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Shan J, Li Z, Ma P, Tun TA, Yonamine S, Wu Y, Baskaran M, Nongpiur ME, Chen D, Aung T, Li S, He M, Yang Y, Han Y. Deep Learning Classification of Angle Closure based on Anterior Segment OCT. Ophthalmol Glaucoma 2024; 7:8-15. [PMID: 37437884 DOI: 10.1016/j.ogla.2023.06.011] [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: 12/15/2022] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/14/2023]
Abstract
PURPOSE To assess the performance and generalizability of a convolutional neural network (CNN) model for objective and high-throughput identification of primary angle-closure disease (PACD) as well as PACD stage differentiation on anterior segment swept-source OCT (AS-OCT). DESIGN Cross-sectional. PARTICIPANTS Patients from 3 different eye centers across China and Singapore were recruited for this study. Eight hundred forty-one eyes from the 2 Chinese centers were divided into 170 control eyes, 488 PACS, and 183 PAC + PACG eyes. An additional 300 eyes were recruited from Singapore National Eye Center as a testing data set, divided into 100 control eyes, 100 PACS, and 100 PAC + PACG eyes. METHODS Each participant underwent standardized ophthalmic examination and was classified by the presiding physician as either control, primary angle-closure suspect (PACS), primary angle closure (PAC), or primary angle-closure glaucoma (PACG). Deep Learning model was used to train 3 different CNN classifiers: classifier 1 aimed to separate control versus PACS versus PAC + PACG; classifier 2 aimed to separate control versus PACD; and classifier 3 aimed to separate PACS versus PAC + PACG. All classifiers were evaluated on independent validation sets from the same region, China and further tested using data from a different country, Singapore. MAIN OUTCOME MEASURES Area under receiver operator characteristic curve (AUC), precision, and recall. RESULTS Classifier 1 achieved an AUC of 0.96 on validation set from the same region, but dropped to an AUC of 0.84 on test set from a different country. Classifier 2 achieved the most generalizable performance with an AUC of 0.96 on validation set and AUC of 0.95 on test set. Classifier 3 showed the poorest performance, with an AUC of 0.83 and 0.64 on test and validation data sets, respectively. CONCLUSIONS Convolutional neural network classifiers can effectively distinguish PACD from controls on AS-OCT with good generalizability across different patient cohorts. However, their performance is moderate when trying to distinguish PACS versus PAC + PACG. FINANCIAL DISCLOSURES The authors have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Jing Shan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California
| | - Zhixi Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ping Ma
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California; Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Tin A Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Sean Yonamine
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California
| | - Yangyan Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Mani Baskaran
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Monisha E Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Dake Chen
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Shuning Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
| | - Mingguang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China; Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia.
| | - Yangfan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
| | - Ying Han
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California; Ophthalmology Section, Surgical Service, San Francisco Veterans Affairs Medical Center, San Francisco, California.
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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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Mirzayev I, Gündüz AK, Aydın Ellialtıoğlu P, Gündüz ÖÖ. Clinical applications of anterior segment swept-source optical coherence tomography: A systematic review. Photodiagnosis Photodyn Ther 2023; 42:103334. [PMID: 36764640 DOI: 10.1016/j.pdpdt.2023.103334] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/25/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023]
Abstract
Optical coherence tomography (OCT) is a non-invasive method that provides the opportunity to examine tissues by taking cross-sectional images. OCT is increasingly being used to evaluate anterior segment (AS) pathologies. Swept-source (SS) OCT allows greater penetration and achieves better visualization of the internal configuration of AS tissues due to the longer wavelength employed and high scan speeds. We reviewed the utilization of AS SS-OCT in various conditions including glaucoma, ocular surface pathologies, iris tumors, refractive surgery, cataract surgery, and scleral diseases. A systematic literature search was carried out on PubMed, Scopus, and Web of Science databases between January 1, 2008, and September 1, 2022 using the following keywords: AS SS-OCT; dry eye and SS-OCT; ocular surface and SS-OCT; cornea and SS-OCT; dystrophy and SS-OCT; glaucoma and SS-OCT; ocular surface tumors and SS-OCT; conjunctival tumors and SS-OCT; refractive surgery and SS-OCT; cataract and SS-OCT; biometry and SS-OCT; sclera and SS-OCT; iris and SS-OCT; ciliary body and SS-OCT; artificial intelligence and SS-OCT. A total of 221 studies were included in this review. Review of the existing literature shows that SS-OCT offers several advantages in the diagnosis of AS diseases. Exclusive features of SS-OCT including rapid scanning, deeper tissue penetration, and better image quality help improve our understanding of various AS pathologies.
