Aqueous shunts with extraocular reservoir lower IOP in adults with OAG

Adults with open-angle glaucoma (OAG) may benefit from the implantation of aqueous shunts with extraocular reservoir, including valved or nonvalved devices, which can reduce intraocular pressure (IOP), as shown in a study.

“Strong level I evidence supports the use of aqueous shunts with extraocular reservoir by clinicians for the management of adult OAG,” the authors said.

In April 2023, the PubMed database was searched for peer-reviewed literature to identify studies published since the last aqueous shunt Ophthalmic Technology Assessment, which evaluated articles published prior to 2008.

The authors examined abstracts of 419 articles and selected 58 studies for full-text analysis. Of these, 28 articles were selected and assigned ratings by the panel methodologist based on the level of evidence. Twenty-five articles were rated level I, and three were rated level II. No articles were rated level III.

Implanted aqueous shunts with extraocular reservoir reduced IOP by between one-third and one-half of the baseline IOP, depending on whether it was carried out as the primary or secondary glaucoma surgery. Aqueous shunts demonstrated better success rates than trabeculectomies in eyes with prior incisional surgery.

On the other hand, implantation of aqueous shunts as the primary glaucoma procedure in eyes without prior incisional surgery showed an overall lower success rate than trabeculectomy.

Both valved and nonvalved aqueous shunts with extraocular reservoir were effective, but the latter device attained slightly lower long-term IOPs with fewer glaucoma medications and less need for additional surgery. The two devices reduced the visual field progression rates, demonstrating an efficacy akin to that of trabeculectomy.

“Early aqueous humor suppression after aqueous shunt implantation is recommended for the management of the postoperative hypertensive phase and long-term IOP control,” the authors said. “No strong evidence supports the routine use of mitomycin C with aqueous shunt implantation for OAG.”