According to the invention, there is provided a device for determining or correcting aberrations of an eye comprising: at least one adjustable wave plate (225), the amplitude and the optic axis angle being adjustable a point source (110) as a viewing target wherein the at least one wave plate (225) is placeable at a conjugate corneal or spectacle plane of a patients eye for a patient to search for predetermined image end points while looking at the point source (110) while wavefront angle and amplitude generated at the wave plate (225) are varied.