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CHAPTER I
INTRODUCTION
The crystalline lens is a remarkable structure that in its normal state functions to
bring images into focus on the retina. Symptoms associated with lens disorders are
primarily visual. The lens is best examined with the pupil dilated. A magnified view
of the lens can be obtained with a slitlamp or by using the direct ophthalmoscope with
a high plus (+1! setting.1
The lens is a vital refractive element of the human eyes. "#resbyopic symptoms
are due to decreased accommodative ability with age and result in diminished ability
to perform near tasks. $oss of lens transparency results in blurred vision (without
pain! for both near and distance. %f the lens is partially dislocated (subluxation! due to
congenital& developmental& or ac'uired causes& visual blur can be due to a change in
refractive error. %n ""& the orld )ealth *rganiation estimated that lens pathology
(cataract! was the most common cause of blindness worldwide& affecting over 1,
million people across the globe. Senile cataract is a vision-impairing disease
characteried by gradual& progressive thickening of the lens. %t is one of the leading
causes of blindness in the world today. 1&"
%n %ndonesia cataract becomes the first rank that cause blindness. *f course
blindness will reduce productivity and cause many impairment to the patient. ataract
surgery is available in %ndonesia but low vision associated with cataracts may still be
prevalent& as a result of long waits for operations and barriers to surgical uptake& such
as cost& lack of information and transportation problems.
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CHAPTER II
LITERATURE REVIEW
2.1 Anatomy of the Lens
The lens is located behind the iris and pupil in the anterior compartment of the
eye. The anterior surface is in contact with the a'ueous on the corneal side/ the
posterior surface is in contact with the vitreous. The anterior pole of the lens and
the front of the cornea are separated by approximately 0.mm."
The lens is held in place by the onular fibers (suspensory ligaments!& which runbetween the lens and the ciliary body. These onular fibers& which originate from
the region of the ciliary epithelium& are a series of fibrillin-rich fibers that
converge in a circular one on the lens. 2oth an anterior and a posterior sheet
meet the capsule 13"mm from the e'uator and are embedded into the outer part
of the capsule (13"4m deep!. %t also is thought that a series of fibers meets the
capsule at the e'uator. "
Fi. 1 !"oss anatomy of the a#$%t h$man %ens
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2.2 Cata"a&t
A. Definition
The crystalline lens is a remarkable structure that in its normal state functions to
bring images into focus on the retina. 2ecause the lens is avascular and has no
innervation& it must derive nutrients from the a'ueous humor. 1
A cataract is present when the transparency of the lens is reduced to the point
that the patient5s vision is impaired. The term cataract comes from the 6reek
word katarraktes (downrushing/ waterfall!.0 A cataract is any opacity or
discoloration of the lens& whether a small& local opacity or the complete loss of
transparency. These ones of opacity may be subcapsular& cortical& or nuclear
and may be anterior or posterior in location. %n addition to of the nucleus and
cortex& there may be a yellow or amber color change to the lens. 7
A senile cataract& occurring in the elderly& is characteried by an initial
opacity in the lens& subse'uent swelling of the lens and final shrinkage with
complete loss of transparency.
8ig. " 9ormal lens and lens with cataract
'. E(i#emio%oy
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Age-related cataract is a common cause of visual impairment and responsible for
7:; of world blindness& which represents about 1: million people& according
to the orld )ealth *rganiation ()*!. %n ""& the orld )ealth
*rganiation calculated that the number of visually impaired people worldwide
was in excess of 1ye Study reported that
0:.:; of men and 7.?; of women older than ,7 years had visually significant
cataracts.
=eveloping countries also face other challenges such as poor uptake of services
because of a lack of patient information& misinformation from traditional healers&
superstition& poor 'uality of services& monetary costs& distance to services& and
the need for an escort. >ven where facilities are available& there is often a lack of
surgeons& instruments& and other e'uipment (exacerbated by poor maintenance!&
and a shortage of consumables and medications. =eveloping intraocular lens
manufacturing facilities in these countries (such as the 8red )ollows 8oundation
in >ritrea and 9epal!& will reduce costs and improve access to surgery. "
C. Etio%oy
The etiology of cataract that are @
1 *ld age (commonest!
" Associated with other ocular and systemic diseases (diabetes& uveitis& previous
ocular surgery!
0 Associated with systemic medication (steroids& phenothiaines!
7 Trauma and intraocular foreign bodies
%oniing radiation (-ray& BC!
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< ongenital (dominant& sporadic or part of a syndrome& abnormal galactose
metabolism& hypoglycaemia!
, Associated with inherited abnormality (myotonic dystrophy& DarfanEs
syndrome& $oweEs syndrome& rubella& high myopia!
D. C%assifi&ation
The following is a classification of the various types of cataracts.
a! Time of occurrence
lassification of cataract according to time of occurence
1! Ac'uired cataract
Senile cataract (F years old!
ataract with systemic disease
2ilateral cataracts may occur in association with the following systemic
disorders@ diabetes mellitus& hypocalcemia (of any cause!& myotonic
dystrophy& atopic dermatitis& galactosemia& and $oweEs& ernerEs& and =ownEs
syndromes. 1
Secondary and complicated cataracts
ataract may develop as a direct effect of intraocular disease upon the
physiology of the lens (eg& severe recurrent uveitis!. The cataract usually
begins in the posterior subcapsular area and eventually involves the entire
lens structure. %ntraocular diseases commonly associated with the
development of cataracts are chronic or recurrent uveitis& glaucoma& retinitis
pigmentosa& and retinal detachment. These cataracts are usually unilateral.
The visual prognosis is not as good as in ordinary age-related cataract. 1
#ostoperative cataract
After-cataract denotes opacification of the posterior capsule following
extracapsular cataract extraction. #ersistent subcapsular lens epithelium may
favor regeneration of lens fibers& giving the posterior capsule a Gfish eggG
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appearance (>lschnigEs pearls!. The proliferating epithelium may produce
multiple layers& leading to frank opacification. These cells may also undergo
myofibroblastic differentiation. Their contraction produces numerous tiny
wrinkles in the posterior capsule& resulting in visual distortion. All of these
factors may lead to reduced visual acuity following extracapsular cataract
extraction. 1
Traumatic ataract
Traumatic cataract is most commonly due to a foreign body inHury to the lens
or blunt trauma to the eyeball. Air rifle pellets and fireworks are a fre'uent
cause/ less-fre'uent causes include arrows& rocks& contusions& overexposure
to heat (GglassblowerEs cataractG!& and ioniing radiation. Dost traumatic
cataracts are preventable. %n industry& the best safety measure is a good pair
of safety goggles. 1
Toxic cataract
orticosteroids administered over a long period of time& either systemically
or in drop form& can cause lens opacities. *ther drugs associated with
cataract include phenothiaines& amiodarone& and strong miotic drops such asphospholine iodide. 1
"! ongenital cataract