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Fang R, Zhang P, Zhang T, Kim D, Sun E, Kuranov R, Kweon J, Huang A, Zhang HF. Freeform robotic optical coherence tomography beyond the optical field-of-view limit. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.595073. [PMID: 38826217 PMCID: PMC11142137 DOI: 10.1101/2024.05.21.595073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Imaging complex, non-planar anatomies with optical coherence tomography (OCT) is limited by the optical field of view (FOV) in a single volumetric acquisition. Combining linear mechanical translation with OCT extends the FOV but suffers from inflexibility in imaging non-planar anatomies. We report the freeform robotic OCT to fill this gap. To address challenges in volumetric reconstruction associated with the robotic movement accuracy being two orders of magnitudes worse than OCT imaging resolution, we developed a volumetric registration algorithm based on simultaneous localization and mapping (SLAM) to overcome this limitation. We imaged the entire aqueous humor outflow pathway, whose imaging has the potential to customize glaucoma surgeries but is typically constrained by the FOV, circumferentially in mice as a test. We acquired volumetric OCT data at different robotic poses and reconstructed the entire anterior segment of the eye. The reconstructed volumes showed heterogeneous Schlemm's canal (SC) morphology in the reconstructed anterior segment and revealed a segmental nature in the circumferential distribution of collector channels (CC) with spatial features as small as a few micrometers.
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Lee SS, Nagar S, Rajagopalan L, Orilla W, Csaky KG, Almazan A, Yang L, Robinson MR. Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation. J Ocul Pharmacol Ther 2024. [PMID: 38687355 DOI: 10.1089/jop.2023.0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024] Open
Abstract
Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.
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Affiliation(s)
- Susan S Lee
- Allergan, an AbbVie company, Irvine, California, USA
| | - Saumya Nagar
- Allergan, an AbbVie company, Irvine, California, USA
| | | | | | - Karl G Csaky
- Retina Foundation of the Southwest, Dallas, Texas, USA
| | | | - Liuqing Yang
- Allergan, an AbbVie company, Irvine, California, USA
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Wu J, Zhou L, Liu Y, Zhang X, Yang Y, Zhu X, Bu Q, Shan X, Yin J, Weinreb RN, Zhou Q, Pan X, Huang AS. VEGF-C and 5-Fluorouracil Improve Bleb Survival in a Rabbit Glaucoma Surgery Trabeculectomy Model. Invest Ophthalmol Vis Sci 2024; 65:32. [PMID: 38771570 PMCID: PMC11114614 DOI: 10.1167/iovs.65.5.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/10/2024] [Indexed: 05/22/2024] Open
Abstract
Purpose To evaluate VEGF-C-induced lymphoproliferation in conjunction with 5-fluorouracil (5-FU) antimetabolite treatment in a rabbit glaucoma filtration surgery (GFS) model. Methods Thirty-two rabbits underwent GFS and were assigned to four groups (n = 8 each) defined by subconjunctival drug treatment: (a) VEGF-C combined with 5-FU, (b) 5-FU, (c) VEGF-C, (d) and control. Bleb survival, bleb measurements, and IOP were evaluated over 30 days. At the end, histology and anterior segment OCT were performed on some eyes. mRNA was isolated from the remaining eyes for RT-PCR evaluation of vessel-specific markers (lymphatics, podoplanin and LYVE-1; and blood vessels, CD31). Results Qualitatively and quantitatively, VEGF-C combined with 5-FU resulted in blebs which were posteriorly longer and wider than the other conditions: vs. 5-FU (P = 0.043 for longer, P = 0.046 for wider), vs. VEGF-C (P < 0.001, P < 0.001) and vs. control (P < 0.001, P < 0.001). After 30 days, the VEGF-C combined with 5-FU condition resulted in longer bleb survival compared with 5-FU (P = 0.025), VEGF-C (P < 0.001), and control (P < 0.001). Only the VEGF-C combined with 5-FU condition showed a negative correlation between IOP and time that was statistically significant (r = -0.533; P = 0.034). Anterior segment OCT and histology demonstrated larger blebs for the VEGF-C combined with 5-FU condition. Only conditions including VEGF-C led to increased expression of lymphatic markers (LYVE-1, P < 0.001-0.008 and podoplanin, P = 0.002-0.011). Expression of CD31 was not different between the groups (P = 0.978). Conclusions Adding VEGF-C lymphoproliferation to standard antimetabolite treatment improved rabbit GFS success and may suggest a future strategy to improve human GFSs.
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Affiliation(s)
- Jingyi Wu
- Shandong First Medical University, Jinan, Shandong Province, China
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Longfang Zhou
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Yameng Liu
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Yuanhang Yang
- Shandong First Medical University, Jinan, Shandong Province, China
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Xinyuan Zhu
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Qianwen Bu
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
| | - Xinmiao Shan
- Shandong First Medical University, Jinan, Shandong Province, China
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Jia Yin
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Robert N. Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Qingjun Zhou
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Xiaojing Pan
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong Province, China
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Alex S. Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
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Strohmaier CA, Wanderer D, Zhang X, Zhang HF, Strohmaier S, Weinreb RN, Huang AS. Lack of Correlation Between Segmental Trabecular Meshwork Pigmentation and Angiographically Determined Outflow in Ex Vivo Human Eyes. J Glaucoma 2024; 33:355-360. [PMID: 37851964 PMCID: PMC10995104 DOI: 10.1097/ijg.0000000000002318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/18/2023] [Indexed: 10/20/2023]
Abstract
PRCIS Trabecular meshwork (TM) pigmentation is not correlated with angiographically determined aqueous humor outflow (AHO) in an ex vivo perfusion model using human eyes. PURPOSE To evaluate whether segmental TM pigmentation is correlated to segmental AHO in human eyes. METHODS Postmortem human eyes were acquired, and anterior segments were dissected. TM pigmentation was photographed 360-degrees around the eye. The anterior segments were then mounted onto a perfusion apparatus and perfused with Dulbecco's phosphate buffered saline (DPBS) until a stabile baseline outflow facility was achieved. Aqueous angiography (AHO angiography) was performed using fluorescein (2%), and segmental AHO was documented around the limbus using an angiographic camera (Spectralis HRA+OCT). Circumferential and nasal TM pigmentation were compared with respective angiographic outflow imaging using a Pearson correlation analysis. RESULTS Segmental TM pigment distribution and segmental AHO were seen. TM pigment was statistically greatest in the inferior quadrant. AHO angiographic outflow was numerically greatest in the nasal quadrant, but this was not statistically significant. No statistically significant correlation was observed (r=-0.083, P =0.06) between segmental TM pigmentation and segmental AHO angiographic signal. Analyzing just the nasal quadrant, a significant weak negative correlation was found (r=-0.296, P =0.001). DISCUSSION Segmental TM pigmentation circumferentially around the eye is not a good proxy for segmental AHO circumferentially around the eye and should not be used to guide trabecular minimally invasive glaucoma surgeries.
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Affiliation(s)
- Clemens A. Strohmaier
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria
| | - Daniel Wanderer
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Susanne Strohmaier
- Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria
| | - Robert N. Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Alex S. Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
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Lusthaus JA. Imaging of aqueous outflow in health and glaucoma. Justifying the re-direction of aqueous. Eye (Lond) 2024:10.1038/s41433-024-02968-8. [PMID: 38429503 DOI: 10.1038/s41433-024-02968-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/17/2023] [Accepted: 01/26/2024] [Indexed: 03/03/2024] Open
Abstract
A wave of less invasive surgical options that target or bypass the conventional aqueous outflow system has been incorporated into routine clinical practice to mitigate surgical risks associated with traditional glaucoma drainage surgery. A blanket surgical approach for open-angle glaucoma is unlikely to achieve the desired IOP reduction in an efficient or economical way. Developing a precise approach to selecting the most appropriate surgical tool for each patient is dependent upon understanding the complexities of the aqueous outflow system and how devices influence aqueous drainage. However, homoeostatic control of aqueous outflow in health and glaucoma remains poorly understood. Emerging imaging techniques have provided an opportunity to study aqueous outflow responses non-invasively in clinic settings. Haemoglobin Video Imaging (HVI) studies have demonstrated different patterns of aqueous outflow within the episcleral venous system in normal and glaucomatous eyes, as well as perioperatively after trabecular bypass surgery. Explanations for aqueous outflow patterns remain speculative until direct correlation with findings from Schlemm's canal and the trabecular meshwork are possible. The redirection of aqueous via targeted stent placement may only be justifiable once the role of the aqueous outflow system in IOP homoeostasis has been defined.
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Affiliation(s)
- Jed A Lusthaus
- Department of Ophthalmology, Sydney Eye Hospital, Sydney, NSW, Australia.
- Discipline of Ophthalmology, The University of Sydney, Sydney, NSW, Australia.
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Gupta S, Zhang X, Panigrahi A, Shakha, Fang R, Strohmaier CA, Zhang HF, Weinreb RN, Gupta V, Huang AS. Reduced Aqueous Humor Outflow Pathway Arborization in Childhood Glaucoma Eyes. Transl Vis Sci Technol 2024; 13:23. [PMID: 38536170 PMCID: PMC10981159 DOI: 10.1167/tvst.13.3.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/16/2024] [Indexed: 04/01/2024] Open
Abstract
Purpose To compare aqueous humor outflow (AHO) pathway patterns between eyes of childhood glaucoma patients and non-glaucomatous patients receiving cataract surgery. Methods Aqueous angiography was performed in childhood glaucoma eyes (n = 5) receiving glaucoma surgery and in pediatric (n = 1) and healthy adult (n = 5) eyes receiving cataract surgery. Indocyanine green (0.4%) was introduced into the anterior chamber, and AHO was imaged using an angiographic camera (SPECTRALIS HRA+OCT with Flex Module). Images were acquired and analyzed (ImageJ with Analyze Skeleton 2D/3D plugin) from the nasal sides of the eyes, the usual site of glaucoma angle procedures. Image analysis endpoints included AHO vessel length, maximum vessel length, number of branches, number of branch junctions, and vessel density. Results Qualitatively, childhood glaucoma eyes demonstrated lesser AHO pathway arborization compared to pediatric and adult eyes without glaucoma. Quantitatively, childhood glaucoma and healthy adult cataract eyes showed similar AHO pathway average branch lengths and maximum branch lengths (P = 0.49-0.99). However, childhood glaucoma eyes demonstrated fewer branches (childhood glaucoma, 198.2 ± 35.3; adult cataract, 506 ± 59.5; P = 0.002), fewer branch junctions (childhood glaucoma, 74.6 ± 13.9; adult cataract, 202 ± 41.2; P = 0.019), and lower vessel densities (childhood glaucoma, 8% ± 1.4%; adult cataract, 17% ± 2.5%; P = 0.01). Conclusions Childhood glaucoma patients demonstrated fewer distal AHO pathways and lesser AHO pathway arborization. These anatomical alternations may result in a new source of trabecular meshwork-independent AHO resistance in this disease cohort. Translational Relevance Elevated distal outflow pathway resistance due to decreased AHO pathway arborization may explain some cases of failed trabecular bypass surgery in childhood glaucoma.
