Overwhelmed by Info

Post your questions and start your research in this forum if more than three months ago you had any type of surgery to reduce the need for glasses and contacts.

Overwhelmed by Info

Postby dan1966 » Mon Jul 27, 2009 12:33 am

I have now spent hours (several hundred, most likely) trying to understand as much as I can about the wonderful world of Lasik. I still feel like I'm walking in quicksand, though. And what is most upsetting is the growing realization that my Lasik provider did not do all that they could have to maximize the chances of success. I was told that the reason why a traditional procedure rather than a custom one was used was because of my small pupils and low level of HOA's. Prior to the surgery my undilated pupil sizes were 5.39 and 4.94. Dilated they were 7.0 and 6.0. That's too small? And my HOA's for the right eye at 5 mm was 0.6 um, which I now know is quite high. The left eye's wavefront diameter was too small to allow a measurement for that. Why was it too small? Because it was undilated. The wavefront measurements should have been done for dimmer lighting than was used. This would have resulted in a large enough pupil size on which to take measurements. I also didn't find out that they hadn't performed the custom procedure until the day after surgery when I happened to notice "Traditional" written on one of the sheets in my file. I made an assumption based on their misleading website. When I asked about this later, I was told that only 1% of their patients would benefit from the custom procedure.

It's frustrating when you don't trust your provider. It's even more frustrating when you know that they took shortcuts in the evaluation procedure and possibly did not perform the procedure (custom) that would have made it more likely that the outcome would have been satisfactory.

The more I learn (and it's a slow process), the more I think I made a big mistake going with the provider that I did. Thank you for allowing me to vent. I'm still in the process of coming to terms with this. It's not easy. The idea that someone would take shortcuts with someone else's vision is tough to stomach. Wading through all the information also requires a lot of patience. Let me conclude this entry with my general feeling: Grrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
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Re: Overwhelmed by Info

Postby LasikExpert » Mon Jul 27, 2009 1:18 am

dan1966 wrote:I have now spent hours (several hundred, most likely) trying to understand as much as I can about the wonderful world of Lasik. I still feel like I'm walking in quicksand, though. And what is most upsetting is the growing realization that my Lasik provider did not do all that they could have to maximize the chances of success. I was told that the reason why a traditional procedure rather than a custom one was used was because of my small pupils and low level of HOA's. Prior to the surgery my undilated pupil sizes were 5.39 and 4.94. Dilated they were 7.0 and 6.0. That's too small?


It is not so much "too small" as it is your naturally dilated pupils are small enough that there may not be enough gain in outcome quality to warrant the additional tissue removal for wavefront-guided ablation. Also, wavefront-guided is not as good on some types of corneal topography as conventional.

dan1966 wrote:And my HOA's for the right eye at 5 mm was 0.6 um, which I now know is quite high.


Not necessarily. If the Zernike polynomial higher order aberration (HOA) defocus was included, then this number would actually be quite low. Also, HOA after the sixth level Zernike have no real effect on clinical outcomes. Measuring them or including them in an overall HOA is just making noise in the analysis.

dan1966 wrote:The left eye's wavefront diameter was too small to allow a measurement for that. Why was it too small? Because it was undilated. The wavefront measurements should have been done for dimmer lighting than was used. This would have resulted in a large enough pupil size on which to take measurements.


This is yet another indication that wavefront was not the best choice for you. If the wavefront analysis cannot get a clear reading - for any reason - then wavefront-guided ablation is contraindicated. Even a low light environment would not necessarily allow for a complete reading. This happens relatively often, BTW.

dan1966 wrote:I also didn't find out that they hadn't performed the custom procedure until the day after surgery when I happened to notice "Traditional" written on one of the sheets in my file. I made an assumption based on their misleading website.


You are probably both at fault here. They absolutely should have discussed your treatment plan and you should not have assumed that they would provide what they promote most on thier website. This happens too often.

dan1966 wrote:When I asked about this later, I was told that only 1% of their patients would benefit from the custom procedure.


That is an odd statistic that I doubt would stand up to analysis. As a general rule, wavefront-guided ablation provides a better outcome, but not always.

dan1966 wrote:It's frustrating when you don't trust your provider.


