older lenses, they allow four times as much oxygen to reach the eye.
Better oxygen flow was seen as a way to possibly lower infection risk
in the eye's cornea.

The FDA ordered postmarketing studies of silicone hydrogel lenses to
check corneal infection rates.

Year-Long Study

The study included 6,245 people who had been given prescriptions for
the silicone hydrogel lenses. Most (80%) wore their lenses nonstop for
at least three weeks.

During the year-long study, few participants had corneal infections.
Two had corneal infections that led to vision loss. Eight others had
corneal infections that didn't cause vision loss.

Overall, the yearly rate of corneal infections was 18 per 10,000
people, the study shows.

That's similar to rates previously reported for conventional,
extended-wear soft lenses worn for fewer consecutive nights, according
to the researchers.

Researchers' Pecking Order

Schein's team calls contact lenses "very safe" in general, though
they note that contact lenses are associated with some extra risks,
compared with eyeglasses.

They rank the risk of vision loss from eye infection for different
types of contact lenses:


Lowest risk: Rigid, gas-permeable contact lenses for daily wear


Next-to-lowest risk: Soft contact lenses for daily wear


Highest risk: Silicone hydrogel contact lenses for extended wear of
three-to-four weeks

However, they're not calling silicone hydrogel lenses dangerous. The
odds appear "reasonable," write the researchers, for people who
understand the risks and want to wear their contacts around the clock.

The study notes that one researcher is a CIBA Vision consultant and one
is a CIBA Vision employee.

SOURCES: Schein, O. Ophthalmology, Dec. 2005; vol 112: pp 2172-2179.
News release, Johns Hopkins University.


By Miranda Hitti
Reviewed by Louise Chang, MD
© 2005, WebMD Inc. All rights reserved.

 

No. This is not a correct conclusion.

The incidence of microbial keratitis is much higher in prospective
studies than it is in retrospective population studies. In
retrospective population-based studies, the incidence of microbial
keratitis in conventional hydrogel overnight lens wear is 1/500 per
year. In a large, multicenter prospective study, the incidence is
1/210 per year, nearly twice as great. Therefore, one should be
comparing apples to apples and not apples to oranges, and comparing an
annual incidence of 1/600 for silicone-hydrogel, vs. 1/210 for
conventional hydrogel.

Also, different classification schemes for corneal infiltrates yields
different results. Some corneal infiltrates are sterile. At the very
least, silicone-hydrogel lenses are 3 times safer.

Finally, do not make the erroneous conclusion that overnight RGP lens
wear is the same as overnight OK lens wear just because the lens
materials are the same.

DrG

 

reserved.

Extended wear today is much safer than old extended wear for several
reasons. See http://www.allaboutvision.com/contacts/extended.htm

 

Overnight extend wear lens countinues to spur debate and controversity.
The biggest reason is because its as quick and easy to pop out your
contacts before going to bed as its to tie your shoes. I have several
friends who wear contacts, most dont sleep in them unless they come
home too drunk to remove the lens that night. They also see no point
when it takes half a minute to pop them out and near a minute to insert
them in. Cleaning them is quick and easy thanks to no-rub solvents. It
is irrevelent how much safer silicone hydrogels are, they are not 100%
safe for sleeping in. There is NO point sleeping in contacts(except
orthoK) and whats even worse than sleeping in contacts is leaving them
on your eyes for 2, 3 even 4 weeks strait. All the dirt and bacteria
can accumulate when you dont clean your contacts for so long! My own
optometrist knows this and he also warns patients against extend wear
contacts reguardless of brand. Some people are stubborn and dumb and
dont listen to their *doctor* then they pay the price with ruined eyes.
Before SHCL's many people were ruining their eyes with improper wear of
hydrogel contacts. They developed infections and uclers and I read the
story of one woman who was going to need a cornea transplant in one eye
and her doctor told her she might go legally blind in that eye. All
because she didnt have the sense or patient to take HALF A MINUTE to
remove her contacts before bed!

 

Anon E. Muss wrote:
..

Is there really any point in debating the issue of overnight wear?
People who sleep in lenses aren't "lazy," any more than people who get
LASIK are irresponsible. We know what the risks are, and they are
reasonably low. In more than 20 years of practice, I have documented
one patient who suffered a loss of one line of acuity from sleeping in
a contact lens, and it was an RGP lens at that.

