Which laser is used in the management of after cataracts?
Ans. is 'c' ie Nd-YAG {Ref: Parson, 19/e, p297; Khurana, 3/e, p208) Nd: YAG (Neodymium-Yttrium-Aluminium-Garnet) laser is used for posterior capsulotomy in cases of after cataract. After cataract, secondary cataract or posterior capsule opacification (PCO), is the opacity which follows extracapsular extraction of the lens. After ECCE the lens is composed of the remaining capsule and the residual epithelial cells and cortical fibres that were not removed at the time of surgery. These epithelial cells still possess the capacity to proliferate, differentiate and undergo fibrous metaplasia. Accumulation of these cells lead to after cataract. After cataract or PCO can be of three type Fibrosis type. Pearl type (Elschnig pearls)* Soemmerring's ring* Fibrosis type the proliferated epithelial cells deposit on the posterior capsule and form multiple layers which leads to frank opacification. Elschnig's pearls at times, the subcapsular cells proliferate and instead of forming lens fibres, develop into large balloon-like cells which sometimes fill the papillary aperture. Soemmerring's ring the proliferated fibres sometimes, form a ring, enclosed between the two layers of the capsule k/ a Soemmerring's ring. Treatment after cataract if thin, can be cleared centrally by Nd-YAG laser capsulotomy. If thick, especially in children, they may require discission or can be removed by vit. reous cutter. LASERS USED IN OPHTHALMOLOGY LASER CLINICAL APPLICATION Nd: YAG Posterior Capsulotomy, iridotomy, vitreolysis Frequency-doubled Nd: YAG Retinal photocoagulation, cyclophotocoagulation Argon green Trabeculoplasty, iridoplasty, pupillo mydriasis, retinal photocoagulation Diode laser Retinal photocoagulation Krypton red Retinal photocoagulation Excimer (Argon fluoride) Photorefractive keratectomy (PRK) Phototherapeutic keratectomy (PTK) LASIK, LASEK
Argon
Krypton
Nd-YAG
Excimer
Surgical Techniques for Cataract Extraction