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Affiliation(s)
- Shikha Gupta
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi, India
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, San Diego, CA, USA
| | - Arnav Panigrahi
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi, India
| | - Shakha
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi, India
| | - Raymond Fang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Clemens A. Strohmaier
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, San Diego, CA, USA
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austriav
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Robert N. Weinreb
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, San Diego, CA, USA
| | - Viney Gupta
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi, India
| | - Alex S. Huang
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, San Diego, CA, USA
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Li HL, Ren R, Gong H. Segmental Unconventional Outflow in Mouse Eyes. Invest Ophthalmol Vis Sci 2023; 64:26. [PMID: 38117243 PMCID: PMC10741088 DOI: 10.1167/iovs.64.15.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023] Open
Abstract
Purpose To investigate the flow pattern in unconventional outflow and its correlation with conventional outflow in mouse eyes. Methods Fluorescent microspheres were injected into the anterior chamber of one eye of anesthetized C57BL/6J mice (n = 4), followed by perfused fixation with 4% paraformaldehyde in situ after 45 minutes. Post-euthanasia, the injected eyes were enucleated, further immersion fixed, and dissected into 12 equal radial segments. Both sides of each segment were imaged using a confocal microscope after nuclear counterstaining. Both unconventional and conventional outflow patterns of each eye were analyzed by ImageJ and ZEN 2.3 imaging software. Results Segmental outflow patterns were observed in both the ciliary body (CB) and the supraciliary space and suprachoroidal space (SCS). In the CB, the tracer intensity was the lowest at 12 o'clock and highest at 9 o'clock, whereas in the SCS it was the lowest at 2 o'clock and the highest at 10 o'clock. Consequently, a segmental unconventional outflow was observed, with the lowest and highest flow regions in the superior and temporal quadrants, respectively. The overall segmental uveoscleral outflow has no correlation with trabecular outflow (P > 0.05). Four different outflow patterns were observed: (1) low-flow regions in both outflows, (2) primarily a high-flow region in conventional outflow, (3) primarily a high-flow region in unconventional outflow, and (4) high-flow regions in both outflows. Conclusions Uveoscleral outflow is segmental and unrelated to the trabecular segmental outflow. These findings will lead to future studies to identify the best location for the placement of drainage devices and drug delivery.
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Affiliation(s)
- Hoi-Lam Li
- Ophthalmology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, United States
| | - Ruiyi Ren
- Ophthalmology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, United States
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Zhejiang, China
| | - Haiyan Gong
- Ophthalmology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, United States
- Anatomy and Neurobiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, United States
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Chan PPM, Larson MD, Dickerson JE, Mercieca K, Koh VTC, Lim R, Leung EHY, Samuelson TW, Larsen CL, Harvey A, Töteberg-Harms M, Meier-Gibbons F, Shu-Wen Chan N, Sy JB, Mansouri K, Zhang X, Lam DSC. Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges. Asia Pac J Ophthalmol (Phila) 2023; 12:537-564. [PMID: 38079242 DOI: 10.1097/apo.0000000000000646] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 10/12/2023] [Indexed: 12/21/2023] Open
Abstract
The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.
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Affiliation(s)
- Poemen P M Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Lam Kin Chung. Jet King-Shing Ho Glaucoma Treatment and Research Centre, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Jaime E Dickerson
- Sight Sciences, Menlo Park, CA, USA
- University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, TX, USA
| | | | - Victor Teck Chang Koh
- Department of Ophthalmology, National University Health System, Singapore
- Centre for Innovation and Precision Eye Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ridia Lim
- Department of Ophthalmology, Sydney Eye Hospital, Sydney, Australia
- Save Sight Institute, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Enne Hiu Ying Leung
- The C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong, China
| | - Thomas W Samuelson
- Minnesota Eye Consultants, Bloomington, MN, US
- Department of Ophthalmology, University of Minnesota, MN, US
| | - Christine L Larsen
- Minnesota Eye Consultants, Bloomington, MN, US
- Department of Ophthalmology, University of Minnesota, MN, US
| | | | - Marc Töteberg-Harms
- Department of Ophthalmology, Augusta University, Medical College of Georgia, Augusta, GA, USA
| | | | | | - Jessica Belle Sy
- Department of Ophthalmology, Sydney Eye Hospital, Sydney, Australia
- Baguio General Hospital and Medical Center, Baguil City, Benguet, Philippines
| | - Kaweh Mansouri
- Glaucoma Center, Swiss Visio, Clinique de Montchoisi, Lausanne, Switzerland
| | - Xiulan Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Dennis S C Lam
- The C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong, China
- The International Eye Research Institute of The Chinese University of Hong Kong (Shenzhen), Shenzhen, China
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Strohmaier CA, Wanderer D, Zhang X, Agarwal D, Toomey CB, Wahlin K, Zhang HF, Stamer WD, Weinreb RN, McDonnell FS, Huang AS. Greater Outflow Facility Increase After Targeted Trabecular Bypass in Angiographically Determined Low-low Regions. Ophthalmol Glaucoma 2023; 6:570-579. [PMID: 37348815 PMCID: PMC10917462 DOI: 10.1016/j.ogla.2023.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/31/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023]
Abstract
PURPOSE To investigate the impact of trabecular bypass surgery targeted to angiographically determined high- vs. low-aqueous humor outflow areas on outflow facility (C) and intraocular pressure (IOP). DESIGN Ex vivo comparative study. SUBJECTS Postmortem ex vivo porcine and human eyes. METHODS Porcine (n = 14) and human (n = 13) whole globes were acquired. In both species, anterior segments were dissected, mounted onto a perfusion chamber, and perfused using Dulbecco's phosphate buffered solution containing glucose in a constant flow paradigm to achieve a stable baseline. Fluorescein was perfused into the anterior chamber and used to identify baseline segmental high- and low-flow regions of the conventional outflow pathways. The anterior segments were divided into 2 groups, and a 5 mm needle goniotomy was performed in either a high- or low-flow area. Subsequently, C and IOP were quantitatively reassessed and compared between surgery in baseline "high-flow" and "low-flow" region eyes followed by indocyanine green angiography. MAIN OUTCOME MEASURES Outflow facility. RESULTS In all eyes, high- and low-flow segments could be identified. Performing a 5-mm goniotomy increased outflow facility to a variable extent depending on baseline flow status. In the porcine high-flow group, C increased from 0.31 ± 0.09 to 0.39 ± 0.09 μL/mmHg/min (P = 0.12). In the porcine low-flow group, C increased from 0.29 ± 0.03 to 0.56 ± 0.10 μL/mmHg/min (P < 0.001). In the human high-flow group, C increased from 0.38 ± 0.20 to 0.41 ± 0.20 μL/mmHg/min (P = 0.02). In the human low-flow group, C increased from 0.25 ± 0.11 to 0.32 ± 0.11 μL/mmHg/min (<0.001). There was statistically significant greater increase in C for eyes where surgery was targeted to baseline low-flow regions in both porcine (0.07 ± 0.09 vs. 0.27 ± 0.13, P = 0.007 μL/mmHg/min, high vs low flow) and human eyes (0.03 ± 0.03 vs. 0.07 ± 0.02, P = 0.03 μL/mmHg/min, high vs. low flow). CONCLUSIONS Targeting surgery to low-flow areas of the trabecular meshwork yields higher overall facility increase and IOP reduction compared to surgery in high-flow areas. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Clemens A Strohmaier
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria; The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California.
| | - Daniel Wanderer
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Xiaowei Zhang
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Devansh Agarwal
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Christopher B Toomey
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Karl Wahlin
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - W Daniel Stamer
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Robert N Weinreb
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | | | - Alex S Huang
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
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10
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Johnstone M, Xin C, Martin E, Wang R. Trabecular Meshwork Movement Controls Distal Valves and Chambers: New Glaucoma Medical and Surgical Targets. J Clin Med 2023; 12:6599. [PMID: 37892736 PMCID: PMC10607137 DOI: 10.3390/jcm12206599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/09/2023] [Accepted: 08/30/2023] [Indexed: 10/29/2023] Open
Abstract
Herein, we provide evidence that human regulation of aqueous outflow is by a pump-conduit system similar to that of the lymphatics. Direct observation documents pulsatile aqueous flow into Schlemm's canal and from the canal into collector channels, intrascleral channels, aqueous veins, and episcleral veins. Pulsatile flow in vessels requires a driving force, a chamber with mobile walls and valves. We demonstrate that the trabecular meshwork acts as a deformable, mobile wall of a chamber: Schlemm's canal. A tight linkage between the driving force of intraocular pressure and meshwork deformation causes tissue responses in milliseconds. The link provides a sensory-motor baroreceptor-like function, providing maintenance of a homeostatic setpoint. The ocular pulse causes meshwork motion oscillations around the setpoint. We document valves entering and exiting the canal using real-time direct observation with a microscope and multiple additional modalities. Our laboratory-based high-resolution SD-OCT platform quantifies valve lumen opening and closing within milliseconds synchronously with meshwork motion; meshwork tissue stiffens, and movement slows in glaucoma tissue. Our novel PhS-OCT system measures nanometer-level motion synchronous with the ocular pulse in human subjects. Movement decreases in glaucoma patients. Our model is robust because it anchors laboratory studies to direct observation of physical reality in humans with glaucoma.
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Affiliation(s)
- Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA;
| | - Chen Xin
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing 100730, China
- Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
| | - Elizabeth Martin
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Ruikang Wang
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA;
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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11
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Strohmaier CA, McDonnell FS, Zhang X, Wanderer D, Stamer WD, Weinreb RN, Huang AS. Differences in Outflow Facility Between Angiographically Identified High- Versus Low-Flow Regions of the Conventional Outflow Pathways in Porcine Eyes. Invest Ophthalmol Vis Sci 2023; 64:29. [PMID: 36939719 PMCID: PMC10043501 DOI: 10.1167/iovs.64.3.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
Purpose To investigate differences in outflow facility between angiographically determined high- and low-flow segments of the conventional outflow pathway in porcine eyes. Methods Porcine anterior segments (n = 14) were mounted in a perfusion chamber and perfused using Dulbecco's phosphate buffered solution with glucose. Fluorescein angiography was performed to determine high- and low-flow regions of the conventional outflow pathways. The trabecular meshwork (TM) was occluded using cyanoacrylate glue, except for residual 5-mm TM areas that were either high or low flow at baseline, designating these eyes as "residual high-flow" or "residual low-flow" eyes. Subsequently, outflow was quantitatively reassessed and compared between residual high-flow and residual low-flow eyes followed by indocyanine green angiography. Results Fluorescein aqueous angiography demonstrated high-flow and low-flow regions. Baseline outflow facilities were 0.320 ± 0.08 and 0.328 ± 0.10 µL/min/mmHg (P = 0.676) in residual high-flow and residual low-flow eyes before TM occlusion, respectively. After partial trabecular meshwork occlusion, outflow facility decreased to 0.209 ± 0.07 µL/min/mmHg (-32.66% ± 19.53%) and 0.114 ± 0.08 µL/min/mmHg (-66.57% ± 23.08%) in residual high- and low-flow eyes (P = 0.035), respectively. There was a significant difference in the resulting IOP increase (P = 0.034). Conclusions Angiographically determined high- and low-flow regions in the conventional outflow pathways differ in their segmental outflow facility; thus, there is an uneven distribution of local outflow facility across different parts of the TM.
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Affiliation(s)
- Clemens A Strohmaier
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Fiona S McDonnell
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Daniel Wanderer
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Robert N Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Alex S Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
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12
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Dimauro G, Camporeale MG, Dipalma A, Guarini A, Maglietta R. Anaemia detection based on sclera and blood vessel colour estimation. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Dada T, Bukke AN, Huang AS, Sharma N, Verma S. Recruitment of Temporal Aqueous Outflow Channels After Bent Needle Ab-Interno Goniectomy Demonstrated by Aqueous Angiography. J Glaucoma 2023; 32:e15-e18. [PMID: 36223300 PMCID: PMC9877127 DOI: 10.1097/ijg.0000000000002131] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022]
Abstract
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.
