Erbium-YAG and holmium-YAG laser ablation of the lens

Er-YAG (2.9 microns, 200 microseconds pulsewidth) and Ho-YAG (2.12 microns, 250 microseconds pulsewidth) lasers were used to irradiate bovine crystalline lenses. Mass ablated increased with increasing fluence for both lasers and was greater for the Er-YAG than the Ho-YAG laser at all fluences. The mass loss vs. fluence curve was nonlinear for the Er-YAG and linear for the Ho-YAG laser. Ablation threshold was lower for the Er-YAG. Grossly, the Er-YAG laser produced less charring and expressed fewer, smaller tissue pieces than the Ho-YAG. Scanning electron microscopy indicated that the Er-YAG produced smoother walled craters. The Ho-YAG laser produced more dessicated and disrupted craters. The Er-YAG radiation, delivered by fiberoptic probes, may provide a method of performing minimally invasive cataract surgery.