Conversion from trabeculectomy to deep sclerectomy. Prospective study of the first 44 cases

To evaluate the outcomes of conversion from trabeculectomy to deep sclerectomy with placement of a drainage implant.

Department of Ophthalmology, Hospital of Buskerud, Drammen, Norway.

Deep sclerectomy was performed in 41 patients (44 eyes) from November 1999 to January 2002. An absorbable implant (AquaFlow((R)), Staar Surgical) and a nonabsorbable implant (T.Flux((R)), IOLTech Laboratories) were used in 75% and 25% of eyes, respectively. Patients with open-angle glaucoma who needed filtering surgery were enrolled consecutively in a prospective study. Patients with 2 or more previous filtering surgeries or neovascular glaucoma were excluded, as were children. Of the original 48 eyes, accidental perforation of the trabeculo-Descemet's membrane occurred in 8.3%; these eyes were excluded from the study. The severity of optic nerve damage was considered in the decision to start therapy. An intraocular pressure (IOP) above 22 mm Hg was always treated.

After a mean follow-up of 12.9 months +/- 7.1 (SD), 61.4% of eyes were controlled without therapy. When eyes with previous surgery were excluded, the rate increased to 66.7% after a mean follow-up of 13.8 +/- 7.2 months. The mean IOP preoperatively and after 12 months was 27.9 +/- 6.9 mm Hg and 14.6 +/- 3.5 mm Hg, respectively (P<.001). The mean number of medications decreased from 3.4 +/- 1.0 preoperatively to 0.6 +/- 1.1 12 months postoperatively (P<.001). A reoperation was required in 2 cases (4.5%). There were no complications related to hypotony or other significant complications.

This study shows that conversion from trabeculectomy to deep sclerectomy with placement of an implant is safe. The postoperative IOP reduction was acceptable, and no significant complications occurred.