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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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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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Huang H, Tian L, Sun X, Chen Y. En face optical coherence tomography detection of Schlemm's canal in primary open angle glaucoma. Front Physiol 2023; 14:1214427. [PMID: 38028808 PMCID: PMC10652746 DOI: 10.3389/fphys.2023.1214427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Purpose: To compare the morphological characteristics of Schlemm's canal (SC) in patients with primary open-angle glaucoma (POAG) and healthy controls, using swept-source optical coherence tomography (SS-OCT) with en face reconstruction. Methods: In this Prospective comparative study, we included 100 eyes from 50 patients diagnosed with POAG and 50 healthy controls. Three-dimensional cube and line scans of the temporal and nasal quadrants of the anterior segment of the limbus were acquired using SS-OCT. SC was identified using en face and cross-sectional images. The diameter and area of SC in cross-sectional images and the visible percentage and area of SC in en face images were measured using ImageJ. Results: SC was observed in 84% of en face images and 81% of cross-sectional images in eyes with POAG but in 92% of en face images and 86% of cross-sectional images in control eyes. Significant differences between the POAG and normal control eyes were found in the en face area (0.35 ± 0.14 mm2 vs. 0.56 ± 0.22 mm2 in the temporal quadrant and 0.36 ± 0.14 mm2 vs. 0.58 ± 0.23 mm2 in the nasal quadrant; both p < 0.001) and visible percentage of SC (85.71% vs. 94.91% and 87.10% vs. 95.52% in the temporal and nasal quadrant respectively, both p < 0.001) in en face images as well as the cross-sectional area (2790.9 ± 942.2 μm2 vs. 4138.6 ± 2027.8 μm2 in the temporal quadrant and 2805.7 ± 947.2 μm2 vs. 4224.0 ± 2002.2 μm2 in the nasal quadrant, both p < 0.001) and diameter of SC (123.1 ± 25.4 μm vs. 149.5 ± 34.7 μm in the temporal quadrant and 126.3 ± 28.9 μm vs. 155.3 ± 36.0 μm in the nasal quadrant, both p < 0.001) in cross-section images. In addition, the mean intraocular pressure (IOP) significantly correlated with the en face area, visible percentage of SC, and cross-sectional area in the temporal and nasal quadrants. Conclusion: SS-OCT can obtain high-quality en face images of SC without post-acquisition processing. Eyes with POAG had a decreased en face SC area compared with normal eyes. A correlation between SC area, visible percentage of en face images, and IOP was also observed.
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Affiliation(s)
- Haili Huang
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China
| | - Lijia Tian
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yuhong Chen
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China
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Carmichael-Martins A, Gast TJ, King BJ, Walker BR, Sobczak M, Burns SA. Imaging fine structures of the human trabecular meshwork in vivo using a custom design goniolens and OCT gonioscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:5267-5281. [PMID: 37854570 PMCID: PMC10581814 DOI: 10.1364/boe.500623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 10/20/2023]
Abstract
The trabecular meshwork (TM), located within the iridocorneal angle, is a target for many glaucoma treatments aimed at controlling intraocular pressure. However, structural variations between individuals are poorly understood. We propose a newly designed gonioscopic lens optimized for high-resolution imaging to image fine structures of the human TM in vivo. The body of the new lens is index-matched to the human cornea and includes a choice of two gonioscopic mirrors (59° and 63°) and matching air-spaced doublets placed on the anterior surface of the goniolens. The new design allows a diffraction-limited image plane at the iridocorneal angle structures. The goniolens design was built and then placed on the subjectś eyes coupled to the cornea with goniogel and a 3D adjustable mount. Images were obtained using a commercially available OCT device (Heidelberg Spectralis). The optical resolution was measured in a model eye as 40.32 and 45.25 cy/mm respectively for each mirror angle. In humans, dense OCT scans with minimum spacing oriented tangential to the iris and ICA were performed on 7 healthy subjects (23-73 yrs). The TM was successfully imaged in all subjects. The custom goniolens improved the contrast of the uveoscleral meshwork structures and corneoscleral meshwork revealing limbus parallel striations, not visible with previous goniolens designs. Transverse OCT images were constructed along the segmentation line, providing an enface image of the TM structures including corneoscleral beams, previously only imaged in vivo using custom adaptive optics systems.
