Bio-Interventional Cyclodialysis and Allograft Scleral Reinforcement for Uveoscleral Outflow Enhancement

Open-angle glaucoma (OAG) remains a leading cause of irreversible blindness worldwide, with intraocular pressure (IOP) reduction serving as the only proven strategy to slow disease progression. While most contemporary minimally invasive glaucoma surgery (MIGS) procedures target the conventional trabecular outflow pathway, relatively few interventions address the uveoscleral pathway despite its substantial contribution to aqueous humor drainage and its role as the primary target of prostaglandin analog therapy. Bio-interventional cyclodialysis with allograft scleral reinforcement is a novel surgical approach that revisits the historical cyclodialysis procedure while addressing its principal limitation: premature fibrotic closure of the supraciliary cleft. This review summarizes the rationale, biomaterial properties, surgical technique, and clinical outcomes associated with the AlloFlo allogeneic scleral bio-scaffold and CycloPen delivery system (Iantrek, Inc., White Plains, NY). The procedure combines ab-interno cyclodialysis, viscocycloplasty, and endoscleral placement of a minimally modified homologous scleral allograft designed to maintain long-term patency of the uveoscleral outflow conduit. The biologic scaffold provides structural reinforcement without rigid intraocular hardware and minimal presence in the anterior chamber. Available clinical evidence, including peer-reviewed studies and a recent preprint, includes the multicenter CREST (Study of the CycloPen Micro-Interventional System and Long-Term Clinical Outcomes) registry, a standalone CREST cohort, and an independent 24-month single-center series. The CREST registry includes both standalone AlloFlo implantation and implantation combined with cataract surgery across 12 study sites. All aforementioned studies demonstrated significant IOP lowering with decreased medication burden. Across these studies, no vision-threatening adverse events, implant migration, severe inflammation, or biotissue-corneal touch were reported. Corneal endothelial cell loss remained within ranges expected following cataract surgery alone. Bio-interventional cyclodialysis with allograft scleral reinforcement represents a promising strategy for surgical uveoscleral outflow enhancement. Early clinical results demonstrate meaningful and durable IOP reduction with a favorable safety profile, although randomized comparative studies and longer-term follow-up are needed to further define its role in glaucoma management.