Different Forms of Optic Opacification

1

Different Forms of Optic Opacification Leading
to Explantation of the MemoryLens
Designs Liliana Werner, MD, PhD1,2 Nick
Mamalis, MD1 Manfred Tetz, MD2 1 John A. Moran
Eye Center, University of Utah, Salt Lake City,
UT, USA 2 Berlin Eye Research Institute, Berlin,
Germany

-The authors have no financial or proprietary
interest in any product mentioned in this
poster -Supported in part by the Research to
Prevent Blindness Olga Keith Wiess Scholar Award
(to Liliana Werner, MD, PhD)
2
Background

• The MemoryLens (Duluth, GA, USA) is a pre-folded
  hydrophilic acrylic intraocular lens (IOL). It
  can be implanted directly from the container
  without any requirement of folding instruments.
  Following intraocular insertion, and under the
  influence of body temperature the lens unfolds
  slowly (approximately 15 minutes). The optic of
  the MemoryLens contains 59 of 2-hydroxyethyl
  methacrylate, 16 of methyl methacrylate, 4 of
  4-methacryloxy 2-hydroxy benzophenone ultraviolet
  absorber and 1 of ethylene glycol
  dimethacrylate. The haptics are made of Prolene.
  The MemoryLens has been in the international
  market since 1994, with good results in the first
  years of clinical use.1

3
Background

• Reports on traces of a polishing compound
  (aluminum oxide) on the MemoryLens causing
  postoperative inflammatory reactions in
  approximately 0.1 of the lenses implanted led
  the manufacturer to voluntarily withdraw the lens
  from the market in April 2000 (models U940A and
  U940S).2
• The lens was re-released in the market in
  September 2000 as model CV232, which has an
  incorporated square posterior optic edge for
  posterior capsule opacification prevention. The
  new CV232 model allows surgeons to place this IOL
  through a 3.2 mm incision, instead of the 3.7 mm
  wound necessary for implantation of the previous
  models.

4

• Starting in 1999, we analyzed at the John A.
  Moran Eye Center and the Berlin Eye Research
  Institute a significant number of the different
  models of the MemoryLens IOLs explanted because
  of optic opacification.3-6
• The objective of this poster is to review the
  different forms of opacification of the
  MemoryLens. Some forms were more specifically
  related to the older designs, than to the new
  design. Also, some patients still undergo
  unnecessary secondary procedures, including
  vitrectomies, because the conditions described
  here were not immediately recognized.

5
Materials/Methods

• Lenses More than 120 explanted MemoryLens IOLs
  of the older models (U940A and U940S), and the
  new CV232 model (with a square posterior optic
  edge).
• Interval implantation/explantation 25.8 /- 11.9
  months (range 3.3-80.7).
• Reasons for explantation Clinically significant
  whitish optic discoloration or localized optic
  defect.
• Laboratory analyses Gross and light microscopy
  histochemical stains for calcium (Alizarin Red
  and Von Kossa method) scanning electron
  microscopy (SEM) energy dispersive x-ray
  spectroscopy for analysis of elemental
  composition (EDS).

6

Results

• More than 110 explanted U940A and U940S had a
  fine granularity covering both surfaces of the
  IOL.
• Laboratorial analyses showed the composition of
  the deposits to be at least in part of calcium
  and phosphate.

A
B
C
D
A Clinical photograph (from Dr. Alan Crandall).
B Gross photograph. C Alizarin red stain. D
Von Kossa stain.
7

Results

• Analyses performed by the manufacturer revealed
  that a biofilm of different proteins, besides
  calcium/phosphate, was covering the optic
  surfaces of the affected lenses. The modified
  tumbling process used would have caused a change
  in the surface of the lenses, favoring biofilm
  formation. The tumbling process was discontinued,
  and, until recently (see later), no similar cases
  have been reported with the new lens design
  (CV232).

C
A
B

A and B SEM photomicrographs. C EDS spectrum
showing the presence of calcium (Ca) and
phosphate (P) within the surface deposits.
8

Results

• We are aware of at least 2 cases of explantation
  of the new MemoryLens design (CV232) because of
  optic opacification.
• The laboratorial features were similar to those
  found with the previous models, although some
  optic areas devoid of surface calcified deposits
  could be observed.

A
B
C

A Gross photograph. B Light photomicrograph. C
SEM photomicrograph showing the square posterior
optic edge (bottom left), and the round anterior
optic edge (top left) of the explanted CV232.
9

Results
A

• More recently, we analyzed cases where a
  localized defect was present within the optic of
  CV232 explanted IOLs. This had the aspect of a
  clear bubble in some cases, or a small lens
  within the lens.
• We are aware of other similar cases with the same
  lens design, but as the patients are
  asymptomatic, explantation was so far not
  necessary.

B

A Clinical photograph (Dr. William Smead). B
Light photomicrograph of the explanted CV232. The
arrows show the optic defect with the aspect of a
clear bubble.
10

Results

• However, in one of these cases, secondary
  opacification occurred within the optic defect.
  Laboratorial analyses revealed that there were
  calcified deposits distributed within the optic
  void, seen as a linear breach in sagittal cuts.
• Whether or not secondary calcification will occur
  within the optic void in all cases of optic
  defect at some point in the postoperative period
  is still unknown.

A
B
C
D
A Clinical photograph (Dr. James Memmen ). B and
C Light photomicrographs of the explanted CV232,
from anterior and sagittal views. D EDS spectrum
showing the presence of calcium (Ca) and
phosphate (P) within the intra-void deposits.
11

Discussion / Conclusions

• Some MemoryLens IOLs models U940A and U940S,
  manufactured in 1999 and 2000 were associated
  with a phenomenon of surface calcification.
• We are aware of at least 2 cases of a similar
  phenomenon of surface calcification occurring in
  MemoryLens IOLs model CV232. Also, some IOLs of
  this latter design exhibited an optic defect
  corresponding to a localized void, with secondary
  calcification in one of them.
• Despite previous reports detailing the
  opacification of hydrophilic acrylic IOLs, many
  ophthalmologists are not aware of this important
  clinical problem. Recognizing the calcification
  and opacification of these lenses will help
  prevent patients from undergoing unnecessary
  procedures and the increased risks of
  complications following repeated interventions.

12

References

• Potzsch DK, Losch-Potzsch CM. Four year follow-up
  of the MemoryLens. J Cataract Refract Surg 1996
  221336-1341.
• Jehan FS, Mamalis N, Spencer TS, et al.
  Postoperative sterile endophthalmitis (TASS)
  associated with the MemoryLens. J Cataract
  Refract Surg 2000 261773-1777.
• Neuhann IM, Werner L, Izak AM, et al. Late
  postoperative opacification of a hydrophilic
  acrylic (hydrogel) intraocular lens A
  clinicopathological analysis of 106 explants.
  Ophthalmology 2004 1112094-2101.
• Hunter B, Werner L, Memmen JE, Mamalis N.
  Postoperative localized opacification of the new
  MemoryLens design Analyses of an explant. J
  Cataract Refract Surg 2005 311836-1840.
• Haymore J, Zaidman G, Werner L, et al.
  Misdiagnosis of hydrophilic acrylic intraocular
  lens optic opacification Report of 8 patients
  with the MemoryLens IOL. Ophthalmology 2007 (in
  press).
• Werner L. MemoryLens IOL Review of recent
  post-op problems and current status.
  http//www.eyeworld.org/article.php?sid3224