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Affiliation(s)
| | - Thomas J. Gast
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brett J. King
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brittany R. Walker
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Marcelina Sobczak
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Stephen A. Burns
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
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Luo S, Holland G, Khazaeinezhad R, Bradford S, Joshi R, Juhasz T. Iridocorneal angle imaging of a human donor eye by spectral-domain optical coherence tomography. Sci Rep 2023; 13:13861. [PMID: 37620338 PMCID: PMC10449890 DOI: 10.1038/s41598-023-37248-0] [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: 10/21/2022] [Accepted: 06/19/2023] [Indexed: 08/26/2023] Open
Abstract
Iridocorneal angle (ICA) details particularly the trabecular meshwork (TM), Schlemm's canal (SC), and collector channels (CCs) play crucial roles in the regulation of the aqueous outflow in the eyes and are closely associated with glaucoma. Current clinical gonioscopy imaging provides no depth information, and studies of 3D high-resolution optical coherence tomography (OCT) imaging of these structures are limited. We developed a custom-built spectral-domain (SD-) OCT imaging system to fully characterize the angle details. Imaging of a human cadaver eye reveals the visibility of details in the TM/SC/CC region via a 'crossline' scanning and a series of image processing. This shows that ICA imaging can be used for preoperative glaucoma inspections in the clinical setting with the proposed prototype.
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Affiliation(s)
- Shangbang Luo
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, 92697, USA
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, 92697, USA
| | | | | | - Samantha Bradford
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, 92697, USA
| | - Rohan Joshi
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, 92697, USA
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, 92697, USA
| | - Tibor Juhasz
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, 92697, USA.
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, 92697, USA.
- ViaLase Inc., Aliso Viejo, CA, 92656, USA.
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Ding X, Huang L, Peng C, Xu L, Liu Y, Yang Y, Wang N, Gu M, Sun C, Wu Y, Guo W. Evaluation of Schlemm's canal with swept-source optical coherence tomography in primary angle-closure disease. BMC Ophthalmol 2023; 23:256. [PMID: 37286943 DOI: 10.1186/s12886-023-03001-4] [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: 02/03/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023] Open
Abstract
PURPOSE To perform an in vivo evaluation of the changes in Schlemm's canal (SC) among patients with primary angle-closure disease (PACD) using swept-source optical coherence tomography (SS-OCT). METHODS Patients diagnosed with PACD who had not undergone surgery were recruited. The SS-OCT quadrants scanned herein included the nasal and temporal sections at 3 and 9 o'clock, respectively. The diameter and cross-sectional area of the SC were measured. A linear mixed-effects model was performed to analyze the effects of parameters on the SC changes. The hypothesis of interest was related to the angle status (iridotrabecular contact, ITC/open angle, OPN), which was further explored with pairwise comparisons of the estimated marginal means (EMMs) of the SC diameter and SC area. In the ITC regions, the relationship between the trabecular-iris contact length (TICL) percentage and SC parameters was also studied by a mixed model. RESULTS A total of 49 eyes of 35 patients were included for measurements and analysis. The percentage of observable SCs in the ITC regions was only 58.5% (24/41), whereas it was 86.0% (49/57) in the OPN regions (χ2 = 9.44, p = 0.002). ITC was significantly associated with a decreasing SC size. The EMMs for the diameter and cross-sectional area of SC at the ITC and OPN regions were 203.34 μm versus 261.41 μm (p = 0.006) and 3174.43 μm2 versus 5347.63 μm2 (p = 0.022), respectively. Sex, age, spherical equivalent refraction, intraocular pressure, axial length, extent of angle closure, history of acute attack and treatment with LPI were not significantly associated with SC parameters. In the ITC regions, a larger TICL percentage was significantly associated with a decrease in SC diameter and area (p = 0.003 and 0.019, respectively). CONCLUSIONS The morphologies of SC could be affected by the angle status (ITC/OPN) in patients with PACD, and ITC was significantly associated with a decreasing SC size. These changes in SC as described by OCT scans might help to elucidate the progression mechanisms of PACD.
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Affiliation(s)
- Xuming Ding
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Lulu Huang
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Cheng Peng
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Li Xu
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Yixin Liu
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Yijie Yang
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Ning Wang
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Mengyang Gu
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Chengyang Sun
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China
| | - Yue Wu
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China.
| | - Wenyi Guo
- Department of Ophthalmology, Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Huangpu District, No. 639 Zhizaoju Road, Shanghai, 200011, China.