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Affiliation(s)
- Ibadulla Mirzayev
- Department of Ophthalmology, Ankara University Faculty of Medicine, Ankara, Turkey; Halil Şıvgın Çubuk State Hospital, Ophthalmology Clinic, Ankara, Turkey
| | - Ahmet Kaan Gündüz
- Department of Ophthalmology, Ankara University Faculty of Medicine, Ankara, Turkey; Private Eye Clinic, Ankara, Turkey.
| | | | - Ömür Özlenen Gündüz
- Department of Ophthalmology, Ankara University Faculty of Medicine, Ankara, Turkey
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Ghadamzadeh M, Karimi F, Ghasemi Moghaddam S, Daneshvar R. Anterior Chamber Angle Changes in Primary Angle-closure Glaucoma Following Phacoemulsification Versus Phacotrabeculectomy: A Prospective Randomized Clinical Trial. J Glaucoma 2022; 31:147-155. [PMID: 35210384 DOI: 10.1097/ijg.0000000000001977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 12/14/2021] [Indexed: 11/26/2022]
Abstract
PRCIS We used anterior segment optical coherence tomography to investigate anterior chamber angle in primary angle-closure glaucoma (PACG) eyes following phacoemulsification and phacotrabeculectomy. Angle widening was significantly greater after phacoemulsification up to 6 months after the surgery. PURPOSE To compare anterior chamber angle following 2 common surgeries for PACG. METHODS One hundred ten glaucoma patients were evaluated in this single center, prospective, randomized clinical trial. Those with concomitant PACG and senile cataract and without a history of ocular surgery, trauma, or chronic miotic use were recruited. Monocular patients were also excluded. Finally, 52 eligible subjects were randomly assigned to phacoemulsification ("Phaco" group, 25 eyes) or phacotrabeculectomy ("Combined" group, 27 eyes) surgeries. A swept-source, anterior segment optical coherence tomography device (CASIA SS-1000 OCT) was used to image the anterior segment. Mask graders used the images to measure the following parameters before and 1 week, 1 month, and 6 months after surgery: angle opening distance at 500 µm, trabecular iris surface area at 500 µm, and trabecular iris angle at 500 µm. RESULTS There was no significant difference between study groups regarding best-corrected visual acuity, intraocular pressure (IOP), and the number of glaucoma medications in preoperative or postoperative visits (P>0.076). Also, the measured angle parameters were not statistically significantly different between the 2 groups before surgery (P>0.123). After surgery, all measured parameters were significantly increased in both groups (P<0.0001). At the 6-month follow-up, nasal angle opening distance at 500 µm was 0.383±0.027 vs. 0.349±0.017, trabecular iris surface area at 500 µm was 0.141±0.007 vs. 0.125±0.005, and trabecular iris angle at 500 µm was 40.1±12.9 vs. 34.6±3.1 in Phaco and Combined groups, respectively (P<0.0001 for all). CONCLUSIONS Anterior chamber angle widening by anterior segment optical coherence tomography was observed in PACG patients following surgery and was significantly greater after phacoemulsification compared with combined phacotrabeculectomy at all time points. Similar IOP and medication burden were noted for up to 6 months as secondary outcomes. The contribution of angle changes to the IOP-lowering effect of phacoemulsification in PACG eyes needs further study.
