When the CO2 laser's energy is defocused and not continuous (pulsed), the dermatologic surgeon can treat warts, shallow tumors and certain precancerous conditions. When the CO2 laser energy is continuous and focused into a small spot of light, the beam is able to cut the skin. It is used in this way to remove skin cancers, to treat a variety of nonvascular and pigmented lesions, and for eyelid operations. This technique is also used to remove warts and for some surgical incisions.