Thirty eyes of 30 patients underwent tight scleral flap trabeculectomy. Of these eyes, 22 underwent laser lysis of the scleral flap sutures, whereas eight eyes did not require such treatment because of low intraocular pressure and active filtering blebs. In the 22 eyes treated, preoperative intraocular pressure was 32.6 +/- 8.3 mm Hg, whereas postoperative and pre-laser intraocular pressure was 29.3 +/- 7.4 mm Hg. Immediately after laser suture lysis, intraocular pressure dropped by 22.7 +/- 9.4 mm Hg (P less than .01) to 6.6 +/- 7.0 mm Hg, with elevation of the conjunctival bleb in all eyes treated. After a mean follow-up of 14.4 months, intraocular pressure was controlled (less than or equal to 18 mm Hg) in 20 of the 22 eyes treated (91%). The only major complication was a single case of anterior chamber flattening with intraocular lens touching the corneal endothelium. Combination of tight scleral flap trabeculectomy with subsequent postoperative laser suture lysis is a safe and effective method for low-level intraocular pressure control. This technique seems to combine the advantages of full-thickness filtration and trabeculectomy by achieving relatively low intraocular pressures while minimizing complications caused by excessive aqueous runoff.