LAUCOMA SURGERY has undergone a G continuous process of evolution. There has been significant impetus to search for more successful surgical techniques because of the risk of surgical failure after conventional filtration procedures. These include trephination, thermal sclerostomy, posterior lip sclerectomy, and trabeculectomy. Failure to control the intraocular pressure may occur because of preoperative characteristics, such as aphakia,lP2 young age,3 and race.4 African Americans respond less well to filtration surgery. Previous filter failures decrease chances of success following subsequent filtration attempt^.^ Perioperative factors contributing to failure include incarceration of iris, vitreous, or ciliary processes into the internal ostium.6 Blood or fibrin may also occlude the ostium. Excessive conjunctival and episcleral inflammation and hemorrhage, tissue manipulation, subconjunctival fibrosis, tight scleral sutures, and uveitis can lead to closure of the sclerectomy opening and bleb Trabeculectomy is a guarded filtration procedure distinct from the other available procedures. Postoperative complications associated with fullthickness surgery are higher, leading to trabeculectomy as the preferred procedure of most surgeon^.^ Patients who have had repeated surgical failures following conventional filtration procedures and patients with neovascular glaucoma that does not respond to routine glaucoma surgery may do better with drainage shunts and implants.lOJ1 The recognition of the importance of wound healing as a cause of surgical failure has led to the widespread use of wound modulating agents, such as 5-flU01-0uracil, and recently mitomycin-C, with improved suc~ess.~~J~