Mitomycin-augmented non-penetrating deep sclerectomy: preoperative gonioscopy and postoperative perimetric, tonometric and medication trends.

Background/aims: Non-penetrating deep sclerectomy (NPDS) can enhance drainage of aqueous humour without disrupting the trabecular endothelial layer, reducing risks of postoperative hypotony and hyphema. This study explores associations of angle morphology with surgical efficacy in eyes with open and obstructed angles.

Methods: Eighty-nine consecutive eyes undergoing successful NPDS (non-implant, with 0.4 mg/ml mitomycin C and limbus-based two-layer closure) were studied in this institutional review board-approved retrospective quality assurance study. Postoperative complication frequency, intraocular pressure (IOP), glaucoma medications required and acuity were monitored (baseline vs 3, 6, 9, 12 and 18-month postoperative levels), along with 30-2 Humphrey MD and corrected pattern standard deviation (CPSD) (baseline vs 6, 12 and 18-month postoperative values). Preoperative gonioscopy was compared with the subsequent requirement for specific postoperative interventions.

Results: IOP at all five postoperative intervals was reduced (22 ± 0.9 to 12 ± 0.5 mm Hg; p<0.0001). No hyphema were observed. Postoperative hypotony (IOP < 4 mm Hg) occurred rarely (8/445; 1.8%). Mean glaucoma medication use dropped from 3.1 ± 0.1 to 0.23 ± 0.1 at 18 months (p<0.0001). Mean 30-2 MD improved by approximately 1.4 dB at 6, 12 and 18 months (p<0.002); CPSD remained stable.

Conclusions: Following NPDS, a sustained IOP decrease of 10 mm Hg (45%) was attained, with stable acuity, increased perimetric generalised light sensitivity and 90% reduction in medical therapy requirement. Morbidity risk was associated with narrow gonioscopic angle insertion and synechia, but not with shallow approach or trabecular pigmentation.