Presbyopia

n. far-sightedness, loss of the ability to see nearby objects clearly (due to age)

Presbyopia (Greek word "presbys" (πρέσβυς), meaning "old person") is the eye's diminished ability to focus that occurs with aging. The most widely held theory is that it arises from the loss of elasticity of the crystalline lens, although changes in the lens's curvature from continual growth and loss of power of the ciliary muscles (the muscles that bend and straighten the lens) have also been postulated as its cause.
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The term presbyopia means "old eye" and is a vision condition involving the loss of the eye's ability to focus [more]Presbyopia - Community and Resources

Noun
1. farsightedness resulting from a reduced ability to focus caused by loss of elasticity of the crystalline lens with age
(hypernym) hyperopia, hypermetropia, hypermetropy, farsightedness, longsightedness

A defect of vision consequent upon advancing age. It is due to rigidity of the crystalline lens, which produces difficulty of accommodation and recession of the near point of vision, so that objects very near the eyes can not be seen distinctly without the use of convex glasses. Called also presbytia.