Zernike Polynomials

A set of mathematical functions used to describe the shape of optical wavefronts, commonly employed in ophthalmology and optometry to characterise the optical aberrations of the human eye. Each Zernike polynomial represents a specific type of optical distortion — for example, defocus (related to myopia or hyperopia), astigmatism, coma, trefoil, and spherical aberration. Wavefront analysers (aberrometers) measure the eye's aberrations and express them as a set of Zernike coefficients, which can then be used to compute the eye's Point Spread Function. In visual accessibility applications, Zernike-based measurements of a user's specific optical aberrations enable personalised image precompensation algorithms that pre-distort screen content to counteract the eye's distortions.