Aqueous angiography guided ab interno trabecular surgery for open-angle glaucoma

Clinical applications of aqueous angiography in glaucoma

Aqueous humor outflow (AHO) pathways are the main site of resistance causing elevated intraocular pressure in glaucoma, especially primary open-angle glaucoma patients. With the recently introduced technique of aqueous angiography (AA); functional, real time assessment of AHO from proximal (trabecuar meshwork) to distal pathways under physiological conditions has been made possible. AHO pathways are segmental, and AA can identify high-flow region (increased angiographic signals) and low flow region (decreased angiographic signals) in an individual. With the introduction of canal-based minimally invasive glaucoma surgeries (MIGS), the assessment of AHO can help guide the placement of stents/incisions during MIGS procedures. This can allow individualized and targeted MIGS procedures in glaucoma patients for better results. Based on the density of AHO pathways visualized on AA, surgeons can decide whether to perform MIGS or conventional glaucoma surgery for improved outcomes for the patient. Immediate intraoperative assessment for functionality of the MIGS procedure performed is possible with AA, allowing for surgical adjustments of MIGS procedure in the same sitting, if needed. This review provides a summary of the studies performed with AA to date, with a special focus on Indian patients. It covers the basics and clinical applications of AA for improving surgical outcomes in glaucoma patients.

Analyzing the Shortcomings of Trabecular Micro-bypass Stents for Surgical Management of Glaucoma

How to cite this article: Dada T, Beri N. Analyzing the Shortcomings of Trabecular Micro-bypass Stents for Surgical Management of Glaucoma. J Curr Glaucoma Pract 2024;18(1):1-3.

Viscodilation of Schlemm's Canal Combined with Goniectomy Using a 30 G Needle (Visco-Bent Ab Interno Needle Goniectomy)

Background and aim

Bent ab interno needle goniectomy (BANG) is a low-cost minimally invasive glaucoma surgery (MIGS) technique that has gained wide popularity in developing nations. However, the risk of injury to surrounding angle structures and especially the outer wall of Schlemm's canal (SC) is the main drawback of this technique. We describe a simple and easy-to-perform modification, "Visco-BANG," to improve the safety and efficacy of the BANG procedure.

Technique

A 30 gauge (G) needle attached to a syringe filled with cohesive viscoelastic is used. The needle is bent at the proximal junction of the bevel with bevel towards the operating surgeon. The needle is then inserted into the SC and viscoelastic injected to dilate the canal, creating a buffer between the inner and outer walls of SC, which is followed by cutting of a trabecular meshwork (TM) strip.

Conclusion

The current modification can prevent damage to adjoining angle structures, including the outer wall of SC, which is critical for aqueous outflow. It can potentially increase efficacy of the BANG procedure by incorporating viscodilation of the SC along with removal of the TM.

Clinical significance

Injury to surrounding structures causes a fibrotic response, which is the main cause of failure for the BANG procedure. Prevention of injury to adjoining structures and dilatation of the SC can potentially increase the long-term success rates of this procedure.

How to cite this article

Dada T, Beri N, Sethi A, et al. Viscodilation of Schlemm's Canal Combined with Goniectomy Using a 30 G Needle (Visco-Bent Ab Interno Needle Goniectomy). J Curr Glaucoma Pract 2023;17(4):210-213.

Recruitment of Temporal Aqueous Outflow Channels After Bent Needle Ab-Interno Goniectomy Demonstrated by Aqueous Angiography

PURPOSE

To demonstrate the utility of operating on the temporal trabecular meshwork with in vivo - aqueous angiography demonstrating new aqueous outflow channels.

METHOD

In a patient with primary open angle glaucoma, nuclear sclerosis, and medically uncontrolled intraocular pressure, Indocyanine green aqueous angiography (0.5%) was performed to visualize baseline functional aqueous outflow channels. This was followed by 30 degrees bent needle ab-interno goniectomy in the temporal quadrant, where no aqueous outflow channels were initially visualized. Aqueous angiography was repeated using 2% fluorescein to visualize aqueous outflow channels after bent needle ab-interno goniectomy.

RESULTS

Prebent needle ab-interno goniectomy, aqueous angiography revealed functional outflow channels in the nasal quadrant although none were visible in the temporal quadrant. Postbent needle ab-interno goniectomy in temporal quadrant aqueous angiography demonstrated 2 new aqueous outflow channels.

CONCLUSION

In a patient with open angle glaucoma, following temporal quadrant ab-interno goniectomy, the recruitment of aqueous outflow channels was demonstrated using aqueous angiography.

Aqueous Angiography-guided Minimally Invasive Glaucoma Surgery

How to cite this article: Dada T, Verma S, Bukke AN, et al. Aqueous Angiography-guided Minimally Invasive Glaucoma Surgery. J Curr Glaucoma Pract 2022;16(1):1-3.