B i.e. Nd-YAG laser Nd. YAG (Neodymium-Yttrium-Aluminium-Garnet) laser is used for posterior capsulotomy in after cataract.Q After cataract/ Secondary cataract/ Posterior Capsular Opacification (PCO) - It is the opacity which persists or develops after ECCE - It may present as thickened posterior capsule or dense membranous after cataract or Soemmering's ringQ (thick ring of after cataract formed behind the iris, enclosed between the two layers of capsule) or Elschnig's pearlsQ (vacuolated subcapsular epithelial cells are clustered like soap bubbles along the posterior capsule) - It is treated by Nd-YAG-laser posterior capsulotomyQ (Neodymium-Yttrium-Aluminium-Garnet laser) or surgical membranectomy Laser Wavelength (nm) Clinical Application of LASERS in Ophthalmology Nd: YAG 1064Q Posterior capsulotomy Q, iridotomy, vitreolysis. Femtosecond laser 1053 Refractory surgery, lamellar corneal surgery. Diode laser 800 Retinal photocoagulation* Krypton laser 714 Retinal photocoagulation* Frequency doubled Nd: YAG 532 Retinal photocoagulation*, cyclophoto-coagulation Argon green 514 Retinal photocoagulation*, trabeculoplasty, iridoplasty, pupillo-mydriasis Excimer (Argon-fluoride) 193 Photorefractive keratectomy (PRK), phototherapeutic keratectomy (PTK), LASIK, LASEK Retinal photocoagulation includes treatment for diabetic retinopathy, other causes of retinal neovascularization or oedema, retinal breaks, central serous retinochoroidopathy, subretinal neovascular membranes, small retinal tumors, angiomas. Argon green laser is m.c. used for this.