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Dr. William Trattler : Second article on Relationship between pupil size and night vi
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| wtrattler@earthlink.net 2005-11-27, 6:00 pm |
| Article by Dr. William Trattler: From Eye World November 2005
Link to Dr. William Trattler's article:
http://www.eyeworld.org/article.php...uery=3Dtrattler
Large pupils lead to night vision problems, physicians suggest
---------------------------------------------------------------------------=
-----
by Matt Young EyeWorld Staff Writer
Starbursts greater in patients with large pupils, study finds.
While some studies have suggested pupil size has little to no effect on
nighttime vision post-refractive surgery, some ophthalmologists point
to new evidence that there is a correlation.
"If you compare patients of the same prescriptions, the larger the
pupil size, the bigger the chance that they're going to have more
night vision problems," said William B. trattler, M.D., Center for
Excellence in Eye Care, Miami.
To back up his assertion, Dr. trattler performed his own studies, one
of which included 119 myopic eyes that underwent LASEK or PRK with
either a standard VISX (Advanced Medical Optics, Santa Ana, Calif.)
Star S3 or S4 laser.
Using a Larson Glarometer, he found that the radius of starbursts was
greater in patients with large pupils compared with those in patients
with small ones. Dr. trattler presentedthe results at the most recent
ASCRS=B7ASOA Symposium & Congress. The Larson Glarometer does not have
a corporate manufacturer yet. It was developed and is distributed by
Bruce Larson, M.D., Hinsdale, Ill.
Meanwhile, James Salz, M.D., clinical professor of ophthalmology,
University of Southern California, Los Angeles, also believes large
pupils can lead to night vision complaints after refractive surgery.
"The larger the pupil size, the greater the aberrations will be,"
said Dr. Salz.
Beyond questionnaires
Two earlier studies found little to no correlation between pupil size
and higher-order aberrations.
One, titled "Pupil size and quality of vision after LASIK," was
published in the August 2003 issue of Ophthalmology by Steven C.
Schallhorn, M.D., Naval Medical Center, San Diego, and colleagues.
In 100 consecutive LASIK patients surveyed, patients with large mesopic
pupils reported more glare, haze, and halos than small-pupil patients
one month after surgery and reported more glare at three months
post-op.
However, no relationship between pupils and glare, haze, or halo
symptoms existed six months after surgery, the study concluded.
Another study by Mihai Pop, M.D., Montreal, Quebec, titled "Risk
factors for night vision complaints after LASIK for myopia," also
concluded that pupil size was not a major risk factor for night vision
complaints.
The reported night-vision complaints that resulted from each of the
1,488 LASIK eyes were rated subjectively based on functional visual
comfort. The study was published in the January 2004 issue of
Ophthalmology.
But Dr. trattler's study relied on the Larson Glarometer.
After conventional LASEK or PRK surgery, he tested 30 eyes with pupils
of 5.5 mm or smaller; 31 eyes with 6-mm pupils; 18 eyes with 6.5-mm
pupils; 24 eyes with 7-mm pupils; and 16 eyes with pupils of 7.5 mm or
larger.
Taking into account all degrees of myopia, the starburst radius on
average was larger for large-pupil patients than it was for small-pupil
patients, Dr. trattler said. The average follow-up time was 9.9 months.
For instance, even in the group with low myopia, the starburst radius
averaged 9.17 mm for those with small pupils and 13.75 mm for those
with large pupils.
Dr. trattler also performed a study of 92 myopic eyes on patients that
underwent LASEK with the VISX CustomVue procedure (Advanced Medical
Optics, Santa Ana, Calif).
"Wavefront provides a significant reduction in nighttime vision
aberrations compared with standard ablation in all pupil sizes," Dr.
trattler said. "But we did see in both groups that as pupil size gets
larger and the level of myopia gets larger, the size of the starburst
increases."
Large-pupil patients that receive custom treatment probably fare better
than their conventional counterparts because of the optimized blend
zone available with all wavefront-guided procedures, Dr. Salz said.
Dr. Schallhorn said that in his study, he looked at symptoms through
questionnaires for a reason.
"We know that aberrations increase with increasing pupil size," Dr.
Schallhorn said. "The question is, though, do those patients have
more problems."
And if patients have more aberrations, but aren't complaining,
ophthalmologists cannot tell them they have more night vision problems,
Dr. Schallhorn said.
Dr. Schallhorn said that in his study, patients with large pupils did
not complain more.
"Maybe they have a different adaptive mechanism," Dr. Schallhorn
said. "There must be other factors we don't understand yet, such as
variability in the Stiles Crawford effect.
"I am not saying the pupil is unimportant, just that we do not find a
relationship between the pupil size and symptoms," he said.
"Pharmacologic constriction of the pupil will reduce symptoms in
patients with either large or small low-light pupils."