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Affiliation(s)
| | - Farshid Karimi
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Ramin Daneshvar
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Ophthalmology, University of Florida, Gainesville, FL
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Zhao Y, Li Y, Hong J, Le Q, Xu J. Fourier-Domain Optical Coherence Tomographic Assessment of Changes in the Schlemm's Canal of Nonglaucomatous Subjects After Keratoplasty. Front Physiol 2021; 12:716117. [PMID: 34925051 PMCID: PMC8675085 DOI: 10.3389/fphys.2021.716117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: This study aimed to evaluate the impact of keratoplasty on the in vivo anatomical structures in the Schlemm's canal (SC) of nonglaucomatous subjects using Fourier-domain optical coherence tomography (FD-OCT). Methods: Sixty-six nonglaucomatous eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), or triple surgery were enrolled in this prospective, comparative, observational study. The SC imaging was performed using FD-OCT before and after surgery in both the nasal and temporal quadrants. Patient demographics, SC parameters [e.g., cross-sectional area (CSA), meridional diameter of SC (MSC), sagittal diameter of SC (SSC), and circumference (CCF)], and the correlations between the variation of SC parameters and intraocular pressure (IOP) were analyzed. Results: The mean age of all subjects was 40.27 ± 18.97 years. Among all cases, the nasal, temporal, and mean MSC significantly decreased on the first day after surgery and then increased at 1 week (p = 0.04, 0.017, and 0.01, respectively). Temporal CSA (tCSA), temporal MSC (tMSC), and temporal circumference (tCCF) after PK (p = 0.017, 0.020, and 0.018, respectively) and nasal MSC (nMSC) after DALK (p = 0.025) decreased significantly on the first day after surgery. The shift in mean IOP was significantly correlated with the changes in tMSC (r = 0.341, p = 0.003) and CCF (r = 0.207, p = 0.048). Conclusion: SC had significant in vivo morphological changes in the early period after keratoplasty in nonglaucomatous eyes, accompanied with elevation of IOP. Early intervention might be necessary to prevent secondary glaucoma early after keratoplasty.
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Affiliation(s)
- Yujin Zhao
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yue Li
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Jiaxu Hong
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Key Laboratory of Myopia, National Health and Family Planning Commission, Shanghai, China
| | - Qihua Le
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Jianjiang Xu
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
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Li Z, Meng Z, Qu W, Li X, Chang P, Wang D, Zhao Y. The Relationship Between Age and the Morphology of the Crystalline Lens, Ciliary Muscle, Trabecular Meshwork, and Schlemm's Canal: An in vivo Swept-Source Optical Coherence Tomography Study. Front Physiol 2021; 12:763736. [PMID: 34867468 PMCID: PMC8640208 DOI: 10.3389/fphys.2021.763736] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/29/2021] [Indexed: 01/07/2023] Open
Abstract
Purpose: To evaluate the effects of age on the morphologies of the crystalline lens, ciliary muscle (CM), Schlemm’s canal (SC), and trabecular meshwork (TM) using swept-source optical coherence tomography (SS-OCT). Methods: Images of the crystalline lens and iridocorneal angle were obtained in healthy participants’ eyes using SS-OCT. Morphological parameters of the crystalline lens, CM, and TM/SC were measured, and the relationship between these parameters and age was evaluated. Results: A total of 62 healthy participants were enrolled, with an age range of 7–79 years. With adjustments for the effects of axial length and sex, both the nasal and temporal SC cross-sectional areas (CSA) and the cross-sectional area of the CM (CMA), distance from the scleral spur to the inner apex of the ciliary muscle (IA-SS), and nasal SC volume were negatively correlated with age (P ≤ 0.041). Meanwhile, the lens thickness (LT) (P < 0.001) and lens vault (LV) (P < 0.001) were positively correlated with age, and the radius of the curvature of the anterior lens (ALR) was negatively correlated with age (P < 0.001). Conclusion: Increasing age was associated with a thicker crystalline lens, a steeper anterior lens curvature, an anteriorly located and smaller CM, and a narrower SC. Clinical Trial Registration:https://register.clinicaltrials.gov/prs/app/action/Select Protocol?sid=S000A3JZ&selectaction=Edit&uid=U00019K7&ts=4&cx=-c5xxp8, identifier [NCT04576884].
