title: Deflectometric method for the measurement of user power for ophthalmic lenses.
abstract: This paper presents a deflectometric technique to measure the power of an ophthalmic lens as perceived by the user. It is based on a calibrated camera acting as a pinhole in order to measure ray deflection along the same path as the visual axis when the lens is held in front of the eye. We have analyzed numerically the accuracy of our technique, and it has been compared experimentally with a commercial "lens mapper" and with the real user power calculated from the measured topography of the lens surfaces to state the reliability and accuracy of the presented technique.
authors.affiliation: Laboratorio de instrumentación espacial (LINES), Instituto Nacional de Técnica Aerospacial (INTA), Carretera de Ajalvir, km 4, 28860 Torrejón de Ardoz, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Vargas
authors.forename: José A
authors.initials: JA
authors.lastname: Gómez-Pedrero
authors.forename: José
authors.initials: J
authors.lastname: Alonso
authors.forename: Juan A
authors.initials: JA
authors.lastname: Quiroga
mesh_terms: D006801:Humans; D007909:Lenses; D055095:Optics and Photonics / Q000295:instrumentation* / Q000379:methods*; D009907:Optometry / Q000379:methods*; D014785:Vision, Ocular