Another clinician's observations
In his own clinic, Dr. Salz said that at least a dozen people with
large pupils have had reduction in their symptoms when their pupils are
reduced.
"If you reduce their pupil size with Alphagan [brimonidine tartrate
ophthalmic solution] or pilocarpine [various manufacturers], their
symptoms go away," Dr. Salz said. Alphagan is manufactured by
Allergan (Irvine, Calif.).
"It's counterintuitive to me to say pupil size is irrelevant,"
Dr. Salz said. "It's not logical that if you have a big pupil at
night and you are letting more light into the eye, that that is not a
risk factor. Intuitively it has to be."
All refractive surgery patients have a chance of nighttime glare and
halos, Dr. Salz said.
"That's in everybody's informed consent," Dr. Salz said. "But
we think if your pupils are large compared with patients with pupils
that are small, that risk for you is higher."
Editors' note: Dr. Salz is a consultant for Alcon (Fort Worth,
Texas). Drs. Schallhorn and trattler have no financial interests
related to their comments.
Contact Information
Salz: 323-653-3800, jjsalzeye@aol.com
Schallhorn: 619-532-6702, scschallhorn@nmcsd.med.navy.mil
trattler: 305-598-2020, wtrattler@earthlink.net
| |
| Glenn - USAEyes.org 2005-11-28, 1:00 am |
| Dr. Trattler,
It saddens me to see that you are being attacked as something less
than the concerned surgeon that you are, and that you find it
necessary to defend yourself against these unjust accusations.
The attacks against you perpetrated by "Eye" are obviously in response
to your decision to request "Eye" to contribute to your bulletin board
at AskLasikDocs in a manner appropriate to that forum, or to not
participate at all. You will not - and should not - allow your
bulletin board to become filled with the kind of twisted
misrepresentations found in this newsgroup.
I'm sure that anyone who reads even a few of the posts published by
"Eye" will quickly understand the limited value this kind of
participation in any forum. I'm sure that all reasonable people will
understand that the accusations made against you by "Eye", no matter
what the aliases used, are unfounded and without any merit whatsoever.
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.
| |
| Ragnar 2005-11-28, 12:57 pm |
| I don't think anyone disputes that larger pupils are prone to
starbursts. That is why with LASIK surgeons must use the appropriate
sized microkeratome aperture when making the flap. They must also
make the appropriate transition zone.
Saying large pupils can lead to night vision problems is like saying
water is wet. If they have problems, it's because the surgeon made
the ablation zone too small and/or did not use a transition zone.
A simple ablation would be like a .25 millimeter deep cylinder
bottom-shaped zone. The starbursts, halos, ghosts result from the
light hitting the perimeter/rim of the abaltions zone and bouncing the
light off in all directions. A transition zone bevels off the edges
of the ablation zone so that the ablation has a sloping rim like a
lake rather than an orthoganal dropoff like a swimming pool.
Salz has an awful habit of using $10 words and techno-babble to point
out problems, but he rarely if ever indicates the solution for them.
In the early days of LASIK, surgeons did not do transition zones.
What IS a critical issue is that many lasik mills - such as LVI - do
not even consider the pupil size when they do their procedures. That
makes it impossible to determine what size ablation zone to make and
what transition zone to use. That is one reason why LVI has a 20%
enhancement rate while competent surgeons have a 3% enhancement rate.
LVI doesn't take the time to properly plan the surgery. They can't
do 40 LASIK procedures a day and take the time to plan for each
procedure.
On 27 Nov 2005 12:31:37 -0800, wtrattler@earthlink.net wrote:
>Article by Dr. William Trattler: From Eye World November 2005
>Link to Dr. William Trattler's article:
>http://www.eyeworld.org/article.php...&query=trattler
>
>Large pupils lead to night vision problems, physicians suggest
>
>
>--------------------------------------------------------------------------------
>by Matt Young EyeWorld Staff Writer
>
>
> Starbursts greater in patients with large pupils, study finds.
>
>While some studies have suggested pupil size has little to no effect on
>nighttime vision post-refractive surgery, some ophthalmologists point
>to new evidence that there is a correlation.
>"If you compare patients of the same prescriptions, the larger the
>pupil size, the bigger the chance that they're going to have more
>night vision problems," said William B. trattler, M.D., Center for
>Excellence in Eye Care, Miami.
>To back up his assertion, Dr. trattler performed his own studies, one
>of which included 119 myopic eyes that underwent LASEK or PRK with
>either a standard VISX (Advanced Medical Optics, Santa Ana, Calif.)
>Star S3 or S4 laser.
>Using a Larson Glarometer, he found that the radius of starbursts was
>greater in patients with large pupils compared with those in patients
>with small ones. Dr. trattler presentedthe results at the most recent
>ASCRS·ASOA Symposium & Congress. The Larson Glarometer does not have
>a corporate manufacturer yet. It was developed and is distributed by
>Bruce Larson, M.D., Hinsdale, Ill.
