Pentacam? Manual fixation?

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Pentacam? Manual fixation?

Postby ryphoenix » Wed Mar 19, 2008 6:43 am

Hi all,

I went to 2 consultation from 2 seemingly excellent doctors within the past week. I'm 28yo male with about -5.50 in each eye, low astigmatism and HOA. Thinnish cornea, around 485 give or take.

One consultation was with a "very conservative" doctor that was concerned with the shape of my cornea, saying that left eye is more "pointy" than normal. (Apparently it's possible Keratoconus as explained by my 2nd doctor) Said along with my thinnish cornea, this concerns him a lot. Wanted me to get a detailed examine, called Pentacam at a select hospital for $100. Said this will give him a much more detailed mapping of my cornea and lots of other info. Said the reason why it cost $100 is cuz machine really expansive, and he and few other docs chipped in to help the hospital pay for it. Also wants me to do a "detailed" dilated examine at his practice, for $250. He said without these examines, he would not feel comfortable operating on me given what he has seen. The guy SEEMS very open and honest and has my best interest etc etc.

Has anyone been asked to do the Pentacam examine and does it help in helping you or the doctor decided whether or not to proceed with the surgery? And while I don't mind shelling out $100 to get a reading since I can hand the results to other doctors, $250 for a dilated examine?? How detailed could it be to cost $250?? These money will go towards my surgery if I'm a candidate and I choose him as my surgeon, but what if I'm not or I don't want him anymore?

2nd doctor was a bit less open and honest, but still took the time to explain a LOT to me, so he is still good in my books. Obviously I asked him what he thinks about the first doc's finding. 2nd doc said he doesn't really it's that big of a deal and still confident I will have a good outcome. Thinks it isn't necessary for me to do Pentacam since it is very new and isn't proven to give useful info "or else every doc would use it", and that this could be just the machine company trying to promote it or some such. Hmm...that pretty much contradicts the first doc.

The other interesting thing I noted was the very low % of enhancement and high % of 20/20 results. The first doc is of course due to his conservativeness and being very careful. The 2nd doc said he uses a technique that less than 5% of docs in this country uses that greatly enhances his results. He called it a "manual fixation device", which is basically a ring that prevents the eye from moving. Said he found this to be a very important factor, and that this will take patients out of the equation.

Has anyone heard of this device or technique?? The 2nd doctor also claims that now a days, the percentages of patients getting 20/20 or better is 98%, and this is a national average?? Anyone else hear this?

Well, I guess maybe third time is the charm, maybe a third doc will shed some lights. :) So far the wife and I both think that both of the docs seem competent and nice, and feel pretty good about either. The only thing against the first doc is the questionable requirement for examine and charging for it. He also cost $1000 more than the 2nd doc, and is actually over my planned upper limit by some. (I can get it done way cheaper if I drove up to L.A., but I accounted for that) The only thing against the 2nd doc is the fact he danced around the question "What is the worst refractive surgery outcome experienced by your own patient" a bit. He said basically the only really bad outcome was from patients who had eye trauma shortly after surgery, and even the worst guy who's flap got removed was able to see 20/40. This guy has done about 30k over the past 8 years...hrm...what do you guys think?

Well, thanks for reading and I hope to hear some of your opinions and findings!
ryphoenix
 
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Re: Pentacam? Manual fixation?

Postby LasikExpert » Wed Mar 19, 2008 4:49 pm

ryphoenix wrote:Has anyone been asked to do the Pentacam examine and does it help in helping you or the doctor decided whether or not to proceed with the surgery?


The Pentacam is tremendously helpful in diagnosing potential problems like keratoconus. You should have this exam whether you are interested in laser eye surgery or not.

ryphoenix wrote:And while I don't mind shelling out $100 to get a reading since I can hand the results to other doctors, $250 for a dilated examine??


After the Pentacam, a detailed exam may be moot. If it shows evidence of keratoconus, you undoubtedly will not be offered laser eye surgery, especially Lasik.

ryphoenix wrote:Thinks it isn't necessary for me to do Pentacam since it is very new and isn't proven to give useful info..."


Other tests are reasonably adequate for a patient with no other indication of a potential problem, however for a keratoconus suspect the Pentacam is an excellent idea. It would be the best $100 you have spent in a long time. Either it will confirm the keratoconus suspected and save you major complications, or it will confirm you do not have keratoconus and give you some additional peace of mind.

ryphoenix wrote:"or else every doc would use it"..."


Not at those prices.

ryphoenix wrote:He called it a "manual fixation device", which is basically a ring that prevents the eye from moving. Said he found this to be a very important factor, and that this will take patients out of the equation.


That's an interesting idea, however most laser systems have an eye tracking device that is much faster than the human hand. It may be helpful to fixate the eye, but I'd like to see comparative studies rather than a doctor's opinion.

ryphoenix wrote:The 2nd doctor also claims that now a days, the percentages of patients getting 20/20 or better is 98%, and this is a national average?? Anyone else hear this?


Oh yes, you hear this quite a lot. That does not mean it applys to you.

Our organization certifies actual patient outcomes. A claim of 98% 20/20 simply is not a complete claim. To start, Snellen 20/20 is a very limited measurement. It is black letters (which you know) with sharp edges on a white background in a controlled lighting environment. That is not the real world. If you can squint and guess that a pyramid shaped letter is an "A", then you can be declared 20/20.

A Lasik study recently publicized by an national ophthalmologist organization claims a 95% “satisfaction” rate for Lasik.

