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Please explain latest PRK techniques/equipment
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serebel
medicine forum addict


Joined: 12 Aug 2005
Posts: 81

PostPosted: Sat Mar 25, 2006 2:02 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

Kevin wrote:

"When I was first considering LASIK in 1996 the tv and newspaper ads
all said, "Throw your glasses away". I'm a runner and was doing the
Pikes Peak Marathon when I descended into a cloud. The mist covered my

glasses making me as blind as a bat. Shortly after that the FDA
released their study that said LASIK was safe. Doing online searches
I could find no reports of complications. If I'd found even one, I
doubt I would have done it, or at least not allowed the doc to do both
eyes."

Abot the same time, I was also researching RS, even RK was still being
done then. I heard that there were complications in many of these. This
is why I waited some more years for the technology to improve. I wonder
if location has anything to do with this info disparity. Incidentally,
none of my info came from the internet.
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acemanvx@yahoo.com
medicine forum Guru


Joined: 15 Nov 2005
Posts: 732

PostPosted: Fri Mar 24, 2006 11:23 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

The sad thing is most of the people who got lasik, especially early on
werent informed of the risks. Half of the lasik disaster stories I
read, they say they had no idea things could go wrong and felt like
they were the only ones. Their surgeon said to the effect "something
like this has never happened before" There was very little info 10
years back and the internet was primitave and many people didnt even
have computers. In recent times, theres no excuse not to be informed
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crvc56@msn.com
medicine forum beginner


Joined: 18 Mar 2006
Posts: 11

PostPosted: Fri Mar 24, 2006 3:01 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

When I was first considering LASIK in 1996 the tv and newspaper ads
all said, "Throw your glasses away". I'm a runner and was doing the
Pikes Peak Marathon when I descended into a cloud. The mist covered my
glasses making me as blind as a bat. Shortly after that the FDA
released their study that said LASIK was safe. Doing online searches
I could find no reports of complications. If I'd found even one, I
doubt I would have done it, or at least not allowed the doc to do both
eyes.
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serebel
medicine forum addict


Joined: 12 Aug 2005
Posts: 81

PostPosted: Fri Mar 24, 2006 3:53 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

the wise one opined:

". Those with thin flaps and low
pescriptions should opt for PRK or better yet, orthoK "


Yes those with thin flaps..............
Says a lot, doesn't it?
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acemanvx@yahoo.com
medicine forum Guru


Joined: 15 Nov 2005
Posts: 732

PostPosted: Fri Mar 24, 2006 3:27 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

If glasses didnt bother you why did you get lasik in the first place?

reguarding PRK, theres the issue of haze for high myopes and MMC is
toxic. I am seeing some surgeons now focusing on IOLs(phakic and
aphakic, also known as clear lens extraction)
I am seeing others do safer methods like orthoK which should be good
for -3 or -4 diopters. I saw a -7 lady get down to -3 with orthoK and
reduced her dependancy on distance glasses without ending up with
reading glasses that she woulda if she got lasik. Something some people
dont think about and they just end up in (reading)glasses after lasik.


PRK is not as bad as lasik because it doesnt use a flap and half the
complications are because of the flap. PRK is often used by pilots or
those that do contact sports. Those with thin flaps and low
pescriptions should opt for PRK or better yet, orthoK
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crvc56@msn.com
medicine forum beginner


Joined: 18 Mar 2006
Posts: 11

PostPosted: Thu Mar 23, 2006 6:00 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

I imagine I would end up a bit farsighted and need glasses for close
work. But at 50 I expected to need glasses anyway due to presbyopia.
My reason for PRK was the hope that it would help the night vision
damage caused by LASIK. I wore glasses for 46 years. It doesn't
bother me. Although RGP lenses solved the night vision problems I
could never tolerate them for more than a couple hours a day.
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Roy Starrin
medicine forum beginner


Joined: 30 Sep 2005
Posts: 44

PostPosted: Thu Mar 23, 2006 5:14 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

On 23 Mar 2006 07:55:43 -0800, crvc56@msn.com wrote:

Quote:
Three weeks post-op the eye is still quite blurry. By doing
one eye I can drive. If I put a soft lens in the PRK eye the vision is
instantly good.
What are you expecting as the end result? No soft lenses and no

glasses, or a soft lens , or glasses to get you 20/20 vision?
I am considering PRK for another eye problem. I fully expect to have
to wear glasses when I am done, and this does not bother me. On the
other hand I have no desire to get into the contact world at my age
(which is damn old), and having to wear some form of contact to get to
my "perfect" vision would tend to drive me away from PRK. I am fully
aware that eyes take time to heal, and adjust. I am 3+ months from
cataract surgery and mine are just settling out. I went to glasses
way early because I needed them, fully congnizant that I might have to
change the lenses a couple of times as times passed.
Works for me. I don't think contacts would, or really, that I could
adapt.