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Affiliation(s)
- Tanuj Dada
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS,
New Delhi, India
| | - Anand Naik Bukke
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS,
New Delhi, India
| | - Alex S Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of
Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA,
USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS,
New Delhi, India
| | - Saurabh Verma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS,
New Delhi, India
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14
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Segmental outflow dynamics in the trabecular meshwork of living mice. Exp Eye Res 2022; 225:109285. [PMID: 36273576 DOI: 10.1016/j.exer.2022.109285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 12/29/2022]
Abstract
Aqueous humour does not drain uniformly through the trabecular meshwork (TM), but rather follows non-uniform or "segmental" routes. In this study, we examined whether segmental outflow patterns in the TM change over time in living mice and whether such changes are affected by age. Segmental outflow patterns were labelled by constant-pressure infusion of fluorescent tracer microparticles into the anterior chamber of anesthetised C57BL/6J mice at 3 or 8 months of age. Two different tracer colours were infused at separate time points with an interval of Δt = 0, 2, 7 or 14 days. In a separate experiment, one tracer was infused in vivo while the second tracer was infused ex vivo after 2 days. The spatial relationship between the two tracer patterns was analysed using the Pearson's correlation coefficient, r. In 3-month-old mice, there was a time-dependent decay in r, which was near unity at Δt = 0 and near zero at Δt = 14 days. In 8-month-old mice, r remained elevated for 14 days. Segmental outflow patterns measured in young mice ex vivo were not significantly different from those measured in vivo after accounting for the expected changes over 2 days. Therefore, segmental outflow patterns are not static in the TM but redistribute over time, achieving near complete loss of correlation by 2 weeks in young healthy mice. There is an age-related decline in the rate at which segmental outflow patterns redistribute in the TM. Further research is needed to understand the dynamic factors controlling segmental outflow.
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15
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Lee JY, Strohmaier CA, Akiyama G, Saraswathy S, Yoo C, Kim YY, Hong YK, Huang AS. Bleb-related Porcine Lymphatic Outflow is Greater from Subconjunctival compared to Subtenon Blebs. J Curr Glaucoma Pract 2022; 16:144-151. [PMID: 36793268 PMCID: PMC9905879 DOI: 10.5005/jp-journals-10078-1382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 07/20/2022] [Indexed: 01/25/2023] Open
Abstract
Aim Understanding the mechanism of fluid outflow by comparing the subconjunctival and subtenon spaces can lead to improved ocular therapeutics. The purpose of the current study is to evaluate subconjunctival vs subtenon lymphatic outflow by creating tracer-filled blebs in each location. Methods Porcine (n = 20) eyes received subconjunctival or subtenon injection(s) of fixable and fluorescent dextrans. Blebs were angiographically imaged using a Heidelberg Spectralis ([Heidelberg Retina Angiograph] HRA + OCT; Heidelberg Engineering) and bleb-related lymphatic outflow pathways were counted. Optical coherence tomography (OCT) imaging of these pathways was used to assess structural lumens and the presence of valve-like structures. Furthermore, a comparison between tracer injection locations (superior/inferior/temporal/nasal) was made. Histologic analyses for subconjunctival and subtenon outflow pathways were performed, to confirm tracer co-localization with molecular lymphatic markers. Results Subconjunctival blebs demonstrated a greater number of lymphatic outflow pathways compared to subtenon blebs in every quadrant [superior: 6.10 ± 1.18 (subconjunctival) vs 0.50 ± 0.27 (subtenon); temporal: 2.30 ± 0.40 vs 0.10 ± 0.10; nasal: 5.30 ± 0.60 vs 0.30 ± 0.21; inferior: 6.00 ±1.29 vs 0.1 ± 0.1; all comparisons p < 0.001]. For subconjunctival blebs, the temporal quadrant showed fewer lymphatic outflow pathways compared to the nasal side (p = 0.005). Discussion Subconjunctival blebs accessed greater lymphatic outflow compared to subtenon blebs. Furthermore, regional differences existed, with fewer lymphatic vessels temporal than at the other locations. Clinical significance Aqueous humor drainage after glaucoma surgery is incompletely understood. The present manuscript adds to our understanding of how lymphatics might influence filtration bleb function. How to cite this article Lee JY, Strohmaier CA, Akiyama G, et al. Bleb-related Porcine Lymphatic Outflow Is Greater from Subconjunctival compared to Subtenon Blebs. J Curr Glaucoma Pract 2022;16(3):144-151.
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Affiliation(s)
- Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Department of Ophthalmology, Gachon University College of Medicine, Gil Medical Center, Incheon, Korea
| | - Clemens Adolf Strohmaier
- Department of Ophthalmology, Johannes Kepler University, Linz, Austria; The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, Hamilton Glaucoma Center, University of California, San Diego, California
| | | | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Chungkwon Yoo
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Yong Yeon Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Young-Kwon Hong
- Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Alex S Huang
- Alfred Vogt Endowed Chair in Ophthalmology, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, Hamilton Glaucoma Center, University of California, San Diego, California, USA
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16
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Panigrahi A, Huang AS, Arora M, Kumari S, Mahalingam K, Gupta V, Gupta S. Indocyanine Green Aided Schlemm Canal Identification During Gonioscopic Assisted Transluminal Trabeculotomy. J Glaucoma 2022; 31:e69-e71. [PMID: 35513892 PMCID: PMC9378495 DOI: 10.1097/ijg.0000000000002047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/27/2022] [Indexed: 02/04/2023]
Abstract
Performing procedures like gonioscopic assisted transluminal trabeculotomy in eyes with congenital glaucoma may be difficult many a times due to difficult visualization of angle structures. Inaccurate identification of the angle landmark may lead to various inadvertent surgical complications. Hence, there is a need for techniques to improve visualization of surgical landmarks during these procedures. In this study, 0.2% indocyanine green was used to stain the trabecular meshwork before the surgeon proceeded with gonioscopic assisted transluminal trabeculotomy. It yielded excellent differentiation of the trabecular meshwork by imparting a bright green hue. This led to successful identification of the site of incision and subsequent 360 degrees cannulation of Schlemm canal in 5/5 cases. Indocyanine green aided Schlemm canal identification is helpful in children with congenital glaucoma undergoing angle surgeries, especially in eyes with poor structure differentiation.
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Affiliation(s)
- Arnav Panigrahi
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS New Delhi
| | - Alex S Huang
- The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Monika Arora
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS New Delhi
| | - Somya Kumari
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS New Delhi
| | | | - Viney Gupta
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS New Delhi
| | - Shikha Gupta
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS New Delhi
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17
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Swain DL, Yasmin S, Fernandes B, Lamaj G, Su Y, Gong H. Schlemm’s Canal Endothelium Cellular Connectivity in Giant Vacuole and Pore Formation in Different Flow-type Areas: A Serial Block-Face Scanning Electron Microscopy Study. Front Cell Dev Biol 2022; 10:867376. [PMID: 35493087 PMCID: PMC9043561 DOI: 10.3389/fcell.2022.867376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/17/2022] [Indexed: 11/28/2022] Open
Abstract
Glaucoma is associated with increased resistance in the conventional aqueous humor (AH) outflow pathway of the eye. The majority of resistance is thought to reside in the juxtacanalicular connective tissue (JCT) region of the trabecular meshwork and is modulated by the inner wall (IW) endothelial cells of Schlemm’s canal (SC). The IW cells form connections with the underlying JCT cells/matrix, and these connections are thought to modulate outflow resistance. Two ways by which AH crosses the IW endothelium are through: 1) the formation of outpouchings in IW cells called giant vacuoles (GVs) and their intracellular pores (I-pores), and 2) intercellular pores between two adjacent IW cells (B-pores). AH outflow is segmental with areas of high-, low-, and non-flow around the circumference of the eye. To investigate whether changes in cellular connectivity play a role in segmental outflow regulation, we used global imaging, serial block-face scanning electron microscopy (SBF-SEM), and 3D reconstruction to examine individual IW cells from different flow areas of ex vivo perfused normal human donor eyes. Specifically, we investigated the differences in cellular dimensions, connections with JCT cells/matrix, GVs, and pores in SC IW cells between high-, low-, and non-flow areas. Our data showed that: 1) IW cell-JCT cell/matrix connectivity was significantly decreased in the cells in high-flow areas compared to those in low- and non-flow areas; 2) GVs in the cells of high-flow areas had significantly fewer connections beneath them compared to GVs in the cells of low- and non-flow areas; 3) Type IV GVs (with I-pores and basal openings) had significantly fewer connections beneath them compared to Type I GVs (no I-pore or basal opening). Our results suggest that a decreased number of cellular connections between the IW and JCT in high-flow areas is associated with increased numbers of GVs with I-pores and larger Type IV GVs observed in previous studies. Therefore, modulating the number of cellular connections may affect the amount of high-flow area around the eye and thereby modulate AH outflow.
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Affiliation(s)
- David L. Swain
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Senila Yasmin
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Beatriz Fernandes
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Ganimete Lamaj
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Yanfeng Su
- The Affiliated Eye Hospital of Wenzhou Medical University, Wenzhou, China
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Haiyan Gong,
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18
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Gan J, Sng CCA, Ke M, Chieh CS, Tan B, Schmetterer L, Ang M. Anterior Segment Optical Coherence Tomography Angiography Following Trabecular Bypass Minimally Invasive Glaucoma Surgery. Front Med (Lausanne) 2022; 9:830678. [PMID: 35321475 PMCID: PMC8936187 DOI: 10.3389/fmed.2022.830678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveTo assess anterior segment optical coherence tomography angiography (AS-OCTA) imaging of the episcleral vessels before and after trabecular bypass minimally invasive glaucoma surgery (MIGS).DesignA prospective, clinical, single-centre, single-arm pilot feasibility study conducted at National University Hospital, Singapore.SubjectsPatients with primary glaucomatous optic neuropathy undergoing Hydrus Microstent (Ivantis Inc., Irvine, CA, USA) implantation, who require at least one intra-ocular pressure-lowering medication. One or two eyes per patient may be enrolled.MethodsWe performed AS-OCTA (Nidek RS-3000 Advance 2, Gamagori, Japan) pre- and up to 6 months post-MIGS implantation using a standard protocol in all cornealimbal quadrants, to derive episcleral vessel densities (VD) using a previously described technique.Main Outcome MeasuresEpiscleral VD pre- and post-surgery, in sectors with and without the implant.ResultsWe obtained serial AS-OCTA images in 25 eyes undergoing MIGS implantation (23 subjects, mean age 70.3 ± 1.5, 61% female) with mean preoperative intraocular pressure (IOP) of 15.5 mmHg ± 4.0. We observed reductions in postoperative episcleral VD compared to preoperative VD at month 1 (mean difference −3.2, p = 0.001), month 3 (mean difference −2.94, p = 0.004) and month 6 (mean difference −2.19, p = 0.039) in sectors with implants (overall 6 month follow-up, p = 0.011). No significant changes were detected in episcleral VD in the sectors without implants (p = 0.910).ConclusionIn our pilot study, AS-OCTA was able to detect changes in the episcleral VD following trabecular bypass MIGS, which may be a useful modality to evaluate surgical outcomes if validated in future studies.
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Affiliation(s)
- Jinyuan Gan
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Chelvin C. A. Sng
- Singapore National Eye Centre, Singhealth, Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University Hospital, Singapore, Singapore
| | - Mengyuan Ke
- Singapore National Eye Centre, Singhealth, Singapore Eye Research Institute, Singapore, Singapore
| | - Chew Shi Chieh
- Department of Ophthalmology, National University Hospital, Singapore, Singapore
| | - Bingyao Tan
- Singapore National Eye Centre, Singhealth, Singapore Eye Research Institute, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Leopold Schmetterer
- Duke-NUS Graduate Medical School, Singapore, Singapore
- Singapore National Eye Centre, Singhealth, Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University Hospital, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Marcus Ang
- Duke-NUS Graduate Medical School, Singapore, Singapore
- Singapore National Eye Centre, Singhealth, Singapore Eye Research Institute, Singapore, Singapore
- *Correspondence: Marcus Ang
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Jabłońska J, Lewczuk K, Konopińska J, Mariak Z, Rękas M. Microinvasive glaucoma surgery: a review and classification of implant-dependent procedures and techniques. Acta Ophthalmol 2022; 100:e327-e338. [PMID: 33988310 PMCID: PMC9291507 DOI: 10.1111/aos.14906] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/08/2021] [Accepted: 04/22/2021] [Indexed: 12/25/2022]
Abstract
The aim of this article is to discuss how physiology and anatomical background affect the effectiveness of implant‐dependent microinvasive glaucoma surgery (MIGS). First, we provide a micro view of aqueous outflow and tissue behaviour. Second, we review studies exploring the mechanisms of the pressure‐lowering effect of MIGS, as well as tissue behaviour during aqueous flow and tissue motion. We also describe and classify microinvasive surgical procedures and the most important types of implants, as well as their mechanisms of action, implantation techniques and efficacy. Further, we summarize the indications and surgical results presented in recent studies, providing an evidence‐based update on novel and emerging MIGS techniques for the treatment of open‐angle glaucoma. These data can help surgeons to personalize the management of glaucoma and to choose the best MIGS option for individual glaucoma patients.
