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Human eye has a natural lens
which is normally transparent and forms a clear
image of the outside world in the eye. When this
lens develops haziness /opacity the sight is
decreased or may be completely lost - this is called
Cataract may develop at any age - right from birth
to old age - but is most commonly seen in the old
after the age of 60 years. By the age of 90 years
almost 98 % of people have had some degree of
Cataract seen in the old age may be caused by normal
aging process but seen at younger age is caused by
many disease processes e.g. some eye diseases like
uveitis, general diseases like diabetes, heredity,
injury, radiation, infections and many more.
The most important symptom of cataract is a decrease
in vision for distance & /or near objects. Other
features are decreased vision in bright or low
light, decreased contrast, altered color
appreciation, seeing many images of one object,
rapid changes in the number / power of glasses, or
sometimes pain, redness and watering. In advanced
cases there is complete loss of vision and pupil
becomes pearly white in color. However, none of
these symptoms are seen exclusively in cataract.
The first thing a person must do on experiencing any
of these symptoms is to consult an Eye Surgeon
(Ophthalmologist) for thorough eye examination.
Answers to the following questions should be sought:
Do I have cataract?
Do I have any other eye
What is the cause of
cataract in my eye?
What are the treatment
What treatment would be
most suitable for me?
What is the expected
outcome of the surgery in my case?
What are the risks
involved and possible complications?
How long can I wait
before I get operated?
What does the surgery
involve in terms of time and expenditure?
What are the different
techniques available & their merits?
What are the different
types of lenses available & the merits of each?
Once it is decided that the
patient has cataract the treatment is essentially
surgical and the only question that arises is when ?
The decision is patientís - whenever the patient
feels his vision has decreased to a level where it
interferes with his routine daily activities he can
get operated (no longer is it required for the
cataract to become mature). However, in certain
cases where there are associated complications or
potential risks of complications an early (even
urgent) operation may be required - here the advise
of consulting eye surgeon should be followed.
The operations done for cataract are the following
(the list includes only established standard
Conventional surgery is
a very small incision (3 mm or less) is made into
the clear part of the eye (Cornea) and the hard core
(nucleus) of the lens is converted in to a soft pulp
using high frequency sound waves (NOT Laser) and
sucked out. Then a foldable lens (IOL) is injected
through the small incision and positioned into
capsular bag. The main advantages of this operation
are early rehabilitation and decreased occurrence of
astigmatism (cylindrical power in glasses) & other
complications. Non-foldable IOLs are not recommended
as they necessitate enlarging the incision and
thereby sacrificing the advantages of the small
All these operations are done under topical
anesthesia (or eye drop anesthesia) which makes
the eye numb/senseless, and the patient although
conscious does not feel any pain. Rarely does one
need to use injection anesthesia. The general
anesthesia , which has its own risks, is used only
in children and uncooperative patients. Topical or
eye drops anesthesia is the preferred method as not
only the painful injections and the eye bandage are
avoided but it also reduces the risk associated with
injection anesthesia (e.g., retro-bulbar hemorrhage,
globe perforations, etc.)
MICS (Micro Incision Cataract Surgery) is
just a variation of Phacoemulsification. Here using
thinner phacoemulsification tips, the surgery is
performed through narrower incision (about 2 mm). It
offers only minimal advantage over standard
phacoemulsification by causing slightly lesser
surgical iduced astigmatism. However, the IOLs
implanted through such small incisions are still
very new and the experience with them is very
Intra-ocular Lenses (IOL) are small (about 6
mm) lenses made of a soft polymer (Acrylic) and are
implanted inside the eye in place of natural lens.
The greatest advantage of IOL is a clear wide field
of vision and the fact that the patient does not
have to constantly wear thick glasses. However,
glasses with low power may be still be required
especially for reading distant and near small print.
The reason being that unlike natural lens the IOL
has a fixed power (estimated by doing Ultrasound of
the eye) which is usually adjusted such that the
mid-range or routine viewing distances are seen
clearly, and for distances closer or further low
powered glasses may still be needed. Since the IOL
stays in the eye lifelong therefore there should not
be any compromise on the quality of the IOL.