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Lee JY, Wu J, Liu Y, Saraswathy S, Zhou L, Bu Q, Su Y, Choi D, Park E, Strohmaier CA, Weinreb RN, Hong YK, Pan X, Huang AS. Subconjunctival Lymphatics Respond to VEGFC and Anti-Metabolites in Rabbit and Mouse Eyes. Invest Ophthalmol Vis Sci 2022; 63:16. [PMID: 36166215 PMCID: PMC9526361 DOI: 10.1167/iovs.63.10.16] [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: 11/24/2022] Open
Abstract
Purpose To characterize and pharmacologically influence subconjunctival lymphatics in rabbit and mouse eyes. Methods Rabbits received subconjunctival injections of trypan blue or fixable fluorescent dextrans. Bleb-related outflow pathways were quantified. Immunofluorescence for vessel-specific markers (lymphatics [podoplanin and LYVE-1] and blood vessels [CD31]) were performed in native rabbit conjunctiva and after fixable fluorescent dextran injection. Vascular endothelial cell growth factor-C (VEGFC) was injected subconjunctivally in rabbits. mRNA and protein were assessed for the above markers using RT-PCR and Western blot. Alternatively, mouse studies used Prox1-tdTomato transgenic reporter mice. Subconjunctival injection conditions included: no injection, balanced salt solution (BSS), VEGFC, 5-fluorouracil (5FU) and two concentrations of mitomycin-C (MMC). Two mouse injection protocols (short and long) with different follow-up times and number of injections were performed. Mouse eyes were enucleated, flat mounts created, and subconjunctival branching and length assessed. Results Rabbit eyes demonstrated clear bleb-related subconjunctival outflow pathways that were distinct from blood vessels and were without nasal/temporal predilection. Immunofluorescence against vessel-specific markers showed lymphatics and blood vessels in rabbit conjunctiva, and these lymphatics overlapped with bleb-related subconjunctival outflow pathways. Subconjunctival VEGFC increased lymphatic (P = 0.004-0.04) but not blood vessel (P = 0.77-0.84) mRNA or protein in rabbits. Prox1-tdTomato transgenic reporter mice demonstrated natively fluorescent lymphatics. Subconjunctival VEGFC increased murine lymphatic branching and length (P ≤ 0.001-0.004) while antimetabolites (P ≤ 0.001-0.043) did the opposite for the long protocol. Discussion Subconjunctival lymphatics are pharmacologically responsive to both VEGFC and antimetabolites in two animal models studied using different methodologies. These results may be important for bleb-forming glaucoma surgeries or ocular drug delivery.
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Affiliation(s)
- Jong Yeon Lee
- Department of Ophthalmology, Gachon University College of Medicine, Gil Medical Center, Incheon, Korea
| | - Jingyi Wu
- Weifang Medical University, Weifang, Shandong Province, China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Yameng Liu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States
| | - Longfang Zhou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Qianwen Bu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Ying Su
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong Province, China
| | - Dongwon Choi
- Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Eunkyung Park
- Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Clemens A Strohmaier
- Department of Ophthalmology, 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
| | - Robert N Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Young-Kwon Hong
- Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Xiaojing Pan
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, Shandong Province, China.,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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Carmichael-Martins A, Gast TJ, Burns SA, Walker BR, King BJ. Characterization of the human iridocorneal angle in vivo using a custom design goniolens with OCT gonioscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:4652-4667. [PMID: 36187241 PMCID: PMC9484429 DOI: 10.1364/boe.465317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 06/16/2023]
Abstract
Intraocular pressure (IOP) is the only modifiable risk factor for glaucoma progression, and many treatments target the trabecular meshwork (TM). Imaging this region in vivo is challenging due to optical limitations of imaging through the cornea at high angles. We propose a gonioscopic OCT approach using a custom goniolens and a commercially available OCT device to improve imaging of the TM, Schlemm's canal (SC) and adjacent structures within the iridocorneal angle (ICA). The goniolens is modified with a plano-convex focusing lens and placed on the eye optically mated with goniogel and aided by a 3D adjustable mount. Gonioscopic OCT volume scans are acquired to image SC. Transverse enface images allowed measurements of SC over a 45° section of the ICA for the first time and revealed locations of SC narrowing. The band of extracanalicular limbal lamina and corneoscleral bands were imaged in most subjects and these bands were confirmed using exterior OCT imaging. The polarization dependence of the visibility of these structures is studied by polarization rotation the OCT beam with a half-wave plate, allowing increased contrast of SC. Gonioscopic OCT has successfully been used to image the human ICA in 3D in vivo. This approach provides more detailed characterization of the TM and SC, enhancing their contrast against their birefringent backgrounds.
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Affiliation(s)
| | - Thomas J. Gast
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Stephen A. Burns
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brittany R. Walker
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brett J. King
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
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Garcia Marin YF, Alonso-Caneiro D, Vincent SJ, Collins MJ. Anterior segment optical coherence tomography (AS-OCT) image analysis methods and applications: A systematic review. Comput Biol Med 2022; 146:105471. [DOI: 10.1016/j.compbiomed.2022.105471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 11/03/2022]
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10
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Alexopoulos P, Madu C, Wollstein G, Schuman JS. The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques. Front Med (Lausanne) 2022; 9:891369. [PMID: 35847772 PMCID: PMC9279625 DOI: 10.3389/fmed.2022.891369] [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: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.
