The acronym ‘LASER’ of Nd:YAG crystal laser stands for light amplification by stimulated emission of radiation. A laser works by emitting a wavelength of high energy light, which when focused on a certain skin condition creates heat and destroys diseased cells. Wavelength is measured in nanometres (nm). The triply ionised neodymium [Nd(III)] dopant is a substance added in minute amounts to another pure substance to alter its conductivity, typically replaces a small fraction of the yttrium ions in the host crystal structure, since the two ions are of similar size. The neodymium ion provides the laser activity in the crystal. Nd:YAG laser has a wavelength of 1064 nm and has the capability to reach deeper layers of skin tissue than other types of lasers.

Nd:YAG laser is generally ineffective for light-coloured (blonde/grey) hair, but effective for treating dark (brown/black) hair in patients of Fitzpatrick types I to III, and perhaps light-coloured type IV skin. Extreme caution is recommended in tanned or darker-skinned patients, as the laser can also destroy melanin, resulting in white patches of skin (leukoderma). There are significant barriers to treatment with oral and topical antifungals. Successful treatment of onychomycosis requires antifungal drugs to penetrate the nail plate and nail bed, but this is often incomplete with oral and topical agents. The treatment of Nd YAG laser machine consists of placing a hand piece against the surface of the skin and activating the laser. Many patients describe each pulse feeling like the snapping of a rubber band against the skin.