Multifocal IOLs offer the advantage clear
distant and near vision and, thus, lesser dependence
on glasses but suffer the disadvantage of lower
contrast, lower color saturation and a subjective
compromise in image quality. Alcon Restor IOL gives
good results for near and distance vision. But both
eyes have to be operated within short interval of
2-6 weeks and it take about 4-8 weeks for complete
adaptation to new visual status.
SICS (Small Incision Cataract Surgery) has
virtually replaced the conventional cataract surgery
for difficult situations. Here although the incision
made is larger (5-6 mm) and the nucleus is removed
using fluid pressure, yet no stitches are required
and the recovery is much faster and more comfortable
than the conventional surgery.
To conclude, the surgeon, the surgical technique and
the quality of the IOL are not the only factors that
decide the result of cataract surgery; but also the
condition of the eye otherwise, the cornea, the
retina and the presence of systemic diseases like
diabetes, hypertension, asthma, infections, etc.
Moreover, the quality of the operation theatres, the
ancillary and the backup facilities, the training of
the support staff, etc. also have a significant
influence on the success of the surgery. Ensuring
good quality in all these areas leads to increase in
the surgical cost for the patient, but it must be
understood that our eyes are worth a lot more...
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Frequently Asked Questions
What is the lens of the eye?
The lens is the part of the eye that
along with cornea helps focus light
onto the retina. The retina is the
light-sensitive layer of the eye
that sends visual signals to the
brain. The lens is located just
behind the iris (the colored part of
the eye). In focusing
(accommodation), the lens changes
shape. It becomes more convex
(curved) when you look at nearby
objects and flatter for distant
What is a cataract (motia-bind /
The lens is made mostly of water and
protein. The protein is arranged to
let light pass through and focus on
the retina. Sometimes some of the
protein clumps together and starts
to cloud a small area of the lens.
This is a cataract. Over time, the
cataract may grow larger and cloud
more of the lens, making it hard to
Aging and exposure to ultra-violet
light have definite role in the
formation of cataract.
What are the symptoms?
The most common symptoms of a
Cloudy or blurry vision.
Problems with light, such as
headlights that seem too bright
at night, glare from lamps or
the sun, or a halo or haze
Colors seem faded
Double or multiple vision (this
symptom goes away as the
Frequent changes in power of
spectacles or contact lenses.
These symptoms can also be a sign of
other eye problems. In the event of
any of these symptoms please consult
an eye surgeon.
In early cataract one may not notice
any changes in vision. Cataracts
tend to grow slowly, so vision
gradually worsens. Some people with
a cataract find that their near
vision suddenly improves (phenomenon
of second-sight), but this is
temporary. Vision is likely to get
worse again as the cataract grows.
What are the different types of
Most cataracts are related to
Congenital cataract: Some
babies are born with cataracts
or develop them in childhood,
often in both eyes. These
cataracts may not affect vision.
If they do, they may need to be
Cataracts are more likely to
develop in people who have
certain other health problems,
such as diabetes. Also,
cataracts are sometimes linked
to steroid use.
Cataracts can develop soon after
an eye injury, or years later.
How is a cataract diagnosed?
A comprehensive eye examination
Visual acuity test: This
eye chart test measures how well
you see at various distances.
Pupil dilation: The pupil
is widened with eye-drops to
allow us to see more of the
retina and look for other eye
Tonometry: This is a
standard test to measure eye
pressure. Increased pressure may
Ultrasound (Biometry) of
the eye to calculate the power
of the lens to be implanted.
Other eye and general test may be
required to establish complete
diagnosis and fitness for cataract
How is Cataract treated?
The treatment of cataract is
essentially surgical and the timing
is decided by the patient's visual
needs. A cataract needs to be
removed only if it affects one's
vision so much that it interferes
with one's daily activities. Patient
makes that decision himself. If you
have cataracts in both eyes, the
operation on the two eyes is
performed preferably with an
interval of one month (unless there
is any emergency).
