If the wavefront aberration can be described in terms of third-order aberrations, it is convenient to specify the wavefront aberration by stating the number of waves of each of the third-order aberrations present.

Circular wavefront profiles associated with aberrations may be mathematically modeled using Zernike polynomials. Developed by Frits Zernike in the 1930s, Zernike's polynomials are orthogonal over a circle of unit radius.

Any deviation from the ideal spherical shape is said to be an aberration. The wavefront error W(x,y) is the difference between a perfect spherical wave and the actual wavefront. It is usually measured in the exit pupil and. W(0,0) = 0. The axis for this system is the Line of Sight.

To study optical metrology, the forms of aberrations that might be present need to be understood. The purpose of this chapter is to give a brief introduction to aberrations in an optical system.

Wavefront deformation is determined by the use of a reference sphere with center at the Gaussian image point and passing by the exit pupil on-axis point. • An axially symmetric system can only have an axially symmetric wavefront deformation for an object point on-axis.

Wavefront mapping is a technology that makes custom laser eye surgery possible by precisely measuring and diagramming the aberrations of an optical system (e.g. the human eye). These aberrations are divided into lower-order aberrations (such as myopia, hyperopia, and astigmatism) and higher-order aberrations (such as trefoil, coma, and ...

wave aberrations, ray caustics, and aberration coefficients, this text covers pupil aberrations, the irradiance function, aberration fields, and polarization aberrations. It also provides a historical perspective by explaining the discovery of aberrations, and two chapters provide insight into classical image formation; these topics of