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Abstract The word laser is a cronym of (light Amplification by Stimulated Emission of Radiation). The laser beam is a highly coherent beam and relatively monochromatic and can be focused in small area. The common laser used in opthalmology are Argon and Krypton (red and yellow), Dye, C0 2 , frequency double neodymium YAG and YAG are more recent lasers and are in use but not common as the previous two. Ruby laser is the oldest one and nearly not in use while excimer laser is the most recent laser now known and it is mostly used exper~nentally. Laser can be used in the treatJJ.ent of the anterior segment disorders as in glaucoma, some iris disorders, pupil disorders, in some lens condition and recently even tried in treatment of pterygium and even more recently excimer laser is tried in corneal surgery. In Glaucoma, there are many procedures used for the treatment of glaucoma as: Trabeculoplasty: In which the laser shots are applied in the anterior part of the trabecular meshwork. This will result in shrinkae;e of the collagenous component of the trabecular meshwork, decreasing its diameter and- 109 - increase the \Vidth of the intertrabecular spaceses and result in improvement in aqueous outflow. 100 laser burns are applied to )60 degrees or 50 burns to 180 degrees of trabecularmeshwork. Goniophotocoagulation: Laser photocoagulation of neovascular vessels where they cross the scleral spur in cases of neovascular glaucoma with open angle. Trabeculostomy: used to control the neovascular glaucoma. In this procedure the trabecular meshwork tissue is vaporised by C0 2 laser until the anterior chamber is perforated. Gonioplasty: coagulation of the iris root to contract the iris away from the angle and trabecular meshwork. Pupilloplasty: used to contract the sphincter in a small area, peak the pupil and establish a connection between the posterior and anterior chamber. Photocoagulation of the ciliary process by the argon or Nd - YAG laser for the treatment of aphakic malignant glaucoma.- no - Cyclocoagulation: 32 laser burns of Ruby laser are applied circurnferentially 3.5 mm from the limbus to decrease the production of aqueous humor. In iris disorders: laser can be used to treat different types of iris cyst as iris cyst in the anterior surface, pigment epithelial cyst and dislodges pigmented iris cyst in the anterior chamber. In pupil disorders: laser photomydriasis: used to minimize the miotic effect of the antiglaucoma medication and to allow aqueous fluid to move from the posterior to the anterior chamber and thereby break an attack of pupillary block glaucoma. Laser coreoplasty: to correct the displacement of the pupil away from the visual axis. This by laser application in a radial direction from the pupilary margin or in the area just il1J3id the outer limit of the iris collerate. In lens disorders: By the Nd- YAG laser can open opaque posterior capsule after extracapsular cataract extraction in aphakic or psudophakic eye. YAG laser anterior capsulotorny one day before extracapsular cataract extraction operation make the procedure of the operation more easier.- 111-- In pterygium: after extraction of the pterygium, laser photocoagulation of the blood vessels in this area Vlill prevent recurrence of the pterygium. |