why is silicone a bad material for an IOL?

[Liz]

Does anyone know why so many eye surgeons don't want to use silicone
IOLs?

I've asked, of course, but no one gives the same reason as anyone
else, and the answers don't seem to explain the level of aversion.

I asked, "What's bad about silicone IOLs?"

I was told, variously:

1) They need a different procedure to implant. (But I also heard that
they don't.)

2) If the patient ever needs silicone oil injected into their eye, the
silicone IOL will react badly with it.

3) Sometimes they shift in the bag later.

4) They might cause more inflammation.

5) I just don't like them.

So then I asked, "If they're inferior, why are they still in use?"

Answers:

1) It's a personal choice. [OK, but based on what?]

2) Because some people like silicone.

3) Because the hospital or surgery center makes more money on a
silicone IOL - they cost less, but the H. or S.C. can bill just as
much for them as for a more expensive lens. [This sounded odd, but I
sure wouldn't know.]

In terms of what I want, the silicone IOLs seem to have much better
optics than any acrylic. So I'd like to get them, but not if there's
a good reason to avoid them. But I'm still not sure whether there is
a good reason. I had the distinct feeling I was missing something
important here.

Does anyone know more?

thanks,

Liz

Indiana

[Jane]

If silicone oil is used during retinal detachment surgery, it can
stick to a silicone IOL and obscure the surgeon's view of the retina.

In all likelihood, if a silicone IOL were implanted in one eye and an
acrylic IOL in the other, you would not perceive a difference in your
vision.

I've heard that some actors preferred silicone IOLs because some
acrylic IOLs tend to glisten, which can be noticeable to onlookers.
(This effect is apparent with some of the AcrySof lenses.) The
newest Tecnis acrylic IOL reportedly does not glisten.

[Jane]

Addendum to above:

Most surgeons use only a few different IOLs. If they become
proficient at implanting Alcon's AcrySof IOLs, they tend to stick to
newer models of this brand, all of which are acrylic.

At the present time, the silicone Crystalens HD is reputed to be the
best of the multifocal/accommodating IOLs. There is a new aspheric
version of the Crystalens scheduled to be introduced soon, which
promises improved night vision. The market for presbyopia-correcting
IOLs is a big revenue generator, and as surgeons switch their
preference from Alcon's ReStor to the newest Crystalens they may re-
think their position on acrylic vs. silicone IOLs.

[Liz]

On Nov 20, 9:58 am, Jane <clinton6...@hotmail.com> wrote:
> Most surgeons use only a few different IOLs.  If they become
> proficient at implanting Alcon's AcrySof IOLs, they tend to stick to
> newer models of this brand, all of which are acrylic.

This is certainly true. In fact, there are practically only 2
monofocal lenses in use here, so far as I can tell - the Acrysof IQ
and the Tecnis aspheric acrylic. Only rarely will a doctor implant
another kind (I don't know what circumstances and didn't ask).

I did finally get SOME concrete, rational answers about silicone, if
they are true.

I was told that it's a more slippery material than acrylic, so when
the ... bag? some part of the eye - scars and heals over after
surgery, sometimes the flesh does not adhere to a silicone IOL very
well, so that later the IOL may slip around or move in the bag. (I
didn't realize that some part of the eye adhered to the LENS itself -
ewwww.)

Also, the haptics of the silicone IOL are made of PMMA (or some other
material different from acrylic. This material doesn't behave the
same way under pressure or tension, so when the bag shrinks later, the
IOL is a bit more likely to shift or move. (I didn't know it
*shrank* - ewwww. :-(

Does any of this sound correct at all?

I wish there were an acrylic IOL that blocked violet light.

thanks,
Liz
Indy