Abstract: Laser energe and power density producing damage at a probability of 0.5 （ie, damage threshold, DT-50） was determined for PMMA （with/without UV absorber）, Silicone, and Glass Intraocular Lenses. In order of increasing laser resistance the fillowing resalts were obtained: Silicone （79.22gW/cm²）, Glass （100.82gW/cm²）, Lathe-cut PMMA （115.23gW/cm²） and Castmoded PMMA （142.49gW/cm²）. It is recommended that only power levels below the damage thrashold to be used in photodiscission for posterior capsulotomy can minimize the risk of Nd, YAG laser IOL damage. Characteristic damage patterns were observed for IOLs ay scanninig electron microscopy.