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Affiliation(s)
- Zhangliang Li
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Ziqi Meng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Wenyong Qu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Xiuyuan Li
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Pingjun Chang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Dandan Wang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Yune Zhao
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
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Ueno Y, Mori H, Kikuchi K, Yamanari M, Oshika T. Visualization of Anterior Chamber Angle Structures With Scattering- and Polarization-Sensitive Anterior Segment Optical Coherence Tomography. Transl Vis Sci Technol 2021; 10:29. [PMID: 34964836 PMCID: PMC8727324 DOI: 10.1167/tvst.10.14.29] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose The purpose of this study was to compare three optical coherence tomography (OCT) modalities in the observation of anterior chamber angle structures; trabecular meshwork (TM), Schlemm's canal (SC), and band of extracanalicular limbal lamina (BELL). Methods Three OCT modalities were used: (1) 2 × 2 Jones-matrix scattering OCT (S-OCT) representing conventional intensity OCT, (2) polarization-diverse S-OCT that was calculated as summation of all elements of the Jones-matrix to eliminate the influence of artifacts caused by sample birefringence, and (3) polarization-sensitive OCT (PS-OCT) to assess depth-resolved phase retardation. Results In a total of 97 eyes of 55 subjects, nasal and temporal angles were scanned. The detection rate of TM and BELL was significantly different among modalities; highest with PS-OCT (95.1% and 99.2%), followed by 2 × 2 Jones-matrix S-OCT (71.1% and 88.7%) and polarization-diverse S-OCT (33.2% and 25.0%), indicating the influence of artifacts on 2 × 2 Jones-matrix S-OCT measurements. SC was visible with 2 × 2 Jones-matrix S-OCT, polarization-diverse S-OCT, and PS-OCT in 14.2%, 14.9%, and 0.3% of images, respectively. The intergrader agreement as evaluated with the prevalence-adjusted bias-adjusted κ value was higher with PS-OCT than with other S-OCTs. Conclusions Visibility of anterior chamber angle structures was assessed with three OCT modalities. For TM and BELL that are rich in collagen fibers, PS-OCT provides significantly better visibility than S-OCT without the influence of artifacts arising from polarization or birefringence. Visualization of SC was more difficult with any OCT modalities. Translational Relevance PS-OCT is a useful tool to investigate the anterior chamber angle structures which are difficult to observe with conventional OCT.
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Affiliation(s)
- Yuta Ueno
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Haruhiro Mori
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Keita Kikuchi
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Masahiro Yamanari
- Department of Technological Development, Tomey Corporation, Nagoya, Japan
| | - Tetsuro Oshika
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
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Mahjoob M, Heydarian S. Changes in corneal and anterior chamber indices due to methamphetamine abuse. Clin Exp Optom 2021; 105:721-725. [PMID: 34592112 DOI: 10.1080/08164622.2021.1983401] [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: 10/20/2022] Open
Abstract
CLINICAL RELEVANCE Considering the significant relationship between methamphetamine abuse and some anterior segment indices, methamphetamine abuse should be considered in differential diagnosis especially in the case of angle closure glaucoma. BACKGROUND To investigate the effect of inhaled methamphetamine (meth) and crystal methamphetamine (crystal meth) on the quantitative indices of the cornea and anterior chamber using pentacam and anterior segment optical coherence tomography. METHODS In this cross-sectional study, the participants were (crystal) meth addicts living in Zahedan. The participants were transported to the examination site to undergo imaging and optometric tests. Pentacam and anterior segment optical coherence tomography imaging were then conducted so as to evaluate corneal and anterior chamber quantitative indices. RESULTS A total of 42 (crystal) meth addicts and 42 healthy subjects with matching age and gender were examined. Out of 42 subjects in the case group, 6 were female and 36 were male (mean age: 35.7 ± 8.6 years). The mean dose of drug used was 0.0074 ± 0.0034 g, and the mean duration of drug use was 6.9 ± 2.6 years (5-12 years). Based on the images of both devices, corneal curvature was significantly steeper in both meridians of anterior and posterior surfaces compared to the control group (p = 0.01). Among the anterior chamber parameters, the anterior chamber depth and volume were lower in the cases than the controls (p < 0.01). However, the lens rise was higher in addicts than controls (p = 0.01). CONCLUSION Quantitative changes in corneal and anterior segment indices including dilated pupils, shallower anterior chamber depth and higher lens rise in addicted cases compared to the control group may precipitate the risk of closed-angle in these individuals.
