Method for determining astigmatism of an eye of a person, the method comprising- a measuring device providing step during which a measuring device adapted to run a Jackson cross cylinder procedure is provided,- a first vector determining step, during which the components of a first vector of the cylinder in a two-dimensional vector cylinder representation are determined,- a second vector determining step, during which the components of a second vector of the cylinder in the two-dimensional vector cylinder representation are determinedwherein the second vector components being determined such that the Euclidian distance between first and second vector is independent of the value of the cylinder.
