contact lenses overnight use

Dear All

I would like to know if the Acuvue 2 are safe for a 1 week overnight use.

Is it better the Acuvue 2 or the Focus Night and Day (I will remove them
anyway after 1 week because I wouldn't trust them for a 30 day overnight
use)


Also is the cornea ulcer risk high ?

My colleague wore purevision for 3 years with no problem but my optician
told me he saw a weakening of the cornea of people using N&D for a
continuous wear

Thank-you for your time and advice

Kind regards

Andy

"ramond" <(E-Mail Removed)> wrote in message
news:eh5Ce.22081$(E-Mail Removed)...
>
> Dear All
>
> I would like to know if the Acuvue 2 are safe for a 1 week overnight use.

In many people, this will work satisfactorily. You are running a risk of
infection however.

>
> Is it better the Acuvue 2 or the Focus Night and Day (I will remove them
> anyway after 1 week because I wouldn't trust them for a 30 day overnight
> use)

It is better to use Focus Night and Day. Even still you are running a
higher risk of eye infection than not wearing lenses overnight but this
brand is better for that than Acuvue 2.

>
>
> Also is the cornea ulcer risk high ?

It is not high, but is can still occur. And when it does, it can be
serious. It is this problem that causes eye doctors to be cautious about
overnight contact lens wear.

The problems are enhanced the longer you sleep in your lenses. Here is what
I tell my patients who insist upon sleeping in their contacts despite my
warnings:

1. instead of 1 week continous wear, why not 2-3 days, then remove them
overnight for one night, and go again for 2-3 days continuously, etc. Cycle
2-3 night in, then one night of rest. During the 1 night rest periods use a
good disinfectant like H2O2 (ClearCare)

2. if you do sleep in your contacts, just take them out for a minute in the
morning and wash them off a little with some multipurpose solution before
putting them in.

3. use lots of rewetting drops frequently throughtout the day to keep your
contacts rinsed out.

4. and most of all, use a silicone hydrogel lens like Focus Night and Day
(or Purevision, or O2 Optix, or Acuvue Advance).

In article <(E-Mail Removed)>, "RM" <(E-Mail Removed)>
wrote:


> 2. if you do sleep in your contacts, just take them out for a minute in the
> morning and wash them off a little with some multipurpose solution before
> putting them in.

I'd take exception, strong exception to your #2 point above. A primary
cause for cornea insult with overnight use of lenses is handling the
lenses and contaminating them. MPS solution residue entering the eye
often causes small breaks in the epithelium, hyperemia, pH balance
changes and more. Removing the lens by itself risks impacting the cornea
and handing the lenses risks damaging the material. All in all, the
"minute in the morning" is a risk factor. If the lens is to be out of
the eye, it's best to properly clean and disinfect them overnight in
ClearCare/AOSept or the like and then return them to the eye the next
morning, and do so in a cycle of 3/4 days or 6/7 days, as you suggested.

A safer and effective morning procedure is to put a few drops of
unpreserved artificial tear/contact lens rewetting/saline solution and
blink. I often suggest gently sliding the lens off the cornea off to the
side with a freshly washed and dried finger along with the extra drops
to help "clean" the lens from overnight debris.

--LB, O.D.

Thanks to everybody,

your advises are helpful, even today I went to an optician (I live in Milan
Italy) and they knew nothing precise about this type of lenses apart from
the fact that they are dangerous , they always tell me;" use them only if
you have to do some camping for the week end...etc"

For the weakening I used an incorrect word they told me they saw some
abrasion and scratches on the cornea surface due, I was told, to the long
period the lenses were sitting continuously on the cornea surface itself.

When I was living in UK opticians generally had no problems with these
lenses, given the correct precautions, as opposed to Italy where at present
I found no one really in favour of the same , generally I have been told "
we can sell them therefore if you want the risk and want to spend the money
we will give them to you"

In any case, seen that there is for sure an additional risk, is very
difficult to understand , given one use them with the utmost care and
removing the N&D very 3/4 days if the risk is 5% higher or 25% or 50%