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Affiliation(s)
- Monireh Mahjoob
- Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Samira Heydarian
- Department of Rehabilitation Sciences, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran
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Bayat AH, Akpolat C. The change of anterior chamber angle parameters after cataract surgery in diabetic patients. Ther Adv Ophthalmol 2021; 13:25158414211034717. [PMID: 34409258 PMCID: PMC8365015 DOI: 10.1177/25158414211034717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/06/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose: The purpose of this study is to investigate the change of anterior chamber angle morphology after cataract surgery in patients with type 2 diabetes mellitus (DM2) using anterior segment optical coherence tomography (AS-OCT). Methods: In this prospective and comparative study, 57 eyes of the patients with cataract were investigated. The patients were divided into two groups. The DM2 group included cataractous type 2 diabetic patients without diabetic retinopathy (n = 30) and the non-DM2 group included nondiabetic participants with cataract (n = 27). The AS-OCT examinations were performed at baseline and 1 month after the cataract surgery. The corrected distance visual acuity (CDVA), intraocular pressure (IOP), angle-opening distance at 500 µm (AOD-500) and trabecular iris space area at 500 µm (TISA-500), and scleral spur angle (SSA) in temporal quadrant were analyzed. Results: The mean age, sex, and axial length values were similar in both groups (p > 0.05 for all). The CDVA was significantly improved in both groups (p < 0.001). The mean AOD-500, TISA-500, and SSA were increased and the mean IOP was decreased after cataract surgery in both groups (p < 0.001 for all). There were not any statistically significant intergroup differences in CDVA, IOP, and AS-OCT measurements between the DM2 and non-DM2 groups (p > 0.05 for all). Conclusion: Cataract surgery showed significant increases in mean anterior chamber angle parameters and reductions in IOP values in both diabetic and nondiabetic patients without intergroup significant differences. These results suggested the safety and effectiveness of cataract surgery, especially regarding anterior chamber angle parameters and so IOP changes.
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Affiliation(s)
- Alper Halil Bayat
- Department of Ophthalmology, Esenler Hospital, Medipol University, Birlik Mah Bahçeler cad. no:5 Esenler 34320, Istanbul, Turkey
| | - Cetin Akpolat
- Department of Ophthalmology, Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
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10
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The effects of cyclopentolate 1% versus tropicamide 1% on anterior segment angle parameters in three refractive pediatric groups. Int Ophthalmol 2021; 41:3781-3787. [PMID: 34259959 DOI: 10.1007/s10792-021-01948-1] [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: 02/11/2021] [Accepted: 07/09/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE This study aims to assess the effects of topical tropicamide 1% versus cyclopentolate hydrochloride 1% on the main numerical anterior chamber angle parameters using anterior segment optical coherence tomography (AS-OCT) in myopic, emmetropic, and hyperopic pediatric populations. METHODS One hundred eight healthy and non-amblyopic children were enrolled in this prospective study. The children were assigned into three refractive groups of myopia, emmetropia, and hyperopia for both tropicamide and cyclopentolate administrations. Half of the children in three groups were instilled tropicamide 1%, and the remaining halves were instilled cyclopentolate hydrochloride 1%. AS-OCT measurements of the anterior chamber angle in three groups were performed at the temporal areas of the right eyes under similar conditions at baseline, 30 min after tropicamide, and 45 min after cyclopentolate instillations. Main measurements including the angle-opening distance at 500 µm anterior to the scleral spur (AOD500), trabecular iris space area at 500 µm anterior to the scleral spur (TISA500), and scleral spur angle (SSA) were compared between three refractive groups. RESULTS The groups were age and gender-matched. The mean baseline spherical equivalents were similar in hyperopia groups of the tropicamide (+2.34 ± 0.44) and cyclopentolate (+2.18 ± 0.32) administrations (p = 0.284), as well as the myopic children administered with tropicamide (-2.68 ± 0.40) and cyclopentolate (-2.74 ± 0.38), (p = 0.406). All baseline measurements of AOD500, TISA500, and SSA measurements were similar in three refractive groups for both tropicamide and cyclopentolate as well as the final measurements and thus measurement changes between two sessions (P > 0.05 for all). Both drops induced an increase of AOD500, TISA500, and SSA measurements in three refractive groups (p < 0.05 for all). CONCLUSIONS Cycloplegic effects of topical instillations of tropicamide and cyclopentolate lead to a significant increase in anterior chamber angle measurements of AS-OCT. This similar effect of the drops should be considered for proper clinical assessment in children.
