Role of Recent Microinvasive Surgeries in Treatment of Open Angle Glaucoma

Abstract

SUMMARY T he term "glaucoma" designates a pathophysiologically heterogeneous group of eye diseases whose common feature is that they result in a characteristic type of optic neuropathy if untreated. Primary open-angle glaucoma is the most common type of glaucoma world wide. Early diagnosis depends on examination of the optic disc, retinal nerve fibre layer, and visual field. The degree of protection is related to the degree to which intraocular pressure is lowered. The delicate cause of glaucomatous optic neuropathy is not known, although many risk factors have been identified, such as: increased IOP, family history, race, age more than 40 years old, and myopia. IOP is the most important and manipulated factor. Treatment of glaucoma starts by pharmacological reduction of the intraocular pressure, followed by laser surgery of the trabecular meshwork and (filtering) glaucoma surgery. Surgical treatment of glaucoma is usually undertaken when medical therapy is not appropriate, not tolerated, not effective, or not properly utilized by a particular patient, and the remains uncontrolled with either documented progressive damage or high risk of further damage. When surgery is indicated, the clinical setting must guide the selection of the appropriate procedure. While classic techniques have risks, they also have an established track record. The results, both good and bad, are well known. New surgical techniques offer the promise of less risky treatment, but their problems and long-term effectiveness is less understood. Several new surgical approaches have been developed in an effort to reduce complications associated with conventional glaucoma surgery. Each approach exploits a specific strategy to reduce the pressure within the eye. • The Ex-Press mini-shunt can be used with conventional trabeculectomy techniques to standardize the operation and perhaps reduce the chances of the eye pressure getting too low in the immediate post-operative period, which is occasionally a problem with conventional approaches. • The Trabectome device removes tissue from the drain inside they eye (the trabecular meshwork) using an electro-surgical handpiece that disrupts the tissue. • Canaloplasty involves the dilation of the entrance to the outflow pathways in the wall of the eye (Schlem's canal) in addition to constructing an artificial fluid outflow mechanism within the eye wall to reduce the pressure in the eye. • Endoscopic cyclophotoagulation (ECP) is 810 nm diode laser ECP is a relatively new method of cyclodestructive procedure to improve lOP control by reducing aqueous production. • The suprachoroidal shunt is designed to augment aqueous outflow from the anterior chamber to the suprachoroidal space. Microinvasive surgeries combine between advantages of classic suergeries and avoing their complications.