A system for photoablating a photoablatable substrate (such as the cornea of a human eye) to create a rounded work surface includes a curved, hollow mirror for reflecting light capable of photoablating such surfaces. The curvature of the mirror determines the shape and curvature of the rounded work surface created. The mirror has an opening of sufficient size and shape to expose the substrate to reflected, photoablating light, and is linked to a mechanism for adjusting mirror tilt and height with respect to the substrate. The system can include a source of photoablating light such as an excimer laser, a mechanism for aligning light from the excimer laser with the mirror surface, a mirror cover for excluding unreflected excimer laser light from desired portions of the substrate, and a high-speed shutter system for controlling the amount and the timing of light transmission from the excimer laser to the reflecting means.