Deep sclerectomy with Nd:YAG laser trabeculotomy ab interno: two-stage procedure

We performed almost the same procedure as Weber's two-stage Nd:YAG laser trabeculotomy. Our technique, developed without knowledge of Weber's findings, also is composed of two stages. In Stage 1, under conjunctival and thin scleral flaps, the deep (4 x 2 mm) scleral block containing the outer wall of Schlemm's canal is removed. Stage 2, the puncturing of the remaining trabeculum with Q-switched Nd:YAG laser, is performed the next day. We evaluated the technique in 16 eyes of 11 patients with medically uncontrolled phakic open-angle glaucoma and one eye of a pseudophakic patient with a Binkhorst 2-loop lens. All eyes had unacceptable intraocular pressures (IOPs), despite maximum tolerated medical therapy, and two 360 degrees argon laser trabeculoplasties. The mean preoperative and final postoperative IOPs were 38.3 +/- 19.1 mm Hg and 16.9 +/- 5.3 mm Hg, respectively. Follow-up time was at least 12 months and the results of a 12-month postoperative period were used in all cases. Final postoperative IOP was less than 21 mm Hg in 12 eyes (70%). The only complication during intraoperative and postoperative periods was extremely slight bleeding from the trabeculum or Schlemm's canal in Stage 2; this bleeding was completely absorbed by the following day.