Commentary on: Bent ab interno needle goniectomy: Redefining the angle-based approach in glaucoma

Bent ab interno needle goniectomy (BANG) has emerged as a promising addition to the armamentarium of minimally invasive glaucoma surgeries (MIGS). Among MIGS techniques, goniectomy-based approaches offer a distinct advantage: achieving intraocular pressure (IOP) reduction while preserving the structural integrity of the trabecular meshwork–Schlemm’s canal (TM–SC) outflow pathway.[1]

BANG employs a 25-gauge hypodermic needle, bent at the tip, to excise a segment of the trabecular meshwork via an ab interno approach.[2] This configuration enhances the surgeon’s ability to access and navigate the angle with greater control, particularly in anatomically challenging eyes. It facilitates precise engagement of the TM, smoother entry into Schlemm’s canal, and minimizes collateral tissue damage.

The ab interno route preserves conjunctival integrity, limits postoperative inflammation, and supports faster visual recovery. The simplicity of the bent-needle design represents a low-cost yet impactful innovation, improving both surgical ergonomics and access to Schlemm’s canal. Its recent evolution into the irrigating BANG (i-BANG) technique further improves intraoperative chamber stability and visualization while maintaining affordability and procedural simplicity.[3]

The American Academy of Ophthalmology’s Glaucoma Preferred Practice Pattern Committee has recently defined surgical success for MIGS combined with cataract extraction and intraocular lens implantation (CE-IOL) as either (1) a reduction in IOP of ≥20% from baseline without an increase in medications or (2) a reduction of at least one glaucoma medication without an increase in IOP—both without requiring additional glaucoma surgery, laser treatment, hypotony, or loss of light perception.[4]

In this context, BANG has demonstrated encouraging early outcomes. Maheshwari et al. and Bukke et al. reported significant IOP reduction and reduced dependence on glaucoma medications following BANG combined with phacoemulsification in patients with open-angle glaucoma.[1,5] Its applicability has also been validated in pediatric glaucoma. Kaushik et al., in a randomized controlled trial, demonstrated that BANG performed comparably to traditional goniotomy in primary congenital glaucoma.[6]

It is a minimally invasive option for managing mild to moderate open-angle glaucoma, but it comes with notable limitations. The procedure depends mainly on clear visualization of the angle and a surgeon’s proficiency with gonioscopic techniques, making it less ideal in patients with corneal opacities or narrow angles. While appealing for its simplicity and affordability, BANG’s IOP-lowering effect is modest and may not suffice for advanced or complex glaucoma. Risks such as hyphema, variable surgical outcomes due to the manual nature of the technique, and limited long-term data further temper its appeal.

However, like other angle-based procedures, BANG’s long-term durability warrants consideration. Dada et al. have reported cases of late closure of the trabecular cleft, suggesting that outflow patency may diminish over time, depending on individual patient and surgical factors.[7] Additionally, its IOP-lowering effect may be less pronounced in advanced glaucoma, and many patients may still require postoperative anti-glaucoma medications.[5]

Aqueous angiography has recently emerged as a valuable adjunct to enhance the precision of angle-based interventions. Dada et al. demonstrated that targeting regions of physiologically high aqueous outflow using angiography can improve outcomes and reduce variability in surgical efficacy.[8] These findings lay the groundwork for personalized MIGS approaches in the future. The development of new surgical procedures should aim not only to lower intraocular pressure but also to minimize complications and be cost-effective.[9]

In conclusion, bent ab interno goniectomy represents a pragmatic, tissue-sparing, and cost-effective enhancement within the MIGS spectrum. Its adaptability, favorable safety profile, and ease of integration with cataract surgery make it a valuable tool for glaucoma surgeons, particularly in settings that prioritize early surgical intervention and resource optimization.