Looking at pre-op journal: 3 questions ( Glenn )

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Looking at pre-op journal: 3 questions ( Glenn )

Postby Olof_LASEK_Sweden » Thu May 22, 2008 3:36 pm

Hello again,
A brief recap of my story, and you can see my data in the bottom signature. I am now 8 weeks post op. My remaining concerns are some ghosting on both eyes, most noticeable when watching TV and mostly the right eye ghost, and hyperopia on the left eye. The ghosts are becoming more faint and closing in to the original, which is encouraging. I have been off steroids since April 27th. My daylight vision is splendid. I have some starbursting at night, but OTOH, my night vision is better than pre-op ( better contrasts or something ).

I am going on my 1st post-op appointment on June 5th ( yes that's the way they do it here, less post op appointments ). I have a copy of my pre-op journal and in addition to the q about hyperopia, I would like to ask about how to interpret some things in that journal.

Here are my questions:

Stable vision 2001-2008?
As you can see in my signature:

Pre-Op:
R: Sph -2.5 ( No astig ) BCVA 20/17 (1.2)
L: Sph -2.75 Cyl -0.5 80 BCVA 20/17 (1.2)
2006:
R:Sph -3.0 (No astig) BCVA: 20/17 (1.2)
L:Sph -3.0 Cyl -0.75 90 BCVA: 20/20 (1.0)
Recommended perhaps using -3 (no astig )contacts
2001:
R:Sph -3.0 (No astig)
L:Sph -3.0 Cyl -0.75 85
Recommended -2.75 (no astig )contacts


it would seem I have regressed a little towards plano the last 2 years, both cyl and astig. However, in 2006 my optometrist told me I could use -3 contacts instead of -2.75 to "take out" some of the astig in the right eye. It seemed, as I recall it, a border case if the 0.25 should be put on the astig or on the sphere. This fits with my pre-op exam where there seems to have been a 0.5 regression on both eyes, but with 0.25 astig "switching" from the cyl to the sph on the left eye.

Q1 Did I still fulfill the stable vision requirement considering this regression between 2006 and 2008?? It looks more stable between 2001 and 2006, and perhaps that normally weighs into the doctor's judgement.

Differences between the wavefront analyser Rx and Subjective Rx
From the corneal WA, I have RX(vd=0) =
R: -2.65 / -0.43 @ 6.3 L: -3.14 / -0.23 @ 69.6

Q2 Is it normal that the WFA prescription differs this much from the subjective ( I suppose so )? What is normally done regarding the ablation, is it done according to the WFA or the subjective estimation Rx? The computer software normally takes both the subjective Rx and the WFA Rx into account? I will ask at the appointment what was exactly done.

HOAs, how to read
I wonder if the values are high or low for me. I guess I will talk to the doctor. This Schwind machine and software is supposed to target spherical abberation specifically ( wider area, something with outer laser beams too ).
R: Coma= 0.395 μm/0.3Deq
SpAb= 0.278 μm/0.21Deq
RMS=3.784 μm/2.91Deq
P-V=15.264 μm

L:Coma=0.189 μm/0.15
SpAb= 0.229 μm/0.18Deq
RMS=4.249 μm/3.27 Deq
P-V=15.869 μm

Q3 Was I a high HOA or a low HOA person pre-op? How do I make the RMS % from these numbers, BTW?

If I was a high HOA I suppose this would give me bigger benefit from the custom wavefront ( and could explain the improved night vision ).

I am looking very much forward to your answers and thanks for taking your time.

BR// Olof

--------------------------------------------------------------
Olof_LASEK_Sweden
36 years old
LASEK with MMC March 27th 2008
Schwind Esiris Laser
Pre-Op:
Pupil: photopic: 5 mm in WFA: ( dark setting ) 6 mm
R: Sph -2.5 ( No astig ) BCVA 20/17 (1.2)
L: Sph -2.75 Cyl -0.5 80 BCVA 20/17 (1.2)
2006:
R:Sph -3.0 (No astig) BCVA: 20/17 (1.2)
L:Sph -3.0 Cyl -0.75 90 BCVA: 20/20 (1.0)
2001:
R:Sph -3.0 (No astig)
L:Sph -3.0 Cyl -0.75 85
Recommended -2.75 (no astig )contacts
Olof_LASEK_Sweden
 
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Re: Looking at pre-op journal: 3 questions ( Glenn )

Postby LasikExpert » Thu May 22, 2008 5:40 pm

Olof_LASEK_Sweden wrote:Q1 Did I still fulfill the stable vision requirement considering this regression between 2006 and 2008?? It looks more stable between 2001 and 2006, and perhaps that normally weighs into the doctor's judgement.


A change of 0.25 diopter is within the normal range of fluctuation for human vision, and your optometrist may have made this adjustment regardless of the actual refractive error. This appears stable.

Olof_LASEK_Sweden wrote:Q2 Is it normal that the WFA prescription differs this much from the subjective ( I suppose so )?


It is very rare that they are identical, but they need to be close for wavefront-guided ablation to be appropriate. Less than 1.00 diopter is the general rule. Your wavefront and manifest were relatively close.

