Sylvia Jungkim, FRCSI

Glaucoma shunt valves are frequently chosen for the treatment of refractory glaucoma that has been unresponsive to medical and surgical filtration measures. The shunt valves mainly fall into two categories, restrictive and nonrestrictive. The Ahmed glaucoma valve, introduced in 1993, is a restrictive valve. Its structural specifications allow a simple operative procedure, self-regulation and prevention of postoperative complications.