title: Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: comment.
abstract: Potentially misleading results follow from an error in a recent paper, namely [Opt. Express24, 5448-5462 (2016)], that contains a comparative analysis of schemes for specifying shape. Some corrections are presented for clarification. Additional comments are offered in relation to practical goals in this area of research.
authors.forename: G W
authors.initials: GW
authors.lastname: Forbes