[医] 屈光度

[ noun ]
a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters; used by oculists
<noun.quantity>

Dioptre \Di*op"tre\, n. [F. See 2d {Dioptric}.] (Optics)
A unit employed by oculists in numbering glasses according to
the metric system; a refractive power equal to that of a
glass whose principal focal distance is one meter.