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Calcium Precipitation on the Optical Surfaces of a Foldable Intraocular Lens: A Clinicopathological Correlation
Arch Ophthalmol. 2002;120:391-393.
An intraocular lens (IOL) (Hydroview; Bausch & Lomb, Rochester,
NY) developed late postoperative opacification of its optical surface, causing
significant visual symptoms that required explantation. The lens was processed
in our laboratory, and the lens optic, composed of a hydrophilic acrylic polymer,
was stained with alizarin red and the von Kossa stain for calcium. The lens
also underwent scanning electron microscopy and energy dispersive x-ray spectroscopy
of its anterior optical surface. These analyses revealed that the opacity
was caused by deposition of calcium phosphate on the lens surface. This process
appeared to be dystrophic calcification of unknown cause.
Recent reports of IOL calcification have raised concerns regarding the
long-term biocompatibility of 2 modern hydrophilic acrylic foldable lenses:
the Bausch & Lomb Hydroview IOL and the Medical Developmental Research
(Clearwater, Fla) SC60B-OUV.1-3
In this study, we describe the typical appearance of late postoperative opacification
of the former lens with pathological confirmation of IOL calcification.
Report of a Case
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An 80-year-old man underwent uneventful phacoemulsification of the left
eye and capsular bag fixation of a Hydroview IOL model H60M by one of us (J.P.G.).
The patient had a history of rheumatoid arthritis and type 2 diabetes mellitus.
The IOL was implanted in the capsular bag under viscoelastics (Viscoat; Alcon
Surgical, Fort Worth, Tex). The intraoperative irrigating solution used was
balanced salt solution with adrenaline (1:1000). Subconjunctival injections
of gentamicin sulfate and betamethasone sodium phosphate were performed at
the end of the procedure. Postoperatively, tobramycin and prednisone ophthalmic
drops were tapered over 4 weeks. The best-corrected visual acuity 1 month
postoperatively was 20/30 OS.
The patient noted a marked loss of vision associated with intense glare
16 months postoperatively. The best-corrected visual acuity was reduced to
light perception. Slitlamp examination of the anterior segment revealed a
dusty haze or granularity present on the optical surfaces of the lens (Figure 1). Evaluation of the posterior segment
was not possible because of hazy media secondary to IOL opacification. As
attempts to clear the optical surfaces of the IOL with the Nd:YAG laser were
not successful, the IOL was explanted 20 months postoperatively. It was freed
from the surrounding capsule by viscodissection and then removed through a
6.0-mm sclerocorneal tunnel. A rigid polymethyl-methacrylate IOL model P 359
(Bausch & Lomb) was placed in the capsular bag. Incisional biopsies of
conjunctiva and iris were performed during IOL removal and exchange to rule
out the presence of dystrophic calcification in those tissues. The patient's
visual acuity improved to 20/400 with absence of glare immediately after the
IOL exchange. Evaluation of the posterior segment at this stage revealed presence
of severe nonproliferative diabetic retinopathy. However, the best-corrected
visual acuity decreased to light perception after 2 months' follow-up because
of the worsening of the diabetic retinopathy/maculopathy, which was further
investigated and treated in consultation with a retina specialist.
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Figure 1. Slitlamp photograph of an implanted
Hydroview intraocular lens (Bausch & Lomb, Rochester, NY) with a granularity
present on the optic.
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Gross and microscopic analyses of the explanted IOL were performed,
and photographs were taken to document the findings. The IOL was then bisected
for histochemical and scanning electron microscopic evaluation. For histochemical
analysis, one half of the IOL was rinsed in distilled water, immersed in a
1% alizarin red solution for 2 minutes, rinsed again in distilled water, and
reexamined under the light microscope. A slice of the optic of the Hydroview
IOL was performed, the resultant cylindrical block was dehydrated and embedded
in paraffin, and sagittal sections were performed. Special stains included
the von Kossa stain for calcium.4-5
The other half of the lens optic was air-dried at room temperature for 7 days,
sputter-coated with aluminum, and examined under a 2500 Delta scanning electron
microscope (Nissei Sangyo America, Schaumburg, Ill) equipped with a Kevex
(Scotts Valley, Calif) x-ray detector. The conjunctival and iris tissue were
also prepared for histological/histochemical examination and stained with
the alizarin red/light green and von Kossa methods.
Pathologic Findings
Gross evaluation revealed that the optical surfaces of the unstained
IOL were covered by a layer of irregular granular deposits. The deposits occurred
on both anterior and posterior optical surfaces, but not on the haptics (Figure 2). They stained positive with alizarin
red (Figure 3). Sagittal sections
of the optic of the IOL stained using the von Kossa method were positive,
showing a continuous layer of dark brown, irregular granules on all surfaces
(anterior, posterior, and edges) of the lens (Figure 4). Scanning electron microscopic analysis of the optic's
anterior surface revealed granular deposits composed of multiple spherical-ovoid
structures (Figure 5). Energy dispersive
x-ray spectroscopy performed on the surface shown in Figure 5 revealed a high peak for calcium and a lesser peak for
phosphate (Figure 6). Histochemical
evaluation of the conjunctival and iris biopsy specimens, using alizarin red
stain and von Kossa silver stain, did not reveal any evidence of calcium salts
(Figure 7).
