In the field of optometry, the refractive errors of sphere (defocus) and cylinder (astigmatism) comprise aberrations of up to the second order. These aberrations can be corrected by spectacle lenses. Higher order aberrations of the eye - such as coma or trefoil - cannot be corrected with spectacle lenses, as they are dependent on the pupil aperture and therefore to a major extent on the viewing eye. However, they have a major influence on the quality of the retinal image: higher-order aberrations are the cause of reduced visual contrast or poor vision in night or twilight conditions.
With i.Scription®, Carl Zeiss has now developed an optimisation algorithm that takes into account higher order aberrations in order to optimise the corrective power of the lens.