>Meanwhile, James Salz, M.D., clinical professor of ophthalmology,
>University of Southern California, Los Angeles, also believes large
>pupils can lead to night vision complaints after refractive surgery.
>"The larger the pupil size, the greater the aberrations will be,"
>said Dr. Salz.
>
>Beyond questionnaires
>
>Two earlier studies found little to no correlation between pupil size
>and higher-order aberrations.
>One, titled "Pupil size and quality of vision after LASIK," was
>published in the August 2003 issue of Ophthalmology by Steven C.
>Schallhorn, M.D., Naval Medical Center, San Diego, and colleagues.
>In 100 consecutive LASIK patients surveyed, patients with large mesopic
>pupils reported more glare, haze, and halos than small-pupil patients
>one month after surgery and reported more glare at three months
>post-op.
>However, no relationship between pupils and glare, haze, or halo
>symptoms existed six months after surgery, the study concluded.
>Another study by Mihai Pop, M.D., Montreal, Quebec, titled "Risk
>factors for night vision complaints after LASIK for myopia," also
>concluded that pupil size was not a major risk factor for night vision
>complaints.
>The reported night-vision complaints that resulted from each of the
>1,488 LASIK eyes were rated subjectively based on functional visual
>comfort. The study was published in the January 2004 issue of
>Ophthalmology.
>But Dr. trattler's study relied on the Larson Glarometer.
>After conventional LASEK or PRK surgery, he tested 30 eyes with pupils
>of 5.5 mm or smaller; 31 eyes with 6-mm pupils; 18 eyes with 6.5-mm
>pupils; 24 eyes with 7-mm pupils; and 16 eyes with pupils of 7.5 mm or
>larger.
>Taking into account all degrees of myopia, the starburst radius on
>average was larger for large-pupil patients than it was for small-pupil
>patients, Dr. trattler said. The average follow-up time was 9.9 months.
>For instance, even in the group with low myopia, the starburst radius
>averaged 9.17 mm for those with small pupils and 13.75 mm for those
>with large pupils.
>Dr. trattler also performed a study of 92 myopic eyes on patients that
>underwent LASEK with the VISX CustomVue procedure (Advanced Medical
>Optics, Santa Ana, Calif).
>"Wavefront provides a significant reduction in nighttime vision
>aberrations compared with standard ablation in all pupil sizes," Dr.
>trattler said. "But we did see in both groups that as pupil size gets
>larger and the level of myopia gets larger, the size of the starburst
>increases."
>Large-pupil patients that receive custom treatment probably fare better
>than their conventional counterparts because of the optimized blend
>zone available with all wavefront-guided procedures, Dr. Salz said.
>Dr. Schallhorn said that in his study, he looked at symptoms through
>questionnaires for a reason.
>"We know that aberrations increase with increasing pupil size," Dr.
>Schallhorn said. "The question is, though, do those patients have
>more problems."
>And if patients have more aberrations, but aren't complaining,
>ophthalmologists cannot tell them they have more night vision problems,
>Dr. Schallhorn said.
>Dr. Schallhorn said that in his study, patients with large pupils did
>not complain more.
>"Maybe they have a different adaptive mechanism," Dr. Schallhorn
>said. "There must be other factors we don't understand yet, such as
>variability in the Stiles Crawford effect.
>"I am not saying the pupil is unimportant, just that we do not find a
>relationship between the pupil size and symptoms," he said.
>"Pharmacologic constriction of the pupil will reduce symptoms in
>patients with either large or small low-light pupils."
>
>Another clinician's observations
>
>In his own clinic, Dr. Salz said that at least a dozen people with
>large pupils have had reduction in their symptoms when their pupils are
>reduced.
>"If you reduce their pupil size with Alphagan [brimonidine tartrate
>ophthalmic solution] or pilocarpine [various manufacturers], their
>symptoms go away," Dr. Salz said. Alphagan is manufactured by
>Allergan (Irvine, Calif.).
>"It's counterintuitive to me to say pupil size is irrelevant,"
>Dr. Salz said. "It's not logical that if you have a big pupil at
>night and you are letting more light into the eye, that that is not a
>risk factor. Intuitively it has to be."
>All refractive surgery patients have a chance of nighttime glare and
>halos, Dr. Salz said.
>"That's in everybody's informed consent," Dr. Salz said. "But
>we think if your pupils are large compared with patients with pupils
>that are small, that risk for you is higher."
>
>Editors' note: Dr. Salz is a consultant for Alcon (Fort Worth,
>Texas). Drs. Schallhorn and trattler have no financial interests
>related to their comments.
>
>Contact Information
>Salz: 323-653-3800, jjsalzeye@aol.com
>Schallhorn: 619-532-6702, scschallhorn@nmcsd.med.navy.mil
>trattler: 305-598-2020, wtrattler@earthlink.net
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