A common eye examination and refraction evaluates low order aberrations (LOA). These are commonly called sphere (myopia or hyperopia) and cylinder (astigmatism). Only a wavefront diagnosis is able to measure high order aberrations (HOA), which are beyond simple sphere and cylinder. HOA are represented in mathematical calculations and are therefore infinite. The more common of these mathematical calculations are Zernike polynomials and have names like spherical aberration, coma, trefoil, and secondary astigmatism. Ophthalmology only deals with about the first eight levels of HOA as represented in Zernike.