·Letter to
the Editor ·Current Issue· ·Achieve· ·Search
Articles· ·Online
Submission· ·About IJO·
Case report of
unilateral electric cataract with transmission electron microscopy image
Li Zhang, Kai Zhang, Ya-Nan Zhu, Qi-Wei
Wang, Ke Yao
Eye Center, the Second Affiliated Hospital, Medical School of Zhejiang
University, Hangzhou 310009, Zhejiang Province, China
Correspondence to: Ke Yao. Eye Center, the Second Affiliated
Hospital, Medical School of Zhejiang University, Hangzhou
310009, Zhejiang Province, China. xlren@zju.edu.cn
Received:
2015-05-06
Accepted: 2015-08-26
DOI:10.18240/ijo.2016.04.27
Zhang L, Zhang K, Zhu YN, Wang QW, Yao K.
Case report of unilateral electric cataract with transmission electron
microscopy image. Int
J Ophthalmol 2016;9(4):636-637
Dear Sir,
We hereby report a case of unilateral electric cataract with transmission
electron microscopy (TEM) image. Ocular injuries induced by electricity can
occur simultaneously or sequentially with the electric event, and occasionally
occur later than the initial event. There are many ocular manifestations, with
the most common one being cataract formation[1]. To provide a better understanding of electric
cataract, we present this case of unilateral electric cataract with the outcome
of TEM examination. To our knowledge, this is the first report about
ultrastructural changes after curvilinear capsulorhexis.
An 18-year-old male presented with painless progressive decreased visual
acuity in left eye for one year. He sustained an electric shock when
accidentally touched a high-voltage electric transmission wire with 10000 V
alternating current by left hand two and a half years ago. The patient remained
unconscious for 1h after the injury with skin burns in left scalp and left
hand. He was admitted to a local hospital for management. There was no sign of
visual loss and other eye irritation and no ocular examination was performed
then. One year ago, patient noticed decreased visual acuity with a white spot
in left pupil area. Patient had no family history or other secondary causes of
cataract such as previous ocular trauma, ocular disease or systemic disease.
General physical examination showed obvious scars on left scalp, left hand
and left eyelid (Figure 1). The scar on left scalp was clear edge, narrow with
alopecia, measuring 5 cm without hair growth. There were two small round scars
on the back of left hand (Figure 1C). Ophthalmologic examination revealed best
corrected visual acuity (BCVA) of 20/20 in right eye and counting figures at 50
cm in left eye. There were also 15° exotropia with mild lower-eyelid
entropion in left eye. Slit-lamp examination of anterior segment of left eye
was unremarkable besides a milky-white cataract with flat, irregular,
snowflake-like anterior subcapsular opacities in left lens. Both direct and
indirect pupillary light reflexes were normal. The view of left fundus was
occluded by cataract. There was no abnormality identified in right eye.
Intraocular pressures (IOP) were 18.5 mm Hg in right eye and 19.0 mm Hg in left
eye. Ultrasound examination of left eye showed an intact globe with clear
vitreous and flat retina.
Fgure 1. An 18-year-old male presented with
progressive decreased visual acuity
A: The left eye shows cataract with subcapsular opacities; B: Left
scalp shows clear boundary, narrow scar; C: Left hand with 2 small round scars
(white arrow).
Based on the history of electric shock with a high voltage wire, skin
burns, typical appearance and location of lens opacities and no previous
systemic disease or ocular trauma, electric cataract was then diagnosed.
Phacoemulsification surgery was performed and a piece of intraocular lens (IOL)
was implanted into posterior chamber (+21.5 diopters; Bausch&Lomb Adapt-AO,
Rochester, New York, USA). During the surgery, we got a better view of the
anterior subcapsular opacities and anterior capsular was collected after
continuous curvilinear capsulorhexis. Interestingly, we found that the cataract
was loose, agglomerated-milk like, without solid nuclear, which could be
removed easily by aspiration.
The BCVA of left eye improved to 20/20 after surgery. Ultrasound
biomicroscopy revealed that the IOL was stable and well centered in the bag.
The fundus photograph found no abnormality. Optical coherence tomography (OCT)
examination revealed a normal retina and macular structure. Anterior lens
capsule with attached lens epithelial cells (LECs) were obtained by continuous
curvilinear. Tissue was further fixed as described previously[2] and examined under TEM (Model
H-7650, Hitachi, Baraki Prefecture, Japan). Ultrastructure of LECs was compared
between the electric cataract and an age-related cataract (Figure 2). Both
anterior capsule were of normal thickness and homogenous in structure. In
age-related cataract, LECs maintain single-layer structure with signs of
nuclear condensation, cytoplasmic degeneration and significant intracellular
vacuolization (Figure 2B, 2D). In electric cataract, the cell membrane was
continuous with extracellular space between cells (Figure 2A). The size of
nucleus was similar to age-related cataract but elongated in shape. Cytoplasm
of LECs was less and contained mitochondria, rough endoplasmic reticulum and
other organelles. Unlike age-related cataract, there were individual cells
containing plenty of collagenous fibrils with the presence of lipid particles,
lipofusin (Figure 2C).
