Evidenced-based comparison of aqueous shunts

Purpose of review This review provides an evidence-based comparison of aqueous shunts in common use. Recent findings Aqueous shunts are being used with increasing frequency in the surgical management of glaucoma. Recent retrospective studies and prospective clinical trials have compared the outcomes of different shunt designs. Larger end-plate size is associated with greater intraocular pressure (IOP) reduction, but there may be an upper limit beyond which a further increase in plate surface area does not contribute beneficially to pressure control. The biocompatibility of plate material may also influence shunt efficacy. The flow restrictor of the Ahmed glaucoma valve provides an added level of safety by reducing the risk of postoperative hypotony, but this implant also appears to have a higher incidence of bleb encapsulation. Summary Several aqueous shunts are commercially available, and all have been shown to be safe and effective in lowering IOP. Studies comparing aqueous shunts have provided valuable information to assist in surgical decision-making in similar patient groups.