An Ultrasound Biomicroscopy Study of Filtering Blebs after Deep Sclerectomy with a New Acrylic Implant

Abstract

To identify the clinical and anatomic characteristics of filtering blebs after nonpenetrating deep sclerectomy (NPDS) using ultrasound biomicroscopy, and to evaluate its influence on intraocular pressure (IOP) control. We conducted a prospective interventional case series in 18 eyes of 18 patients who had undergone nonpenetrating deep sclerectomy with Esnoper® implant. A complete ophthalmic examination and ultrasound biomicroscopy (UBM) exploration were performed at 1, 3, and 6 months postoperatively. Intraocular pressure significantly decreased from a mean of 23.5 mmHg (SD 3.5) preoperatively to a mean of 13.1 mmHg (SD 7.6), 13.2 mmHg (SD 4.3), and 13.3 mmHg (SD 3) at 1, 3, and 6 months postoperatively, respectively. At 6 months, lower IOP levels significantly correlated with hyporeflective blebs (r=-0.82, p=0.000), with the presence of hyporeflective suprachoroidal space (r=-0.67, p=0.003) and with the presence of hyporeflective area around the scleral lake (r=-0.55, p=0.02). The presence of these 3 filtration signs together correlated with lower IOP levels compared with the presence of only 1 or 2 (p=0.000, p=0.004, p=0.0005) at 1, 3, and 6 months postoperatively, respectively. A thinner trabeculo-descemetic membrane (TDM) was significantly correlated with lower postoperative IOP value at the first postoperative month (r=0.45, p=0.05). Intraocular pressure mean values and UBM characteristics were not significantly different between eyes with single NPDS and eyes following combined NPDS-phacoemulsification. At 6 months, eyes without goniopuncture had lower IOP values (p=0.02), higher bleb (p=0.015), and thinner TDM (p=0.01) than those needing goniopuncture. Ultrasound biomicroscopy is a useful method to evaluate outflow mechanisms after NPDS and their correlation with postoperative IOP control.