title: An optical device with variable astigmatic power.
abstract: A new variable power cross-cylinder lens set is described. It differs from the well known Stokes variable power cross-cylinder lens set, which is made of cylinder lenses of equal but opposite power, in that in the new variable power cross-cylinder lens set both lens elements are identical. These elements can be sphero cylindrical of any type and can be designed to give the same effect as a Stokes lens set or create a spherical bias or offset of a desired amount. The action of this lens set is analyzed using 3-dimensional refractive space.
authors.affiliation: Humphrey Systems, Dublin, California, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Foley
authors.forename: C
authors.initials: C
authors.lastname: Campbell
mesh_terms: D001251:Astigmatism / Q000534:rehabilitation*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007909:Lenses; D055096:Optical Devices; D055095:Optics and Photonics / Q000295:instrumentation*; D011474:Prosthesis Design; D012029:Refraction, Ocular; D013499:Surface Properties