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Figure 2. Photomicrograph of the explanted
opacified Hydroview intraocular lens (Bausch & Lomb, Rochester, NY) showing
the confluent deposits on the anterior optical surface. The polymethyl-methacrylate
haptics are free of any deposits (original magnification x100).
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Figure 3. Photomicrograph of the bisected
Hydroview intraocular lens (Bausch & Lomb, Rochester, NY) with the optical
surface stained positive (alizarin red, original magnification x20).
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Figure 4. Photomicrograph of a sagittal
section through the optic of the Hydroview intraocular lens (Bausch &
Lomb, Rochester, NY). The lens material was dissolved during the preparation
for histological examination, but the optical edge is delineated by a continuous
layer of dark brown, irregular granules (von Kossa stain, original magnification
x200).
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Figure 5. Scanning electron photomicrograph
from the anterior optical surface of the Hydroview intraocular lens (Bausch
& Lomb, Rochester, NY). The deposits are composed of multiple globules
of variable sizes (original magnification x800).
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Figure 6. Energy dispersive x-ray spectrum
from the Hydroview intraocular lens (Bausch & Lomb, Rochester, NY) (coated
with aluminum) with peaks of calcium (Ca) and phosphate (P) (arrows) at the
level of the granular deposits. S indicates sulfur; O, oxygen; Na, sodium;
and Al, aluminum.
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Figure 7. Photomicrographs from the histological
sections of the conjunctiva (A) and iris (B). No dystrophic calcification
was observed in the sections (alizarin red/light green, original magnification
x200).
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Comment
We have recently reported on the lens described here, the Bausch &
Lomb Hydroview,1-2 as well
as another hydrophilic IOL, the Medical Developmental Research SC60B-OUV.3 With both lens designs, the opacification appears
to be related in part to calcium deposition on the external optical surfaces
(in the case of the Hydroview) or within the IOL optic (in the case of the
SC60B-OUV). Our first publication on calcification of the Hydroview design
reported on 1 explant from Australia and 4 explants from Sweden.2
This is the first report of calcification of Hydroview lenses observed in
Canada. As in the previous cases, the dystrophic calcification was limited
to the external optical surfaces of the lens. In the case reported here, the
absence of dystrophic calcification in ocular anatomical structures of the
patient, such as conjunctiva and iris, was confirmed histopathologically.
More than 400 000 Hydroview lenses have been implanted in 4000 centers
worldwide. We are aware of 272 similar cases of late postoperative opacification,
from which 83 lenses were explanted because of significant visual impairment.
These reports have been clustered in 29 centers, including Hong Kong, Canada,
Sweden, Germany, and Australia, among others. One of us (J.P.G.) has explanted
several Hydroview IOLs for similar reasons. Although the composition of the
deposits has been determined to be hydroxyapatite, the pathogenesis of this
complication is still obscure. Awareness of this condition is warranted as
Nd:YAG laser treatment does not seem to be helpful in removing the deposits
from the lens surfaces and possibly damages the surrounding capsule, compromising
in-the-bag fixation of a new IOL after explantation of the opacified lens.
AUTHOR INFORMATION
This study was supported in part by an unrestricted grant from Research
to Prevent Blindness Inc, New York, NY.
This study was presented in part at the annual meeting of the American
Academy of Ophthalmology, Dallas, Tex, October 24, 2000.
We thank Joyce Edmonds, HTL (Storm Eye Institute), who provided assistance
with histochemical analysis, and Dana G. Dunkelberger, PhD (Electron Microscopy
Center, University of South Carolina, Columbia), who kindly provided assistance
with surface analysis.
Suresh K. Pandey, MD;
Liliana Werner, MD, PhD;
David J. Apple, MD
Charleston, SC
Jean-Pierre Gravel, MD
Quebec City, Quebec
Corresponding author and reprints: Liliana Werner, MD, PhD, Department
of Ophthalmology, Storm Eye Institute, Medical University of South Carolina,
167 Ashley Ave, PO Box 250676, Charleston, SC 29425-5536 (e-mail: wernerl{at}musc.edu).
REFERENCES
1. Apple DJ, Werner L, Escobar-Gomez M, Pandey SK. Deposits on the optical surfaces of Hydroview intraocular lenses [letter]. J Cataract Refract Surg. 2000;26:796-797.
ISI
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2. Werner L, Apple DJ, Escobar-Gomez M, et al. Postoperative deposition of calcium on the surfaces of a hydrogel intraocular
lens. Ophthalmology. 2000;107:2179-2185.
FULL TEXT
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3. Werner L, Apple DJ, Kaskaloglu M, Pandey SK. Dense opacification of the optical component of a hydrophilic acrylic
intraocular lens: a clinicopathological analysis of 9 explants. J Cataract Refract Surg. 2001;27:1485-1492.
FULL TEXT
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4. McGee-Russell SM. Histochemical methods for calcium. J Histochem Cytochem. 1958;6:22-42.
ABSTRACT
5. Carr LB, Rambo ON, Feichtmeir TV. A method of demonstrating calcium in tissue sections using chloranilic
acid. J Histochem Cytochem. 1961;9:415-417.
ABSTRACT
SECTION EDITOR: W. RICHARD GREEN, MD
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