Abstract: A disk enabling modification of the power of an optical component consists of a Fresnel lens. The disk is initially formed with a general rounded shape which corresponds to the shape of the optical component. In this way, the disk does not lose its shape or does not lose it very much when it is applied against the component. It does not cause image distortion or optical aberration when an object is observed through the component provided with the disk. Such a disk is particularly adapted to obtain correction of ametropia or to a solar mask initially lacking optical power.

Abstract: A disk enabling modification of the power of an optical component consists of a Fresnel lens. The disk is initially formed with a general rounded shape which corresponds to the shape of the optical component. In this way, the disk does not lose its shape or does not lose it very much when it is applied against the component. It does not cause image distortion or optical aberration when an object is observed through the component provided with the disk.

Abstract: A translucent synthetic material article such as an ophthalmic lens comprises a plurality of well-shaped cells, some of which have at least one upstanding projection on their bottom walls. The projection have a height between 1/5 and 1/1 the cell depth and are upwardly tapering and wedge-shaped. The plurality of cells are arranged in rows and columns to define a matrix. When the translucent article is illuminated, the well-shaped cells with upstanding projections display enhanced contrast compared with such cells without upstanding projections, thereby producing an identification marking or the like.