Which laser is used in the management of after cataracts: March 2011
Ans. C: Nd-YAG 'After' cataracts, if thin, can be cleared centrally by a YAG laser capsulotomy Nd:YAG/ Neodymium-doped yttrium aluminium garnet/ Nd:Y3A15O12 It is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, typically replaces yttrium in the crystal structure of the yttrium aluminium garnet (YAG), since they are of similar size. Generally the crystalline host is doped with around 1% neodymium by atomic percent. Nd:YAG lasers are optically pumped using a flashtube or laser diodes. Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940,1120,1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so called Q-switching mode: Nd:YAG absorbs mostly in the bands between 730-760 nm and 790-820 nm. At low current densities krypton flashlamps have higher output in those bands than do the more common xenon lamps, which produce more light at around 900 nm. The former are therefore more efficient for pumping Nd:YAG lasers Uses Nd:YAG lasers are used in ophthalmology to correct posterior capsular opacification, a condition that may occur after cataract surgery, and for peripheral iridotomy in patients with acute angle-closure glaucoma, where it has superseded surgical iridectomy. Frequency-doubled Nd:YAG lasers (wavelength 532 nm) are used for pan-retinal photocoagulation in patients with diabetic retinopathy. In oncology, Nd:YAG lasers can be used to remove skin cancers. These lasers are also used extensively in the field of cosmetic medicine for laser hair removal and the treatment of minor vascular defects such as spider veins on the face and legs. Using hysteroscopy the Nd:YAG laser has been used for removal of uterine septa within the inside of the uterus. In podiatry, the Nd:YAG laser is being used to treat onychomycosis, which is fungus infection of the toenail.
Argon
Krypton
Nd-YAG
Excimer