Regards

Andy



"Mike Tyner" <(E-Mail Removed)> wrote in message
news:kD7Ce.4410$(E-Mail Removed) nk.net...
>
> "ramond" <(E-Mail Removed)> wrote
>
> > I would like to know if the Acuvue 2 are safe for a 1 week overnight
use.
>
> The US FDA rates Acuvue 2 safe for one week of continuous wear. That
doesn't
> mean everyone can do it without problems.
>
> > Is it better the Acuvue 2 or the Focus Night and Day (I will remove them
> > anyway after 1 week because I wouldn't trust them for a 30 day overnight
> > use)
>
> Side-by-side, the N&D is somewhat safer for two reasons: it breathes
better
> (higher oxygen permeability) and germs don't seem to adhere to the N&D
> material as well as with Acuvue and other lenses.
>
> Neither one is "safe" if you insist on wearing them when there's a
problem.
>
> > Also is the cornea ulcer risk high ?
>
> The risk is lower with silicone hydrogels but it's still there.
>
> > My colleague wore purevision for 3 years with no problem but my
optician
> > told me he saw a weakening of the cornea of people using N&D for a
> > continuous wear
>
> I've been looking at corneas for 20 years and I'm not sure what a
"weakened"
> cornea looks like.
>
> Instead, I'd say the risk of ulcer is always higher when sleeping in
lenses,
> compared to the same lens taken out at night. Ulcers still happen with N&D
> and Purevision. Usually the lenses have been worn past the point where
> discomfort was noted ("if I just wear it a little longer, it'll feel
> better...").
>
> -MT
>
>

>I'd take exception, strong exception to your #2 point above. A primary
>cause for cornea insult with overnight use of lenses is handling the
>lenses and contaminating them. MPS solution residue entering the eye
>often causes small breaks in the epithelium, hyperemia, pH balance
>changes and more. Removing the lens by itself risks impacting the cornea
>and handing the lenses risks damaging the material.

has this been proven in any studies? if this were really true then
extended
wear patients would have LESS problems than daily wear.

the "quick rinse in the morning" approach seems logical to me. corneal
ulcers
most likely result from accumulation of bacteria adhering to the
underside of a contact lens. removing the lens and giving it a quick
rinse and rub should aid in cleansing the lens. right?

In article <(E-Mail Removed) .com>,
(E-Mail Removed) wrote:

> >I'd take exception, strong exception to your #2 point above. A primary
> >cause for cornea insult with overnight use of lenses is handling the
> >lenses and contaminating them. MPS solution residue entering the eye
> >often causes small breaks in the epithelium, hyperemia, pH balance
> >changes and more. Removing the lens by itself risks impacting the cornea
> >and handing the lenses risks damaging the material.
>
> has this been proven in any studies? if this were really true then
> extended
> wear patients would have LESS problems than daily wear.

Studies? Yes indeed, but comparing specifically silicone hydrogel
overnight wear at 30 days, and lesser intervals. There was no clinically
significant difference between 30 days and 14 days but an increase in
infection rate with decreasing overnight intervals and a statistically
significant but still very small increase over daily wear use. However I
wouldn't put too much value into the studies as there was an issue with
control groups and monitoring patient lens care in the shorter term
extended wear protocols.

But that is exactly my point. The more you handle the lenses, the
greater the risk for some people----that group that doesn't wash their
hands prior to handling the lenses, stores the lenses in inappropriate
solutions or in dirty containers. You'd be amazed at what some people
do! Someone who is non-compliant with daily lens care is going to be at
LESS risk of infection if they stick the lens in and leave it there,
untouched.

On the other hand, someone who DOES follow appropriate lens care
protocol would be at less risk of infection using the lenses for daily
wear and NOT extended/continuous wear. Wearing contact lenses in any
modality carries a certain risk. So does wearing eyeglasses. So does
crossing the street, even at a crosswalk with the green light.

So which has the lower risk: extended wear or daily wear? Compliance
being equal, daily wear by a small margin. Not doing the right
thing---all bets are off.

> the "quick rinse in the morning" approach seems logical to me. corneal
> ulcers
> most likely result from accumulation of bacteria adhering to the
> underside of a contact lens. removing the lens and giving it a quick
> rinse and rub should aid in cleansing the lens. right?