Quote:
The best reason for PRK is never having to worry about flap problems.
I've had no haze or dryness either.
Confirming my research, you have cited the three things that also tend

to make me choose PRK. My recent surgery showed my that statistics
are for populations, not for individuals, but at least the odds I have
seen state that there is less of a chance for haze and dryness after
PRK than Lasik.
And I suppose folks will jump all over me for that.
One thing I have found in my excursions into the opthamology world.
is that it seems to suffer from the
if-your-only-tool-is-a-hammer-every problem-looks-like-a-nail
syndrome. I guess if I had invested all that money in all that
equipment I might feel the same way. Unfortunately, sometimes the
patients suffer and remember folks - First, Do No Harm.
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crvc56@msn.com
medicine forum beginner


Joined: 18 Mar 2006
Posts: 11

PostPosted: Thu Mar 23, 2006 5:00 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

I found the message I had posted on a different website concerning the
PRK:

Nine years ago I had bilateral LASIK. And it's been a nightmare ever
since. I can't drive at night. I can't even take out the trash at
night. I lost a good portion of my business because of not being
available in the evenings.

I tried every remedy that this and other boards have suggested. I have
5 pairs of RGP lenses from 4 different ODs. I have a closet filled with
flashlights. I have a medicine cabinet filled with eyedrops.

I knew that sooner or later I would have to try surgery again. I knew
the odds weren't great. But after nine years I was more than desperate.
So I did it. On Friday my wife and I drove down to Salt Lake City where
I had PRK in one eye only. The doctor had trained at Moran, the place
that did my original procedure. She admitted that back then there was
no such thing as a blend zone. Basically a small piece of stroma was
burned out of the eye and the flap was replaced.

This procedure was very different from the original LASIK. The biggest
difference was there was no smell of burning tissue. One odd thing,
during the procedure the doctor said my pupils were too small. When she
said it the nurse grabbed my earlobe and pinched it. HARD! I was ready
to yell when the doc said, "Okay that's better" and the nurse let go.
After the procedure my wife and I went to a nearby restaurant for
lunch. After that we went back and the doctor checked that the bandage
lens hadn't shifted. Then we were done and Ellen drove us home. For the
rest of the day I kept an icepack over my eye. The next day I went back
to work.

The treated eye has no focus. Everything is a blur. I can recognize
everything but nothing is clear. I'm not sure what haze is so I don't
know if I have it or not. Although it is fuzzy, I can read newsprint if
it is 6 inches from my eye. Having one good eye seems to be enough. I
can thread a needle. It's been a busy day at work and I haven't had any
problems working.

I've had a dozen second opinions about my starbursts. This was the
first doctor to agree that my ablation zone was too small. I don't know
if it will mean anything, or if she was merely placating me. I
understand this may not work and may even make my vision worse. PRK was
not the painful experience I was expecting.

Sometimes in life you need to gamble. I'm not suggesting that anyone
who is on the fence about surgery go ahead just because of what I say
here. My nightmare may not be over. It may be worse. Time will tell.
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crvc56@msn.com
medicine forum beginner


Joined: 18 Mar 2006
Posts: 11

PostPosted: Thu Mar 23, 2006 3:55 pm    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

I had LASIK nine years ago. It left me with poor night vision, striae
and scar tissue in the flap. Three weeks ago I had PRK on one eye.
The PRK was not painful. I was back to work the next day. PRK is
allowed for navy pilots. Those who have had LASIK cannot become navy
pilots. Three weeks post-op the eye is still quite blurry. By doing
one eye I can drive. If I put a soft lens in the PRK eye the vision is
instantly good. The doctor says it's okay to use the lens if I need it
for close work. I'm a surgeon and definitely need it for close work.
The best reason for PRK is never having to worry about flap problems.
I've had no haze or dryness either.
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Glenn - USAEyes.org
medicine forum Guru Wannabe


Joined: 05 May 2005
Posts: 129

PostPosted: Thu Mar 23, 2006 7:18 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

Once you have had Lasik, you have always had Lasik. Although the Lasik
flap heals, it does not heal like a cut on your arm. The interface of
the flap is always different. Flaps have been able to be lifted at as
much as 12 years after initial surgery. "Lifted" is probably not the
correct word. It is more like separating the cornea at the location of
the original incision.

