Presbyopia (from Greek
presbys (πρέσβυς) = old man +
ops (ὤψ) = see like, sight > meaning literally
trying to see as old men do) is a condition associated with aging in which the
eye exhibits a progressively diminished ability to focus on near objects. Presbyopia’s exact mechanisms are not fully understood; research evidence most strongly supports a 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.