| wtrattler@earthlink.net 2005-11-27, 6:00 pm |
| Article: Link:
http://www.eyeworld.org/article.php...uery=3Dtrattler
>From EyeWorld February 2005 Edition:
Study finds correlation between night vision troubles, larger pupils
---------------------------------------------------------------------------=
-----
by David Udoff EyeWorld Staff Writer
Radius of starbursts in refractive patients increased along with
pupil size.
Patients with larger pupils that have had LASIK or LASEK are at higher
risk for larger starburst phenomena than patients with smaller pupils,
according to a recent study by William B. trattler, M.D., refractive
surgeon, Center For Excellence In Eye Care, Miami, Fla., and Bruce
Larson, M.D., Larson Eye Center, Hinsdale, Ill.
While presenting the study at the most recent American Academy of
Ophthalmology meeting in New Orleans, Dr. trattler said a small
percentage of LASIK and LASEK patients have excellent daytime vision,
but have experienced significant nighttime vision problems.
"It makes sense that pupil size is a risk factor for nighttime vision
problems since the treatment for night vision problems is to constrict
the pupil with Alphagan (brimonidine tartrate ophthalmic solution
0=2E15%, Allergan, Irvine, Calif.), dilute pilocarpine (various
manufacturers), or even leaving the interior light on while driving in
a car," Dr. trattler said.
Other observations from Dr. trattler's study using the Larson
Glarometer (Bruce Larson, M.D., manufacturer) to quantify the size of
the starburst phenomena on patients who have undergone LASIK or LASEK
on the VISX laser include the following:
=B7 The risk of significant night-time vision problems increases for
large pupil patients as their level of preoperative myopia increases;
=B7 The risk of night-time vision problems can be reduced in large
pupil patients by using the VISX wavefront-guided treatments; and
=B7 In a comparison of eyes that underwent LASIK versus LASEK - the
LASIK eyes had a larger average starburst score when controlling for
pupil size and level of pre-operative myopia. (presented at the LASEK
Congress in 2003 in Cleveland by Dr. Larson.)
Methods and results
Drs. trattler and Larson studied patients that previously underwent
LASIK or LASEK with the VISX S3 or S4 laser with "large zones" and
"transition zone" settings. All patients were operated on by the
same surgeon (WT) and had uncomplicated refractive surgery and had a
post-op best corrected visual acuity of 20/25 or better.
A total of 123 eyes were reviewed. The average time between the surgery
and eye exam was 11.5 months. The radius of the starbursts was measured
by having patients report their levels of starburst with the Larson
Glarometer in darkness.
Source: William trattler, M.D.Patients with larger pupils tended to be
younger, Dr. trattler said. The average age for the large pupil
patients in the study was 31.4, while the small pupil patients had an
average age of 42.1
Patients were grouped by pupil size (6 mm or less versus 7 mm or more),
then broken down by low myopia (less than 3.5 D), moderate myopia (3.51
D to 6.5 D) and high myopia (6.51 D or higher). The starburst radius
was measured in mm.
"For the low myopes, the starburst radius was 9.4 mm for the small
pupil size patients, while patients with large pupils had a starburst
radius of 16.7 mm," Dr. Trattler said. "If you look at the high
myopes, the starburst radius remained low - 9.2 mm for the small
pupil patients, but was 24.3 mm for the large pupil patients." Dr.
trattler added that these were average scores-some patients scored
higher while others scored lower.
Another way to look at the data was to determine the percentage of eyes
that had a starburst radius of 20 mm or more. For the low myopia group
(less than 3.5 D of myopia), only 16.0% of the small pupil patients had
a starburst radius of 20 mm or more, while 60% of the large pupil
patients had a starburst score of 20 mm or more. For the high myopia
group (6.5 D or more), 15.3% of the small pupil patients had a
starburst radius of 20 mm or more, while 86.6% of the large pupil
patients had a starburst score of 20 mm or more.
Results useful in measuring starburst risk
Pupil size appears to be an important pre-op measurement prior to laser
refractive surgery, Dr. trattler said, as it is useful in identifying
patients who are at increased risk for nighttime vision problems.
Dr. trattler is currently finalizing the starburst results of patients
who have undergone wavefront-guided treatments, which he will be
presenting at ASCRS. The preliminary results show that wavefront-guided
treatments on the VISX laser reduce the size of starbursts as compared
to similar eyes treated with conventional treatments.
Editors' note: Dr. trattler has no financial interests related to his
comments. Dr. Larson has a financial interest in the Larson Glarometer.
At press time, this study was being prepared for submission to Cornea.
Contact Information
Larson: 630-325-5200, fax 630-325-5569, bclmd293@aol.com
trattler: 305-598-2020, fax 305-274-0426, wtrattler@earthlink.net
|