The lens of a normal healthy eye is clear and allows light rays to easily pass through it. When a cataract develops, the lens becomes cloudy and opaque, and its ability to transmit light decreases. The process of cataract formation gradually reduces sights quality.
Type
Most cataracts are caused by changes in the chemical composition of eye lens.
The most common type of cataract is senile cataract which accounts for 80% of total cataract's cases. It occurs mostly in patients over the age of 50.
Congenital cataract are rare. They can be caused by an infection of the mother that is transmitted to the foetus during pregnancy, or they may be hereditary.
Traumatic cataracts are caused by injury to the eye. A hard blow, puncture, cut, intense heat or a chemical burn can damage the lens and lead to cataract formation.
Secondary cataract are caused by diseases such as glaucoma, iritis, eye tumours and diabetes may lead to cataracts.
Drug-induced cataracts may be caused by excessive used of steroid drugs
Symptoms
Symptoms of cataract varies from blurring vision or dimness of vision to double vision. Apart from sensitivity to light which is a major sign of cataract; change in pupil's colouration or feeling of film over the eyes are another signs of cataract development.
Treatment
Removal of the cloudy lens by surgical procedure is the only treatment. Neither medical nor changes in glasses will improve vision.
A cataract operation may be performed under local anaesthesia which includes the replacement of clouded lens with either an intraocular lens (IOL) or Aphakic glasses.
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