Sometimes, a cataract may have to be
operated for medical reasons. For
example, if it prevents examination
or treatment of another eye problem
such as age-related macular
degeneration or diabetic
retinal detachment, etc.
cataract surgery effective?
Cataract removal is one of the most
common operations performed in India
today. It is also one of the safest
and most effective. More than 90
percent of people who have cataract
surgery have better vision
How is a cataract removed?
The lens is enclosed in a capsule,
an outer covering that holds it in
place. There are many different
techniques for cataract surgery, but
all fall into one of two basic
The front of the capsule is
opened and the cataract is
removed, leaving the back of the
capsule in place. Sound waves
(ultrasound) may be used to
soften and break up the cloudy
lens so that it can be removed
through a small cut. This is
with a foldable intraocular lens
implantation through a 3 mm
incision is the most preferred
method of cataract surgery and
has the best results, all over
the world. In MICS or Micro-Phaco
the incision size is about 2 mm.
Other types of operations are
performed in special
Currently, lasers are not used to
remove cataract (although some
patients mistakenly use the term
Laser for Phacoemulsification).
Although research is under way to
use lasers in cataract surgery and
some success has been reported with
use of "Dodick Laser" in the
treatment of soft cataracts.
What are artificial Intraocular
The lens is important for focusing. When it's
removed, it usually needs to be replaced. 90 percent
of times IOLs help achieve 6/12 vision or better.
An IOL is a clear, polymer (Acrylic) lens that is
placed in the eye during cataract surgery. It does
not need any after-care. With IOL one does not need
to wear glasses for most of their work and moving
about. Moreover, the area of clear vision is much
wider. However, for fine near of distant work one
may still need low powered glasses.
With phacoemulsification a special type of foldable
IOL is implanted through a small 3 mm cut.
What is done for the preparation
Before surgery, some test are performed including
tests to measure the curvature and the length of the
eye ball by a special Ultrasound machine. This helps
in calculating the power of the IOL to be implanted.
Some other tests e.g., blood, urine, ECG, etc may
have to be performed to establish general fitness of
What happens after surgery?
Most people who have cataract surgery can go home
the same day. It's normal to feel itching, sticky
eyelids, and mild discomfort for a while after
cataract surgery. Some fluid discharge is also
common. In most cases, reasonable amount of healing
will take in about 4 weeks.
Mild pain, irritation, redness and watering is
common occurrence after cataract surgery but
subsides in a few days. Problems after surgery are
uncommon, but they can occur. These can include
infection (in severe cases endophthalmitis),
bleeding, higher pressure inside the eye (glaucoma),
inflammation (pain, redness, swelling), haziness of
the cornea and detachment of the retina. Any problem
occurring should be immediately reported to the eye
surgeon especially in the event of unusual pain,
loss of vision, or flashing lights.
When does the vision become normal?
After the surgery, you can read and watch TV almost
right away, but your vision may be blurry. The
healing eye needs time to adjust so that it can
focus properly with the other eye, especially if the
other eye has a cataract. This healing period may
take many weeks. How long it will be before you can
see normally depends on the vision in your other
eye, the lens you choose, and your vision before
surgery. With an IOL, for example, you may notice
that colors have a blue tinge, and that after you've
been in bright sunlight, everything is reddish for a
few hours. It doesn't take long to adjust to these
What is an "after-cataract"?
Sometimes people after cataract
surgery develop an opacification of
the lens capsule called
after-cataract. This can easily be
treated by a Laser called YAG Laser
which makes a small opening in the
capsule - YAG Capsulotomy.
What are the preventive measures?
Regular eye examinations after the
age of 50 years are mandatory to
detect eye diseases early and to
institute timely treatment. Exposure
to UV rays in sun light especially
in tropical countries predisposes to
early development of cataract,
therefore, prevention of exposure to
UV rays by regular use of UV
protective sun glasses may confer
certain degree of protection.
However, this conjecture is not
supported by any research or studies.
Author: Sanjay Dhawan, New Delhi, India
Last updated on 31 May 2011
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