Corneal Endothelial Cell Changes After LASIK Using a Femtosecond Laser

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Shinagawa LASIK Center
Corneal Endothelial Cell Changes After LASIK
Using a Femtosecond Laser
Minoru Tomita, MD, PhD, Masaru Aoyama, MD,
Tadayuki Nakamura, MD, Nobuo Nakamura, MD, PhD,
Tadahiko Tsuru, MD, PhD
Shinagawa Lasik Center, Tokyo, Japan
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Shinagawa LASIK Center
Purpose
LASIK with Femtosecond Laser (FS laser) has been
widely performed all over the world. However,
the influence of the LASIK with FS Laser on the
corneal endothelial cell density (ECD) has not
been fully reported yet. In this study, we
examined the changes of ECD after LASIK. In
addition, we reported the effects of anterior
chamber gas bubble (AC-bubble) formed during FS
laser operations on ECD.
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Shinagawa LASIK Center
Subjects and Methods 441 eyes of 225 patients
who underwent Intra-LASIK using Intralase FS60
(American Medical Optics) were enrolled. The
preoperative and postoperative (3 months) ECD was
examined by NONCON ROBO FA-3509(KONAN), and
pre/post-operative ECD was statistically
studied. Pre/post-operative visual acuity and
refractive power were also examined. ALLGRETTO
WAVE Eye-Q 400 Hz (WAVELIGHT) was used for
Excimer Laser ablations.
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Shinagawa LASIK Center
Patients ages 32.37.04 years (MeanSD)
Preoperative Data
Mean UCVA 20/25, Mean BSCVA 20/12.5 Sphere
-5.002.23D, Cylinder -1.090.93D
Number of ECD2942124 cells/mm2
Postoperative Data
Mean UCVA 20/12.5, Mean BSCVA 20/12.5 Sphere
-0.130.59D, Cylinder -0.510.32D
3 Months Postoperative Effective
coefficient0.99, Safety coefficient1.05
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Shinagawa LASIK Center
Correction Formula for the Post-Operative ECD
Power of Figure R1(1/n)(t1?K?tK2) ?t t1 -
t2 ?K K1 -K2
CD 1/R2
K the refractive power of the cornea, n the
refractive index of cornea t the central
thickness of the cornea, CD the changes of cell
density R the postoperative/preoperative
magnification ratio of the image
Uosato et alJ.Cataract Refract Surg
291543-1545 2003.
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Shinagawa LASIK Center
Mean Postoperative (3 Months) ECD After
Correction 2927117 cells/mm2
Change of Preoperative/Postoperative ECD

Preoperative ECD Postoperative ECD with
compensation
-16102 cells/mm2

Decreased by approx. 0.53
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Shinagawa LASIK Center
Previous Reports on ECD Changes After LASIK
Mean reduction rate of ECD at 1 year after
LASIK 1.54.
Simoroj et al J Refractive Surg 200319S237-240.
Mean reduction rate of ECD at 3 months 1.
Jones et al Am J Ophthalmology 1998125465-471.
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Shinagawa LASIK Center
Discussions

1. The mean reduced rate after LASIK with FS Laser
   was 0.53. No significant differences on ECD
   values between Preoperative and Postoperative(
   with compensated) (t-test Pgt0.05)

2. Although previous findings using microkeratome
reported approx. 1.0 - 1.5 decrease in ECD,
Intralase using FS Laser has less reduction rate,
thus confirmed as a safer method.
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Shinagawa LASIK Center
Aberration of gas bubbles into Anterior Chamber
(AC-bubble)
As for the cases with the small corneal diameter,
when the laser crosses over the blood vessel
around the cornea peripherals, gas gets mixed
into anterior chamber.
Lifshitz T et al. J cataract Refract Surg. 2005
31 2227-9.
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Shinagawa LASIK Center
Effects of AC-bubble on ECD
We also examined whether AC-bubbles make ECD
changes.
Subjects and Methods
24 eyes of 18 patients who developed AC-bubble
during flap preparation with Intralase FS60 were
examined. The Preoperative/Postoperative (3
months) ECD was statistically compared.
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Shinagawa LASIK Center
Comparison of ECD (cells/mm2) and AC-bubble
Preoperative ECD (cells/mm2)
Postoperative (3 months) ECD (cells/mm2)
AC-bubble(-) AC-bubble ()
2942124 (n 441 )
2927117 (n 441 )
2920130 (n 24 )
2901120 (n24 )
No significant differences were observed between
the groups of AC-bubble(-) and AC-bubble() in
terms of ECD before or after LASIK at 3 months
(Pgt0.05)
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Shinagawa LASIK Center
Summary

1. The average decrease of ECD was 0.5 at 3 months
   after LASIK with FS laser. No significant
   decrease of ECD was found by LASIK with FS laser.
2. No significant differences were recognized in
   Preoperative and Postoperative ECD even when
   AC-bubble was formed during flap preparations
   with FS laser.

Acknowledgments Thank you for good help and
jobs. Ms. Tomomi Kanamori, Ms. Yuko Yoshida, and
Ms. Naoko Inoue