Certain yellow light lasers may also be used to treat stretch marks and are safe and effective for infants and children. The krypton and Nd:YAG lasers are dual light systems. The uses of the yellow light are similar to those already described. The green light, in contrast, is used for the treatment of benign brown pigmented lesions, such as café-au-lait spots, the "old age" spots commonly found on the backs of the hands and lentigines or freckles. Green light lasers are also used for the treatment of small blood vessels on the face and legs. Red Light Lasers The red light spectrum produced by the ruby or alexandrite light laser is emitted in extremely short, high-energy pulses due to a technique known as Q-switching. The Q-switched ruby or alexandrite laser systems were initially used to remove tattoos, but are now commonly used to treat many brown pigmented lesions, such as freckles or café-au-lait spots. When the pulse duration of the ruby or alexandrite lasers is lengthened, it is effective in removing unwanted hair for long periods of time, sometimes even permanently. Other Lasers The Q-Switched Neodymium Yag (Nd: Yag) Delivering infrared light, it is used to remove tattoos and deep dermal pigmented lesions, such as nevus of Ota. This laser can also be tuned to produce a green light for the treatment of superficial pigmented lesions like brown spots, as well as orange-red tattoos. KTP The KTP emits a green light and is capable of treating certain red and brown pigmented lesions. When the pulse duration is lengthened, the Nd:YAG laser is also effective in removing hair and an inflammatory condition termed pseudofolliculitis barbae for months and sometimes permanently. This is particularly useful in the treatment of dark-skinned patients. PREVIOUS NEXT