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The word Cataract brings up lot of anxiety, doubts, myths, queries and fear in the mind
of the person affected by it, or his / her kin. This article aims to clear such doubts and
myths and educate public about cataract and its current methods of treatment.
Cataract
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.
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.
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 can be 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 disease?
What is the cause of cataract
in my eye?
What are the treatment
modalities available?
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?
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 patient’s - 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 procedures):
Phacoemulsification with foldable
IOL.
Small Incision Cataract Surgery (SICS) with Intra-ocular Lens (IOL) Implantation.
Conventional surgery is
virtually obsolete.
In Phacoemulsification a very small
incision
(3.2 mm) 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). Non-foldable IOLs are not recommended as
they necessitate enlarging the incision and thereby sacrificing the
advantages of the small incision.
All these operations are done under local or
topical anesthesia
which makes the eye numb/senseless, and the patient although
conscious does not feel any pain. 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.)
Intra-ocular Lenses (IOL) are small (5-7 mm)
lenses made of a soft polymer (Silicone or 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 slightly 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...
Click here to read a detailed
medical article on Cataract.
Frequently Asked Questions:
1 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 eye's light-sensitive layer that sends visual signals to the
brain. The lens is located just behind the iris, the colored (brown, blue or green) 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 objects.
2 What is a cataract (motia-bind / safed motia)?
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 see.
Although researchers are learning more about cataracts, no one knows for sure what
causes them. Scientists think there may be several causes, including smoking and diabetes.
Or, it may be that the protein in the lens just changes as it ages. There is also some
evidence that cataracts are linked to certain vitamins and minerals.
Exposure to ultra-violet light has definite role in the formation of
cataract.
3 What are the symptoms?
The most common symptoms of a cataract are:
- 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 around lights.
- Colors that seem faded.
- Double or multiple vision (this symptom goes away as the cataract grows).
- Frequent changes in your eyeglasses 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 worsens gradually. 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.
4 What are the different types of cataract?
- Age-related cataract: Most cataracts are related to aging.
- 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
removed.
- Secondary cataract: 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.
- Traumatic cataract: Cataracts can develop soon after an eye injury, or years later.
5 How is a cataract diagnosed?
A comprehensive eye examination
usually includes:
- 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 problems.
- Tonometry: This is a standard test to measure eye pressure. Increased pressure may cause
glaucoma.
- 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 surgery.
6 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 retinopathy, intraocular-tumor, retinal detachment, etc.
Cataract Surgery
7 Is 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 afterward.
8 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
categories:
- Phacoemulsification: 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 called phacoemulsification.
Currently phacoemulsification 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.
- Other types of operations are performed in special circumstances.
Currently, lasers are not commonly 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.
9 What are artificial Intraocular Lenses (IOL)?
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.
Intraocular lens
An IOL is a clear, polymer (Silicone or 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
3.2 mm cut. 
10 What is done for the preparation before surgery?
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 the patient.
11 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.
12 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
changes.
13 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.
14 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 - Dr. Sanjay Dhawan Last Update -
30 June, 2007 New
Delhi, India |
