[医] 老视

Presbytia \Pres*byt"i*a\, n. [NL. See {Presbyte}.] (Med.)
Presbyopia.

Presbyopia \Pres`by*o"pi*a\[NL., from Gr. ? old, n., an old man
+ ?, ?, the eye.] (Med.)
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}.