Definition of cataract

What is cataract?
Cataract is a common eye disease and the leading cause of visual impairment across the world (48% of cases).
A cataract is clouding of the lens. The lens is a natural structure located inside the eye behind the iris (the coloured part of the eye). The lens is crucial for sight and also for visual accommodation, i.e. the ability to switch between near and far focus.
The commonest cause of cataracts is age and therefore ageing, but cataracts can also result from eye injury (post-traumatic cataract), a pre-existing eye disorder (pigmentary retinopathy, previous eye surgery, etc.), medical treatment (corticoids, orbital radiotherapy, etc.), or chronic illnesses such as diabetes. In children, cataract can also be congenital.
A number of factors increase the risk of developing cataracts, including smoking, excessive alcohol consumption and exposure to sunlight (ultraviolet rays).
Symptoms of cataract are various.
The only option to treat cataract is surgical treatment.

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