An apparatus for generating an alteration of biomechanical properties of ocular tissue, into which a photosensitizer (14) has been introduced, contains means (18, 20) for radiating into the tissue electromagnetic radiation (12′) which reacts with the photosensitizer for the purpose of generating a cross-linking. The setting means permit an inhomogeneous distribution of the irradiance in the tissue and a setting of the depth of action (16′).
