Glaucoma Unit, Sydney Eye Hospital.
Discipline of Ophthalmology, The University of Sydney, Sydney, NSW.
J Glaucoma. 2020 Aug;29(8):656-665. doi: 10.1097/IJG.0000000000001561.
Hemoglobin Video Imaging (HVI) provides a noninvasive method to quantify aqueous outflow (AO) perioperatively. Trabecular bypass surgery (TBS) is able to improve, and in some cases re-establish, conventional AO.
The purpose of this study was to use HVI to illustrate and quantify effects of TBS on AO through the episcleral venous system.
This is a prospective observational cohort study.
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) 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.
We used HVI, a novel clinic-based tool, to visualize and quantify AO perioperatively 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.
AqCA, number of aqueous veins, intraocular pressure (IOP) before and after surgery, and number of IOP-lowering medications.
Patients with glaucoma had reduced AqCA compared with normal controls (P=0.00001). TBS 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 before 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.
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 AO. Cataract surgery may augment this. Some aqueous veins were first seen after TBS and these patients had unstable postoperative IOP control, which possibly suggests reorganization 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 personalized treatment decisions.
血红蛋白视频成像（HVI）提供了一种非侵入性的方法来定量评估手术期间房水流出（AO）。小梁旁路手术（TBS）能够改善，在某些情况下重新建立传统的 AO。
本研究旨在使用 HVI 来说明和定量评估 TBS 对巩膜静脉系统 AO 的影响。
这是一项前瞻性观察队列研究。
参与者从澳大利亚悉尼眼科医院招募。该研究包括 25 名患者的 29 只眼睛，其中 15 只患有青光眼，14 只正常对照。对 14 只青光眼眼（9 只联合超声乳化/TBS 和 5 只单纯 TBS）进行 TBS（iStent Inject）。青光眼组的另一只眼和对照组的 2 只眼接受单纯白内障手术。
我们使用 HVI，一种新的基于诊所的工具，在常规随访期间可视化和定量评估手术期间的 AO，随访时间长达 6 个月。在鼻侧和颞侧眼部表面的明显房水静脉内观察到血管造影血流模式。比较手术前后的房水柱横截面积（AqCA）。
AqCA、房水静脉数量、手术前后眼压（IOP）、降眼压药物数量。
与正常对照组相比，青光眼患者的 AqCA 降低（P=0.00001）。TBS 在术后 1 个月增加了 14 只眼的 AqCA（n=14；P<0.002），表明 AO 得到改善。7 只眼（n=9，P≤0.05）在 6 个月时仍保持这一效果。所有在术前无记录 AO 的患者（n=3；2 只单纯 TBS，1 只联合白内障/TBS）在 TBS 后建立了可测量的血流。接受 TBS 的每位患者的 IOP 和/或药物负担均有所降低。单纯白内障手术（n=3）在术后 4 周时增加了鼻侧和颞侧血管的 AqCA。
HVI 为门诊环境下围手术期 AO 的检测和监测提供了一种安全的方法。TBS 后预期 AO 会改善并进入巩膜静脉系统，并且可以使用 HVI 进行可视化。TBS 能够改善，在某些情况下重新建立传统的 AO。白内障手术可能会增强这一点。一些房水静脉是在 TBS 后首次出现的，这些患者术后眼压控制不稳定，这可能表明房水稳态机制的重新组织。HVI 可能在短期随访期间确认手术的充分性，但需要进一步工作来评估 HVI 预测手术结果和协助制定个性化治疗决策的潜力。