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Affiliation(s)
- Joanna Jabłońska
- Department of Ophthalmology Military Institute of Medicine Warsaw Poland
| | - Katarzyna Lewczuk
- Department of Ophthalmology Military Institute of Medicine Warsaw Poland
| | - Joanna Konopińska
- Department of Ophthalmology Medical University of Bialystok Białystok Poland
| | - Zofia Mariak
- Department of Ophthalmology Medical University of Bialystok Białystok Poland
| | - Marek Rękas
- Department of Ophthalmology Military Institute of Medicine Warsaw Poland
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20
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Dada T, Bukke AN. Aqueous angiography guided ab interno trabecular surgery for open-angle glaucoma. BMJ Case Rep 2022; 15:e248261. [PMID: 34996772 PMCID: PMC8744117 DOI: 10.1136/bcr-2021-248261] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2021] [Indexed: 11/03/2022] Open
Affiliation(s)
- Tanuj Dada
- Ophthalmology, RPCentre for Ophthalmic Sciences, AIIMS, New Delhi, India
| | - Anand Naik Bukke
- Ophthalmology, RPCentre for Ophthalmic Sciences, AIIMS, New Delhi, India
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21
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Kim J, Mansouri K. Impaired/dysfunctional aqueous collector channels may primarily contribute to the pathogenesis of primary open-angle glaucoma. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Dada T, Verma S, Bukke AN, Strohmaier CA, Huang AS. Aqueous Angiography-guided Minimally Invasive Glaucoma Surgery. J Curr Glaucoma Pract 2022; 16:1-3. [PMID: 36060039 PMCID: PMC9385386 DOI: 10.5005/jp-journals-10078-1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
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.
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Affiliation(s)
- Tanuj Dada
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India,Tanuj Dada, All India Institute of Medical Sciences, New Delhi, India, e-mail:
| | - Saurabh Verma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Anand N Bukke
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | | | - Alex S Huang
- Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States of America
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Lee JY, Heilweil G, Le P, Saraswathy S, Hong YK, Girkin CA, Huang AS. Structural Confirmation of Lymphatic Outflow from Subconjunctival Blebs of Live Human Subjects. OPHTHALMOLOGY SCIENCE 2021; 1. [PMID: 35005679 PMCID: PMC8740887 DOI: 10.1016/j.xops.2021.100080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Purpose To uncover the mechanism of subconjunctival outflow in humans. Design Cross-sectional study. Participants Fifteen patients receiving subconjunctival anesthesia before intravitreal injection for routine clinical care. Methods Anterior segment (AS) OCT was performed in patients with various instances of conjunctival edema or subconjunctival fluid. Other patients received a subconjunctival mixture of 0.005% indocyanine green and 2% lidocaine. After subconjunctival injection of the tracer and anesthetic mixture, blebs and associated outflow pathways were imaged angiographically and the time for appearance was recorded. The pattern and structure of outflow pathways were studied using AS OCT. Angiographic and AS OCT results were compared with trabecular and conventional outflow imaging, which demonstrates veins. Main Outcome Measures Ocular surface lymphangiography and AS OCT images. Results Anterior segment OCT of the conjunctiva in a normal eye demonstrated thin nonedematous conjunctiva with absent intraconjunctival lumens or subconjunctival fluid. Patients with a history of trabeculectomy, subconjunctival drug injection, or chemosis demonstrated thickened conjunctiva and intraconjunctival luminal pathways that contained valve-like structures. Tracer-based studies in patients demonstrated blebs with irregular subconjunctival bleb-related outflow patterns that arose in a time-dependent fashion. These angiographic pathways were luminal on OCT, sausage shaped, and contained intraluminal valve-like structures. This was in contrast to trabecular and conventional outflow imaging, where pathways were classically Y-shaped, of even caliber, and lacked valve-like structures. Conclusions Outflow pathways were seen in patients with conjunctival edema and after subconjunctival tracer injection. These pathways were lymphatic based on pattern and structural study. Better understanding of bleb-related lymphatic outflow may lead to improved bleb-requiring glaucoma surgeries and subconjunctival drug delivery.
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Affiliation(s)
- Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, USA.,Department of Ophthalmology, Gachon University College of Medicine, Gil Medical Center, Incheon, Korea
| | - Gad Heilweil
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Phuc Le
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Young-Kwon Hong
- Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christopher A Girkin
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alex S Huang
- The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
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Burn JB, Huang AS, Weber A, Komáromy AM, Pirie CG. Aqueous angiography in pre-glaucomatous and glaucomatous ADAMTS10-mutant canine eyes: A pilot study. Vet Ophthalmol 2021; 25 Suppl 1:72-83. [PMID: 34724299 PMCID: PMC9056585 DOI: 10.1111/vop.12938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 08/30/2021] [Accepted: 09/06/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate intravenous scleral and intracameral aqueous angiography in normotensive (n = 4) and hypertensive glaucomatous (n = 6) ADAMTS10-mutant canine eyes. ANIMALS STUDIED Ten ADAMTS10-mutant dogs were used in this study. PROCEDURES Dogs were sedated and one eye from each dog underwent scleral angiography following intravenous injection of 0.25% indocyanine green (ICG). After a 24-h recovery period, the same eye underwent aqueous angiography via intracameral administration of ICG. Imaging of identical scleral sectors from the same eye was performed using a Heidelberg Spectralis® Confocal Scanning Laser Ophthalmoscope. Intrascleral vessel depth and lumen diameters were measured using Heidelberg Spectralis® optical coherence tomography and computer software. RESULTS Scleral angiography permitted visualization of vascular components associated with conventional aqueous humor outflow pathways with an average time from injection to fluorescence of 35.8 ± 10.6 s (mean ± SD). Two normotensive eyes (2/10;20%) demonstrated turbulent dye movement, while 4 hypertensive eyes (4/10;40%) exhibited laminar flow. Aqueous angiography demonstrated dye fluorescence within the post-trabecular conventional aqueous humor outflow pathways in all 10 eyes at 34.3 ± 11.0 s post-injection. Sectoral and dynamic outflow patterns were observed primarily within the superotemporal sector in nine eyes (9/10; 90%). Seven eyes (7/10; 70%) demonstrated pulsatile dye movement and five eyes (5/10; 50%) exhibited laminar flow. The degree of laminar movement of dye was greatest in hypertensive eyes. Vessel lumen diameters measured 133.85 ± 28.36 µm and 161.18 ± 6.02 µm in hypertensive and normotensive eyes, respectively. CONCLUSIONS Aqueous angiography allowed for visualization of fluorescent dye in the superotemporal sclera. Laminar flow and smaller lumen vessels were observed mainly in hypertensive eyes.
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Affiliation(s)
| | | | - Arthur Weber
- Michigan State University, East Lansing, Michigan, USA
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25
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Aqueous outflow channels and its lymphatic association: A review. Surv Ophthalmol 2021; 67:659-674. [PMID: 34656556 PMCID: PMC9008077 DOI: 10.1016/j.survophthal.2021.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 10/07/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022]
Abstract
The human eye has a unique immune architecture and behavior. While the conjunctiva is known to have a well-defined lymphatic drainage system, the cornea, sclera, and uveal tissues were historically considered "alymphatic" and thought to be immune privileged. The very fact that the aqueous outflow channels carry a clear fluid (aqueous humor) along the outflow pathway makes it hard to ignore its lymphatic-like characteristics. The development of novel lymphatic lineage markers and expression of these markers in aqueous outflow channels and improved imaging capabilities has sparked a renewed interest in the study of ocular lymphatics. Ophthalmic lymphatic research has had a directional shift over the last decade, offering an exciting new physiological platform that needs further in-depth understanding. The evidence of a presence of distinct lymphatic channels in the human ciliary body is gaining significant traction. The uveolymphatic pathway is an alternative new route for aqueous outflow and adds a new dimension to pathophysiology and management of glaucoma. Developing novel animal models, markers, and non-invasive imaging tools to delineate the core anatomical structure and physiological functions may help pave some crucial pathways to understand disease pathophysiology and help develop novel targeted therapeutic approaches for glaucoma.
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26
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Telle MR, Snyder KC, Oikawa K, Nilles JP, Gehrke S, Teixeira LBC, Kiland JA, Huang A, McLellan GJ. Development and validation of methods to visualize conventional aqueous outflow pathways in canine primary angle closure glaucoma. Vet Ophthalmol 2021; 25 Suppl 1:84-95. [PMID: 34581493 PMCID: PMC8958177 DOI: 10.1111/vop.12943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Angle closure glaucoma (PACG) is highly prevalent in dogs and is often refractory to medical therapy. We hypothesized that pathology affecting the post-trabecular conventional aqueous outflow pathway contributes to persistent intraocular pressure (IOP) elevation in dogs with PACG. The goal of this study was to determine the potential for aqueous angiography (AA) and optical coherence tomography (OCT) to identify abnormalities in post-trabecular aqueous outflow pathways in canine PACG. METHODS AA and anterior segment OCT (Spectralis HRA + OCT) were performed ex vivo in 19 enucleated canine eyes (10 normal eyes and 9 irreversibly blind eyes from canine patients enucleated for management of refractory PACG). Eyes were cannulated and maintained at physiologic IOP (10-20 mmHg) prior to intracameral infusion of fluorescent tracer. OCT scleral line scans were acquired in regions of high and low perilimbal AA signal. Eyes were then perfusion fixed and cryosections prepared from 10/10 normal and 7/9 PACG eyes and immunolabeled for a vascular endothelial marker. RESULTS Normal canine eyes showed segmental, circumferential limbal AA signal, whereas PACG eyes showed minimal or no AA signal. AA signal correlated with scleral lumens on OCT in normal dogs, but lumens were generally absent or flattened in PACG eyes. Collapsed vascular profiles were identified in tissue sections from PACG eyes, including those in which no lumens were identified on AA and OCT. CONCLUSIONS In canine eyes with PACG, distal aqueous outflow channels are not identifiable by AA, despite normalization of their IOP, and intra-scleral vascular profiles are collapsed on OCT and histopathology.
