Reticular patterned episcleral venous plexus and 360-degree episcleral venous fluid wave after hemi-gonioscopy assisted transluminal trabeculotomy

Abstract

We describe a method for eliciting an episcleral venous fluid wave (EVFW) in eyes presenting with reticular patterned episcleral venous plexus, after a hemi-gonioscopy assisted transluminal trabeculotomy (hemi-GATT). To reduce the risk of post-operative hyphema and reduce intraoperative tissue manipulation, a hemi-GATT (targeting 180-degrees of Schlemm’s canal) was performed. Post-hemi-GATT, the ability to inject balanced salt solution and obtain an EVFW in both the treated (inferior) and untreated (superior) sectors of the eye supports the surgical success of the technique, and demonstrates an enhanced fluid outflow and subsequent vessel blanching. The pre-operative intraocular pressure of 20/21 mmHg in a single subject decreased to 18-, 12- and 15-mmHg after one day, one month and 3 months post-op, respectively, and the subject was rendered medication-free. This method of performing a hemi-GATT to effectively obtain an EVFW provides evidence for novel treatment algorithms in patients with a reticular episcleral venous plexus where identification of major outflow vessels is less apparent.

Keywords

Gonioscopy assisted transluminal trabeculotomy / micro-invasive glaucoma surgeries / glaucoma surgery / episcleral venous fluid wave

References

[1] Agrawal P.Systematic literature review of clinical and economic outcomes of micro-invasive glaucoma surgery (MIGS) in primary open-angle glaucoma..Ophthalmol Ther2018;7:49-73 PMCID:PMC5997597

[2] Saheb H.Micro-invasive glaucoma surgery: current perspectives and future directions..Curr Opin Ophthalmol2012;23:96-104

[3] Fellman RL,Grover DS.Episcleral venous fluid wave correlates with trabectome outcomes: intraoperative evaluation of the trabecular outflow pathway..Ophthalmology2015;122:2385-91

[4] Bostan C.Episcleral venous outflow: a potential outcome marker for iStent surgery..J Glaucoma2017;26:1114-9

[5] Grover DS,Smith O,Montes de Oca I.Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: technique report and preliminary results..Ophthalmology2014;121:855-61

[6] Fellman RL.Episcleral venous fluid wave: intraoperative evidence for patency of the conventional outflow system..J Glaucoma2014;23:347-50

[7] Richter GM.Minimally invasive glaucoma surgery: current status and future prospects..Clin Ophthalmol2016;10:189-206 PMCID:PMC4734795

[8] Grieshaber MC,Olivier J.Clinical evaluation of the aqueous outflow system in primary open-angle glaucoma for canaloplasty..Invest Ophthalmol Vis Sci2010;51:1498-504

[9] Arora A, Nazarali S, Cote S, Duimering A, Schlenker M, Ford B, et al. Gonioscopy assisted transluminal trabeculotomy (GATT): a hemispheric approach. The Canadian Ophthalmologial Society 2018 in Glaucoma Research: the cutting edge symposium, Toronto, Canada, June 2018. Available from: https://cos-sco.ca/toronto2018/wp-content/uploads/2018/04/AbstractBooklet-PaperPresentations.pdf. [Last accessed on 25 Jun 2021]