English

Noun

dioptry ‎(plural dioptries)

1. (obsolete) Alternative form of diopter
   • 1900, Charles Frederick Prentice, Ophthalmic lenses:

     The Dioptral System of numbering prisms alone possesses the great desideratum of establishing a direct and simple relation between the prism-dioptry and the lens-dioptry, as demonstrated by the authors' law, that "a lens decentered one centimeter will produce as many prism-dioptry as the lens has dioptry of refraction."