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Affiliation(s)
- Mary Rebecca Telle
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kevin C Snyder
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kazuya Oikawa
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jacob P Nilles
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Shaile Gehrke
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Leandro B C Teixeira
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Julie A Kiland
- Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Alex Huang
- Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California, San Diego, California, USA
| | - Gillian J McLellan
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Khatib TZ, Meyer PAR, Lusthaus J, Manyakin I, Mushtaq Y, Martin KR. Hemoglobin Video Imaging Provides Novel In Vivo High-Resolution Imaging and Quantification of Human Aqueous Outflow in Patients with Glaucoma. Ophthalmol Glaucoma 2021; 2:327-335. [PMID: 31788668 PMCID: PMC6876656 DOI: 10.1016/j.ogla.2019.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Purpose Noninvasive, detailed measurement of the dynamics of human aqueous outflow is difficult to achieve with currently available clinical tools. We used hemoglobin video imaging (HVI) to develop a technique to image and quantify human aqueous outflow noninvasively and in real time. Design A prospective observational study to describe characteristics of aqueous veins and a pilot prospective interventional feasibility study to develop quantification parameters. Participants Patients were recruited from the Cambridge University Hospitals NHS Foundation Trust Glaucoma clinic. The observational study included 30 eyes, and the pilot interventional feasibility study was performed on 8 eyes undergoing selective laser trabeculoplasty (SLT). Our SLT protocol also included the installation of pilocarpine and apraclonidine eye drops. Methods Participants underwent HVI alongside their usual clinic visit. Main Outcome Measures The change in cross-sectional area (CSA) of the aqueous column within episcleral veins was correlated with intraocular pressure (IOP) reduction and change in visual field mean deviation (MD) before and after intervention. Fluctuations in contrast and pixel intensity of red blood cells in an aqueous vein were calculated to compare the flow rate before and after intervention using autocorrelation analysis. Results Hemoglobin video imaging enables the direct observation of aqueous flow into the vascular system. Aqueous is seen to centralize within a laminar venous column. Flow is pulsatile, and fluctuations of flow through globe pressure or compression of the aqueous vein are observed. There was a significant increase in the aqueous column after the administration of our SLT protocol (n = 13; P < 0.05). This correlated with the degree of IOP reduction (n = 13; Pearson’s correlation coefficient 0.7; P = 0.007) and the improvement in MD observed postintervention (n = 8; Pearson’s correlation coefficient 0.75; P = 0.03). Autocorrelation analysis demonstrated a faster rate of decay in an aqueous vein after intervention, indicating an increase in flow rate. Conclusions Hemoglobin video imaging can be incorporated into a routine clinic slit-lamp examination to allow a detailed assessment and quantification of aqueous outflow in real time. It has the potential to be used to help target therapeutic interventions to improve aqueous outflow and further advance our understanding of aqueous outflow dysregulation in the pathogenesis of glaucoma.
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Affiliation(s)
- Tasneem Z Khatib
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom.,Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Paul A R Meyer
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Jed Lusthaus
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.,Sydney Eye Hospital Glaucoma Unit, Sydney, Australia.,Discipline of Ophthalmology, The University of Sydney, Sydney, Australia
| | - Ilya Manyakin
- Department of Physics, University of Cambridge, Cambridge, United Kingdom
| | - Yusuf Mushtaq
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Keith R Martin
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom.,Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.,Cambridge NIHR Biomedical Research Centre, Cambridge, United Kingdom.,Wellcome Trust - MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
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28
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Gietzelt C, Kiessling D, Widder RA, Heindl LM, Cursiefen C, Dietlein TS, Enders P. Combined ab-interno trabeculectomy and cataract surgery induces comparable intraocular pressure reduction in supine and sitting positions. Int J Ophthalmol 2021; 14:1192-1198. [PMID: 34414083 DOI: 10.18240/ijo.2021.08.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/26/2021] [Indexed: 11/23/2022] Open
Abstract
AIM To analyze the therapeutic effect of combined ab-interno trabeculectomy and cataract surgery on intraocular pressure (IOP) levels in supine and sitting postures during a 24-hour IOP profile. METHODS Twenty-six eyes of twenty-six patients receiving ab-interno trabeculectomy using electroablation of the trabecular meshwork combined with cataract surgery or stand-alone were included in this retrospective analysis. IOP change during 24-hour IOP profiles within two years postoperatively were analyzed for eyes receiving surgery ("study eyes") and compared to fellow eyes, which had not received surgery. Clinical data including mean sitting IOP (siIOP), mean supine IOP (suIOP) and the number of topical antiglaucomatous medications (TAM) were extracted from patients' files. RESULTS Preoperatively, siIOP was 17.6±5.3 mm Hg in study and 17.1±4.7 mm Hg in fellow eyes (P=0.347). Patients were treated with an average of 2.8±1.0 TAM. Best corrected visual acuity (BCVA) was significantly worse in study eyes (P<0.001), visual field function was marginally not significantly different (P=0.057). After surgery 9.6±6.8mo, study eyes had a mean siIOP of 14.5±3.6 mm Hg (IOP reduction: -3.2 mm Hg, P=0.009), a mean suIOP of 18.0±3.5 mm Hg, and an average of 1.3±1.34 TAM (P<0.001), while in fellow eyes, mean siIOP was 16.2±3.4 mm Hg and mean suIOP was 20.5±5.1 mm Hg. Postoperatively, the relative IOP increase between sitting and supine postures was approximately 30% in both study and fellow eyes (P=0.99). CONCLUSION IOP after ab-interno trabeculectomy shows a comparable relative reduction in both supine and sitting position. Classical trabeculectomy is known to lower suIOP overproportionally.
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Affiliation(s)
- Caroline Gietzelt
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany.,Glaucoma Imaging Center University of Cologne (GICC), Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany
| | - David Kiessling
- Department of Ophthalmology, St Martinus-Krankenhaus Duesseldorf, Gladbacher Straße 26, Düsseldorf 40219, Germany
| | - Randolf A Widder
- Department of Ophthalmology, St Martinus-Krankenhaus Duesseldorf, Gladbacher Straße 26, Düsseldorf 40219, Germany
| | - Ludwig M Heindl
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany
| | - Claus Cursiefen
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany
| | - Thomas S Dietlein
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany
| | - Philip Enders
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany.,Glaucoma Imaging Center University of Cologne (GICC), Faculty of Medicine and University Hospital Cologne, Kerpener Straße 62, Cologne 50924, Germany
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Mendez-Martinez S, Martínez-Rincón T, Subias M, Pablo LE, García-Herranz D, Feijoo JG, Bravo-Osuna I, Herrero-Vanrell R, Garcia-Martin E, Rodrigo MJ. Influence of Chronic Ocular Hypertension on Emmetropia: Refractive, Structural and Functional Study in Two Rat Models. J Clin Med 2021; 10:jcm10163697. [PMID: 34441992 PMCID: PMC8397123 DOI: 10.3390/jcm10163697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 12/29/2022] Open
Abstract
Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (<20 mmHg) and an OHT cohort (>20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time.
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Affiliation(s)
- Silvia Mendez-Martinez
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- Correspondence: ; Tel.: +34-9-7676-5558
| | - Teresa Martínez-Rincón
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - Manuel Subias
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - Luis E. Pablo
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
| | - David García-Herranz
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415 Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
- Health Research Institute, San Carlos Clinical Hospital (IdISSC), 28040 Madrid, Spain
- University Institute for Industrial Pharmacy (IUFI), School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain
| | - Julian García Feijoo
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
- Department of Ophthalmology, San Carlos Clinical Hospital (IdISSC), Complutense University of Madrid, 28040 Madrid, Spain
| | - Irene Bravo-Osuna
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415 Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
- Health Research Institute, San Carlos Clinical Hospital (IdISSC), 28040 Madrid, Spain
| | - Rocío Herrero-Vanrell
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415 Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
- Health Research Institute, San Carlos Clinical Hospital (IdISSC), 28040 Madrid, Spain
| | - Elena Garcia-Martin
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
| | - María J. Rodrigo
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (T.M.-R.); (M.S.); (L.E.P.); (E.G.-M.); (M.J.R.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain; (J.G.F.); (I.B.-O.); (R.H.-V.)
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30
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Johnstone M, Xin C, Tan J, Martin E, Wen J, Wang RK. Aqueous outflow regulation - 21st century concepts. Prog Retin Eye Res 2021; 83:100917. [PMID: 33217556 PMCID: PMC8126645 DOI: 10.1016/j.preteyeres.2020.100917] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022]
Abstract
We propose an integrated model of aqueous outflow control that employs a pump-conduit system in this article. Our model exploits accepted physiologic regulatory mechanisms such as those of the arterial, venous, and lymphatic systems. Here, we also provide a framework for developing novel diagnostic and therapeutic strategies to improve glaucoma patient care. In the model, the trabecular meshwork distends and recoils in response to continuous physiologic IOP transients like the ocular pulse, blinking, and eye movement. The elasticity of the trabecular meshwork determines cyclic volume changes in Schlemm's canal (SC). Tube-like SC inlet valves provide aqueous entry into the canal, and outlet valve leaflets at collector channels control aqueous exit from SC. Connections between the pressure-sensing trabecular meshwork and the outlet valve leaflets dynamically control flow from SC. Normal function requires regulation of the trabecular meshwork properties that determine distention and recoil. The aqueous pump-conduit provides short-term pressure control by varying stroke volume in response to pressure changes. Modulating TM constituents that regulate stroke volume provides long-term control. The aqueous outflow pump fails in glaucoma due to the loss of trabecular tissue elastance, as well as alterations in ciliary body tension. These processes lead to SC wall apposition and loss of motion. Visible evidence of pump failure includes a lack of pulsatile aqueous discharge into aqueous veins and reduced ability to reflux blood into SC. These alterations in the functional properties are challenging to monitor clinically. Phase-sensitive OCT now permits noninvasive, quantitative measurement of pulse-dependent TM motion in humans. This proposed conceptual model and related techniques offer a novel framework for understanding mechanisms, improving management, and development of therapeutic options for glaucoma.
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Affiliation(s)
| | - Chen Xin
- Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, China.
| | - James Tan
- Doheny Eye Institute and UCLA Department of Ophthalmology, USA.
| | | | | | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, USA; Department of Bioengineering, University of Washington, USA.
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31
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In-vivo imaging of the conventional aqueous outflow system. Curr Opin Ophthalmol 2021; 32:275-279. [PMID: 33653980 DOI: 10.1097/icu.0000000000000751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE OF REVIEW The aim of this study was to provide a comprehensive summary of in-vivo imaging techniques of the aqueous outflow system and discuss its role in improving our understanding of glaucoma pathogenesis and management. RECENT FINDINGS Our understanding of the aqueous outflow system is largely derived from ex-vivo studies. Recent innovations in imaging technology and techniques enable in-vivo evaluation of the conventional outflow system in real-time. Optical coherence tomography allows for noninvasive, high-resolution, volumetric imaging of ocular tissues. Dynamic structural changes have been observed at the trabecular meshwork and Schlemm's canal. In parallel, aqueous angiography using injected tracers show a similar dynamism with variable and pulsatile flow signals. SUMMARY In-vivo imaging enable real-time evaluation of the conventional aqueous outflow pathway. This emerging field shows great promise to expand our understanding of the pathogenesis and treatment of glaucoma.
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Abtahi M, Rudnisky CJ, Nazarali S, Damji KF. Incidence of steroid response in microinvasive glaucoma surgery with trabecular microbypass stent and ab interno trabeculectomy. Can J Ophthalmol 2021; 57:167-174. [PMID: 33992593 DOI: 10.1016/j.jcjo.2021.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 03/26/2021] [Accepted: 04/12/2021] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To determine the incidence and risk factors for steroid response in patients undergoing combined phacoemulsification cataract extraction (PCE) and microinvasive glaucoma surgery with either trabecular microbypass stent implantation (iStent) or ab interno trabeculectomy (Trabectome). DESIGN Retrospective, noncomparative, single-institutional observational chart review. PARTICIPANTS Consecutive patients with open-angle glaucoma who underwent PCE with iStent or Trabectome with 3 months of follow-up. METHODS Data were collected from patient charts, including pre- and postoperative intraocular pressure (IOP) following application of topical corticosteroid on postoperative visits for at least 3 months. A steroid response was defined as an IOP rise of greater than 5 mm Hg beginning at least 3 days after surgery with no other obvious explanation and with IOP < 20 mm Hg following rapid tapering or withdrawal of the steroid. RESULTS A total of 118 eyes from 89 patients, average age of 71.4 ±12.1 years, were included. Overall, a steroid response was seen in 12.7% of eyes (n = 15), and no difference was noted between Trabectome (11.8%) and iStent (13.6%, p = 0.782) eyes. Axial length (AL; p = 0.01), younger age (p = 0.009), traumatic glaucoma (p = 0.004), and normal-tension glaucoma (NTG; p = 0.0048) were significant predictors of steroid response in a multivariate analysis. In eyes with AL ≥ 25 mm, the steroid response rate was 40%, in contrast to eyes with AL < 25 mm, where it was 10.2%. CONCLUSION A steroid response develops in approximately 1 in 8 patients undergoing PCE with Trabectome or iStent. Young age, AL > 25 mm, traumatic glaucoma, and NTG were found to be significant predictors of steroid response.