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11
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Zhao T, Zhao M, Xie Q, Fong CW, Chen J, Liu Y, Feng H, Li S, Arnold BF, Aung T, He M, Oatts JT, Han Y. Repeatability and Reproducibility of Anterior Chamber Angle Measurement with Swept-Source Optical Coherence Tomography in Patients with Primary Angle Closure Suspect. Curr Eye Res 2021; 46:1853-1860. [PMID: 34253093 DOI: 10.1080/02713683.2021.1942069] [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: 10/20/2022]
Abstract
Purpose: To evaluate the inter- and intra-observer reliability of anterior chamber (AC) angle measurements obtained by swept-source optical coherence tomography (SS-OCT).Methods: Forty-eight consecutive patients diagnosed with primary angle closure suspect (PACS) were included. Three masked observers at different training levels (one glaucoma specialist, one ophthalmology resident, and one pre-medical college student) measured 192 SS-OCT images of the PACS patients. One observer (the glaucoma specialist) repeated measurements 1 week later. SS-OCT parameters included: Anterior segment volume, including corneal, AC, and iris volume; anterior segment dimensions, including AC depth and width (ACD, ACW), and lens vault (LV); and angle parameters, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and the trabecular iris angle (TIA). Intraclass correlation coefficients (ICCs) were used to measure reliability.Results: For inter-observer reproducibility, ICCs of corneal, AC, and iris volumes were 0.952 to 0.998. ICCs of ACD at all axes were above 0.989. ICCs of ACW and LV were smallest in the 90°-270° axis (0.751 and 0.768) but not significantly different from other axes. ARA, TISA, and TIA at all angles had significantly smallest ICCs 250 µm from the scleral spur compared with 500 µm and 750 µm. The ICCs comparing observers with different training levels had similar ranges and followed similar trends. For intra-observer repeatability, the smallest ICC was 0.843. Decreasing AC depth correlated with increased inter-observer reproducibility.Conclusions: We found excellent intra-observer repeatability for all SS-OCT parameters. Angle measurements have more variation among the observers when taken 250 µm from the scleral spur. Shallow AC might lead to more variability for angle parameters. Non-expert observers may be recruited for high-quality image grading with standard training.