Silicone hydrogels are only the beginning.

DrG

 

I have been wearing Ciba Vision Night & Day since they first came out
and there is no way I would go back to taking lenses out every day.
If you are long sighted like I am it takes ages trying to get them back
in even using a strong magnifying mirror.I have very dry eyes and these
are the only contact lenses I am happy with. The only time I take
them out is when they have to be changed after a month.I personally
think the little you have to handle your lenses the better.

Mary

--

 

I am guilty of some bad habits, almost everyone is. I can see why there
is a market for EW lenses, its probably to serve those who have been
sleeping in the older hydrogel lenses which are much worse. However one
thing I dont like is the way they market those EW lenses as "safe" then
people who would never think about sleeping in contacts may be under
the false impression that its perfectly safe with the new EW lenses. I
understand the issue needs to be addressed, but what should be done is
perhaps provide a disclaimer for EW lenses so the patient is informed
or verbally warn about the risks. I am glad my optometrist did or I
could be sleeping in contacts and wearing them for several weeks strait
without even knowing how risky that is.

The less bad habits, the better. Maybe they get lots of enjoyment from
alcohol but it makes no difference to them if they save a few seconds
it takes to pop out their lenses if they arent too tired or intoxicated
to do so.

There is always glasses they can reach for. If they have a low(er)
prescription, its not such an emergency. I am in the -4 range and even
I can do perfectly fine without correction after waking to brush my
teeth and eat. What can be done is warn them of the risks of sleeping
in contacts and if they insist on sleeping in them, then the least they
can do is take them out for cleaning everyday.

should people be rubbing their contacts? Should they be using a
different solvent?

That much ill agree. However wearing contacts for a month strait
without taking them out increases the risk 20x fold then its not so
safe at all, in fact there is controversity which is riskier, EW
contacts or lasik, especially when we look into the long term damage
each does to one's eyes. There is no excuse to get either, just take
proper care of your contacts and eyes. Many people who get lasik in
fact have worn and abused contacts for many years and damaged their
eyes and/or their eyes have rejected contacts. They could not get used
to glasses having worn only contacts for many years and also it may be
a vanity thing. It appears that 75% of those getting lasik are contact
wearers, nearly all of them with problems with contacts.

The less nights they sleep in them, the more often they remove and
clean them, the safer.

The difference with orthoK is you can remove it when you wake up,
giving your eyes the chance to breath and you get to see clearly for
many hours too. OrthoK is great for athlates, pilots, cops, swimmers
where regular contacts would not be very approperate. Much less risky
than lasik and less risky than EW contacts in fact. OrthoK can be worn
8 hours at night every other day. Thats 8 hour orthoK wear out of 48
hours vs. nonstop wear with EW contacts for a week or more. If someone
wants good vision, there is natural vision improvement and orthoK, both
which are far better. Lasik is a last resort choice when none of the
other options work AND when you have very good reasons why you refuse
to stick with glasses.

I dont really have much reason not to stick with glasses. I admit itll
be nice to reduce dependancy on glasses, but nothing riskier than
orthoK is worth taking. Most people regret lasik if it backfires on
them, others just go into denial.

 

You are going to ruin your eyes soon. There are tricks to taking them
out. What you could do is take one contact out, clean it then insert it
then take out the other one to clean then insert it. You really
shouldnt be going a month strait without cleaning them! You will have
problems in a matter of time and may have to go back to glasses.

 

Actually, there are a couple of studies recently published that
underscore this experience. One studied the adherence of bacteria to
the surfaces of lotrafilcon A and balafilcon A lenses at 2 and 4 weeks
of wear. The researchers found that the lotrafilcon A surface was
initially rougher and less wettable than the balafilcon A surface, but
that these differences became insignificant after 4 weeks. But,
lotrafilcon showed decreased adherence of all bacterial strains at 4
weeks compared to 2. The balafilcon A showed declining adherence of
pseudomonas a., but an increasing adherence of staph. aureus 835.

The second bit of evidence is found within the study quoted by our
resident amateur scientist, "Ace." The rate of presumed microbial
keratitis was lower for users reporting typical wear of 3 or more weeks
than for those wearing the lens for less than a 3-week continuous
period (P = 0.02).

DrG