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

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.

Advancements in high-resolution imaging of the iridocorneal angle

High-resolution imaging methods of the iridocorneal angle (ICA) will lead to enhanced understanding of aqueous humor outflow mechanisms and a characterization of the trabecular meshwork (TM) morphology at the cellular level will help to better understand glaucoma mechanics (e.g., cellular level biomechanics of the particulate glaucomas). This information will translate into immense clinical value, leading to more informed and customized treatment selection, and improved monitoring of procedural interventions that lower intraocular pressure (IOP). Given ICA anatomy, imaging modalities that yield intrinsic optical sectioning or 3D imaging capability will be useful to aid in the visualization of TM layers. This minireview examines advancements in imaging the ICA in high-resolution.

Ab-interno Trabeculotomy Procedures: A Review

Purpose

To discuss the safety and efficacy of various forms of ab-interno trabeculotomy procedures.

Methods

A comprehensive search in PubMed and Google Scholar was done using the keywords "glaucoma", "microinvasive glaucoma surgery", "complications", "goniotomy", and "trabeculotomy". Publications discussing ab-interno trabeculotomy procedures were selected; furthermore, the relevant references in these articles were gathered and the search was updated during the article preparation. Since gonioscopy-assisted transluminal trabeculotomy was first introduced in 2014, we had no time restriction.

Results

Ab-interno trabeculotomy procedures, as a type of minimally invasive glaucoma surgeries, facilitate the natural trabecular outflow and lower the intraocular pressure (IOP) while preserving the conjunctiva for possible future glaucoma surgeries. It can be done alone or in combination with cataract surgery and effectively lowers the IOP and the number of antiglaucoma medications in various forms of glaucoma.

Conclusion

By appropriate patient selection, ab-interno trabeculotomy could be selected as a safe and effective procedure in the management of various forms of glaucoma either as an isolated procedure or in combination with cataract extraction.