DSAEKにおける角膜不正乱視の検討

Evaluation of Biomechanical
Characteristics in Penetrating
Keratoplasty by Trephine
Blade and Femtosecond Laser
Koichi Wakimasu1, Osamu Hieda2, and Shigeru Kinoshita2
1Baptist
Eye Clinic, Kyoto, Japan.
2Department of Ophthalmology, Kyoto Prefectural University of Medicine,
Kyoto, Japan.
The authors have no financial interests in the subject matter of this poster.
Background
• Recently, zig-zag penetrating keratoplasty
(z-PKP) by use of a femtosecond laser has
become available.
• z-PKP is expected to increase postoperative
corneal strength more than penetrating
keratoplasty by trephine blade (t-PKP).
Form of the Zig-Zag Cut
7.2mm
30°
Anterior Side Cut
Ring Lamellar Cut
30°
Posterior Side Cut
6.6mm
8.3mm


Ring Lamellar Cut: depth 300 μm, width 1.00 mm
The start position (depth) of the cut is in the anterior chamber for
the donor, and at the thinnest corneal endothelium for the recipient.
z-PKP
anterior segment OCT（Visante™）
t-PKP
Corneal Biomechanics
• Objects are deformed by pressurization, and attempt to
return to their original shape through decompression.
• Viscoelastic bodies have a
deformation
different deformation process
between pressurization and
decompression.
= “hysteresis”
pressure
Ocular Response AnalyzerTM (ORA, Reichert)
first “inward” applanation
second “outward” applanation
(pressurization)
(decompression)
applanation signal
P1
pressure
P2
*
*corneal hysteresis (CH) = P1-P2(mmHg)
#corneal resistance factor (CRF) = P1-k1P2(mmHg);
parameter considered to be more related to the corneal elastic resistance than CH
Purpose
• To evaluate corneal biomechanics
after t-PKP and z-PKP.
Patients and Methods
Corneal
IOP(mmHg)
Thickness(μm)
M/F
Age
t-PKP (23 eyes)
12 / 9
72.9±10.8
586±63
12±4
z-PKP (10 eyes)
6 / 4
67.2±12.6
568±48
15±5
DSAEK (6 eyes)
2 / 4
66.7±17.1
635±50
15±6
Control (27 eyes)
6 / 21
73.6±6.8
564±20
14±3
・ IntraLase FS-60TM in 7 eyes and iFS in 3 eyes (AMO) were used for femtosecond laser.
・ There was no significant difference in age, corneal thickness , and IOP between each group.
・ CH and CRF were measured by ORA more than 6 months after keratoplasty,
and after removal of the running suture in t-PKP and z-PKP.
Results 1: CH
CH
(mmHg)
10
t-PKP ：8.29±1.53mmHg
z-PKP ：9.75±1.76mmHg
5
(p < 0.05)
DSAEK ：9.95±1.45mmHg
(p < 0.05)
control ：10.7±1.43mmHg
(p < 0.0001)
0
t-PKP
z-PKP
DSAEK
control
・ CH of t-PKP was significantly lower than that of z-PKP, DSAEK, and the Controls.
Results 2: CRF
CRF
(mmHg)
10
t-PKP ：7.73±2.29mmHg
z-PKP ：9.77±2.41mmHg
5
DSAEK ：9.93±3.62mmHg
(p < 0.05)
control ：9.90±1.58mmHg
(p < 0.05)
(p < 0.01)
0
t-PKP
z-PKP
DSAEK
control
・ CRF of t-PKP was also significantly lower than that of z-PKP, DSAEK, and the Controls.
References
<CH>
t-PKP
results
8.29
1)
10.16
2)
8.9
3)
8.95
control
10.7
11.43
10.6
9.78
<CRF>
t-PKP
control
results
7.73
9.90
1)
9.94
11.53
2)
8.1
10.2
3)
10.26
9.75
1)Yenerel NM, et al. Cornea 2010;29:1247-51.
2)Laiquzzaman M, et al. Clinical and Experimental Ophthalmology 2010;38:758-63.
3) Joo Young Shin, et al. Korean J Ophthalmology 2010;24:139-142.
Discussion
・Corneal strength after penetrating keratoplasty
by trephine blade is considered to be less than
that of the normal eye and of after DSAEK.
・Corneal strength after zig-zag penetrating
keratoplasty by femtosecond laser is close to that
of the normal eye and of after DSAEK.

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