Absolutely! When the trust is broken, it's time for a second opinion.

dan1966 wrote:The more I learn (and it's a slow process), the more I think I made a big mistake going with the provider that I did. Thank you for allowing me to vent. I'm still in the process of coming to terms with this. It's not easy. The idea that someone would take shortcuts with someone else's vision is tough to stomach. Wading through all the information also requires a lot of patience. Let me conclude this entry with my general feeling: Grrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr


I understand your feeling. There are so many variables with Lasik that it is easy to find alternatives that may have provided a different result.
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Re: Overwhelmed by Info

Postby dan1966 » Mon Jul 27, 2009 2:39 am

Just out of curiosity, is it unusual to have pupils of such different sizes?

7.0 mm is larger than average, which makes it seem odd that this would lead them away from the custom procedure.

The measurements for the Zernike RMS were 0.60 for Higher Order, 0.60 for HO w/o Z400, and 3.37 um for Total. I'm not sure what to make of those. After the surgery, those measurements were 0.23, 0.23, and 0.71 um. Is it unusual for those readings to go down like that? That's part of the problem. I haven't been able to find anything on the internet that goes into any detail about those measurements.

Why would they have been unable to get a reading for more than 5 mm for my left eye? You say that it's quite common. What accounts for this? They sure don't mention it at websites for Lasik providers. They also really play up how much better custom is than traditional.

After the procedure, my right eye's undilated measurement was 6.08 and my left eye's was 5.47. Why would they have increased from the initial 5.39 and 4.94, respectively?

Regression doesn't account for much, if any, of my visual problems since they are about the same now as they were the day after the surgery. The astigmatism was there right from the start. A slight overcorrection combined with residual astigmatism has made seeing out of my left eye an unhappy experience. It is often strained when I'm reading, staring at the computer screen, or watching TV. When I'm outside on a sunny day, it is almost always blurred. Luckily, the right eye is my dominant eye and it takes over at those times. The poor sight of my left eye does make my vision less than ideal, though, since I'm affected somewhat by it even though my right eye has taken over. My right eye seems to weaken during the course of the day, as well as being off in dim lighting, so I can't even say that one is a real success.

I didn't get my medical records until long after my procedure. I'm trying to make sense of things after the fact. Had things gone as I had hoped, I would never have looked back. I feel somewhat foolish to be doing this because it seems a little too late to be tending to this now. The horse has already left the barn. I can't seem to help it, though, possibly because of obsessive/compulsive tendencies. I still want to know why things turned out as they did. I was an ideal candidate, according to them. I followed their regimen to the letter. All the eyedrops were put in at the proper times. I made sure not to touch my eyes. So an ideal candidate who does everything that he is told and is operated on by an experienced surgeon winds up with visual distortions. And as I said, it's not related to the healing process since my eyes were like this immediately after the procedure. It just doesn't add up. Only when I understand things as well as I possibly can will I be able to move on with my life. Thank you.
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Re: Overwhelmed by Info

Postby LasikExpert » Mon Jul 27, 2009 6:15 pm

dan1966 wrote:7.0 mm is larger than average, which makes it seem odd that this would lead them away from the custom procedure.


Wavefront-guided ablation is able to fully correct only about 6.5mm, less if you have astigmatism. You may want to read about Lasik and pupil size.

dan1966 wrote:The measurements for the Zernike RMS were 0.60 for Higher Order, 0.60 for HO w/o Z400, and 3.37 um for Total. I'm not sure what to make of those. After the surgery, those measurements were 0.23, 0.23, and 0.71 um. Is it unusual for those readings to go down like that?


As a general rule higher order aberrations go up after laser correction surgery. In your case they went down and went down considerably. This means your optics, as measured by wavefront analysis, have vastly improved. The final number, 0.71um, indicates that you have some defocus. Simply put, you were either slightly undercorrected or overcorrected and need glasses for a small amount of refractive error.


dan1966 wrote:That's part of the problem. I haven't been able to find anything on the internet that goes into any detail about those measurements.


It is not likely that you will find anything about Zernike polynomials for wavefront-guided excimer laser ablation on a general public website. You can go to PubMed.com and look at peer-reviewed journal articles.

dan1966 wrote:Why would they have been unable to get a reading for more than 5 mm for my left eye? You say that it's quite common. What accounts for this?


