The Effects of Trabecular Bypass Surgery on Conventional Aqueous Outflow, Visualized by Hemoglobin Video Imaging.
Lusthaus, Jed A
Meyer, Paul AR
Khatib, Tasneem Z
Journal of glaucoma
Wolters Kluwer Health
MetadataShow full item record
Lusthaus, J. A., Meyer, P. A., Khatib, T. Z., & Martin, K. (2020). The Effects of Trabecular Bypass Surgery on Conventional Aqueous Outflow, Visualized by Hemoglobin Video Imaging.. Journal of glaucoma, 29 (8), 656-665. https://doi.org/10.1097/ijg.0000000000001561
Purpose: To use Haemoglobin Video Imaging (HVI) to illustrate and quantify effects of trabecular bypass surgery (TBS) on aqueous outflow (AO) through the episcleral venous system. Design: Prospective observational cohort study. Participants: Patients were recruited from Sydney Eye Hospital, Australia. The study included 29 eyes from 25 patients, 15 with glaucoma and 14 normal controls. TBS (iStent Inject®, Glaukos Corporation) was performed on 14 glaucomatous eyes (9 combined phacoemulsification/TBS and 5 standalone TBS). Cataract surgery alone was performed on the remaining eye from the glaucoma group and 2 eyes from the control group. Methods: We used HVI, a novel clinic-based tool, to visualise and quantify AO peri-operatively during routine follow-up to 6 months. Angiographic blood flow patterns were observed within prominent aqueous veins on the nasal and temporal ocular surface. Aqueous column cross-section area (AqCA) was compared before and after surgery. Main Outcome Measures: AqCA, number of aqueous veins, intraocular pressure (IOP) before and after surgery, and number of IOP-lowering medications. Results: Patients with glaucoma had reduced AqCA compared to normal controls (P = 0.00001). Trabecular bypass surgery increased AqCA in 13 eyes at 1 month (n = 14; P < 0.002), suggesting improved AO. This effect was maintained at 6 months in 7 eyes (n = 9, P = <0.05). All patients with unrecordable AO prior to surgery (n=3; 2 standalone TBS, 1 combined cataract/TBS) established measurable flow after TBS. IOP and/or medication burden became reduced in every patient undergoing TBS. Cataract surgery alone (n = 3) increased AqCA in nasal and temporal vessels at 4 weeks after surgery. Conclusions: HVI provides a safe method for detecting and monitoring AO perioperatively in an outpatient setting. Improvement of AO into the episcleral venous system is expected after TBS and can be visualized with HVI. TBS is able to improve, and in some cases re-establish, conventional aqueous outflow. Cataract surgery may augment this. Some aqueous veins were first seen after TBS and these patients had unstable post-operative IOP control, which possibly suggests reorganisation of aqueous homeostatic mechanisms. HVI may confirm adequacy of surgery during short-term follow-up, but further work is required to assess the potential of HVI to predict surgical outcomes and assist with personalised treatment decisions.
1. Haemoglobin Video Imaging facilities funded by Sydney Eye Hospital Foundation, Carl Zeiss Meditec, and Glaukos Corporation. 2. iStent Inject devices for standalone cases were donated by Glaukos Corporation. 3. A core support grant from the Wellcome Trust and MRC to the Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute. 4. Cambridge Eye Trust
Embargo Lift Date
External DOI: https://doi.org/10.1097/ijg.0000000000001561
This record's URL: https://www.repository.cam.ac.uk/handle/1810/308862
All rights reserved