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Affiliation(s)
- Maryam Abtahi
- Department of Ophthalmology, University of Ottawa, Ottawa, Ont..
| | - Chris J Rudnisky
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alb
| | - Samir Nazarali
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alb
| | - Karim F Damji
- Department of Ophthalmology and Visual Sciences, University of Alberta and the Walter C. Mackenzie Health Sciences Centre, Edmonton, Alb
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Gao K, Song S, Johnstone MA, Zhang Q, Xu J, Zhang X, Wang RK, Wen JC. Reduced Pulsatile Trabecular Meshwork Motion in Eyes With Primary Open Angle Glaucoma Using Phase-Sensitive Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2021; 61:21. [PMID: 33326017 PMCID: PMC7745620 DOI: 10.1167/iovs.61.14.21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Purpose The purpose of this study was to investigate the difference in pulsatile trabecular meshwork (TM) motion between normal and eyes with POAG using phase-sensitive optical coherence tomography (PhS-OCT). Methods In this cross-sectional study, eight healthy subjects (16 eyes) and nine patients with POAG (18 eyes) were enrolled. A laboratory-based prototype PhS-OCT system was used to measure pulsatile TM motion. PhS-OCT images were analyzed to obtain parameters of pulsatile TM motion (i.e. maximum velocity [MV] and cumulative displacement [CDisp]). Outflow facility and ocular pulse amplitude were measured using pneumotonography. Detection sensitivity was compared among various parameters by calculating the area under the receiver operating characteristic curves (AUCs). Results A pulsatile TM motion waveform synchronous with digital pulse was observed using PhS-OCT in both healthy and POAG eyes. The mean MV in eyes with glaucoma was significantly lower than healthy eyes (P < 0.001). The mean CDisp in POAG eyes was also significantly lower than healthy eyes (P < 0.001). CDisp showed a significant correlation (r = 0.46; P = 0.0088) with ocular pulse amplitude in the study. Compared with the outflow facility, both the MV and CDisp were found to have a better discrimination of glaucoma (P < 0.001 and P = 0.0074, respectively). Conclusions Pulsatile TM motion was reduced in patients with POAG compared to healthy subjects. The underlying mechanism may be due to the altered tissue stiffness or other biomechanical properties of the TM in POAG eyes. Our evidence suggests that the measurement of pulsatile TM motion with PhS-OCT may help in characterizing outflow pathway abnormalities.
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Affiliation(s)
- Kai Gao
- Department of Bioengineering, University of Washington, Seattle, Washington, United States.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Murray A Johnstone
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Xiulan Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States.,Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Joanne C Wen
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States.,Duke Eye Center, Durham, North Carolina, United States
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Kiessling D, Rennings C, Hild M, Lappas A, Dietlein TS, Roessler GF, Widder RA. Predictability of ab-interno trabeculectomy success in the subsequent eye: A contralateral eye comparison study. Clin Exp Ophthalmol 2021; 49:242-250. [PMID: 33550686 DOI: 10.1111/ceo.13905] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/28/2020] [Accepted: 01/25/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND To determine whether the outcome of the first eye may serve as a predictor for intraocular pressure (IOP)-lowering effectiveness in the second eye following bilateral ab interno trabeculectomy. METHODS This retrospective single-centre study included 168 eyes from 84 participants, who underwent combined Trabectome surgery with phacoemulsification cataract surgery in a hospital setting. The clinical endpoint was defined as either 'success' or 'failure' based on four separate scores at the longest follow-up time point: IOP at follow-up <21 mm Hg (Score A) or IOP < 18 mm Hg (Score B), without re-surgery and IOP reduction >20%; IOP ≤15 mm Hg without re-surgery and IOP reduction ≥40% (Score C); and the sole absence of re-surgery according to the discretion of the surgeon (Score D). RESULTS No significant difference was observed between the outcomes of first and second eyes. The frequency of success in the second eye after effective surgery in the first eye significantly exceeded that after prior failure. Within our analysis, the probability calculations determined a 75% chance of success following prior success for Score A. If surgery in the first eye failed, the chance of success in the subsequent eye was 37%. The corresponding probabilities were 79% and 32% for Score B, 56% and 9% for Score C, and 99% and 50% for Score D. CONCLUSION The results of our study offer a useful tool to assess the success of subsequent eye surgeries based on the outcome in the initial eye, owing to the high predictive potential.
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Affiliation(s)
- David Kiessling
- Department of Ophthalmology, St. Martinus-Krankenhaus, Düsseldorf, Germany
| | - Corinna Rennings
- Department of Ophthalmology, St. Martinus-Krankenhaus, Düsseldorf, Germany
| | - Matthias Hild
- Department of Ophthalmology, St. Martinus-Krankenhaus, Düsseldorf, Germany
| | - Alexandra Lappas
- Department of Ophthalmology, University Hospital of Cologne, Cologne, Germany
| | - Thomas S Dietlein
- Department of Ophthalmology, University Hospital of Cologne, Cologne, Germany
| | - Gernot F Roessler
- Department of Ophthalmology, St. Martinus-Krankenhaus, Düsseldorf, Germany.,Department of Ophthalmology, RWTH Aachen, Aachen, Germany
| | - Randolf A Widder
- Department of Ophthalmology, St. Martinus-Krankenhaus, Düsseldorf, Germany.,Department of Ophthalmology, University Hospital of Cologne, Cologne, Germany
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Swain DL, Le TD, Yasmin S, Fernandes B, Lamaj G, Dasgupta I, Gao Y, Gong H. Morphological factors associated with giant vacuoles with I-pores in Schlemm's canal endothelial cells of human eyes: A serial block-face scanning electron microscopy study. Exp Eye Res 2021; 205:108488. [PMID: 33571532 DOI: 10.1016/j.exer.2021.108488] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/14/2021] [Accepted: 02/02/2021] [Indexed: 10/22/2022]
Abstract
Increased intraocular pressure (IOP) is the main risk factor for primary open-angle glaucoma and results from impaired drainage of aqueous humor (AH) through the trabecular outflow pathway. AH must pass the inner wall (IW) endothelium of Schlemm's canal (SC), which is a monolayer held together by tight junctions, to exit the eye. One route across the IW is through giant vacuoles (GVs) with their basal openings and intracellular pores (I-pores). AH drainage through the trabecular outflow pathway is segmental. Whether more GVs with both basal openings and I-pores are present in the active flow areas and factors that may influence formation of GVs with I-pores have not been fully elucidated due to limitations in imaging methods. In this study, we applied a relatively new technique, serial block-face scanning electron microscopy (SBF-SEM), to investigate morphological factors associated with GVs with I-pores in different flow areas. Two normal human donor eyes were perfused at 15 mmHg with fluorescent tracers to label the outflow pattern followed by perfusion-fixation. Six radial wedges of trabecular meshwork including SC (2 each from high-, low-, and non-flow areas) were imaged using SBF-SEM (total: 9802 images). Total GVs, I-pores, basal openings, and four types of GVs were identified. Percentages of GVs with I-pores and basal openings and number of I-pores/GV were determined. Overall, 14.4% (477/3302) of GVs had I-pores. Overall percentage of GVs with both I-pores and basal openings was higher in high- (15.7%), than low- (12.6%) or non-flow (7.3%) areas. Of GVs with I-pores, 83.2% had a single I-pore; 16.8% had multiple I-pores (range: 2-6). Additionally, 180 GVs (90 with I-pores and 90 without I-pores) were randomly selected, manually segmented, and three-dimensionally (3D) reconstructed to determine size, shape, and thickness of the cellular lining. Size of GVs (including median volume, surface area, and maximal cross-sectional area) with I-pores (n = 90) was significantly larger than GVs without I-pores (n = 90) using 3D-reconstructed GVs (P ≤ 0.01). Most I-pores (73.3%; 66/90) were located on or close to GV's maximal cross-sectional area with significant thinning of the cellular lining. Our results suggest that larger size and thinner cellular lining of GVs may contribute to formation of GVs with I-pores. More GVs with I-pores and basal openings were observed in high-flow areas, suggesting these GVs do provide a channel through which AH passes into SC and that increasing this type of GV may be a potential strategy to increase aqueous outflow for glaucoma treatment.
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Affiliation(s)
- David L Swain
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Thuy Duong Le
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Senila Yasmin
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Beatriz Fernandes
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Ganimete Lamaj
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Indira Dasgupta
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Yanyun Gao
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA.
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The Effects of Trabecular Bypass Surgery on Conventional Aqueous Outflow, Visualized by Hemoglobin Video Imaging. J Glaucoma 2020; 29:656-665. [PMID: 32773669 DOI: 10.1097/ijg.0000000000001561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PRECIS 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. PURPOSE The purpose of this study was to use HVI to illustrate and quantify effects of TBS on AO through the episcleral venous system. DESIGN This is a 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) 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 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. 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 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. 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 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.
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Lee JY, Akiyama G, Saraswathy S, Xie X, Pan X, Hong YK, Huang AS. Aqueous humour outflow imaging: seeing is believing. Eye (Lond) 2020; 35:202-215. [PMID: 33060830 DOI: 10.1038/s41433-020-01215-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 12/22/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the primary risk factor for blindness in glaucoma. IOP is determined by many factors including aqueous humour production and aqueous humour outflow (AHO), where AHO disturbance represents the primary cause of increased IOP. With the recent development of new IOP lowering drugs and Minimally Invasive Glaucoma Surgeries (MIGS), renewed interest has arisen in shedding light on not only how but where AHO is occurring for the trabecular/conventional, uveoscleral/unconventional, and subconjunctival outflow pathways. Historical studies critical to understanding outflow anatomy will be presented, leading to the development of modern imaging methods. New biological behaviours uncovered by modern imaging methods will be discussed with relevance to glaucoma therapies emphasized.
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Affiliation(s)
- Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Department of Ophthalmology, Gachon University, College of Medicine, Gil Medical Center, Incheon, Korea
| | - Goichi Akiyama
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Jikei School of Medicine, Tokyo, Japan.,Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Xiaobin Xie
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaojing Pan
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Qindao Eye Hospital of Shandong First Medical University, Shandong Eye Institute, Qindao, China
| | - Young-Kwon Hong
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Alex S Huang
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Aqueous outflow imaging techniques and what they tell us about intraocular pressure regulation. Eye (Lond) 2020; 35:216-235. [PMID: 32826996 DOI: 10.1038/s41433-020-01136-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/19/2020] [Accepted: 08/07/2020] [Indexed: 02/06/2023] Open
Abstract
Recent advances in the medical and surgical management of open-angle glaucoma have increased the number of treatment options available. Several new intraocular pressure (IOP)-lowering treatments target the conventional aqueous outflow (AO) system. However, success rates are variable and outcomes in individual patients are often difficult to predict. Variable treatment responses remain unexplained and highlight deficiencies in our current understanding of AO regulation and IOP homeostasis. Imaging is often relied upon to confirm diagnoses and monitor treatment responses in other ocular and systemic pathologies. As yet no suitable AO imaging tool has been developed to fulfil this role in glaucoma. A variety of imaging techniques have been used to study the AO tracts of humans and animals in ex vivo and in vivo eyes. In this review, results from novel imaging techniques that assess aqueous drainage through the episcleral venous system are considered and we argue these provide new insights into AO regulation. We suggest that the ability to objectively measure AO responses to interventions would be a significant clinical advance, and we have demonstrated that this can be achieved with direct visualisation of aqueous drainage. We predict that the evolution of AO imaging technology will continue to reveal critical components of AO and IOP regulation, and that personalised IOP-lowering treatment in glaucoma care may well become a reality in the near future.
