1. Method for identification of a given geometrical feature of an optical component ( 12 ), chosen within the list consisting of an ophthalmic lens or a semi-finished lens blank for ophthalmic lens, said method comprising the following steps consisting of: providing ( 32 ) the optical component ( 12 ) made of an organic material with the proviso that said material can emit light at an emission wavelength λ e when being lighten at an illumination wavelength λ i which is different from the emission wavelength λ e ; illuminating ( 34 , 74 ) a surface ( 16 , 64 ) of the optical component with an incident light beam comprising at least light at the illumination wavelength but devoid from the light at the emission wavelength, wherein said surface of the optical component is illuminated in an illumination direction with an incident light beam having the form of a sheet of light ( 56 ) substantially perpendicular to said surface of the optical component; collecting ( 36 , 76 ) light emitted at the emission wavelength by the illuminated surface of the optical component to build an image of the said surface; and processing ( 38 ) said image by implementing computer means and applying a metrics to compare the image with reference data that are specific to the given geometrical feature and providing an identification output of said given geometrical feature.