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Affiliation(s)
- Palaiologos Alexopoulos
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Chisom Madu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
- Department of Electrical and Computer Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
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11
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Choy KC, Li G, Stamer WD, Farsiu S. Open-source deep learning-based automatic segmentation of mouse Schlemm's canal in optical coherence tomography images. Exp Eye Res 2022; 214:108844. [PMID: 34793828 PMCID: PMC8792324 DOI: 10.1016/j.exer.2021.108844] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 01/03/2023]
Abstract
The purpose of this study was to develop an automatic deep learning-based approach and corresponding free, open-source software to perform segmentation of the Schlemm's canal (SC) lumen in optical coherence tomography (OCT) scans of living mouse eyes. A novel convolutional neural network (CNN) for semantic segmentation grounded in a U-Net architecture was developed by incorporating a late fusion scheme, multi-scale input image pyramid, dilated residual convolution blocks, and attention-gating. 163 pairs of intensity and speckle variance (SV) OCT B-scans acquired from 32 living mouse eyes were used for training, validation, and testing of this CNN model for segmentation of the SC lumen. The proposed model achieved a mean Dice Similarity Coefficient (DSC) of 0.694 ± 0.256 and median DSC of 0.791, while manual segmentation performed by a second expert grader achieved a mean and median DSC of 0.713 ± 0.209 and 0.763, respectively. This work presents the first automatic method for segmentation of the SC lumen in OCT images of living mouse eyes. The performance of the proposed model is comparable to the performance of a second human grader. Open-source automatic software for segmentation of the SC lumen is expected to accelerate experiments for studying treatment efficacy of new drugs affecting intraocular pressure and related diseases such as glaucoma, which present as changes in the SC area.
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Affiliation(s)
- Kevin C Choy
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Guorong Li
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | - W Daniel Stamer
- Department of Biomedical Engineering, Duke University, Durham, NC, United States; Department of Ophthalmology, Duke University, Durham, NC, United States
| | - Sina Farsiu
- Department of Biomedical Engineering, Duke University, Durham, NC, United States; Department of Ophthalmology, Duke University, Durham, NC, United States.
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12
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Xie X, Sultan W, Corradetti G, Lee JY, Song A, Pardeshi A, Yu F, Chopra V, Sadda SR, Xu BY, Huang AS. Assessing accommodative presbyopic biometric changes of the entire anterior segment using single swept-source OCT image acquisitions. Eye (Lond) 2022; 36:119-128. [PMID: 33633350 PMCID: PMC8727625 DOI: 10.1038/s41433-020-01363-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND/OBJECTIVES To evaluate biometric changes throughout the anterior chamber during accommodation and presbyopia using single image acquisition swept-source anterior-segment optical coherence tomography (AS-OCT). SUBJECT/METHODS Anterior-segment images were obtained using a new swept-source AS-OCT device (ANTERION, Heidelberg Engineering) from healthy volunteers (n = 71) across two centers in this prospective observational case series. In one image acquisition, cornea through posterior lens, including the ciliary muscle on both sides of the right eye, was imaged. Subjects undertook no accommodative effort and -1, -3, and -5 D of target vergence. Two-way repeated measures ANOVA modeling was performed for ciliary muscle measurements, lens parameters, aqueous depth (AD), and pupil diameter (PD). The first ANOVA factor was accommodative stimuli, and the second factor included age and refractive status. RESULTS Maximum ciliary muscle thickness increased with accommodative stimuli (p < 0.001), while the distance from the scleral spur to the maximal point on the ciliary muscle and posterior ciliary muscle thickness (CMT2) decreased (p < 0.001-0.002). Older individuals showed no accommodative changes for ciliary muscle parameters, lens thickness, lens vault, PD, and AD (p = 0.07-0.32). Younger- and middle-aged eyes showed statistically significant accommodative structural alterations for these endpoints (p < 0.001-0.002), but with different patterns, including early loss of CMT2 contraction in middle-aged eyes. Within the middle-aged group, myopic eyes maintained better capacity for accommodative structural change. CONCLUSIONS Swept-source AS-OCT demonstrated multiple simultaneous anterior-segment biometric alterations in single acquisition images, including early loss of posterior ciliary muscle function and better maintained capacity for anterior-segment structural change in myopia.
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Affiliation(s)
- Xiaobin Xie
- grid.410318.f0000 0004 0632 3409Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China ,grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - William Sultan
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Giulia Corradetti
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Jong Yeon Lee
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.256155.00000 0004 0647 2973Department of Ophthalmology, College of Medicine, Gil Medical Center, Gachon University, Incheon, South Korea
| | - Abe Song
- grid.42505.360000 0001 2156 6853Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, CA USA
| | - Anmol Pardeshi
- grid.42505.360000 0001 2156 6853Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, CA USA
| | - Fei Yu
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Vikas Chopra
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Srinivas R. Sadda
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Benjamin Y. Xu
- grid.42505.360000 0001 2156 6853Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, CA USA
| | - Alex S. Huang
- grid.19006.3e0000 0000 9632 6718Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
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13
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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: 9] [Impact Index Per Article: 3.0] [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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14
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Yao X, Tan B, Ho Y, Liu X, Wong D, Chua J, Wong TT, Perera S, Ang M, Werkmeister RM, Schmetterer L. Full circumferential morphological analysis of Schlemm's canal in human eyes using megahertz swept source OCT. BIOMEDICAL OPTICS EXPRESS 2021; 12:3865-3877. [PMID: 34457385 PMCID: PMC8367246 DOI: 10.1364/boe.426218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 05/16/2023]
Abstract
We performed full circumferential imaging of the Schlemm's canal (SC) of two human eyes using a Fourier domain mode-lock laser (FDML) based 1.66-MHz SS-OCT prototype at 1060 nm. Eight volumes with overlapping margins were acquired around the limbal area with customized raster scanning patterns designed to fully cover the SC while minimizing motion artifacts. The SC was segmented from the volumes using a semi-automated active contour segmentation algorithm, whose mean dice similarity coefficient was 0.76 compared to the manual segmentation results. We also reconstructed three-dimensional (3D) renderings of the 360° SC by stitching the segmented SCs from the volumetric datasets. Quantitative metrics of the full circumferential SC were provided, including the mean and standard deviation (SD) of the cross-sectional area (CSA), the maximum CSA, the minimum and maximum SC opening width, and the number of collector channels (CC) stemming from the SC.