If the patient group being tested was hyperopes (farsighted, longsighted), or a high myopes (nearsighted, shortsighted) over about 8.00 diopters you would not expect a 98% 20/20 rate. If the patient group's astigmatism is more than half the myopia or hyperopia, you would not expect a 98% 20/20 rate.

If the patient group was only young mild myopes with small pupils, thick corneas, no dry eye issues, and very tolerant of imperfection, then you might come up with a 98% 20/20 rate.

Additionally, about 3% of patients at six months postop have some sort of unresolved complication. Seeing 20/20 in the daytime but unable to drive at night because of debilitating halos around light sources is not a happy patient. Not 20/happy.

Lasik is wildly successful by medical standards, but it is surgery. All surgery has risks. There is no such thing as a perfect surgery, perfect surgeon, or perfect patient for that matter.

ryphoenix wrote:The only thing against the first doc is the questionable requirement for examine and charging for it.


A medical eye examination to determine potential medical pathology like keratoconus after an initial diagnosis would undoubtedly be covered under your major medical insurance plan. You may need to go through your general physician for a referral to a corneal specialist, however if you present the preliminary findings of Doctor No. 1 to your general physician, I am certain you would get that referral.

ryphoenix wrote:what do you guys think?


Don’t even consider laser eye surgery until the comprehensive evaluation necessary to determine if you have keratoconus. If you do not, then come back and let’s discuss your options again.
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Postby ryphoenix » Thu Mar 20, 2008 5:17 am

Thanks Glenn,

Would Pentacam be able to tell me for sure if I have keratoconus or not? I'm pretty sure I don't have it yet, since it is obvious that none of the other consultations I ever went to said anything. (I did go through 3 or 4 other ones about two years ago, along with a comprehensive eye examine at a OD in a hospital) I do vaguely remember seeing similar topography pics before that was also a slight concern to one doctor, but I was still accepted for surgery. Doesn't seem to have become worse in the past 2 years...does that say anything? :P How fast does keratoconus develop?

Re: manual device, he said that patients can have trouble staying focus at the center of laser correctly, either due to not able to see well enough or just snoring away. The ring makes sure the laser is centered correctly and with the addition of eye tracker it makes the procedure almost fail proof. Mentioned ever he started using it, patient happiness have been greatly enhanced, with a lot less night time issues.

One more thing I wanted to ask. One of the doctor dilated my eyes before doing the Snellen test. Said that they want to measure my eyes at the worst condition so they can't over correct. Is that a correct assumption?
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Postby LasikExpert » Thu Mar 20, 2008 6:11 am

ryphoenix wrote:Would Pentacam be able to tell me for sure if I have keratoconus or not?


The Pentacam may be able to show irregularities that other scans do not show and from that information your surgeon may diagnose early keratoconus or that you are a keratoconus suspect.

ryphoenix wrote:I'm pretty sure I don't have it yet, since it is obvious that none of the other consultations I ever went to said anything.


Yes, but then none of them have had the benefit of viewing the results of a Pentacam scan.

ryphoenix wrote:Doesn't seem to have become worse in the past 2 years...does that say anything?


It indicates that your cornea is currently stable. That stability could change if it is weakened by disease or laser.

ryphoenix wrote:How fast does keratoconus develop?


Reducing the thickness of the diseased cornea can cause an almost immediate onset of the symptoms of keratoconus. That is why the additional scan is prudent before Lasik or PRK.

Keratoconus may exist and never present any significant symptoms. Symptoms may develop, but rigid gas permeable (RGP) contact lenses may be enough to resolve the vision problems. Keratoconus can also progress to the point a corneal transplant is necessary.

ryphoenix wrote:Re: manual device


All the theory behind the use of manual fixation during Lasik or PRK is sound, but there is nothing that screws up a perfectly good theory faster than reality. I'd be delighted if this doctor or others were to publish a comparative study.

ryphoenix wrote:One of the doctor dilated my eyes before doing the Snellen test.


A cycloplegic refraction (eyes dilated and crystalline lens fixed) and a manifest refraction (crystalline lens able to change focus) are both valuable and the difference in refractive error between the two may provide useful information about how best to treat your refractive error.
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Postby ryphoenix » Sat Mar 22, 2008 6:00 am

Thanks again Glenn.

I've asked for a third opinion, and the third doctor was also not concerned about possible kerotoconus. And she also does not think pentacam would be necessary to determine eligibility for PRK.

I've gone ahead and scheduled for the test anyway, but should I not be as worried, or should I skip both of these doctors since perhaps they may not have enough interest in the long term health of my eyes?
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Postby LasikExpert » Sat Mar 22, 2008 6:44 am

The first doctor may simply be more conservative than the others and want to clear you of having keratoconus first.

Another advantage of the Pentacam is that it will give you a baseline for the thickness and shape of your cornea. Two or five years from now another Pentacam can be compared to this one to see if there are any progressive changes. That would be the very best method to verify the stability and health of anyone's eyes; a series of scans over an extended period of time.
Glenn Hagele
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Postby excimer_guy » Sun Jun 22, 2008 12:36 am

The advantage of the Pentacam is that it has a high central resolution due to it using a Scheimpflug camera that rotates around the corneal center. Placido-based topographers like the Orbscan have to interpolate central data since their camera is located right in the middle.

The Pentacam is a great tool for diagnosing keratoconus. It can measure the posterior surface of the cornea. Placido-based systems will only ASSUME the shape of the posterior surface. Therefore, forward-bulging of the posterior surface as an early sign of keratokonus will become obvious with the Pentacam as will a more progressed stage of keratoconus.
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