Four eyes underwent cicatricial closure of the filtering bleb within the 6 weeks postoperatively. They failed to respond to digital massage and conventional therapy, resulting in loss of bleb and elevated intraocular pressure. The average pre-YAG laser treatment intraocular pressure was 34.5 mmHg. Three hundred to five hundred applications from the mode-locked Neodymium:YAG laser ( Meditec ) delivered at 3.5 mJ were directed through a goniocontact prism to the surgical area. Prompt vaporization of scar tissue and sclera resulted in a dramatic reversal of the pathology. Forty-eight hours after treatment and with a cessation of carbonic anhydrase inhibitors, an average 20 mm Hg drop in intraocular pressure was achieved. The bleb reformed in each case and maintained its patency for a minimum follow-up of 6 months.