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Burn JB, Huang AS, Weber AJ, Komáromy AM, Pirie CG. Aqueous Angiography in Normal Canine Eyes. Transl Vis Sci Technol 2020; 9:44. [PMID: 32934894 PMCID: PMC7463224 DOI: 10.1167/tvst.9.9.44] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/02/2020] [Indexed: 01/09/2023] Open
Abstract
Purpose To conduct aqueous angiography (AA) using a clinically applicable technique in normal dogs and to compare findings to intravenous scleral angiography (SA). Methods We examined 10 canine cadaver eyes and 12 eyes from live normal dogs. A gravity-fed trocar system delivered 2% sodium fluorescein and 0.25% indocyanine green (ICG) intracamerally (IC) in cadaver eyes. In vivo AA was subsequently performed in one eye of each of the 12 dogs via IC bolus of ICG under sedation. The same 12 dogs received SA via intravenous ICG (mean ± SD) 10.7 ± 3.3 days later. Identical scleral sectors were imaged using a Spectralis confocal scanning laser ophthalmoscope. Results The gravity-fed trocar system permitted visualization of the conventional aqueous humor outflow (CAHO) pathways in cadaver eyes, but not in vivo. Fluorescence was observed superonasally in four of the 10 cadaver eyes within 24.0 ± 3.6 seconds. A single IC bolus of ICG showed CAHO pathways in vivo, demonstrating sectoral outflow patterns in the superotemporal sclera in 10 of the 12 eyes within 35.0 ± 4.3 seconds; four of the 12 eyes exhibited pulsatile aqueous movement. SA exhibited fluorescence patterns comparable to AA with weak pulsatile aqueous humor outflow. Conclusions Angiography (AA or SA) in dogs permits visualization of the CAHO pathway and its vascular components in vivo. AA may be a more useful modality to assess aqueous humor outflow. Translational Relevance Intracameral AA has potential utility for evaluating CAHO in vivo in dogs, an important animal model species.
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Affiliation(s)
- Jessica B. Burn
- Michigan State University Veterinary Medical Center, East Lansing, MI, USA
| | - Alex S. Huang
- Doheny Eye Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Arthur J. Weber
- Michigan State University Veterinary Medical Center, East Lansing, MI, USA
| | - Andras M. Komáromy
- Michigan State University Veterinary Medical Center, East Lansing, MI, USA
| | - Chris G. Pirie
- Michigan State University Veterinary Medical Center, East Lansing, MI, USA
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Abstract
Spaceflight-associated neuro-ocular syndrome (SANS) describes a series of morphologic and functional ocular changes in astronauts first reported by Mader and colleagues in 2011. SANS is currently clinically defined by the development of optic disc edema during prolonged exposure to the weightless (microgravity) environment, which currently occurs on International Space Station (ISS). However, as improvements in our understanding of the ocular changes emerge, the definition of SANS is expected to evolve. Other ocular SANS signs that arise during and after ISS missions include hyperopic shifts, globe flattening, choroidal/retinal folds, and cotton wool spots. Over the last 10 years, ~1 in 3 astronauts flying long-duration ISS missions have presented with ≥1 of these ocular findings. Commensurate with research that combines disparate specialties (vision biology and spaceflight medicine), lessons from SANS investigations may also yield insight into ground-based ocular disorders, such as glaucomatous optic neuropathy that may have the potential to lessen the burden of this irreversible cause of vision loss on Earth.
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Akiyama G, Saraswathy S, Bogarin T, Pan X, Barron E, Wong TT, Kaneko MK, Kato Y, Hong Y, Huang AS. Functional, structural, and molecular identification of lymphatic outflow from subconjunctival blebs. Exp Eye Res 2020; 196:108049. [PMID: 32387381 PMCID: PMC7328765 DOI: 10.1016/j.exer.2020.108049] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/05/2020] [Accepted: 04/27/2020] [Indexed: 01/26/2023]
Abstract
The purpose of this study is to evaluate outflow pathways from subconjunctival blebs and to identify their identity. Post-mortem porcine (n = 20), human (n = 1), and bovine (n = 1) eyes were acquired, and tracers (fluorescein, indocyanine green, or fixable/fluorescent dextrans) were injected into the subconjunctival space to create raised blebs where outflow pathways were visualized qualitatively and quantitatively. Rodents with fluorescent reporter transgenes were imaged for structural comparison. Concurrent optical coherence tomography (OCT) was obtained to study the structural nature of these pathways. Using fixable/fluorescent dextrans, tracers were trapped to the bleb outflow pathway lumen walls for histological visualization and molecular identification using immunofluorescence against lymphatic and blood vessel markers. Bleb outflow pathways could be observed using all tracers in all species. Quantitative analysis showed that the nasal quadrant had more bleb-related outflow pathways compared to the temporal quadrant (nasal: 1.9±0.3 pathways vs. temporal: 0.7±0.2 pathways; p = 0.003). However, not all blebs resulted in an outflow pathway (0-pathways = 18.2%; 1-pathway = 36.4%; 2-pathways = 38.6%; and 3-pathways = 6.8%). Outflow signal was validated as true luminal pathways using optical coherence tomography and histology. Bicuspid valves were identified in the direction of flow in porcine eyes. Immunofluorescence of labeled pathways demonstrated a lymphatic (Prox-1 and podoplanin) but not a blood vessel (CD31) identity. Therefore, subconjunctival bleb outflow occurs in discrete luminal pathways. They are lymphatic as assessed by structural identification of valves and molecular identification of lymphatic markers. Better understanding of lymphatic outflow may lead to improved eye care for glaucoma surgery and ocular drug delivery.
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Affiliation(s)
- Goichi Akiyama
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Jikei School of Medicine, Tokyo, Japan
| | - Sindhu Saraswathy
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Thania Bogarin
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Xiaojing Pan
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong First Medical University, Qingdao, China
| | - Ernesto Barron
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tina T Wong
- Singapore National Eye Center and Singapore Research Institute, Singapore, Singapore
| | - Mika K Kaneko
- Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yukinari Kato
- Tohoku University Graduate School of Medicine, Miyagi, Japan; New Industry Creation Hatchery Center, Tohoku University, Miyagi, Japan
| | - Young Hong
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Alex S Huang
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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The Effectiveness of First-Generation iStent Microbypass Implantation Depends on Initial Intraocular Pressure: 24-Month Follow-Up-Prospective Clinical Trial. J Ophthalmol 2020; 2020:8164703. [PMID: 32676205 PMCID: PMC7330650 DOI: 10.1155/2020/8164703] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/04/2020] [Accepted: 05/27/2020] [Indexed: 11/18/2022] Open
Abstract
Background Evaluation of efficacy of the iStent trabecular bypass implant in reducing intraocular pressure (IOP) depending on the value pretreatment IOP and number of medications used before surgery in patients with primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PXG) and coexisting cataract. Methods A prospective, uncontrolled, interventional case series. 72 patients, on a mean age of 72.42 ± 9.17, were divided into two groups depending on baseline IOP: group I < 26 mmHg and group II ≥ 26 mmHg. All subjects underwent ab interno implantation of a single iStent together with cataract surgery. Best-corrected visual acuity (BCVA), IOP, number of antiglaucoma medications, visual field, and number and type of complications were examined before and after surgery. Postoperative patients were followed up at 1, 7, and 30 days and 3, 6, 12, and 24 months. All the patients were washed out preoperatively as well as postoperatively. Results The mean observation time was 20 months. The mean preoperative IOP was 21.03 ± 1.44 mmHg in group I and reduced to mean 15.60 ± 2.12 mmHg after operation. In group II, mean IOP reduced from 26.00 ± 0.00 to 18.56 ± 1.81 (p=0.003). Mean glaucoma medications decreased from 1.35 ± 0.65 to 0.29 ± 0.52 in group I (p < 0.001) and from 2.89 ± 1.18 to 1.33 ± 1.50 in group II (p < 0.001). At 24 months, medication reduction was significantly greater in group I than group II (p=0.026). Conclusions Combined cataract surgery with implantation of iStent seems to be an effective procedure in patients with mild-to-moderate open-angle glaucoma and cataract. In patients with baseline IOP < 26 mmHg, surgery reduced IOP and medication use significantly declined to 2 years, with greater reductions achieved versus patients with baseline IOP ≥ 26 mmHg. This trial is registered with NCT03807869.
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Saraswathy S, Bogarin T, Barron E, Francis BA, Tan JCH, Weinreb RN, Huang AS. Segmental differences found in aqueous angiographic-determined high - and low-flow regions of human trabecular meshwork. Exp Eye Res 2020; 196:108064. [PMID: 32439396 DOI: 10.1016/j.exer.2020.108064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 01/28/2023]
Abstract
This work sought to compare aqueous angiographic segmental patterns with bead-based methods which directly visualize segmental trabecular meshwork (TM) tracer trapping. Additionally, segmental protein expression differences between aqueous angiographic-derived low- and high-outflow human TM regions were evaluated. Post-mortem human eyes (One Legacy and San Diego eye banks; n = 15) were perfused with fluorescent tracers (fluorescein [2.5%], indocyanine green [0.4%], and/or fluorescent microspheres). After angiographic imaging (Spectralis HRA+OCT; Heidelberg Engineering), peri-limbal low- and high-angiographic flow regions were marked. Aqueous angiographic segmental outflow patterns were similar to fluorescent microsphere TM trapping segmental patterns. TM was dissected from low- and high-flow areas and processed for immunofluorescence or Western blot and compared. Versican expression was relatively elevated in low-flow regions while MMP3 and collagen VI were relatively elevated in high-flow regions. TGF-β2, thrombospondin-1, TGF-β receptor1, and TGF-β downstream proteins such as α-smooth muscle actin were relatively elevated in low-flow regions. Additionally, fibronectin (FN) levels were unchanged, but the EDA isoform (FN-EDA) that is associated with fibrosis was relatively elevated in low-flow regions. These results show that segmental aqueous angiographic patterns are reflective of underlying TM molecular characteristics and demonstrate increased pro-fibrotic activation in low-flow regions. Thus, we provide evidence that aqueous angiography outflow visualization, the only tracer outflow imaging method available to clinicians, is in part representative of TM biology.
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Affiliation(s)
- Sindhu Saraswathy
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Thania Bogarin
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ernesto Barron
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Brian A Francis
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - James C H Tan
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology University of California, San Diego, CA, USA
| | - Alex S Huang
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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Xin C, Wang H, Wang N. Minimally Invasive Glaucoma Surgery: What Do We Know? Where Should We Go? Transl Vis Sci Technol 2020; 9:15. [PMID: 32821487 PMCID: PMC7401977 DOI: 10.1167/tvst.9.5.15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/02/2019] [Indexed: 12/17/2022] Open
Abstract
With the arrival of a plethora of new and revolving minimally invasive glaucoma surgery techniques, glaucoma specialists currently are fortunate to have various surgical options that aim to recovery of the function of the aqueous outflow system in different ways. Meanwhile, the aqueous outflow system has become the hot point of researching. In ARVO 2019, a special interest group session was held on new perspectives on minimally invasive glaucoma surgery. Ten surgeons, clinical professors, and experimental scientists were invited to report their latest studies and discussed on five hot topics in this special interest group. This review summarizes the special interest group session and posts the issues of greatest concern, providing insight to the aqueous outflow system and areas that require further study.
