Premium
Interconverting the matrix and principal meridional representations of dioptric power in general including powers with nonorthogonal and complex principal meridians
Author(s) -
Harris W.F.
Publication year - 2001
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1046/j.1475-1313.2001.00564.x
Subject(s) - zonal and meridional , principal (computer security) , representation (politics) , matrix (chemical analysis) , power (physics) , principal component analysis , mathematics , matrix representation , computer science , physics , chemistry , quantum mechanics , statistics , law , atmospheric sciences , chromatography , politics , political science , operating system , group (periodic table)
Summary The principal meridians of the powers of thick astigmatic systems, like the eye, are not necessarily at right angles. The consequence is a class of phenomena included in the category commonly described as irregular astigmatism. The conventional principal meridional representation of power, however, is unsuited to quantitative analysis. This paper presents equations for converting from the principal meridional form of power to a representation, the dioptric power matrix, which is amenable to quantitative analysis. It generalizes an earlier paper which treated only powers of a conventional form in which the principal meridians are always at right angles. It copes in particular with what are known as asymmetric powers. A routine is also presented for converting in the reverse direction, from the power matrix to the principal meridional form of power. The principal meridional form of power turns out not always to be unique, there being distinct powers (they are asymmetric) with the same principal powers andmeridians. Thus, in general, the dioptric power matrix is a satisfactory representation of power while the principal meridional representation is not.