The flap does not provide any structural support to the cornea,
therefore whatever the thickness of the flap the cornea's stability is
potentially compromised by that amount. For most people Lasik leaves
more than enough residual cornea to keep stability, however more is
always better.

There are all potential complications in the creation of the flap.
While these are relatively rare, they do occur with both a mechanical
microkeratome and a laser microkeratome.

The flap is subject to damage and disease throughout the life of the
patient. Trauma to the eye can dislocate the flap or remove it
completely. Sterile infiltrates can cause a wound response (DLK) years
after surgery.

These issues become problematic relatively rarely, however eliminating
the possibility of a problem is always better than reducing the
probability of a problem.

PRK has a greater risk of infection, but that is almost nonexistent
with current techniques and certainly less often than DLK. Vision
rehabilitation is significantly longer and discomfort is more with
PRK, but for many people and in the opinion of many leading surgeons,
the short term difficulties with PRK (or similar surface ablation
techniques LASEK and Epi-LASIK) are most certainly outweighed by the
long term advantages.

At the very least, surface ablation techniques PRK, LASEK, and
Epi-Lasik should be considered by the patient and doctor and not
automatically rejected for the sake of instant gratification.
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Kopan Family
medicine forum beginner


Joined: 22 Mar 2005
Posts: 4

PostPosted: Thu Mar 23, 2006 7:04 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

Unless you have a very thin cornea and/or a very high myopic prescription,
why would you prefer PRK to LASIK? Don't get me wrong - there is a place
for PRK. Working in a laser center, we do about a half dozen per week.

The beauty of LASIK is the creation of the flap about 8mm in diameter. After
surgery, this flap becomes an instant bandage to the open wound modified by
the laser. After your nap following surgery, there should be no discomfort
at all and your vision should be near perfect except for the usual glare and
haze over the next few days during healing. This is caused by tissue
swelling..

PRK on the other hand, unless specifically indicated, will produce an 8 mm
open wound to the cornea which takes 2-4 days to heal. Alcohol is used to
loosen the epithelium and this tissue is scraped away. After surgery, the
wound is covered with a "bandage" contact lens until the epithelium grows
back over the cornea. Then the lens is removed. However, I have seen these
cases take months to resolve and many times not to the patient's
satisfaction. The procedure is uncomfortable enough to give the patient 2nd
thoughts about doing an enhancement or "touch-up" down the road.

LASIK preserves the integrity of the cornea. There are five specific
corneal layers: Epithelium, Bowman's External Limiting Membrane, the central
Stroma (80% of the thickness), Descemet's internal Limiting Membrane and the
endothelium. All layers are preserved with LASIK. Bowman's Membrane is
eliminated in PRK. It does not grow back.

If you are concerned about the flap or if your prescription is very high,
find a doctor who does Intralase - creating a flap using a laser. This is
the most accurate method of ensuring the exact thickness of the flap. My
doctors still prefer the microkeratome for flaps because it creates a much
cleaner cut and heals more rapidly.

To answer your questions

Does the laser shoot
Quote:
holes in my eye or does it leave a perfectly smooth corneal surface,
like I have now only corrected?
It resurfaces the cornea and reshapes smoothly to correct the prescription.

Does "custom PRK" exist?
Yes.

I hope this is helpful.

Thomas C. Kopan, O.D.
"sportsfan" <topsportsfan2006@yahoo.com> wrote in message
news:1143076729.149718.297780@i40g2000cwc.googlegroups.com...
Quote:
I have pretty much decided to have my vision corrected using PRK. I
have a hard time finding out about this technique and would like to
know the latest and greatest equipment used. All I have been able to
discover is that there is equipment that makes a 'no touch' PRK
possible and then there are doctors that use alcohol and I have no idea
what this does or does not mean or if they oppose each other or go hand
in hand, etc. I do understand what the alcohol is used for, so are the
current techniques which eliminate the use of it? Does the laser shoot
holes in my eye or does it leave a perfectly smooth corneal surface,
like I have now only corrected? The only graphic I have seem regarding
PRK left the cornea looking like a volcano with a hole lasered into the
center. This is not correct, is it? I want to find a doctor in my
area that will be using the best, most precise equipment. But before I
see him I want to be armed with information and know the questions to
ask. Medicine seems to only be interested in LASIK for the moment. I
have seen enough movies and animations that I know so much about LASIK,
I think I could perform an operation tomorrow. PRK, on the otherhand,
no one is interested in. I do at least understand that with PRK the
surface of the eye is lasered away to correct the cornea and then it
heals from there. There most certainly is a void of information on
this procedure unless you are interested in stuff from 1996 and even
with this information I am unable to fully visualize the procedure and
the exact outcome with regards to the cornea and its surface, shape,
etc. Does "custom PRK" exist? Could this even be applicable to PRK?
Your help or any links to current information are greatly appreciated.
Thanks, Thomas
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Glenn - USAEyes.org
medicine forum Guru Wannabe


