dioptry

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."

   • 1974, Lawrence Durrell, Monsieur, New York: Viking, 1975, “Macabru,” p. 176,

     They also shared a fearful myopia of identical dioptry, were apt to bump into inanimate objects, sit down on invisible chairs, or bounce off each other as they shambled about talking and gesticulating.

• tripody