Abstract: A high speed, high resolution, programmable laser beam modulating apparatus includes a computer connected to a high resolution micromirror array having individually addressable and movable mirrors. The computer is also connected to a pulsed laser for controlling the emission thereof. A beam homogenizing optic changes an ablating input beam from the laser into a homogeneous beam having a uniform cross-sectional energy density. The mirrors are movable between an "on" position for reflecting a portion of the homogeneous beam onto a cornea, and an "off" position for reflecting the beam away from the cornea. The computer is programmed to move the mirrors to the "on" position in a series of predetermined patterns, and the remaining mirrors to the "off" position, and to fire the laser during the presence of each pattern, so that corresponding patterns of tissue on the cornea are successively ablated therefrom.