A trabeculectomy is the most common type of surgical procedure performed to relieve pressure caused by glaucoma. During the procedure, a new drainage channel is created to ease drainage of fluid from the eye. This new opening allows fluid to drain out of the eye forming a bleb covered by the white outer covering (the conjunctiva) of the eye. Over time the drainage site can scar and therefore close up. Scarring is the main reason for failure of trabeculectomy. Anitmetabolites can be used to reduce the risk of scarring. Mitomycin C (MMC) is most commonly used antimetabolite in trabeculectomy surgery. Mitomycin C inhibits the multiplication of cells which produce scar tissue, thus preventing the scar formation.
Trabeculectomy with antimetabolites is generally recommended for reducing intraocular pressure in patients with advanced glaucoma.