The most common type of wavefront analysis sends light signals into the eye, bounce them off the retina, and then measure those signals as the return through the front of the eye. If these signals are not able to be read completely, or if too many light points are scattered or otherwise lost, the system will not be able to analyze the results.

dan1966 wrote:They sure don't mention it at websites for Lasik providers. They also really play up how much better custom is than traditional.


Car dealerships are not likely to advertise the terrible gas mileage on their highest priced cars either.

dan1966 wrote:After the procedure, my right eye's undilated measurement was 6.08 and my left eye's was 5.47. Why would they have increased from the initial 5.39 and 4.94, respectively?


Many people have fluctuation in their pupil size, based upon many factors. Even taking a cold medicine can affect this. Time of day can affect this. There are many variables.

dan1966 wrote:I didn't get my medical records until long after my procedure. I'm trying to make sense of things after the fact. Had things gone as I had hoped, I would never have looked back. I feel somewhat foolish to be doing this because it seems a little too late to be tending to this now. The horse has already left the barn.


Yes, but the horse is only in the pasture. You have been overcorrected or undercorrected. Once that is resolved, your numbers indicate you should have very good vision.

dan1966 wrote:I can't seem to help it, though, possibly because of obsessive/compulsive tendencies. I still want to know why things turned out as they did.


Because you are dealing with biological tissue. It appears that you are about 0.50 diopter off of target on the one eye. To correct one full diopter, about 12 microns of tissue are removed. So you are about 6 microns of tissue off of the desired result. A human hair is about 60 microns thick. Your surgery is within 1/10th of a human hair's width of the target. I realize that you are having trouble, but understanding these numbers may put things into perspective.

And yes, the doctor can remove only 6 microns if necessary for enhancement.

dan1966 wrote:So an ideal candidate who does everything that he is told and is operated on by an experienced surgeon winds up with visual distortions.


That can happen. There is no such thing as perfect surgery every time (any surgery), but enhancement surgery would likely resolve the issue.

dan1966 wrote:It just doesn't add up. Only when I understand things as well as I possibly can will I be able to move on with my life. Thank you.


To me, it is not such a mystery. Your results are very slightly off the mark, but this is enough to provide less than optimal results. The doctor used conventional ablation because s/he wanted to be certain your fully corrected optical ablation zone was as large as necessary and because, for whatever reason, the wavefront analysis could not get a good reading. The target was missed by a few microns. This all makes sense to me, based upon the information you have provided.

I don't know how much you will eventually be able to understand, but keep in mind that we don't know what electricity is...however we don't need to sit in the dark.
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Re: Overwhelmed by Info

Postby Still Hoping » Fri Aug 21, 2009 5:20 am

I, too, was told I "qualified for the most accurate procedure" (refering to custom), only to find out several weeks after the surgery that they did "standard" or "traditional". I was very upset by this as well, especially considering all the problems I'm having. My doc said it had to do with my thin cornea, (which reinforced that he never discussed it with me ahead of time, because our conversation would have led to questions about PRK or not having it done at all). As it turned out, he still made my flaps the same thickness as normal, which I don't quite understand. Anyway, just letting you know you're not alone in the boat!
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Re: Overwhelmed by Info

Postby dan1966 » Fri Aug 21, 2009 10:57 pm

Were you going to be charged the same amount whether you had custom or traditional done? If so, it may have been in their financial interest to have the traditional done. I think that's what happened in my case. They were going to be paid the same amount either way and going with traditional was less costly for them, hence their profit margin would be higher. Many places charge a higher fee for custom, which removes this conflict of interest. If it is true that they sacrificed my eyes for a few hundred more dollars of profit I will not be happy. So far, I'm still not sure. I know that what they're saying about custom doesn't jibe with a lot of the things that I've read on the net. They told me that only 1% of their patients have had the custom done.

You're probably in the same boat that I am. If only I knew then what I know now...
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Re: Overwhelmed by Info

Postby Still Hoping » Mon Aug 31, 2009 4:22 am

The cost was the same for both types in my case, too. I feel exactly the same as far as having a great desire to UNDERSTAND why this happened to me. Even if they can't fix it (or if I don't allow them to recut my nerves), I still feel I need explanations...
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