• (a.) Alt. of Dioptrical • (n.) A dioptre. See Dioptre. • (a.) Of or pertaining to the dioptre, or to the metric system of numbering glasses. Found on http://thinkexist.com/dictionary/meaning/dioptric/
Di·op'tric adjective (Optics) Of or pertaining to the dioptre, or to the metric system of numbering glasses. -- noun A dioptre. See Dioptre . Found on http://www.encyclo.co.uk/webster/D/70