Deep sclerectomy versus subscleral trabeculectomy in glaucomatous eyes with advanced visual field loss

Abstract

Aim of the studyThe aim of the study was to determine the efficacy and safety of deep sclerectomy (DS) compared with subscleral trabeculectomy (SST) in patients with medically uncontrolled primary open angle glaucoma (POAG) and advanced visual field (VF) loss.DesignThe study was designed as a prospective, interventional, comparative trial.PlaceThe study was conducted at Ain Shams University Hospitals and in private practices.Patients and methodsForty eyes of 30 patients with medically uncontrolled POAG with advanced field loss underwent either DS or SST under topical anesthesia. Preoperative assessment included best-corrected visual acuity (BCVA) using Snellen's chart, anterior segment slit-lamp biomicroscopy, gonioscopy, applanation tonometry with the Goldmann tonometer, VF testing using Humphrey Field Analyzer, central 24°-2 and 10°-2 threshold test, and fundus examination including optic nerve head evaluation. The main outcome measures were BCVA, intraocular pressure (IOP), VF, lens status, and postoperative complications. The follow-up period was 24 months.ResultsPatients' mean age was 60 ± 8.6 years. Preoperatively, VF was constricted to less than central 10°, mean deviation was worse than −12 dB, cup/disc ratio was greater than 0.7, and neural rim thinness was found in all eyes. Preoperative IOP was 28.2 ± 2.5 mmHg (range 28-35 mmHg) and 27.8 ± 4.2 mmHg (range 24-36 mmHg) in groups I and II, respectively. Postoperative IOP was 17 ± 5.5 mmHg (range 12-20 mmHg) (P = 0.0066) and 18.2 ± 2.2 mmHg (range 12-22 mmHg) (P = 0.0077) at 24 months in groups I and II, respectively. The difference in mean IOP was statistically significant in comparison with baseline for both groups (P = 0.0001), but not significant between the two groups. The complete success rate was 60 and 65% and the qualitative success was 95 and 85% in groups I and II, respectively. Postoperative hyphema was reported in two eyes in group II, anterior uveitis in three eyes in group II, and self-limited shallow choroidal detachment was seen in two eyes in group I and in three eyes in group II. Long-term complication in the form of late bleb fibrosis occurred in two eyes in group II. Only one eye in group II developed more VF defects, and cortical cataract progressed in two eyes in group II.ConclusionDS appears to provide considerable control over IOP decrease with few postoperative complications and allows VF stabilization as well as preservation of BCVA. We believe that DS could be a valuable alternative to SST, especially in eyes with medically uncontrolled POAG and advanced field loss.