The Yag Laser is a laser emitted by Nd:Yag, with a wavelength of 1064 nm (neodymium), is a crystal used in solid state lasers (as opposed to others contained in gas chambers), which causes tissue rupture by delivering a short, high-power pulse.
Initially used in ophthalmology to open the posterior capsule of the lens (YAG capsulotomy) in cataract surgery, because in some cases, after a few months or years, the posterior capsule of the lens becomes opacified and vision becomes blurred. The posterior capsule is the only structure of the lens that is maintained during cataract surgery as it is used to house the intraocular lens that replaces the opacified lens. As the lens is much thinner than the natural lens, the capsule tends to retract and sometimes creates areas of scarring. This causes a loss of transparency with a low acuity similar to the initial one. The YAG laser easily resolves the situation, in a simple, painless procedure carried out in the consultation room. Clear vision is immediately restored.
Later, it was also used in glaucoma closed angle glaucoma (YAG iridotomy).
The Yag laser iridotomy is a quick and painless procedure which consists of making a small hole in the periphery of the iris using a laser. The procedure is indicated as prophylactic treatment in situations where the irido-corneal angle is narrow in order to avoid acute glaucoma This is caused by the closure of the angle by the iris root, causing pupillary blockage (the aqueous humour is prevented from draining and accumulates, thus increasing the ocular pressure). In other situations, the blockage may be caused by an anterior or posterior chamber phakic lens or as a result of iris adhesions to the posterior surface of the cornea (anterior syncytia) or to the anterior capsule of the lens after very severe inflammatory situations, as is the case with uveitis.
The iridotomy can open a passage, a bypass, for the aqueous humour, solving the blockage between the anterior chamber (the space between the cornea and the iris) and the posterior chamber (the place behind the iris where the ciliary processes, responsible for the production of aqueous humour, are located), balancing the ocular pressure.