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Home > Archive > Lasik Eyes Surgery > May 2005 > A little survey about halo in LASIK
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A little survey about halo in LASIK
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| Pauli Soininen 2005-05-18, 11:46 am |
| I don't know if this is going to get reliable results, but I'll try anyway.
I do hope that there will be many truthful and accurate answers.
If you had LASIK (or other refractive surgery, but mention about it if it's
other than LASIK), you are most welcome to participate in this survey. This
is just for informative purposes.
1. How long since you had the (first) surgery?
2. Do you see distortion of any kind, in daylight or in dark? If you answer
No, you can stop the survey here, but add a comment about your vision (be
critical, show that you do pay attention to visual quality).
3. Do you see disturbing starburst around small/distant lamps at dark?
4. Do you see disturbing halos around bigger/closer lamps at dark?
5. Does the starburst/halo size around lamps change when the pupil size
changes? If yes, does the halo reduce to zero or practically almost zero
(you can test this for example by looking out a window at night and then
constricting the pupils by the use light, eg. flash light)?
6. Has your starburst/halo size or brightness changed after surgery? If yes,
please tell how did you measure this (looking at the same lamps month after
month from the same spot can be a good test).
7. Do you see a less blurred image if you look through "finger binoculars"?
Roll your index fingers and look through the small holes formed. Look at
something in room illumination with high contrast, for example a black
poster with white text or a white object on black background.
8. Do you have difficulties recognizing faces if the person is standing in
front of a bright window -- or do you see everything more or less foggy in
room illumination?
9. Your happiness about the result (0-100%), where
- 100% = aquity is 20/20 or better, there are no side-effects
and any distortion is totally non-disturbing
- 50% = some disturbing side-effects, you don't have to
worry about glasses anymore, but the vision is far from perfect
- 0% = major difficulties at reading and recognizing faces,
driving a car at dark is hazardous (or other complications).
10. Your pre-operative prescription, dilated pupil size, perfect correction
optical zone size and transition zone size (if you know them). And your age,
if you wish.
X. If you have something else to comment about your vision, please add it
here.
Thank you very much for your time and effort!
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| Pauli Soininen 2005-05-18, 11:46 am |
| Here are my own responses to the survey.
1. How long since you had the (first) surgery?
3 months.
2. Do you see distortion of any kind, in daylight or in dark?
Yes, in dark. Bright daylight is better than pre-op with spectacles.
3. Do you see disturbing starburst around small/distant lamps at dark?
Yes.
4. Do you see disturbing halos around bigger/closer lamps at dark?
Yes.
5. Does the starburst/halo size around lamps change when the pupil size
changes?
Yes. It reduces to almost zero when the pupil is about 5.0mm or so. The
maximum starburst diameter is quite big and it's very bright too (covering
cars behind it etc.).
6. Has your starburst/halo size or brightness changed after surgery?
Not at all (since two days after surgery my vision has remained the same).
I've measured my distortions for example by looking out of my room window at
two lamps. Their starburst max. diameter is now the same as it was before
surgery without glasses (the two starbursts are just touching eachother when
they're at maximum).
7. Do you see a less blurred image if you look through "finger binoculars"?
Yes, I see a very sharp and stable image by looking that way.
8. Do you have difficulties recognizing faces...
Yes.
9. Your happiness about the result (0-100%)
50%.
10. Your pre-operative prescription, dilated pupil size, perfect correction
optical zone size and transition zone size (if you know them). And your age,
if you wish.
-4.75 both eyes (-0.25 astigmatism), 7.66mm (horizontal), 6.0mm and with
transition zone about 8.2mm. Age is 26.
X. If you have something else to comment about your vision, please add it
here.
I don't have any severe complications or side-effects other than this
starburst/fog problem. I use eye drops very rarely anymore (dryness is not
severe anymore). I can't see as near as I could anymore, the limit is about
10cm now.
