Eligible eyes are randomly assigned to one of two intervention sequences: (1) trabeculectomy, followed by argon laser trabeculoplasty (ALT) should trabeculectomy fail, followed by a second trabeculectomy should ALT fail; or (2) ALT, followed by trabeculectomy should ALT fail, followed by another trabeculectomy should the first trabeculectomy fail. Antifibrotic agents may be used as an adjunct to trabeculectomy, but only in eyes with a previous history of invasive surgery. Eyes that fail the entire assigned sequence of interventions are managed at the discretion of the AGIS physician in collaboration with the patient.