Prevention of Blindness and Visual Impairment

Priority eye diseases


Cataract

Definition

Cataract is clouding of the lens of the eye which prevents clear vision. Although most cases of cataract are related to the ageing process, occasionally children can be born with the condition, or a cataract may develop after eye injuries, inflammation, and some other eye diseases.

Magnitude

According to the latest assessment, cataract is responsible for 51% of world blindness, which represents about 20 million people (2010). Although cataracts can be surgically removed, in many countries barriers exist that prevent patients to access surgery. Cataract remains the leading cause of blindness. As people in the world live longer, the number of people with cataract is anticipated to grow. Cataract is also an important cause of low vision in both developed and developing countries.

Prevention and treatment

Reduction of cigarette smoking and ultraviolet light exposure may prevent or delay the development of cataract. Diabetes mellitus and high body mass index are identified as additional risk factors.
The treatment of cataract is surgical and very successful in restoring sight. The opaque lens is removed and replaced by an artificial intraocular lens. In many remote parts of the developing world, people remain blind from cataract, due to a lack of access to eye care.

WHO role

To advocate for the elimination of barriers to access eye care, to provide guidance and technical support of the development of comprehensive eye care systems to address the burden of cataract and other chronic eye diseases.

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Bilateral cataract