Not exactly. Bacteria do not accumulate on or adhere to silicone
hydrogel lenses. At least nothing like the older hydrogel lenses. The
thinking is that the infection starts because the cornea epithelium has
been compromised--opened, cut, (rubbing a dry lens across the cornea, a
piece of sand or particulate in the air caught under the lens, the ashes
from the smoker in line next to you) and introduced bacteria (the dirty
finger syndrome, or someone coughing in your face, a contaminated
insect, a flake of dandruff) colonize in the wound. The presence of the
contact lens inhibits epithelial cell replacement at the cornea surface
repair mechanism isn't fast enough to knock out the germs and re-seal.
Once in a while, it's just because some exceptionally nasty pathogen
(bacteria or virus) get in there and wrecks havoc. (BTW, removing the
lens at the first sign of trouble will almost always reduce the risk
back to near zero. Leaving the lens in when it hurts is pretty damn
stupid. But too often the case.)

In any event, in real life, I've seen far more cornea infection in daily
wear lens users than in (current) extended wear lens users, and the
numbers in total are still very, very small, at least in my practice
patient group. And that mostly because patients of mine who are not
compliant with lens care (cleaning, disinfection, follow-up visits,
replacing lenses appropriately) are asked to leave and find another
doctor. The contact lens related infections I see each year occur
exclusively in non-compliant patients. It's never a mystery.

(The rate in extended wear users of the old, non-silicone lenses was
unacceptably high, even in compliant users, and I never recommended that
modality except for the few people who were carefully informed of the
risks and I knew would be compulsive about lens care and limited
overnight use to three days.)

All that being said, I remain cautious with overnight use of lenses.
I've dozens of patients doing 100% fine in 30 days continuous wear and
many of them self-limit to something less than that more often than not.
But most contact lens wearers are better off limiting overnight use to 6
or 7 days and more than a few do best at 3 or 4 days. Everyone is
different. Some people build up lipid deposits in a few days and others
have lenses that look pristine after a month. Someone who works long
hours in a hospital or around potential sources of infection is not a
good risk for extended wear lenses. The very nearsighted parent with a
young child who is in excellent health with no lens-related risk factors
is someone who might benefit from continuous wear lenses. And so being
lazy and too tired to take care of daily wear lenses might be considered
a GOOD reason to sleep in them! Or perhaps no lenses at all!

This turned out far longer that I had planned. Sorry to go on so long. I
just hope to present a clear picture of the issue and to underscore the
need for contact lens wearers to seek quality professional care and
advice. It's not a do-it-yourself thing.

--LB, O.D.

ramond wrote:
> Dear All
>
> I would like to know if the Acuvue 2 are safe for a 1 week overnight use.
>
> Is it better the Acuvue 2 or the Focus Night and Day (I will remove them
> anyway after 1 week because I wouldn't trust them for a 30 day overnight
> use)

The risk of bacterial keratitis in patients who remove their hydrogel
lenses daily is 1/5000 per year. The risk of bacterial keratitis from
sleeping in a conventional hydrogel lens (Acuvue, Acuvue 2, etc.) is
1/500 per year (Chang, et. al., The Lancet, 1999).

Preliminary results from ongoing post-marketing surveilance studies of
silicone-hydrogel lenses (Focus N&D, Purevision, etc.) is about 1/3000
to 1/4000 incidence of bacterial keratitis.

>
>
> Also is the cornea ulcer risk high ?

See above. 1/5000 conventional daily, 1/500 conventional overnight,
1/3000-1/4000 silicone-hydrogel overnight per year.

>
> My colleague wore purevision for 3 years with no problem but my optician
> told me he saw a weakening of the cornea of people using N&D for a
> continuous wear
>
I doubt this kind of "corneal weakening" can be observed with a
conventional slitlamp. It would require a research grade confocal
microscope. The research on this has already been done by Cavanagh,
et. al. at the University of Texas Southwestern Medical School. They
looked at corneas following overnight wear as a function of the oxygen
permeability, or DK of the lens material. What they found was that
with lower DK materials, the epithelium of the corneas became thin and
atrophic. The tight junctions between cells became compromised. The
infection is initiated when a bacterium adheres to the roughened
surface and begins a colony. Above a certain DK -- about 80 as I
recall -- the epithelium was essentially unchanged in appearance, and
maintained its tight junctions. The bacterium has a difficult time
adhering to this kind of surface. Currently, the only soft lenses with
this level of oxygen permeability are the silicone-hydrogel lenses.