Olof_LASEK_Sweden wrote:What is normally done regarding the ablation, is it done according to the WFA or the subjective estimation Rx?


That depends upon the opinion of the surgeon. Most tend to rely more on the patient's subjective opinion of refractive error, but there are a multitude of issues that would be evaluated from the wavefront data to come to this conclusion.

Olof_LASEK_Sweden wrote:The computer software normally takes both the subjective Rx and the WFA Rx into account?


That is the job of the surgeon, not the computer.

Olof_LASEK_Sweden wrote:Q3 Was I a high HOA or a low HOA person pre-op?


As a (very) general rule, RMS between about .35 and .40 for coma and spherical aberration is normal for humans. You seem to be a bit below that, which is good.

On the whole, all laser vision correction procedures increase HOA, however not always and not all HOA. Since you started low, it is likely that any increase would simply bring you up to normal. It is also possible that HOAs will be reduced by laser vision correction, however that is not reliably predictable.

You would need a postop wavefront scan to determine what changes occured in your HOA.
Glenn Hagele
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Re: Looking at pre-op journal: 3 questions ( Glenn )

Postby Olof_LASEK_Sweden » Sat May 24, 2008 7:54 am

Thanks for a thorough and prompt answer, Glenn :D .
LasikExpert wrote:
Olof_LASEK_Sweden wrote:What is normally done regarding the ablation, is it done according to the WFA or the subjective estimation Rx?


That depends upon the opinion of the surgeon. Most tend to rely more on the patient's subjective opinion of refractive error, but there are a multitude of issues that would be evaluated from the wavefront data to come to this conclusion.

Olof_LASEK_Sweden wrote:The computer software normally takes both the subjective Rx and the WFA Rx into account?


That is the job of the surgeon, not the computer.


I am putting together a set of questions for the post-op appt and this will be one of them. The only thing I have been told was by the nurse when I called. She said that "the manual override that is sometimes done" was NOT done in my case. I don't know if the referred overide is to use the manifest Rx instead of the WFA Rx or an override due to other discoveries in the corneal topography scan.

Basically I don't really get this stuff. The WFA should always be right it would seem to me, since it really analyses how the light "bounces" in your eye. The manifest puts a lens a certain distance from the eye.

Other than that I can say that the nighttime/TV-ghosting ( both eyes ) and hyperopia ( left eye ) is about the same as during the last 2-3 weeks.

Just to repeat Glenn, if the ghosts go away when the pupils are small, it really doesn't tell me if the ghosting is temporary or permanent ( permanent astig ), right?

I really had this demonstrated the other day when I had a migraine. I have a very strong pain med for that, which makes the pupils constrict to the verge of looking silly. After the migraine and before this effect wore off I could watch TV ghost free and the vision was really rocking, like 20/15 or something!

Also, ghost free in the morning or after nap, could indicate a healing and/or dry eye issue rather than permanent astig as per your earlier answer.

That the ghost became more faint, and sometimes appears more like a group of very faint ghosts ( right eye ), does this tell me anything?

As for future enhancements, the right eye is really ultra sharp. I think it will do 20/15 on the Snellen chart, so I wouldn't want to touch it just for the nighttime ghost. It is also my dominant eye. As for the left, I'll just have to see how the hyperopia develops or (hopefully) recedes. I am obviously able to function and enjoy my current vision so there is absolutely no need to rush. My guess when testing the +1.0 readers is that the left has 0.25-0.5 hyperopia. In less than two weeks when I have my post-op appt I will know.
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Post-op appointment finally coming up

Postby Olof_LASEK_Sweden » Sun Jun 01, 2008 6:53 pm

I am putting together a set of questions for the post-op appt and that one about WFA Rx vs Subjective Rx will be one of them. How those were or were not used in the actual lazing.

I have my appointment next week and normally, it is only the nurse that does the Schnellen chart and looks in the microscope, and that's that.

However, I have requested to also see the surgeon to ask all these advanced questions. I will prepare a sheet and also call once more ahead of the appt to ensure that the surgeon will actually have time to sit down with me for a while.

I really started to read up on LASEK 2-3 weeks after the procedure which was a "worry period" with little or no progress weeks 1-3.

I will share the results of that post-op appointment with the readers of this forum for everyone's benefit.
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After post-op appointment

Postby Olof_LASEK_Sweden » Fri Jun 06, 2008 8:31 am

2 months post-op. Post op appointment
Nurse check ( normal post op appt )
Yesterday I was at my first post-op appointment. The nurse checked the eyes in the microscope and said that they looked really good. There was a little bit of healing left to do in the left eye as I recall it. As I thought, I am seeing better than 20/20 on the Snellen chart, hooray! My values were around
R 20/13 ( 1.5 )
L 20/17 ( 1.2 )

I think they do around 20/13 or 20/14 working together.

As I thought prior to the test, I am seeing better than ever before. :D

The nurse didn't want to run the complete test to see what manifest refraction I had. She said remaining refractive errors would still change a lot with healing.
Q&A session with surgeon ( requested as an extra by me )
I sat down to wait to see the doctor with my questions. He finally appeared and we had a good and long conversation about all the issues I had brought.