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| Scott 2005-05-18, 11:47 am |
| > 1. How long since you had the (first) surgery?
7 years
> 2. Do you see distortion of any kind, in daylight or in dark? If you
> answer No, you can stop the survey here, but add a comment about your
> vision (be critical, show that you do pay attention to visual quality).
yes
> 3. Do you see disturbing starburst around small/distant lamps at dark?
yes
> 4. Do you see disturbing halos around bigger/closer lamps at dark?
sometimes
> 5. Does the starburst/halo size around lamps change when the pupil size
> changes? If yes, does the halo reduce to zero or practically almost zero
> (you can test this for example by looking out a window at night and then
> constricting the pupils by the use light, eg. flash light)?
yes
> 6. Has your starburst/halo size or brightness changed after surgery? If
> yes, please tell how did you measure this (looking at the same lamps month
> after month from the same spot can be a good test).
no
> 7. Do you see a less blurred image if you look through "finger
> binoculars"? Roll your index fingers and look through the small holes
> formed. Look at something in room illumination with high contrast, for
> example a black poster with white text or a white object on black
> background.
yes
> 8. Do you have difficulties recognizing faces if the person is standing in
> front of a bright window -- or do you see everything more or less foggy in
> room illumination?
sometimes
> 9. Your happiness about the result (0-100%), where
> - 100% = aquity is 20/20 or better, there are no side-effects
> and any distortion is totally non-disturbing
> - 50% = some disturbing side-effects, you don't have to
> worry about glasses anymore, but the vision is far from perfect
> - 0% = major difficulties at reading and recognizing faces,
> driving a car at dark is hazardous (or other complications).
50% - although I am completely happy with my outcome and have NO regrets
> 10. Your pre-operative prescription, dilated pupil size, perfect
> correction optical zone size and transition zone size (if you know them).
> And your age, if you wish.
-14/-18, BCVA 20/40
> X. If you have something else to comment about your vision, please add it
> here.
>
> Thank you very much for your time and effort!
>
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| > 1. How long since you had the (first) surgery?
I had bilateral Zyoptix performed on june 12 2003.
>
> 2. Do you see distortion of any kind, in daylight or in dark? If you
> answer No, you can stop the survey here, but add a comment about your
> vision (be critical, show that you do pay attention to visual quality).
I did see starburst around bright lights decreasingly the first six months
after the surgery, but since then I've had no problem with that or anything
else regarding my visual acuity or ability to see details in the dark. The
only side effect I've noticed is that my eyes tend to get dry a little
easier these days, but not to the extent that I need any tear fluid
substitutes, I just blink a little more when I feel that they get dry and it
helps.
>
> 3. Do you see disturbing starburst around small/distant lamps at dark?
Only the first six months after surgery.
>
> 4. Do you see disturbing halos around bigger/closer lamps at dark?
Only slightly the first six months after surgery.
>
> 5. Does the starburst/halo size around lamps change when the pupil size
> changes? If yes, does the halo reduce to zero or practically almost zero
> (you can test this for example by looking out a window at night and then
> constricting the pupils by the use light, eg. flash light)?
Not that I noticed during the six months I saw starburst.
>
> 6. Has your starburst/halo size or brightness changed after surgery? If
> yes, please tell how did you measure this (looking at the same lamps month
> after month from the same spot can be a good test).
They're gone now. The first six months I noticed it mostly around headlights
of opposing cars while driving in darkness.
>
> 7. Do you see a less blurred image if you look through "finger
> binoculars"? Roll your index fingers and look through the small holes
> formed. Look at something in room illumination with high contrast, for
> example a black poster with white text or a white object on black
> background.
No.
>
> 8. Do you have difficulties recognizing faces if the person is standing in
> front of a bright window -- or do you see everything more or less foggy in
> room illumination?
No.