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Affiliation(s)
- Xinwen Yao
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Bingyao Tan
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Yijie Ho
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Xinyu Liu
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Damon Wong
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Jacqueline Chua
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Tina T. Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Shamira Perera
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Marcus Ang
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - René M. Werkmeister
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Academic Clinical Program, Duke-NUS Medical School, 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
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15
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Xie X, Corradetti G, Song A, Pardeshi A, Sultan W, Lee JY, Yu F, Zhang L, Chen S, Chopra V, Sadda SR, Xu B, Huang AS. Age- and refraction-related changes in anterior segment anatomical structures measured by swept-source anterior segment OCT. PLoS One 2020; 15:e0240110. [PMID: 33095821 PMCID: PMC7584205 DOI: 10.1371/journal.pone.0240110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To assess the effects of age and refractive status on anterior segment anatomical structures, including the ciliary body, using a new swept-source anterior segment optical coherence tomography (AS-OCT) device. METHODS This prospective observational study included 63 healthy volunteers (mean age: 44.2 years). Images of the anterior segment were obtained using a new swept-source AS-OCT (ANTERION, Heidelberg Engineering GmbH, Heidelberg, Germany) with tracking and image averaging from the right eye of all participants. Repeatability as well as inter- and intra-observer reliability of biometric measurements were evaluated. The impact of image tracking and averaging on ciliary muscle measurements was tested. Univariate and multivariable statistical models were developed to evaluate the relationship of age and refractive status on anterior segment biometric measurements. RESULTS For all test-retest repeatability and inter- and intra-observer reproducibility of swept-source AS-OCT measurements, high intraclass correlation (ICC) was noted (0.88-1.00). The nasal maximum ciliary muscle thickness (CMTMAX) and distance between scleral spur to the thickest point of the ciliary muscle (SSMAX) were larger than those on the temporal side (p<0.001 and p = 0.006, respectively). Nasal and temporal CMTMAX (p = 0.004 and p<0.001, respectively) and lens thickness (p<0.01) increased with age. Nasal and temporal SSMAX decreased with older age and increasing hyperopia (p = 0.01 and p<0.001, respectively). Image averaging resulted in improved ciliary muscle measurements (p = 0.008 to 0.02). Lens vault increased with older age and increased hyperopia (p<0.01). OCT measurements of the angle decreased with older age and increased hyperopia (p<0.001 to 0.03). Aqueous depth decreased with older age and increased hyperopia (p<0.01). Pupil diameter decreased with older age (p<0.01). CONCLUSIONS Repeatability and reproducibility of biometric measurements using the ANTERION AS-OCT were excellent. Image averaging improved the accuracy of ciliary muscle measurements. The device produced measurements of biometric parameters that described superficial and deep structures including the ciliary body and full lens thickness from a single image.
