title: Mean of a sample of equivalent dioptric powers.
abstract: Keating's method for finding dioptric power is generalized to include compound optical systems. Other methods can not be generalized in this way.
authors.affiliation: Department of Optometry, Rand Afrikaans University, Johannesburg, South Africa.
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
mesh_terms: D005139:Eyeglasses; D008433:Mathematics; D055095:Optics and Photonics