>
> 9. Your happiness about the result (0-100%), where
> - 100% = aquity is 20/20 or better, there are no side-effects
> and any distortion is totally non-disturbing
> - 50% = some disturbing side-effects, you don't have to
> worry about glasses anymore, but the vision is far from perfect
> - 0% = major difficulties at reading and recognizing faces,
> driving a car at dark is hazardous (or other complications).
100%
>
> 10. Your pre-operative prescription, dilated pupil size, perfect
> correction optical zone size and transition zone size (if you know them).
> And your age, if you wish.
OD: -5.0/-0.75/175°, dilated pupil size 5.5 mm, optical zone 6.0 mm
OS: -4.5/-1.5/177°, dilated pupil size 5.5 mm, optical zone 6.0 mm
BCVA pre-op (OD & OS): 36/20 (1.8), bilateral 36/20 (1.8)
UCVA post-op (OD & OS): 32/20 (1.6), bilateral 40/20 (2.0)
Laser system used was Bausch & Lomb Technolas 217z with Chiron Hansatome 160
?m (for both eyes).
My age at the time of surgery was 35, I'm 37 today.
>
> X. If you have something else to comment about your vision, please add it
> here.
>
> Thank you very much for your time and effort!
>
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| Glenn - USAEyes.org 2005-05-20, 11:59 am |
| Here we have a patient whose optical ablation zone was 0.5mm larger
than pupil size, and yet he experienced temporary night vision
problems. This is consistent with the studies that pupil size alone
is a poor predictor, albeit in this case the existence of night vision
problems resolved during the normal six month healing period.
Also note that the Zyoptix wavefront-guided ablation was not generally
available in the US at the time of the patient's surgery.
Glenn Hagele
Executive Director
USAEyes.org
"Consider and Choose With Confidence"
Email to glenn dot hagele at usaeyes dot org
http://www.USAEyes.org
http://www.ComplicatedEyes.org
I am not a doctor.
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| Dr. Leukoma 2005-05-20, 11:59 am |
| I'm not sure that proves what you think it proves. It merely proves
that LASIK can induce NVD's even if the programmed ablation zone is
larger than the ostensible pupil size. Only topography would show
whether the actual ablation was as large as planned, and only very
careful measurement will reveal the actual size of the pupil under
scotopic conditions. What is doesn't prove is that a patient with an
ablation zone smaller than their scotopic pupil size will not have
NVD's.
DrG
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| Pauli Soininen 2005-05-20, 5:57 pm |
| > This is consistent with the studies that pupil size alone
> is a poor predictor
But this doesn't mean that the whole business is a total and unsolvable
mystery (I know you don't think so either). There are simply simultaneously
different causes for NVC. In my speculation, pupil size is a very good
predictor for the transition zone induced problem. And, simply, there is
also other kind of disturbance which can be similar to the transition zone
induced disturbance, but they are still (easily) separable. Pupil size
indeed doesn't have very much to do with this "second type" disturbance.
> Also note that the Zyoptix wavefront-guided ablation was not generally
> available in the US at the time of the patient's surgery.
To me it seems that wavefront does not offer a solution to the biggest
problem, which is the transition zone problem. The wavefront doesn't grow
more thickness to the stroma which is what would really help.
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| Pauli Soininen 2005-05-20, 5:57 pm |
| Of course, this one case isn't adequate to make conclusions, but to me it
seems like it's perfectly consistent with my "theory". Larger pupil than
perfect ablation zone causes severe, possibly non-healing distortion and the
other type of distortion (which doesn't change radius with pupil size) heals
more easily and that healing is much easier to explain than the healing of
the transition zone.
> Only topography would show whether the actual ablation
> was as large as planned
I would guess that at least with equipment of today's generation the
lasering part is close to fool-proof itself, what changes the mathematically
predicted result is what happens with the flap, alignment and growth of
cells, hydration etc. (And what is the mathematically predicted result is
not the ideal result if/because there isn't enough of stroma to ablate.)
