An ophthalmic illumination system includes planar shapes serially positioned in a path for a collimated beam, along an optical axis. The shapes are rotationally symmetric with one another relative to the optical axis. Each shape has a central rotational axis intersecting the optical axis. Generally wedge-shaped segments of the shapes are spaced apart around and converge at the optical axis to provide generally wedge-shaped apertures to the beam between the segments. The shapes are rotatable on the rotational axes along the optical axis to assume a plurality of configurations to vary intensity of the beam. The beam can fill spatial modes at substantially all radii of the optical fiber entrance pupil.