Another measure of corneal health and integrity is edema, or the amount
of corneal swelling following overnight contact lens wear. With a
conventional hydrogel approved for overnight wear, this can be as much
as 11%. The normal cornea without a contact lens swells 3.5 to 4.0%
depending on which studies you read. It has been found that a lens
must have a minimum DK of 100 and above to prevent any edema beyond
that which would occur without a lens (Holden; Holden-Mertz). Only the
silicone-hydrogel lenses meet that criteria in a soft lens.

DrG

>corneal
> ulcers
> most likely result from accumulation of bacteria adhering to the
> underside of a contact lens.

This is correct. There is extensive scientific evidence demonstrating
adherence of bacteria to the undersurface of contact lenses, most likely via
the glycocalyx on the bacterial cell wall. This adherence seems to be less
in silicone hydrogel lenses. Hence another reason, in addition to increased
oxygen permeability, for using them for patients who insist on extended
wear.

As you say, the beginning of infection in extended wear patients is the
large bacterial load created by wearing a lens for a long time without
cleaning, as well as the disruption of the eyes normal mechanism for
clearing itself (blinking, tearing).

I wouldn't argue against the idea that disrupting the corneal epithelium by
removing the lens in a clumsy and unclean fashion could defeat the purpose
of cleaning the lenses. That is common sense. But given that patients
remove their lenses properly, I believe the "quick rinse in the morning"
suggestions is quite valid. I recommend it without reservation.

In article <axQCe.624$(E-Mail Removed)>,
William Stacy <(E-Mail Removed)> wrote:

> RM wrote:
>
> But given that patients
> > remove their lenses properly, I believe the "quick rinse in the morning"
> > suggestions is quite valid. I recommend it without reservation.
>
> I don't recommend that. If the patient is going to remove the lens, why
> not do it at night, when they can clean and disinfect the lens properly,
> plus giving their eyes a break overnight from the lenses. For one
> thing, a subclinical keratitis or abrasion might become noticeable by
> morning, while it could be "overlooked" with a quick removal, rinse and
> re-insertion.
>
> w.stacy, o.d.

I'm glad you added that. I was about to amend my post, but there you go!
Sometimes it takes 10 minutes or so without the lens in for the eye to
respond to break in the epithelium. If it's serious enough to feel it
right a way, it's, well, serious enough.

A further reason for overnight removal is to allow the outermost
epithelial layer to be sloughed off by blink action and to normalize and
repair overnight. Additionally, the normal physiological tearing
antibacterial/cleaning system can address the potential bacteria
overgrowth/infection. I add the following instruction: remove lenses at
least one half hour before going to bed and wait at least one half hour
in the morning, preferably and hour, before re-inserting lenses.

The basic rule: if the eye doesn't feel right, don't wear the lens. If
putting in the lens causes discomfort, don't wear the lens. If there is
pain, light sensitivity, changes in vision, fluid discharge and red eye,
don't wear the lens and seek immediate professional care. Can't follow
those guidelines, don't wear contact lenses.

From what I've read, the "bacteria load" issue is just not valid with
silicone-hydrogels, as long as the lens is free of surface defects or
lipid deposits. A peek with slit lamp at one week of continuous wear
will easily reveal if those are issues and then the wearer can told to
limit overnight use appropriately or not sleep in the lenses at all.

--LB, O.D.

I would agree completely.

You came into this thread at the end. My 1st post in reply ramond offered
the "quick rinse in the morning" recommendation with the following caveat--
"Here is what
I tell my patients who insist upon sleeping in their contacts despite my
warnings:"

I still disfavor extended wear contact use but I unfortunately have a lot of
patients who insist on doing it anyway!

=======

"William Stacy" <(E-Mail Removed)> wrote in message
news:axQCe.624$(E-Mail Removed). ..
> RM wrote:
>
> But given that patients
>> remove their lenses properly, I believe the "quick rinse in the morning"
>> suggestions is quite valid. I recommend it without reservation.
>
> I don't recommend that. If the patient is going to remove the lens, why
> not do it at night, when they can clean and disinfect the lens properly,
> plus giving their eyes a break overnight from the lenses. For one thing,
> a subclinical keratitis or abrasion might become noticeable by morning,
> while it could be "overlooked" with a quick removal, rinse and
> re-insertion.
>
> w.stacy, o.d.
>
>