Nonpenetrating Glaucoma Surgery (Deep Sclerectomy, Viscocanaloplasty, and Canaloplasty)

Performing nonpenetrating glaucoma procedures (NPGS) requires a high level of skill. The proposed advantages of NPGS have to be considered in context of the long learning curve and the complications. Inadequate dissection of the filtration membrane, the trabeculo-Descemet’s membrane (TDM) is not uncommon and may result in filtration failure. Intraoperative perforations of the TDM make the procedure similar to a trabeculectomy with the attendant risks. Complications after a routine NPGS procedure are rare and self-limiting. Early hypotony after deep sclerectomy (DS), a conjunctival bleb-dependent NPGS procedure should not be considered a complication. Viscocanaloplasty and canaloplasty (VCT), nonbleb dependent NPGS procedures, often have transient hyphema in the immediate postoperative period due to Schlemm’s canal manipulation. DS procedures have bleb-related complications similar to trabeculectomy. Adjunctive use of mitomycin C may increase the risk of bleb-related infections and hypotony. Detachment of the Descemet’s membrane is an uncommon complication s and may result in failure of the procedure. Laser goniopuncture (LGP) is often performed after DS and can reestablish filtration in a significant majority of eyes. The sudden lowering of IOP after LGP may result in choroidal detachments and suprachoroidal hemorrhage. LGP also increases the risk of iris incarceration and occasionally acute, symptomatic IOP elevation.