Acuvue Advance and Oasys

I had worn contacts (Acuvue/AV2) for about 5 years, pretty happily.
About 3 years ago, when I went in for a checkup and refit, my OD told
me that I had the beginnings of neovascularization, probably from
overwear. (I had been wearing the Acuvues EW for 2 weeks at a time).
At that time, I cut back to one-week wear, and used them happily for
about 6-8 months.

At that time, at the end of the day, my eyes would get a bit red, and
my vision blurry; I needed to blink hard a few times to clear things
up, every hour or so. At the time, I thought the problem was related
to the NV, and that I ought to give my eyes a rest, and I ended up
switching to glasses, and wearing no contacts for 2 or 3 years.

Recently, I went back for new glasses, and talked to my OD about
contacts; They said that the NV they saw was very mild, and looked to
be receding, and that I could wear contacts again (or, didn't need to
stop), told me my problem was probably just dry eye, and he gave me
AV2s (I actually still have a couple of non-expired pairs left). I
tried these out, and they were OK, but still uncomfortable at the end
of the day. The AVs and AVA's are both 8.7 BC

I went back for a refit (and also, to pick up my glasses), and there
was another doc on duty, who I explained my problem to, and she gave me
a pair of Acuvue advance lenses. These didn't seem to be much better,
actually, although now that I've been reading about them, I think I'm
sold on trying to get silicone hydrogels, to reduce the possibility of
NV being a problem.

I think my main issue with the advances (and maybe also the AV2s) is
that when they get a bit dry, they don't stay centered -- they get a
bit sticky, and my blink brings them upwards, which leads to a bit
blurry vision (halos, I guess? although I don't think I have very large
pupils). In both cases, rewetting drops seem to help (At first, I
tried bargain drops, but then I got hypo tears which seemed to work
well).

I'm interested in trying the Oasys lenses, or one of the Ciba SiHi
lenses. Aside from the better permeability of the other lenses (and,
at least with the Ciba for now, the approval for overnight wear),
perhaps the tighter BC of the oasys lenses might help keep them
centered better?

I hate being a pain and keep coming back to my doc -- but I remember
when I first started with contacts how great it was to just drop them
in and forget about them, and never notice them, and not have to mess
with rewetting drops, etc.

Anyone have experience with the oasys or ciba lenses, think they'd be
better for me? Or am I just being suckered in by the marketing?

 

I use the Oasys. It bears little resemblance to the Advance. Given
what you have described, I think you will be pleased.

I've worn them all, incidentally.

DrG

 

Thanks, guys, for your advice.

Here's another question, more about the business than my situation --
and, I guess it makes more sense before the oasys came out than before.

Why hasn't vistakon gotten approval for Acuvue Advance as extended
wear? Is there something that makes them less safe for EW as compared
to Av2? Or is it just a marketing thing to not hurt sales of their top
seller?

I guess it might be that they just wanted to get the Oasys out there,
and get EW approval for that -- or maybe they're not even going to get
EW approval for oasys?


Did the other SH lenses get approval for DW before EW also (i.e. Focus
N&D?) -- it seems like they might have been initially marketed as EW..

 

Right now, fitness for extended wear is largely determined by the
oxygen flux through the lens, or Dk/t. Using that measure, the Acuvue
Advance is several times better than the the AV2. However, it doesn't
quite meet the latest defacto benchmarks of Dk/t for continuous wear.
You will have to ask Vistakon marketing why they brought it out when
they did.

The other SiH lenses were introduced as EW. Purevision was introduced
originally as a two-week EW lens, but later went back for 30-day EW
approval. Focus N&D was released with 30-day EW designation.

DrG

 

Is there more to the FTA's fitness tests than shows up on the PMA
filing, or is that the _only_ paperwork that a manufacturer need to
file. Because it seems like they basically only need to determine that
the material is non-toxic, meets the mechanical/optical specifications,
and has a certain Dk.

Doesn't the non-ionicity of SiH lenses help make them safer for EW?
(less protein and potentially bacterial buildup?).

I suppose (or hope) that the Mfr does a lot more testing than that, and
maybe there's something else that they've uncovered as an issue?

Or, It could just be marketing..

 

I believe that multi-center clinical trials are required as part of the
filing, as well as post-marketing studies. That would explain the
expense.

Does non-ionicity of SiH lenses help make them safer? No. As I said,
it's the Dk/t. These studies were done by Dwight Cavanagh, MD, Ph.D at
UTSW medical center. Dk/t is directly related to epithelial integrity.
I assume most eye docs were familiar with this information, but I
could be wrong.

The surface is important from the immunological standpoint.

DrG