A method of measuring a surface or profile (P) of an optical element , wherein the optical element comprises a first surface and a second surface opposite the first surface , the method comprising the steps of: - defining of at least a first measurement point , a second measurement point and a third measurement point on a measurement surface of the optical element , the measurement surface being one of the first surface and the second surface , - measuring of a first position of the first measurement point by directing of a measurement beam from a measurement head onto the first measurement point and by detecting a measurement beam portion reflected at the first measurement point , - subsequently measuring of at least a second position of the second measurement point and of a third position of the third measurement point by directing of the measurement beam onto the second measurement point and onto the third measurement point and by detecting a measurement beam portion reflected at the second measurement point and the third measurement point , respectively, - i) determining of at least one of a decenter (D) and a tilt (T) of the measurement surface relative to a reference axis and/or - ii) deriving of a measured surface or measured profile of the optical element on the basis of at least the first position, the second position and the third position, - wherein one of the first surface and the second surface of the optical element faces towards the measurement head and wherein the other one of the first surface and the second surface facing away from the measurement head is the measurement surface and wherein the first position, the second position and the third position is measured by directing the measurement beam onto a first target point , a second target point and a third target point , wherein the first, the second and the third target points are located on that one of the first surface and the second surface facing towards the measurement head and wherein the measurement beam propagates through the medium of the optical element . - defining of at least a first measurement point , a second measurement point and a third measurement point on a measurement surface of the optical element , the measurement surface being one of the first surface and the second surface , - measuring of a first position of the first measurement point by directing of a measurement beam from a measurement head onto the first measurement point and by detecting a measurement beam portion reflected at the first measurement point , - subsequently measuring of at least a second position of the second measurement point and of a third position of the third measurement point by directing of the measurement beam onto the second measurement point and onto the third measurement point and by detecting a measurement beam portion reflected at the second measurement point and the third measurement point , respectively, - i) determining of at least one of a decenter (D) and a tilt (T) of the measurement surface relative to a reference axis and/or - ii) deriving of a measured surface or measured profile of the optical element - wherein one of the first surface and the second surface of the optical element faces towards the measurement head and wherein the other one of the first surface and the second surface facing away from the measurement head is the measurement surface and wherein the first position, the second position and the third position is measured by directing the measurement beam onto a first target point , a second target point and a third target point , wherein the first, the second and the third target points are located on that one of the first surface and the second surface facing towards the measurement head and wherein the measurement beam propagates through the medium of the optical element . <EOS>