Definitive managenment in primary angle closure glaucoma: March 2005
Ans. C: Laser iridotomy Although intraocular pressure is only one of the major risk factors for glaucoma, lowering it various pharmaceuticals and/or surgical techniques is currently the mainstay of glaucoma treatment. A. Medications used for lowering intraocular tension: Prostaglandin analogs like latanoprost, bimatoprost and travoprost increase uveoscleral outflow of aqueous humor. Bimatoprost also increases trabecular outflow Topical beta-adrenergic receptor antagonists such as timolol, levobunolol, and betaxolol decrease aqueous humor production by the ciliary body. Alpha2-adrenergic agonists such as brimonidine work by a dual mechanism, decreasing aqueous production and increasing uveo-scleral outflow. Less-selective sympathomimetics like epinephrine and dipivefrin increase outflow of aqueous humor through trabecular meshwork and possibly through uveoscleral outflow pathway, probably by a beta2-agonist action. Miotic agents parasympathomimetics like pilocarpine work by contraction of the ciliary muscle, tightening the trabecular meshwork and allowing increased outflow of the aqueous humour. Carbonic anhydrase inhibitors like dorzolamide, brinzolamide, acetazolamide lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body. B. Conventional surgery to treat glaucoma makes a new opening in the meshwork. This new opening helps fluid to leave the eye and lowers intraocular pressure. Canaloplasty is a nonpenetrating procedure utilizing microcatheter technology. By opening the canal, the pressure inside the eye may be relieved. Laser trabeculoplasty may be used to treat open angle glaucoma. It is a temporary solution, not a cure. Nd: YAG Laser peripheral iridotomy reduces the risk of developing an attack of acute angle closure. In most cases it also reduces the risk of developing chronic angle closure or of adhesions of the iris to the trabecular meshwork. It is mandatory after reducing the intraocular pressure in all eyes with any form of primary angle-closure glaucoma and also prophylactically in the unaffected eye. Diode laser cycloablation lowers IOP by reducing aqueous secretion by destroying secretory ciliary epithelium. Trabeculectomv allows fluid to flow out of the eye through this opening, resulting in lowered intraocular pressure.
Trabeculectomy
Surgical iridectomy
Laser iridotomy
Pilocarpine