The use of a neodymium-YAG laser is described for opening the opacified posterior capsule in a pseudophakic eye. Both pigmented and nonpigmented ocular tissues were cut without causing adverse thermal effects and without opening the eye. The laser's instantaneous release of energy causes total ionization of the medium and formation of a plasma, followed by a hydrodynamic shock wave originating at the energy zone boundary. The temperature at the site of laser contact cannot exceed 2 x 10(-3) degrees C, which is not harmful to the eye. Further, this procedure requires no anesthesia and does not involve introduction of foreign material into the eye. The degree of aiming accuracy, the very small diameter of the laser beam (50 microns) and the use of selector pulses make the laser so precise that it virtually eliminates the risk of damage to the eye or the intraocular lens.