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Affiliation(s)
- Xiaobin Xie
- Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- * E-mail:
| | - Giulia Corradetti
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Abe Song
- Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, California, United States of America
| | - Anmol Pardeshi
- Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, California, United States of America
| | - William Sultan
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Department of Ophthalmology, College of Medicine, Gil Medical Center, Gachon University, Incheon, Korea
| | - Fei Yu
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Lixia Zhang
- Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Shuang Chen
- Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Vikas Chopra
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Srinivas R. Sadda
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Benjamin Xu
- Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, California, United States of America
| | - Alex S. Huang
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
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16
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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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17
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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: 15] [Impact Index Per Article: 3.8] [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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18
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Sunaric Megevand G, Bron AM. Personalising surgical treatments for glaucoma patients. Prog Retin Eye Res 2020; 81:100879. [PMID: 32562883 DOI: 10.1016/j.preteyeres.2020.100879] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023]
Abstract
Surgical treatments for glaucoma have relied for decades on traditional filtering surgery such as trabeculectomy and, in more challenging cases, tubes. Antifibrotics were introduced to improve surgical success in patients at increased risk of failure but have been shown to be linked to a greater incidence of complications, some being potentially vision-threatening. As our understanding of glaucoma and its early diagnosis have improved, a more individualised management has been suggested. Recently the term "precision medicine" has emerged as a new concept of an individualised approach to disease management incorporating a wide range of individual data in the choice of therapeutic modalities. For glaucoma surgery, this involves evaluation of the right timing, individual risk factors, targeting the correct anatomical and functional outflow pathways and appropriate prevention of scarring. As a consequence, there is an obvious need for better knowledge of anatomical and functional pathways and for more individualised surgical approaches with new, less invasive and safer techniques allowing for earlier intervention. With the recent advent of minimally invasive glaucoma surgery (MIGS) a large number of novel devices have been introduced targeting potential new sites of the outflow pathway for lowering intraocular pressure (IOP). Their popularity is growing in view of the relative surgical simplicity and apparent lack of serious side effects. However, these new surgical techniques are still in an era of early experiences, short follow-up and lack of evidence of their superiority in safety and cost-effectiveness over the traditional methods. Each year several new devices are introduced while others are withdrawn from the market. Glaucoma continues to be the primary cause of irreversible blindness worldwide and access to safe and efficacious treatment is a serious problem, particularly in the emerging world where the burden of glaucoma-related blindness is important and concerning. Early diagnosis, individualised treatment and, very importantly, safe surgical management should be the hallmarks of glaucoma treatment. However, there is still need for a better understanding of the disease, its onset and progression, the functional and structural elements of the outflow pathways in relation to the new devices as well as their long-term IOP-lowering efficacy and safety. This review discusses current knowledge and the future need for personalised glaucoma surgery.
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Affiliation(s)
- Gordana Sunaric Megevand
- Clinical Eye Research Centre Memorial Adolphe de Rothschild, Geneva, Switzerland; Centre Ophtalmologique de Florissant, Geneva, Switzerland.
| | - Alain M Bron
- Department of Ophthalmology, University Hospital, Dijon, France; Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000, Dijon, France
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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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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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Bogarin T, Saraswathy S, Akiyama G, Xie X, Weinreb RN, Zheng J, Huang AS. Cellular and cytoskeletal alterations of scleral fibroblasts in response to glucocorticoid steroids. Exp Eye Res 2019; 187:107774. [PMID: 31449795 PMCID: PMC6759408 DOI: 10.1016/j.exer.2019.107774] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 08/22/2019] [Accepted: 08/22/2019] [Indexed: 11/16/2022]
Abstract
Steroid-induced ocular hypertension can be seen even after trabecular meshwork (TM) bypass/ablation. Thus, the purpose was to investigate steroid-response in cells distal to the TM by using primary scleral fibroblasts. Primary scleral cell cultures were generated using mid-depth scleral wedges from human donor corneo-scleral rims (n = 5) after corneal transplantation. Cells were treated with dexamethasone (DEX; 100 nM) and compared to media (MED)/vehicle (DMSO) controls. Cell size, shape, and migration were studied using the IncuCyte Live-Cell Analysis System. Cytoskeleton was compared using Alexa Fluor-568 Phalloidin and senescence tested by evaluating beta-galactosidase. Western blot comparison was performed for α-SMA, FKBP-51, fibronectin, phospho-myosin light chain, and myocilin. Scleral fibroblasts upregulated FKBP-51 in response to DEX indicating the existence of steroid-responsive pathways. Compared to controls, DEX-treated cells proliferated slower (~50%; p < 0.01-0.02), grew larger (~1.3-fold; p < 0.001), and migrated less (p = 0.01-0.006). Alexa Fluor 568 Phalloidin actin stress fiber labeling was more diffuse in DEX-treated cells (p = 0.001-0.004). DEX-treated cells showed more senescence compared to controls (~1.7-fold; p = 0.01-0.02). However, DEX-treated cells did not show increased cross-linked actin network formation or elevated myocilin/fibronectin/α-SMA/phospho-myosin light chain protein expression. For all parameters, MED- and DMSO-treated control cells were not significantly different. Primary scleral fibroblasts, grown from tissue collected immediately distal to the TM, demonstrated scleral-response behaviors that were similar to, but not identical with, classic TM steroid-response. Further study is needed to understand how these scleral cellular alterations may contribute to steroid-response IOP elevation after TM bypass/ablation surgery.
