What is a cataract?
If you have been told that you have a cataract, don't be alarmed.
Quite a few people over 65
have some cataract development and most cases can be treated
successfully with surgery.
A cataract is a clouding of the eye's
lens, which lies behind the iris and the pupil.
Normally light enters the eye from the front, passes through a clear
lens, and reaches the back of the eye so you can see.
If the lens becomes cloudy like frosted glass, light cannot pass
through, and you cannot see properly. 'Cataract' is the name of the
'cloudy' human lens.
The lens
Think of a camera, with a lens that bends the light so that the light
'focuses' onto the film at the back. If this lens becomes scratched or
greasy, it cannot bend the light in the correct direction, and the light
is scattered in all directions. You may notice blurred or misty sight,
see double, or notice colours appear much duller than they did
previously.
The lens is mostly made of water and
protein. The protein is arranged in a precise way that keeps the lens
clear and lets light pass through it. But as we age, some of the protein
may clump together and start to cloud a small area of the lens. This is
a cataract, and over time, it may grow larger and cloud more of the
lens, making it harder to see.
What causes a cataract?
No one knows for sure why the eye's
lens changes as we age, forming cataracts. Researchers are gradually
identifying factors that may cause cataracts — and information that may
help to prevent them.
Cataracts can form at any age, but most often develop as people get
older. In younger people they can result from an injury, certain drugs,
long-standing inflammation or illnesses such as diabetes.
A cataract will not damage your eye in any way. It can be operated
on safely at any time, thick or thin. A cataract may change the focusing
in the eye, and you may need new spectacles now and again.
If you think you do, ask your optometrist (optician) or the doctor in
the hospital eye clinic. But glasses themselves do not help you see
better if you have a cataract.
Some cataracts get worse quickly, others slowly: most do get worse
over months or years. If your sight gets worse very slowly, the cataract
is only slowly becoming thick.
The thicker or cloudier the cataract becomes, the worse the sight. A
doctor cannot predict with certainty.
Some symptoms
`I'm not seeing as well as I used to'. You may
notice that some things seem blurred round the edges, or that your
glasses seem dirty or scratched.
Seeing double The cloudiness in the eye lens may occur
in more than one place, so that the light rays which reach the retina
are split, causing a double image.
Poor vision in bright light You may find that bright
light or very sunny days make it more difficult to see.
Change of colour vision As the cataract develops its
centre becomes more and more yellow, giving everything you see a
yellowish tinge.
What can be done to help?
The most effective treatment for cataracts is a small operation to
remove the cloudy lens. This cannot be performed by laser, although
laser treatment is sometimes needed afterwards. Diets or drugs have not
been shown to slow or stop the development of the cataract.
What is a lens implant?
When the cloudy lens has been surgically removed it is usually
replaced by a plastic lens so that the eye can focus properly.
Occasionally a doctor will decide that someone's eye is not suitable
for a lens implant. In these cases contact lenses or special glasses
will be prescribed instead.
When should I have the operation?
Usually, you can decide if, and at what stage to have the operation.
Obviously you need to bear in mind that there may be a waiting list for
this.
In the past, eye specialists often waited until the cataract became
`ripe' before suggesting you had it removed. Nowadays, with modern
surgery the operation can be carried out at any stage of the cataract's
development. If visual impairment interferes with your ability to read,
to work, or to do the things you enjoy then you will probably want to
consider surgery.
For most people, it is possible to have your operation and go home on
the same day, as long as you have someone to look after you at home.
Sometimes surgery will mean a short stay in hospital.
What happens in the operation?
Just before the operation you will be given eye drops to enlarge your
pupil and something to help you relax if you want this. Normally
cataract surgery is performed with a local anaesthetic and some
sedation. The local anaesthetic numbs the area that is being operated
on. You will be wide awake but feel nothing in your eye. Usually the eye
specialist will explain what is happening as the operation goes along,
and a nurse will be there to hold your hand and make sure you are all
right.
Sometimes your doctor may decide to give you a general anaesthetic.
This means that you are completely unconscious, and it will be like
sleeping through the operation.
The operation is performed with the aid of a microscope through a
small cut in the top of the eye. This is closed using small stitches at
the end of the operation. The operation generally takes up to 45
minutes. A pad or shield will probably be put over your eye to protect
it from accidental rubbing and bumping after the operation.
We want to reassure you that your eye is not taken out of its socket
during surgery. The operation is not painful and the stitches cannot be
seen.
After the operation
Your sight will usually improve within a few days, although complete
healing may take several months. It is a good idea to have some help at
home if you can, especially if you find it difficult to put your eye
drops in. You will need to take it easy for a couple of weeks so that
your eye can heal:
- Avoid rubbing your eye; wear an eyeshield if you are a restless
sleeper.
- Don't do any heavy lifting, and avoid strenuous exercise and
swimming.
- You can do light housework or cooking, but try to get some help if
you can.
- You don't need to stay indoors but take care if it is windy, in
case anything blows in your eye.
- Wash your hair leaning backwards rather than forwards.
- Avoid eye make-up for six weeks.
- You can resume your sex life a week or two after the operation.
- Avoid driving until your surgeon tells you it is safe.
- New glasses are usually prescribed four to eight weeks after the
operation.
- How long you are off work will depend on the job you do. Ask your
eye specialist about this.
See animation
With thanks to Good Hope
Hospital -
see
their web site for more detailed information |
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