The Human Eye and the Colourful World


   
 
Presbyopia

Presbyopia is caused when the centre of the eye lens hardens making it unable to accommodate near vision. This condition generally affects almost everyone over the age of 50 - even those with myopia. Eyeglasses with bifocal or progressive lenses are prescribed to correct or improve the condition. The contact lenses used by presbyopes are multifocal lenses.

Note
Progressive lenses -- Also called progressive addition lenses or PALs are multifocal lenses whose corrective powers change progressively throughout the lens. A wearer looks through one portion of the lens for distance vision, another for intermediate vision, and a third portion for reading or close work. Each area is blended invisibly into the next, without the lines that traditional bifocals or trifocals have.

 
 
     
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