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Affiliation(s)
- Thania Bogarin
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sindhu Saraswathy
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Goichi Akiyama
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Xiaobin Xie
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, and the Viterbi Family Department of Ophthalmology University of California, San Diego, CA, USA
| | - Jie Zheng
- Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, 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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Shan J, DeBoer C, Xu BY. Anterior Segment Optical Coherence Tomography: Applications for Clinical Care and Scientific Research. Asia Pac J Ophthalmol (Phila) 2019; 8:146-157. [PMID: 31020820 PMCID: PMC7903991 DOI: 10.22608/apo.201910] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Anterior segment optical coherence tomography (AS-OCT) is a non-contact imaging technique that produces high-resolution images and quantitative measurements of the anterior segment and its anatomical structures. There has been rapid development of OCT technology over the past 2 decades, with the transition from time-domain to Fourier-domain OCT devices. By integrating these advancements in OCT technology, AS-OCT devices have evolved into versatile clinical and research tools for studies of the anterior segment and ocular surface. The primary purpose of this article was to review OCT technology and AS-OCT devices as well as applications of AS-OCT for clinical practice and scientific research. We first describe the different types of OCT technology, how they have been adapted for AS-OCT imaging, and differences between various AS-OCT devices. We then review the applications of AS-OCT for characterizing the anatomical structures of the anterior segment and aqueous outflow pathways, including the anterior chamber angle, trabecular meshwork, and Schlemm canal. We also describe glaucoma-related applications of AS-OCT imaging, which include evaluating patients for static and dynamic biometric risk factors of primary angle closure disease and assessing the efficacy of glaucoma interventions, such as laser peripheral iridotomy and glaucoma surgery. Finally, we review other clinical applications of AS-OCT imaging for detection and management of diseases of the ocular surface, cornea, and lens.
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Affiliation(s)
- Jing Shan
- From the USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, California, United States
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Xie X, Akiyama G, Bogarin T, Saraswathy S, Huang AS. Visual Assessment of Aqueous Humor Outflow. Asia Pac J Ophthalmol (Phila) 2019; 8:126-134. [PMID: 30916496 PMCID: PMC7028348 DOI: 10.22608/apo.201911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
In the past decade, many new pharmacological and surgical treatments have become available to lower intraocular pressure (IOP) for glaucoma. The majority of these options have targeted improving aqueous humor outflow (AHO). At the same time, in addition to new treatments, research advances in AHO assessment have led to the development of new tools to structurally assess AHO pathways and to visualize where aqueous is flowing in the eye. These new imaging modalities have uncovered novel AHO observations that challenge traditional AHO concepts. New behaviors including segmental, pulsatile, and dynamic AHO may have relevance to the disease and the level of therapeutic response for IOP-lowering treatments. By better understanding the regulation of segmental, pulsatile, and dynamic AHO, it may be possible to find new and innovative treatments for glaucoma aiming at these new AHO behaviors.
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Affiliation(s)
- Xiaobin Xie
- From the Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China; and UCLA Department of Ophthalmology, Doheny Eye Institute, Los Angeles, CA, United States
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Huang AS, Penteado RC, Papoyan V, Voskanyan L, Weinreb RN. Aqueous Angiographic Outflow Improvement after Trabecular Microbypass in Glaucoma Patients. Ophthalmol Glaucoma 2018; 2:11-21. [PMID: 31595267 DOI: 10.1016/j.ogla.2018.11.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Purpose To study changes in aqueous humor outflow (AHO) patterns after trabecular micro-bypass (TMB) in glaucoma patients using intraoperative sequential aqueous angiography. Design Prospective comparative case series. Subjects Fifteen subjects (14 with glaucoma and 1 normal). Methods Sequential aqueous angiography (Spectralis HRA+OCT; Heidelberg Engineering) was performed on fourteen glaucoma patients undergoing routine TMB (iStent Inject; Glaukos Corporation) and cataract surgery and one normal patient undergoing cataract surgery alone. Indocyanine green (ICG) aqueous angiography established initial baseline nasal angiographic AHO patterns. Two TMB stents were placed in regions of baseline low or high angiographic AHO in each eye (n = 2 eyes with enough space to place two stents in both low angiographic regions; n = 8 eyes with two stents both placed in high angiographic regions; n = 4 eyes with enough space to place one stent in a low angiographic region and the other stent in a high angiographic region). Subsequent fluorescein aqueous angiography was utilized to query alterations to angiographic AHO patterns. Main Outcome Measure Angiographic signal and patterns before and after TMB. Results At baseline, all eyes showed segmental angiographic AHO patterns. Focused on the nasal hemisphere of each eye, for each stent TMB in initially low ICG angiographic signal regions showed transient or persistently improved fluorescein angiographic signal (11.2-fold; p = 0.014). TMB in initially high ICG signal regions led to faster development of fluorescein angiographic patterns (3.1-fold; p = 0.02). Conclusion TMB resulted in different patterns of aqueous angiographic AHO improvement whose further understanding may advance basic knowledge of AHO and possibly enhance intraocular pressure reduction after glaucoma surgery in the future.
