title: Squaring the sphero-cylinder, the equivalent of squaring the refractive power matrix.
authors.affiliation: Department of Optometry, Rand Afrikaans University, Johannesburg, South Africa.
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
mesh_terms: D008433:Mathematics; D009907:Optometry; D012029:Refraction, Ocular