Influence of picosecond and nanosecond YAG laser capsulotomy on intraocular pressure

To evaluate laser-induced intraocular pressure rise with three YAG lasers, I performed posterior capsulotomies on three groups of patients. Each group contained 100 nonglaucomatous patients who had extracapsular cataract extraction with and without lens implantation. In each group 50 patients were treated with prophylactic medications. The three YAG lasers were (1) a picosecond TEMoo, mode locked, ten-degree cone angle; (2) a nanosecond TEMoo, Q-switched, 16-degree cone angle, delivering the energy in five nanoseconds per pulse; and (3) a Q-switched, 15-degree cone angle, closer to multimode than TEMoo, delivering energy in 14 nanoseconds seconds per pulse. The energy delivered per pulse, the thickness of the lens material, the shape (mode) of the pulse, the optical delivery system, and the width of the shock wave appear to act on intraocular pressure and to be factors influencing the possibility of marking the lens.