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Complications and management of the filtration bleb.

Filtration surgery is the commonest operation performed for closed angle or open angle glaucoma when medical treatment or laser trabeculoplasty has failed to control the intraocular pressure. It is characterized by the formation of an artificial drainage fistula between the anterior chamber and subconjunctival space. The successful operation is evidenced by the appearance of a subconjunctival filtration bleb which in turn depends on the patency of this pathway. Despite numerous modification, the procedure trabeculectomy first described by Sugar in 1961 and later on popularized by Watson and Cairns in 1968 is the most popular filtration surgery performed nowadays. It is a safe, relatively easy operation which carries a success rate of around 76% to 84% with a small complication rate. Repeat filtration surgery, however, is often less successful, making a successful initial surgery critically important. A successful outcome of filtration surgery can be enhanced by preoperative preparation, meticulous technique with modification for individual case, and early identification and prompt treatment of the complications arisen.