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Affiliation(s)
- Tong Zhao
- Department of Ophthalmology, University of California, San Francisco, California, USA.,Department of Ophthalmology, China-Japan Friendship Hospital, Beijing, China
| | - Mengya Zhao
- Department of Ophthalmology, University of California, San Francisco, California, USA.,Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qinghong Xie
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Christopher W Fong
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Jeremy Chen
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Yingna Liu
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Hui Feng
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Science Key Lab, Capital Medical University, Beijing, People's Republic of China
| | - Shuning Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Science Key Lab, Capital Medical University, Beijing, People's Republic of China
| | - Benjamin F Arnold
- Department of Ophthalmology, University of California, San Francisco, California, USA.,Francis I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Mingguang He
- State Key Laboratory of Ophthalmology, Clinical Research Center, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China.,Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Julius T Oatts
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Ying Han
- Department of Ophthalmology, University of California, San Francisco, California, USA
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12
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Yuan Y, Lin TPH, Gao K, Zhou R, Radke NV, Lam DSC, Zhang X. Aerobic exercise reduces intraocular pressure and expands Schlemm's canal dimensions in healthy and primary open-angle glaucoma eyes. Indian J Ophthalmol 2021; 69:1127-1134. [PMID: 33402660 PMCID: PMC8186587 DOI: 10.4103/ijo.ijo_2858_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Purpose Aerobic exercise (AE) has been reported to decrease intraocular pressure (IOP) in healthy subjects and there are concomitant morphological changes in the anterior segment of the eye including the Schlemm's canal (SC). However, its effects on IOP and SC morphology in glaucoma patients had not been studied before. We aim to investigate the effect of AE on the IOP and SC dimension in both healthy and primary open-angle glaucoma (POAG) eyes. Methods The area and diameter of SC and IOP were measured in 35 primary open-angle glaucoma (POAG) patients (59 eyes) and 36 healthy subjects (72 eyes) before and after performing moderate intensity of AE by running on a treadmill for 30 min. SC was imaged by swept-source optical coherence tomography (SS-OCT) for evaluation. Results In comparison with baseline values, mean IOP decreased significantly following AE in both POAG and healthy eyes (both P < 0.001), in which POAG eyes showed a greater degree of reduction compared to healthy eyes (P = 0.002). In comparison with baseline values, in both POAG and healthy eyes, the average cross-sectional area (POAG: 80.48 +/- 59.54 vs. 99.20 +/- 54.87 pixels; healthy: 151.84 +/- 52.76 vs. 198.23 +/- 53.70 pixels; both P < 0.001) and diameter (POAG: 3.73 +/- 1.69 vs. 4.33 +/- 1.74 pixels; healthy: 5.61 +/- 1.02 vs. 6.47 +/- 1.20 pixels; both P < 0.001) of SC significantly increased after AE. In POAG, both treated and untreated with IOP-lowering medications, a significant reduction in mean IOP and increase in SC dimensions following AE were observed (all P < 0.05), and there were no significant differences of such measurements between the two subgroups (all P > 0.05). Conclusion AE-induced reduction in IOP and an increase in SC dimensions in POAG eyes as in healthy eyes. Further studies to evaluate the long-term effect of AE on IOP control and SC morphology in POAG seem warranted.
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Affiliation(s)
- Ye Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Timothy P H Lin
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kai Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Rouxi Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | | | - Dennis S C Lam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; C-MER (Shenzhen) Dennis Lam Eye Hospital, Shenzhen; C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong; International Eye Research Institute of the Chinese University of Hong Kong (Shenzhen), Shenzhen; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xiulan Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Pujari A, Agarwal D, Sharma N. Clinical role of swept source optical coherence tomography in anterior segment diseases: a review. Semin Ophthalmol 2021; 36:684-691. [PMID: 33689554 DOI: 10.1080/08820538.2021.1897854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To note the comprehensive role of swept source anterior segment optical coherence tomography (SS-ASOCT) in anterior segment diseases. METHODS A systematic literature search was carried out on various medical databases using the keywords, swept source anterior segment optical coherence tomography; SS-ASOCT; Cornea and SS-ASOCT; SS-ASOCT and glaucoma; SS-ASOCT and cataract; SS-ASOCT and biometer; SS-ASOCT and tear film and ocular surface.Original works and novel reports describing the potential role of SS-ASOCT in various anterior segment conditions were included. RESULTS After a thorough assessment of literature, it was clear that the SS-ASOCT did provide newer insights into many anterior eye conditions. The rapid scan acquisition, deeper tissue penetration, and higher magnification did enhance many of our understandings, which were previously not possible. In addition, lenticular assessment under complex clinical scenarios with automated values on objective scale has made it a worthy tool with immense future possibilities. CONCLUSIONS SS-ASOCT unveiled various anterior segment findings which were of clinical importance.