WFA vs Subjective Rx, Custom WF or not
One of my main Qs was the one about the WFA Rx vs the Subjective Rx. It turns out that the Subjective Rx had been used. This clinic uses the Schwind Esiris laser and is the biggest clinic in Sweden, i.e. a lot of operations. With that laser their experience is that choosing "Aspherical profile" gives the best results, and should be used as much as possible. It is not custom wavefront! They choose custom wavefront only when someone has some very high HOA values. What is put in for each individual is the curvature from the keratomic scan. The argument for not doing so much custom wf is that the back part of the eye are soft and changing so the "fingerprint" will anyway look different at different times. OTOH, I have seen a lot of praise for WF guiding around here. Oh, well, different schools I guess. I for my part sure cant complain about this choice ( of not having custom WF ), having less glare and better contrast vision in the dark than before the surgery.

This aspherical profile compensates for energy loss at the outer parts of the treatment area ( curved ) and ablates a wider area, giving the cornea a more natural shape. I have an image of it but can't seem to insert it here. It is supposed to above all give less night vision artefacts but also a cleaner daytime vision ( "abberation free", sounds kind of promotional, ha! ). I asked him if my observation about better night vision than pre-op could be correct and he said yes, although they dont want to market this. Not having glasses or a contact lense in front of the eye in itself gives some improvment too, he said.

MMC
We talked about the MMC, ( Mitomycin C ) and I had been given 0,02% for 1 minute. The benefits in the form of predictable results are great and the limits for when using is creeping down in the litterature according to the doc.

Ablation Zone
My ablation zone was optical 7 mm, with fringe zones of R 0,71 mm L 0,85 mm.

Hyperopia on left - regression
Regarding what I suspect is hyperopia on the left he said regression happens mostly in the 1st 3 months but can go on for up to a year.

Nighttime ghosting
Regarding the nighttime ghost, when it is reg. astig ghosting it would look more like "beams" rather than perfect ghost images. Does this make sense, Glenn? It kind of makes sense to me because the left eye had some beams coming out of my benchmark TV logo weeks 2-5 or something as I recall it. He sort of echoed that it could be a good sign that the ghosts are becoming more faint and sometimes appear in groups.

I thanked for the Q&A session and told him I am just amazed about the results and I am mindfully enjoying my vision every day.


Upcoming appointment with optometrist
I have now set up an appointment to see my optometrist just to get a real and precise Rx for what refraction is remaining. It may sound silly to some, but I have been reading up on this, following forums, etc, so much that I want a "complete data set" for myself as well.

I guess it will be a little wierd walking in to the optometrist saying I had an op and wont be needing glasses or contacts from him, but still want an exam. My argument will be that I suspect some astig or a dash of hyperopia and I could be interested in some glasses that would provide me with the ultimate, ultimate, superb TV watching! I guess this is sort of true. Although it seems you cant just have hyperopia corr with glasses on just one eye, at least not with +1 readers. I will get dizzy ( tried it, taking out the glass on the right side). Perhaps if the optometrist has some 0.25 readers for both eyes, and cheap, I'd be interested. In stores here, +1 are the weakest readers you can buy.
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Hooray!!

Postby Olof_LASEK_Sweden » Tue Jun 10, 2008 5:36 pm

Back from appointment with optometrist
I sat in her chair for around 10 minutes and she flipped back and forth between different lenses ( one of those machines you look through and it flips the lenses when they press a button). Included was the test with dots surrounded by green or red circle, perhaps that's astig.

The result: Ladies and Gentlemen - I am plano! As plano as plano can be :D

as in
R: 0 0
L: 0 0


I was almost jumping up and down with joy.

The test was taken 3 pm and although the vision didnt feel like at its best, my visus data was

R: 1.2+ ( 20/16 )
She put down 1.2 with a plus, since I could discern som letters on the 20/13 line

L: 1.0- ( 20/20 )
Between 0.9 and 1.0 ( 20/22 and 20/20 ). She called it 1.0 with a minus, because of failing one letter on the 20/20 line ) )

I don't think we tested both eyes together so much, when I asked she said they'd do 20/13 ( 1.5 ) as a combo. I recall seeing some letters at the 1.5 line.

It was good to get this data from the optometrist's Snellen chart. In the eye clinic, the nurse didnt dim down the light and in general got better results than the opt, so now I feel I've had a real and objective test.


So, now I am so very happy that I have landed right on target. The surgeon and his machine were obviously able to land me right on the spot! The remaining nighttime "stuff" now looks more likely to clear away with healing.

I got the exam for free and will thank them by buying some sunglasses I think.
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Postby LasikExpert » Tue Jun 10, 2008 9:32 pm

Thanks for the continued update on your process and it is great to see that you have hit your target. Now it is time for some of those Maui Jims.
Glenn Hagele
Volunteer Executive Director
USAEyes

Lasik Info &
Lasik Doctor Certification

I am not a doctor.
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