Cataracts
When we look at an object, light passes through
the cornea, the lens and the vitreous into the
eye before reaching the retina. The lens bundles
the incoming rays of light to produce a focussed
image on the retina. A cataract is a gradual
clouding over of the lens over the course of
a person's life.
Symptoms
A slight cloudiness at the start usually goes
unnoticed except for perhaps an increased sensitivity
to light. It is only as the lens becomes cloudier
that vision is impaired:
• The sensitivity to bright light increases
substantially.
• Contours become increasingly less focussed
and blurred.
• Colours become paler – often without
the person noticing.
• Double vision can occur.
• As the cataract progresses, everything
appears "grey in grey" and "in
a blur".
The term "cataract" comes from Greek
and means "waterfall". The Greeks
believed that the cloudiness of the eye flowed
down from the brain.
Causes
In some rare cases cataracts may be congenital.
Injuries, such as trauma to the eyeball or infections
in the eye can cause the lens to become clouded.
Some rare metabolic disorders and skin diseases
as well as the prolonged intake of cortisone
can also cause cloudiness of the lens. Cataracts
are usually, however, associated with the natural
aging process which is why we sometimes refer
to "senile cataract". More than 90
per cent of people who suffer from cataracts
are over sixty.
Go to Cataract surgery
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