title: Proof that the prismatic effect is perpendicular to the lens thickness contour.
abstract: It is sometimes assumed that the prismatic effect in any astigmatic lens is orthogonal or perpendicular to the iso-thickness curves. This paper offers a formal proof of the validity of the assumption.
authors.affiliation: Department of Optometry, Rand Afrikaans University, Johannesburg, South Africa.
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
authors.forename: M P
authors.initials: MP
authors.lastname: Keating
mesh_terms: D006801:Humans; D007908:Lens, Crystalline / Q000033:anatomy & histology*; D008433:Mathematics; D008954:Models, Biological; D055095:Optics and Photonics