Figure 2 TEM result of anterior capsular
obtained from electric cataract and age-related cataract A: LECs with
elongated nucleus and less cytoplasm were found in electric cataract with
enlargement extracellualr gap between cells andcontinous cell membrane (white
arrow), mitochondria (asterisk) and rough endoplasmic reticulum (R) in
cytoplasm (12000×); B: LECs maintain single layer structure with cytoplasmic
vacuoles in age-related cataract (4000×); C: Individual cells containing plenty
of collagenous fibrils (black arrow) with the presence of lipid particles
(black triangle), lipofusin (white arrow) and significant edema of mitochondria
(asterisk) in electric cataract(20000×); D: LECs with nuclear condensation and
multiple cytoplasmic vacuoles in age-related cataract (8000×).
The high water content and its surroundings of the crystalline lens make
it a good conductor of electric current. Anterior subscapular opacities are
common change in recently reported cases[1,3],
which is considered to be caused by metaplasia of the epithelium, producing
capsular wrinkling and a fibrous plaque over the visual axis[4]. Our report aims to
provide further understanding of the mechanism of electric cataract by
comparing the ultrastructure with age-related cataract. In age-related
cataract, LECs cells present typical apoptosis with nuclear condensation,
cytoplasmic degeneration and intracellular vacuolization, which were similar as
previous studies[2]. TEM
examination of AC opacity collected from this patient revealed elongated LECs
with distinguishable intracellular organelles. Individual cells with
collagenous fibrils were also observed beneath the central AC[5]. The ultrastructure
changes of LECs from electric cataract suggested elongation of LECs and scar tissue
formation[3]. The
ultrastructure difference between electric and age-related cataract might be
due to different pathological process. In age-related cataract, LECs went
through apoptosis with years of exposure to risk factors. However, electric
current cause the damage to LECs in a comparatively short term. Electricity can
directly cause pore formation in the lipid bilayers that form cell membranes[6]. When the strength of
voltage or the number of pulses reaches a threshold, the membrane is broken down
permanently thereby inducing cell death and thereafter, cellular and tissue
debris triggers local or systemic inflammation and immunoreaction. Secondary
injury processes may be disruptive or even fatal to the cell[7].
Cataractogenesis following electrical trauma usually occur with a latency
period varying from immediately after injury to years[3,5]. Detailed ocular examinations with careful
follow-up are required to patients with electrical injuries near head, neck or
shoulder. Additional longitudinal studies are needed to determine the
progression of electrical injuries and the mechanism of electric cataract over
time.
ACKNOWLEDGEMENTS
Thanks to Dr. Jun-Ying Li, Analysis and Testing
Center, Zhejiang University, for generous suggestions.
Foundations:
Supported by the Medical Health Science and Technology Plan Project of Zhejiang
Province (No. 2012KYB090); the Fundamental Research Funds for the Central
Universities (No. 2015FZA7008).
Conflicts of
Interest: Zhang L, None; Zhang K, None; Zhu YN, None; Wang QW,
None; Yao K, None.
REFERENCES [Top]
1 Grewal DS, Jain R, Brar GS, Grewal SP. Unilateral
electric cataract: Scheimpflug imaging and review of the literature. J Cataract Refract Surg 2007;33(6):1116-1119.
[CrossRef] [PubMed]
2 Shentu XC, Zhu YN, Gao YH, Zhao SJ, Tang YL. Electron
microscopic investigation of anterior lens capsule in an individual with true
exfoliation. Int J Ophthalmol 2013;6(4):553-556.
[PMC free article]
[PubMed]
3 Hashemi H, Jabbarvand M, Mohammadpour M. Bilateral
electric cataracts: clinicopathologic report. J Cataract Refract Surg 2008;34(8):1409-1412. [CrossRef] [PubMed]
4 Al-Ghoul KJ, Kuszak JR. Anterior polar cataracts in CS
rats: a predictor of mature cataract formation. Invest Ophthalmol Vis Sci 1999;40(3):668-679. [PubMed]
5 Hanna C, Fraunfelder FT. Electric cataracts. II.
Ultrastructural lens changes. Arch
Ophthalmol 1972;87(2):184-191. [CrossRef]
[PubMed]
6 Teissie J, Golzio M, Rols MP. Mechanisms of cell
membrane electropermeabilization: a minireview of our present (lack of ?)
knowledge. Biochim Biophys Acta
2005;1724(3):270-280. [CrossRef]
[PubMed]
7 Zhou W, Xiong Z, Liu Y, Yao C, Li C. Low voltage
irreversible electroporation induced apoptosis in HeLa cells. J Cancer Res Ther 2012;8(1):80-85. [CrossRef] [PubMed]
[Top]