Joined: 05 May 2005
Posts: 129

PostPosted: Thu Mar 23, 2006 6:39 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

Donald Johnson, MD of London Place Eye Centre, Canada, developed a "No
Touch" PRK technique before his tragic death in 2002. He used the full
width of a broadbeam laser to remove the epithelium. This technique
has also been used as a pseudo-PTK for patients with slightly
irregular corneas. His son, who now operates the practice, continues
to promote the "No Touch" PRK technique.

Bausch & Lomb has recently created a 50-micron ablation algorithm for
the purpose of "no touch" PRK. Although the B&L Technolas 217z Zyoptix
laser has at its largest a 2.0mm beam, the new 100 Hz version is much
quicker so this process does not take quite as much time as it would
with the older machines.

The problem with B&L's idea is that by the time the surgery is
finished you will have used three cards with three royalty fees. A few
cents worth of alcohol (LASEK) looks pretty good compared to several
hundred dollars of royalty fees.

Heck, at that point B&L is nearing the cost of using an Epi-Lasik
blade to fully remove the epithelium. This is a technique gaining
favor. The Epi-Lasik blade creates a nice round shaped treatment zone
with sharp edges that seem to promote healing without the common
"Mercedes Benz" epithelial haze during early healing. Without alcohol
there is less toxicity at the epithelium.
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Irv Arons
medicine forum beginner


Joined: 19 Mar 2006
Posts: 25

PostPosted: Thu Mar 23, 2006 5:01 am    Post subject: Re: Please explain latest PRK techniques/equipment Reply with quote

As far as I know, there is no such thing as "no touch" PRK. The
epithelium (the top layer of the cornea) has to be removed or pushed
aside (LASEK), and then the laser beam applied to the new corneal
surface to change its shape to give you the correction you require.

I've written about both PRK and about LASEK. The PRK writeup is on my
web Journal, but I haven't as yet put up the columns that I've written
about LASEK.

I haven't checked recently, but someone is probably doing custom PRK.

You might want to check out www.allaboutvision.com.

If you want to see what I've written about PRK, check out my web
Journal at

www.irvaronsjournal.blogspot.com

and go to the second or third posting by going into the December
archive. It's all about the history and beginnings of PRK.

If you send me an email -- there is a link on my website, I'll try and
find the columns I wrote that appeared in Ocular Surgery News about
LASEK and send them to you.

Regards,

Irv Arons
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sportsfan
medicine forum beginner


Joined: 23 Mar 2006
Posts: 1

PostPosted: Thu Mar 23, 2006 1:18 am    Post subject: Please explain latest PRK techniques/equipment Reply with quote

I have pretty much decided to have my vision corrected using PRK. I
have a hard time finding out about this technique and would like to
know the latest and greatest equipment used. All I have been able to
discover is that there is equipment that makes a 'no touch' PRK
possible and then there are doctors that use alcohol and I have no idea
what this does or does not mean or if they oppose each other or go hand
in hand, etc. I do understand what the alcohol is used for, so are the
current techniques which eliminate the use of it? Does the laser shoot
holes in my eye or does it leave a perfectly smooth corneal surface,
like I have now only corrected? The only graphic I have seem regarding
PRK left the cornea looking like a volcano with a hole lasered into the
center. This is not correct, is it? I want to find a doctor in my
area that will be using the best, most precise equipment. But before I
see him I want to be armed with information and know the questions to
ask. Medicine seems to only be interested in LASIK for the moment. I
have seen enough movies and animations that I know so much about LASIK,
I think I could perform an operation tomorrow. PRK, on the otherhand,
no one is interested in. I do at least understand that with PRK the
surface of the eye is lasered away to correct the cornea and then it
heals from there. There most certainly is a void of information on
this procedure unless you are interested in stuff from 1996 and even
with this information I am unable to fully visualize the procedure and
the exact outcome with regards to the cornea and its surface, shape,
etc. Does "custom PRK" exist? Could this even be applicable to PRK?
Your help or any links to current information are greatly appreciated.
Thanks, Thomas
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