> only very careful measurement will reveal the actual size of
> the pupil under scotopic conditions.
I really don't know how it's with others, but my pupils seem to behave quite
consistently - I think they're quite reliably close to the maximum always
when it's dark. The reaction time of pupil is also very minimal (about 200ms
or so). Therefore I would imagine it should be easy to make quite reliable
measurements. Of course, only one small but
bright light source can change the result greatly. I don't think it has to
be absolutely pitch black to make a decent measurement. I'm sure I would
find out problems with measurement reliability though if started doing it
for my living.
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| Glenn - USAEyes.org 2005-05-20, 5:57 pm |
| >To me it seems that wavefront does not offer a solution to the biggest
>problem, which is the transition zone problem. The wavefront doesn't grow
>more thickness to the stroma which is what would really help.
It is my understanding that the transition zone does not benefit from
wavefront analysis. The transition is essentially a conventional
ablation.
Glenn Hagele
Executive Director
USAEyes.org
"Consider and Choose With Confidence"
Email to glenn dot hagele at usaeyes dot org
http://www.USAEyes.org
http://www.ComplicatedEyes.org
I am not a doctor.
| |
| Dr. Leukoma 2005-05-20, 5:57 pm |
|
Pauli Soininen wrote:
> Of course, this one case isn't adequate to make conclusions, but to
me it
> seems like it's perfectly consistent with my "theory". Larger pupil
than
> perfect ablation zone causes severe, possibly non-healing distortion
and the
> other type of distortion (which doesn't change radius with pupil
size) heals
> more easily and that healing is much easier to explain than the
healing of
> the transition zone.
I admit to have trouble following your "other type of distortion." Do
you mean a non-homogeneous area of ablation, edema, or something else?
>
>
> I would guess that at least with equipment of today's generation the
> lasering part is close to fool-proof itself, what changes the
mathematically
> predicted result is what happens with the flap, alignment and growth
of
> cells, hydration etc. (And what is the mathematically predicted
result is
> not the ideal result if/because there isn't enough of stroma to
ablate.)
Foolproof, you say? Why do calibrations, then? I think you need to
take a look at what happened as opposed to what was supposed to happen.
If it happened the way it was supposed to happen, then you can make a
case for a design flaw.
>
>
> I really don't know how it's with others, but my pupils seem to
behave quite
> consistently - I think they're quite reliably close to the maximum
always
> when it's dark. The reaction time of pupil is also very minimal
(about 200ms
> or so). Therefore I would imagine it should be easy to make quite
reliable
> measurements. Of course, only one small but
> bright light source can change the result greatly. I don't think it
has to
> be absolutely pitch black to make a decent measurement. I'm sure I
would
> find out problems with measurement reliability though if started
doing it
> for my living.
I think you might have missed my point, which is that there is lack of
consistency not only in the devices used to measure pupil size, but
also in the conditions used to measure pupil size. If one states the
pupil size, then one needs to qualify how it was measured.
DrG
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| Pauli Soininen 2005-05-20, 5:57 pm |
| > I admit to have trouble following your "other type of distortion." Do
> you mean a non-homogeneous area of ablation, edema, or
> something else?
I mean to continue saying what I said on that message from yesterday which
begins "Ok.". There I put my speculation about the causes. If I wasn't
clear, there were mistakes or it is difficult to understand what I wrote,
I'll be glad to discuss about it. Basically what I called "second type of
distortion" is caused by light being scattered because of the changes
between the surface of the stroma and the epithelium, where cellular
structure is violated (and cracks etc. easily visible to the ultrasound are
present as well).
> Foolproof, you say? Why do calibrations, then?
I don't know at all how they calibrate it. If it's human calibrated at
micron level (as opposed to rough positioning), I'm surprised. At least I
suppose the real-time eye tracking has to be very highly effective and
accurate. I accidentally turned my eye completely at the wrong direction in
the middle of lasering, but that eye is actually the better one now.