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Affiliation(s)
- Alex S Huang
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Rafaella C Penteado
- Hamilton Glaucoma Center, Shiley Eye Institute, and Department of Ophthalmology University of California, San Diego, CA, USA
| | - Vahan Papoyan
- Department of Ophthalmology, Yerevan State Medical University, Ophthalmological Center after S.V. Malayan
| | - Lilit Voskanyan
- Department of Ophthalmology, Yerevan State Medical University, Ophthalmological Center after S.V. Malayan
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, and Department of Ophthalmology University of California, San Diego, CA, USA
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Huang AS, Penteado RC, Saha SK, Do JL, Ngai P, Hu Z, Weinreb RN. Fluorescein Aqueous Angiography in Live Normal Human Eyes. J Glaucoma 2018; 27:957-964. [PMID: 30095604 PMCID: PMC6218293 DOI: 10.1097/ijg.0000000000001042] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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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Affiliation(s)
- Alex S Huang
- Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles
| | - Rafaella C Penteado
- Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, CA
| | - Sajib K Saha
- Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles
| | - Jiun L Do
- Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, CA
| | - Philip Ngai
- Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, CA
| | - Zhihong Hu
- Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles
| | - Robert N Weinreb
- Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, CA
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Ang M, Baskaran M, Werkmeister RM, Chua J, Schmidl D, Aranha dos Santos V, Garhöfer G, Mehta JS, Schmetterer L. Anterior segment optical coherence tomography. Prog Retin Eye Res 2018; 66:132-156. [DOI: 10.1016/j.preteyeres.2018.04.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/20/2018] [Accepted: 04/04/2018] [Indexed: 02/03/2023]
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McDonnell F, Dismuke WM, Overby DR, Stamer WD. Pharmacological regulation of outflow resistance distal to Schlemm's canal. Am J Physiol Cell Physiol 2018; 315:C44-C51. [PMID: 29631366 DOI: 10.1152/ajpcell.00024.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The trabecular meshwork (TM) and Schlemm's canal generate the majority of outflow resistance; however, the distal regions of the conventional outflow pathway account for 25-50% of total resistance. Sections of distal vessels are surrounded by α-smooth muscle actin-containing cells, indicating that they may be vasoregulated. This study examined the effect of a potent vasodilator, nitric oxide (NO), and its physiological antagonist, endothelin-1 (ET-1), on the regulation of outflow resistance in the distal regions of the conventional outflow pathway. Using a physiological model of the conventional outflow pathway, human and porcine anterior segments were perfused in organ culture under constant flow conditions, while intrachamber pressure was continually monitored. For porcine anterior segments, a stable baseline outflow facility with TM intact was first achieved before anterior segments were removed and a trabeculotomy was performed. For human anterior segments, a trabeculotomy was immediately performed. In human anterior segments, 100 nM ET-1 significantly decreased distal outflow facility from 0.49 ± 0.26 to 0.31 ± 0.18 (mean ± SD) µl·min-1·mmHg, P < 0.01. Perfusion with 100 µM diethylenetriamine-NO in the presence of 1 nM ET-1 immediately reversed ET-1 effects, significantly increasing distal outflow facility to 0.54 ± 0.35 µl·min-1·mmHg, P = 0.01. Similar results were obtained in porcine anterior segment experiments. Therefore, data show a dynamic range of resistance generation by distal vessels in both the human and the porcine conventional outflow pathways. Interestingly, maximal contraction of vessels in the distal outflow tract of trabeculotomized eyes generated resistance very near physiological levels for both species having an intact TM.
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Affiliation(s)
- Fiona McDonnell
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - W Michael Dismuke
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London , London , United Kingdom
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University , Durham, North Carolina.,Department of Biomedical Engineering, Duke University , Durham, North Carolina
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Huang AS, Francis BA, Weinreb RN. Structural and functional imaging of aqueous humour outflow: a review. Clin Exp Ophthalmol 2017; 46:158-168. [PMID: 28898516 DOI: 10.1111/ceo.13064] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 01/15/2023]
Abstract
Maintaining healthy aqueous humour outflow (AHO) is important for intraocular cellular health and stable vision. Impairment of AHO can lead to increased intraocular pressure, optic nerve damage and concomitant glaucoma. An improved understanding of AHO will lead to improved glaucoma surgeries that enhance native AHO as well as facilitate the development of AHO-targeted pharmaceuticals. Recent AHO imaging has evolved to live human assessment and has focused on the structural evaluation of AHO pathways and the functional documentation of fluid flow. Structural AHO evaluation is predominantly driven by optical coherence tomography, and functional evaluation of flow is performed using various methods, including aqueous angiography. Advances in structural and functional evaluation of AHO are reviewed with discussion of strengths, weaknesses and potential future directions.
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Affiliation(s)
- Alex S Huang
- Doheny Eye Institute, Los Angeles, California, USA.,Doheny Eye Centers, Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, USA
| | - Brian A Francis
- Doheny Eye Institute, Los Angeles, California, USA.,Doheny Eye Centers, Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, USA
| | - Robert N Weinreb
- Shiley Eye Institute and Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, California, USA
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