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Affiliation(s)
- Chen Xin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Huangzhou Wang
- Ophthalmology Department, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
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Episcleral Venous Fluid Wave in the Living Human Eye Adjacent to Microinvasive Glaucoma Surgery (MIGS) Supports Laboratory Research: Outflow is Limited Circumferentially, Conserved Distally, and Favored Inferonasally. J Glaucoma 2020; 28:139-145. [PMID: 30461548 DOI: 10.1097/ijg.0000000000001126] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to describe downstream patterns of outflow with the episcleral venous fluid wave (EVFW) in the living human eye adjacent to microinvasive glaucoma surgery (MIGS) and determine if the EVFW supports existing ex-vivo laboratory outflow research. DESIGN Retrospective, noncomparative case series. PATIENTS A total of 10 eyes of 10 patients who underwent phaco-Trabectome and 10 eyes of 10 patients who underwent phaco-iStent consecutively at Glaucoma Associates of Texas for cataract and uncontrolled glaucoma who demonstrated an episcleral wave. METHODS The EVFW was visualized and recorded during irrigation and aspiration. To describe the hydrodynamic properties of the fluid wave, its degrees, extent, and characteristics were measured with a protractor in Photoshop. RESULTS The incised Trabectome arc produced adjacent episcleral blanching of 134±11 degrees (range, 112 to 150 degrees) with an additional 54 degrees of marginal recruitment (41 degrees inferonasal plus 13 degrees superonasal) adjacent to the ends of the Trabectome incision. The mean episcleral blanch for the iStent was 51±19 degrees (range, 19 to 90 degrees), comprised of 29 degrees inferonasal plus 22 degrees superonasal. CONCLUSIONS Downstream episcleral flow in the living human eye adjacent to the iStent is variable and mainly confined to 2 clock hours indicating a lack of significant circumferential flow in glaucomatous eyes. Flow distal to the Trabectome site encompasses the Trabectome incisional arc with an additional 2 clock hours of lateral fluid wave favoring the inferonasal over superonasal quadrant 3 to 1. These in-vivo findings made visible with MIGS, corroborate recent in-vivo and long-standing ex-vivo laboratory research that outflow is largely segmented, favored inferonasally and conserved distally.
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Akagi T, Uji A, Okamoto Y, Suda K, Kameda T, Nakanishi H, Ikeda HO, Miyake M, Nakano E, Motozawa N, Tsujikawa A. Anterior Segment Optical Coherence Tomography Angiography Imaging of Conjunctiva and Intrasclera in Treated Primary Open-Angle Glaucoma. Am J Ophthalmol 2019; 208:313-322. [PMID: 31102577 DOI: 10.1016/j.ajo.2019.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/04/2019] [Accepted: 05/06/2019] [Indexed: 01/18/2023]
Abstract
PURPOSE To investigate conjunctival and intrascleral vasculature in glaucoma eyes using anterior segment (AS)-optical coherence tomography angiography (OCTA) and assess the factors contributing to the vessel density in AS-OCTA images. DESIGN Prospective, cross-sectional study. METHODS Thirty-four patients with primary open-angle glaucoma and 20 healthy subjects were included. A swept-source OCT system was used to obtain the AS-OCTA images of the corneoscleral limbus at the nasal and temporal quadrants. Vessel densities were measured in the superficial (from the conjunctival epithelium to a depth of 200 μm) and deep (from a depth of 200 to 1000 μm) layers. The vessel density was compared between healthy and glaucoma eyes, and the associations of the vessel density with possible confounding factors were analyzed using univariable and multivariable analyses. RESULTS The vessel density was not significantly different between healthy eyes and eyes with glaucoma. There was a significant association of superficial vessel density with the use of a prostaglandin analog (P = .007) and with nasal location (P = .016) in eyes with glaucoma. Deep vessel density was significantly smaller with advancing age (P = .029) in healthy eyes and greater with higher intraocular pressure (P = .021) in eyes with treated glaucoma. CONCLUSIONS AS-OCTA images may be useful for the objective assessment of conjunctival hyperemia and helpful for understanding the pathophysiology of post-trabecular aqueous humor outflow.
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Liu X, Kale AU, Capewell N, Talbot N, Ahmed S, Keane PA, Mollan S, Belli A, Blanch RJ, Veenith T, Denniston AK. Optical coherence tomography (OCT) in unconscious and systemically unwell patients using a mobile OCT device: a pilot study. BMJ Open 2019; 9:e030882. [PMID: 31699727 PMCID: PMC6858135 DOI: 10.1136/bmjopen-2019-030882] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE This study aims to evaluate the feasibility of retinal imaging in critical care using a novel mobile optical coherence tomography (OCT) device. The Heidelberg SPECTRALIS FLEX module (Heidelberg Engineering, Heidelberg, Germany) is an OCT unit with a boom arm, enabling ocular OCT assessment in less mobile patients. DESIGN We undertook an evaluation of the feasibility of using the SPECTRALIS FLEX for undertaking ocular OCT images in unconscious and critically ill patients. SETTING This study was conducted in the critical care unit of a large tertiary referral unit in the United Kingdom. PARTICIPANTS 13 systemically unwell patients admitted to the critical care unit were purposively sampled to enable evaluation in patients with a range of clinical states. OUTCOME MEASURES The primary outcome was the feasibility of acquiring clinically interpretable OCT scans on a consecutive series of patients. The standardised scanning protocol included macula-focused OCT, OCT optic nerve head (ONH), OCT angiography (OCTA) of the macula and ONH OCTA. RESULTS OCT images from 13 patients were attempted. The success rates of each scan type are 84% for OCT macula, 76% for OCT ONH, 56% for OCTA macula and 36% for OCTA ONH. The overall mean success rate of scans per patient was 64% (95% CI 46% to 81%). Clinicians reported clinical value in 100% scans which were successfully obtained, including both ruling in and ruling out relevant ocular complications such as corneal thinning, macular oedema and optic disc swelling. The most common causes of failure to achieve clinically interpretable scans were inadequately sustained OCT alignment in delirious patients and a compromised ocular surface due to corneal exposure. CONCLUSIONS This prospective evaluation indicates the feasibility and potential clinical value of the SPECTRALIS FLEX OCT system on the critical care unit. Portable OCT systems have the potential to bring instrument-based ophthalmic assessment to critically ill patients, enabling detection and micron-level monitoring of ocular complications.
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Affiliation(s)
- Xiaoxuan Liu
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Health Data Research UK, London, United Kingdom
| | - Aditya Uday Kale
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Nicholas Capewell
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Nicholas Talbot
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Sumiya Ahmed
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Pearse A Keane
- Health Data Research UK, London, United Kingdom
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Susan Mollan
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Centre for Rare Diseases, Institute of Translational Medicine, Birmingham, UK
| | - Antonio Belli
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Institute of Inflammation and Ageing, University of Birmingham, College of Medical and Dental Sciences, Birmingham, UK
- Department of Critical Care Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Richard J Blanch
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham, UK
| | - Tonny Veenith
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Department of Critical Care Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Alastair K Denniston
- Ophthalmology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Health Data Research UK, London, United Kingdom
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Centre for Rare Diseases, Institute of Translational Medicine, Birmingham, UK
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Sheheitli H, Tirpack AR, Parrish RK. Which Patients Would Most Likely to Benefit: MIGS or MEGS, Which One Is It? Asia Pac J Ophthalmol (Phila) 2019; 8:436-440. [PMID: 31789645 PMCID: PMC6903319 DOI: 10.1097/apo.0000000000000260] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/19/2019] [Indexed: 12/03/2022] Open
Abstract
The availability of ab interno minimally invasive glaucoma surgery (MIGS) has promoted an international interest in this procedure. Our purpose is to define the role of MIGS in the constant evolving glaucoma treatment algorithm. Current MIGS approaches to lowering intraocular pressure (IOP) include increasing trabecular outflow (iStent trabecular microbypass stent, iStent inject, Hydrus Microstent, Kahook Dual Blade goniotomy, Trabectome ab interno trabeculectomy, Excimer laser trabeculotomy, and goniotomy-assisted transluminal trabeculotomy), increasing uveoscleral outflow with suprachoroidal shunts (Cypass microstent), and developing subconjunctival filtration (XEN gel stent and InnFocus microshunt). The efficacy of each depends on the achievement of desired target IOP reduction in a specific patient. The determination of whether a procedure is either a MIGS or minimally effective glaucoma surgery (MEGS) procedure is based on their efficacy and complications. Aqueous humor angiography suggests that success of trabecular bypass MIGS may not be patient-dependent only, but it may be affected by the location and flow of aqueous through collector channels. The future use of aqueous angiography may permit customized treatment of trabecular meshwork dependent MIGS procedures.
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Affiliation(s)
- Huda Sheheitli
- University of Miami, Bascom Palmer Eye Institute, Miami, Florida; Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL
- American University of Beirut, Department of Ophthalmology, Beirut, Lebanon
| | - Aubrey R. Tirpack
- University of Miami, Bascom Palmer Eye Institute, Miami, Florida; Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL
- Cincinnati Eye Institute, University of Cincinnati, Department of Ophthalmology, Cincinnati, OH
| | - Richard K. Parrish
- University of Miami, Bascom Palmer Eye Institute, Miami, Florida; Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL
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Abstract
PURPOSE To evaluate aqueous humor outflow (AHO) in intact eyes of live human subjects during cataract surgery using fluorescein aqueous angiography. METHODS Aqueous angiography was performed in 8 live human subjects (56 to 86 y old; 2 men and 6 women). After anesthesia, fluorescein (2%) was introduced into the eye [either alone or after indocyanine green (ICG; 0.4%)] from a sterile, gravity-driven constant-pressure reservoir. Aqueous angiographic images were obtained with a Spectralis HRA+OCT and FLEX module (Heidelberg Engineering). Using the same device, anterior-segment optical coherence tomography (OCT) and infrared images were also concurrently taken with aqueous angiography. RESULTS Fluorescein aqueous angiography in the live human eye showed segmental AHO patterns. Initial angiographic signal was seen on average by 14.0±3.0 seconds (mean±SE). Using multimodal imaging, angiographically positive signal colocalized with episcleral veins (infrared imaging) and intrascleral lumens (anterior-segment OCT). Sequential aqueous angiography with ICG followed by fluorescein showed similar segmental angiographic patterns. DISCUSSION Fluorescein aqueous angiography in live humans was similar to that reported in nonhuman primates and to ICG aqueous angiography in live humans. As segmental patterns with sequential angiography using ICG followed by fluorescein were similar, these tracers can now be used sequentially, before and after trabecular outflow interventions, to assess their effects on AHO in live human subjects.
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How many aqueous humor outflow pathways are there? Surv Ophthalmol 2019; 65:144-170. [PMID: 31622628 DOI: 10.1016/j.survophthal.2019.10.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 09/29/2019] [Accepted: 10/04/2019] [Indexed: 12/31/2022]
Abstract
The aqueous humor (AH) outflow pathways definition is still matter of intense debate. To date, the differentiation between conventional (trabecular meshwork) and unconventional (uveoscleral) pathways is widely accepted, distinguishing the different impact of the intraocular pressure on the AH outflow rate. Although the conventional route is recognized to host the main sites for intraocular pressure regulation, the unconventional pathway, with its great potential for AH resorption, seems to act as a sort of relief valve, especially when the trabecular resistance rises. Recent evidence demonstrates the presence of lymphatic channels in the eye and proposes that they may participate in the overall AH drainage and intraocular pressure regulation, in a presumably adaptive fashion. For this reason, the uveolymphatic route is increasingly thought to play an important role in the ocular hydrodynamic system physiology. As a result of the unconventional pathway characteristics, hydrodynamic disorders do not develop until the adaptive routes cannot successfully counterbalance the increased AH outflow resistance. When their adaptive mechanisms fail, glaucoma occurs. Our review deals with the standard and newly discovered AH outflow routes, with particular attention to the importance they may have in opening new therapeutic strategies in the treatment of ocular hypertension and glaucoma.
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