> If it happened the way it was supposed to happen, then you
> can make a case for a design flaw.
I would imagine that with today's generation equipment it is not a problem
to make very accurate lasering. And that when unpredicted result occurs,
it's rarely because of inaccurate lasering but because of the unpredictable
nature of the stuff piled back on the stroma (and the space between the
stuff and the ablated stroma).
> I think you might have missed my point, which is that there is lack of
> consistency not only in the devices used to measure pupil size, but
> also in the conditions used to measure pupil size.
Yes, it is possible. But I find the task quite simple compared to many other
things humans are capable of (the required accuracy is just 0.01mm level
which shouldn't be that difficult). Let's analyse it at practical level: if
the measurement is made always horizontally and the equipment has 0.1mm
accuracy (including the deviation caused by different interpretation) and
the sealed room is very dark, is there much that can go wrong?
If the situation is something like so that the devices have 0.5mm accuracy
(or huge differencies among different models) and the room illumination is
sometimes dark and sometimes lots of light is coming in through the
windows - well, then something is horribly wrong. What is the purpose of
measuring pupil size if it's not confirmed that the method and conditions
are accurate?
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>1. How long since you had the (first) surgery?
3 years
>2. Do you see distortion of any kind, in daylight or in dark? If you answer
>No, you can stop the survey here, but add a comment about your vision (be
>critical, show that you do pay attention to visual quality).
Yes.
>3. Do you see disturbing starburst around small/distant lamps at dark?
At night, I see "slight" starbursts around small/distant lamps. It is
almost unnoticeable, but I am very "picky" about my vision.
>4. Do you see disturbing halos around bigger/closer lamps at dark?
Not any more, although I did for the first 18-24 months after
surgery.
>5. Does the starburst/halo size around lamps change when the pupil size
>changes? If yes, does the halo reduce to zero or practically almost zero
>(you can test this for example by looking out a window at night and then
>constricting the pupils by the use light, eg. flash light)?
Yes and yes.
>6. Has your starburst/halo size or brightness changed after surgery? If yes,
>please tell how did you measure this (looking at the same lamps month after
>month from the same spot can be a good test).
I had changes all along, but the most dramatic changes were during the
18-24 month period after surgery. I "measured" this by looking at the
same street lights in my neighborhood from month to month.
>7. Do you see a less blurred image if you look through "finger binoculars"?
>Roll your index fingers and look through the small holes formed. Look at
>something in room illumination with high contrast, for example a black
>poster with white text or a white object on black background.
Yes, no distortion at all.
>8. Do you have difficulties recognizing faces if the person is standing in
>front of a bright window -- or do you see everything more or less foggy in
>room illumination?
No, although these were issue during the first 6 months or so after
surgery.
>
>9. Your happiness about the result (0-100%), where
> - 100% = aquity is 20/20 or better, there are no side-effects
> and any distortion is totally non-disturbing
> - 50% = some disturbing side-effects, you don't have to
> worry about glasses anymore, but the vision is far from perfect
> - 0% = major difficulties at reading and recognizing faces,
> driving a car at dark is hazardous (or other complications).
100%, now that my eyes have "healed." I would say 75% for the first 3
months after surgery, gradually rising during the 3-month to 24 month
period to 100% now.
>10. Your pre-operative prescription, dilated pupil size, perfect correction
>optical zone size and transition zone size (if you know them). And your age,
>if you wish.
-6.5 left, -6.0 right, 6.5 mm, but I don't know optical and transition
zone sizes. Age is 43.
>
>X. If you have something else to comment about your vision, please add it
>here.
I would just say that patience pays off. I was a little upset and the
starbursts/halos, and I certainly thought they would have "gone away"
quicker than they did. Now that they're practically unnoticeable, I
am a happy camper.
>Thank you very much for your time and effort!
No problem. Great idea!
>
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