The acronym "Laser" stands for light amplification by stimulated emission of radiation.  1. CO2 laser.  This laser allows wounds to heal rapidly with minimal scarring and is used for surface lesions such as genital warts or carcinoma in situ of the skin or glans penis. The CO2 laser may also be useful for the anastomosis in a vas reversal and possibly an evaporation of a meatal stricture. 2. ND:YAG laser.  This laser may be useful in transurethral removal of the prostate for treatment of prostatic obstruction and may bring about less bleeding. One application V-lap may ablate the tissue, whereas another may evaporate prostatic tissue. The ND:YAG laser may also be useful in treatment of urethral strictures, although stricture recurrence is still a major problem, as it is in any treatment option for urethral strictures. Surface lesions of the genitalia and the perineum in both men and women, such as genital warts and various superficial cancers, can be treated with the ND:YAG laser. However, the ND:YAG laser does cause a deeper thermal injury than the CO2 laser; but this may ensure a more complete treatment of the lesion.  3. Argon laser.  This type of laser has been used for bladder tumor coagulation and evaporation of urethral strictures.  4. Pulsed dye lasers Pulsed dye lasers, such as the Holmium laser. Usually the laser light is conducted from the laser tube to an endoscope, such as the ureteroscope, in a very thin monofilament quartz fiber to achieve a high power density at the tip. Commonly, the Holmium laser and the laser fiber are combined with a ureteroscope for ureteroscopic surgery, such as in the treatment of ureteral stones. The ureteroscope with attached camera may be advanced into the ureter and the laser fiber advanced onto the stone to break it up, whether in the ureter or in the kidney. This is usually done under an outpatient general anesthetic. The stones are fragmented by the light pulses exploding the stone. Stone fragments, if small enough, will be flushed out, whereas others may need to be retrieved with a small wire basket. Calciumoxalate monohydrate stones are the hardest to break, while uric acid, apatite, calcium oxalate dihydrate, and struvite stones are easier to break. A double-J stent ureteral catheter is placed in the involved ureter at the end of this case to prevent ureteral swelling causing pain. The stent is usually removed after 48 hours.  5. Continuous wave dye lasers Continuous wave dye lasers and photodynamic therapy have been used to treat bladder cancer by instilling a dye into the bladder and then activating the photochemically active substance through the laser light to make it cytotoxic to bladder cancer cells.