This video explains Zernike polynomials and the optical principles behind wavefront technology. Topographic wavefront measurement is used to identify and quantify higher-order aberrations, such as coma and spheral aberrations, that deleteriously affect the quality of vision even in patients who have 20/20 visual acuity. Dr. Roger Steinert explains how wavefront measurement can be applied in practice for refractive correction of these higher-order aberrations.