Nonpenetrating glaucoma surgery.

Nonpenetrating glaucoma surgery continues to evolve and improve. New technical refinements and increased experience among its practitioners have led to improved efficacy and longer duration of filter survival. These refinements include the use of intraoperative and postoperative antimetabolites, adjunctive space-maintaining devices, and postoperative yttrium-aluminum-garnet laser goniopuncture. Deep sclerectomy and viscocanalostomy vary significantly in their surgical approaches and mechanisms of aqueous outflow. An understanding of the microanatomy of the aqueous outflow structures is necessary to gain surgical access to Schlemm's canal and to augment aqueous outflow surgically through the trabecular meshwork. Indications and contraindications for nonpenetrating glaucoma surgery are discussed.