Alteration of Anterior Chamber Angle after Implantation of Irisfixated Phakic Intraocular Lens

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Alteration of Anterior Chamber Angle after
Implantation of Iris-fixated Phakic Intraocular
Lens

• Takefumi Yamaguchi, Kazuno Negishi, Megumi Saiki,
  Kenya Yuki,
• Nanae Kawaguchi, Kazuo Tsubota
• Keio University, School of Medicine

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Introduction

• The iris-fixated PIOL implantation has been
  proved to be a effective and predictable
  refractive technique for treatment of high
  myopia. However, severe postoperative
  complications have been reported.
• One of the concerns is that PIOLs inevitably
  cause some postoperative intraocular structure
  change pupil ovalization, anterior chamber
  depth, and crystalline lens rise.
• We evaluated the ACA after PIOL implantation.

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Objective

• We evaluated the alteration of anterior chamber
  angle (ACA) after implantation of iris-fixated
  intraocular lens (PIOL) for myopia and its
  postoperative effects on anterior chamber
  structure and inflammation.

Subjects
Twenty eyes of 11 patients (7 female and 4
males) The mean age 38.411.1years old (2658)
The mean preoperative spherical equivalent
9.84.5 D (-18.25-2.25D)
(Artisan Model 204 were implanted
for myopia in all eyes.)
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Methods

• The Scheimpflug image was obtained before and 1
  month after implantation of PIOL using the
  Pentacam (Oculus, Germany). The angle at 2, 3, 4,
  8, 9, 10 oclock were measured by a protractor.

Data Analysis
Alteration of ACA (?ACA) Postoperative
intraocular pressure (IOP) at 1 month Effects
of ?ACA on change in anterior chamber depth (ACD)
and anterior chamber volume (ACV)
Postoperative flare at 1 month and 1 year
measured by laser flarimetry (FC-2000, Kowa,
Tokyo, Japan)
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Example of the Scheimpflug image after
implantation of iris-fixated PIOL
A
B
The anterior chamber angle is narrowed near the
iris-fixation point (A) compared with the other
points (B).
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Pre- and postoperative ACA
degree
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Alteration of ACA
N20
?ACA(preoperative ACA) (postoperative ACA)
ACA Anterior chamber angle
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Pre- and postoperative IOP
IOP
There was no significant difference between
before and after surgery. (pgt0.05)
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Effects of ?ACA on ACV and ACD
?ACV mm3
?ACD mm3
P0.74
P0.08
degree
degree
?ACA
?ACA
?ACV(Preoperative ACV) (Postoperative ACV)
ACA Anterior chamber angle ACVAnterior chamber
volume ACDAnterior chamber depth
?ACD(Preoperative ACD) (Postoperative ACD)
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Postoperative flare and ?ACA
1 month after surgery
1 year after surgery
(photons/mm2)
(photons/mm2)
p0.0071
p0.004
degree
Correlation between ?ACA and aqueous flare A, 1
month and B, 1 year after surgery.
(Pearsons correlation coefficient A, r0.573,
p0.0071 1 month B, r0.700, p0.004 1 year
after surgery.)
?ACA (average preoperative ACA) (average
postoperative ACA) (degree) ACA anterior
chamber angle
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Discussion

• Partial narrowing of the angle near the
  fixation points was induced by implantation of
  the iris-fixated PIOL and that postoperative
  acute and chronic anterior chamber inflammation
  had a significant correlation with the amount of
  the alteration of the angle.
• The angle alteration was thought to be caused
  by pinching the iris by the claw of the PIOL.
  However the amount of the angle alteration varied
  between individuals. The difference between
  patients could be due to surgical factors such as
  the amount of pinched iris and the position of
  the PIOL, and the individual patients factors
  such as iris hysteresis (stiffness of the iris).
  Further evaluation of the iris change is
  necessary for the iris-fixated PIOL and other
  types of phakic IOLs.

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Conclusion

• Partial narrowing of the ACA was induced
  after implantation of PIOL for high myopia, which
  is correlated with postoperative acute and
  chronic anterior chamber inflammation.
• It would be desirable to observe ACA over
  long-term, especially in patients with large
  angle alterations.