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Affiliation(s)
- Amar Pujari
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Divya Agarwal
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Namrata Sharma
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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14
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Moghadas Sharif N, Shoeibi N, Heydari M, Yazdani N, Ghasemi-Moghaddam S, Ehsaei A. Effect of cyclopentolate versus tropicamide on anterior segment angle parameters in three refractive groups. Clin Exp Optom 2020; 104:151-155. [PMID: 32519368 DOI: 10.1111/cxo.13103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
CLINICAL RELEVANCE Frequent clinical application of cycloplegia in clinical practice makes it essential to assess how this condition influences anterior segment angle parameters. BACKGROUND This study aims to compare the effects of cyclopentolate and tropicamide on anterior segment angle parameters in three adult refractive groups. METHODS Sixty healthy individuals were recruited and assigned into three refractive groups according to inclusion criteria. At baseline visit, anterior segment angle parameters were measured using anterior segment optical coherence tomography in the right eye. All measurements were repeated at two separate visits, one week apart, after administration of tropicamide 1% and cyclopentolate 1% at similar conditions. Main outcome measures were angle-opening distance, trabecular iris angle, trabecular iris space area and anterior chamber depth. Anterior segment angle parameters were recorded at temporal areas (180 degrees). RESULTS Sixty participants (29 men and 31 women, age: 27.82 ± 4.71-years) completed the experiment. Baseline mean spherical equivalents were +1.52 ± 1.20 D, -0.04 ± 0.33 D and -1.91 ± 0.91-D in hyperopic, emmetropic and myopic groups, respectively. No statistically significant differences were found between tropicamide and cyclopentolate for all angle parameters in three refractive groups. Both drops induced an increase in all parameters in three refractive groups. Analysis between refractive groups revealed that a more hyperopic refraction was associated with less trabecular iris angle, angle-opening distance and anterior chamber depth parameters in baseline, after tropicamide and cyclopentolate instillations. CONCLUSIONS Topical application of cycloplegic eye drops in healthy individuals leads to small but significant changes in anterior chamber depth and anterior segment angle parameters, regardless of refractive status. Moreover, lower values of anterior chamber depth and anterior segment angle parameters in hyperopic individuals after administration of cycloplegic drops should be taken into account during biometric measurement and phakic intraocular lens implantation. Due to shorter effect and recovery time and less ocular/systemic reaction of tropicamide versus cyclopentolate, tropicamide could be a recommended cycloplegic agent for diagnostic and therapeutic procedures.
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Affiliation(s)
- Nasrin Moghadas Sharif
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nasser Shoeibi
- Eye Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Heydari
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Negareh Yazdani
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Somayeh Ghasemi-Moghaddam
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Asieh Ehsaei
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.,Refractive Errors Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
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15
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Gómez-Correa JE, Torres-Treviño LM, Moragrega-Adame E, Mayorquin-Ruiz M, Villalobos-Ojeda C, Velasco-Barona C, Chávez-Cerda S. Intelligent-assistant system for scleral spur location. APPLIED OPTICS 2020; 59:3026-3032. [PMID: 32400579 DOI: 10.1364/ao.384440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
A system based on the use of two artificial neural networks (ANNs) to determine the location of the scleral spur of the human eye in ocular images generated by an ultrasound biomicroscopy is presented in this paper. The two ANNs establish a relationship between the distance of four manually placed landmarks in an ocular image with the coordinates of the scleral spur. The latter coordinates are generated by the expert knowledge of a subject matter specialist. Trained ANNs that generate good results for scleral spur location are incorporated into a software system. Statistical indicators and results yield an efficiency performance above 95%.
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16
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Diagnostic power of scleral spur length in primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 2020; 258:1253-1260. [PMID: 32146558 PMCID: PMC7237521 DOI: 10.1007/s00417-020-04637-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 02/17/2020] [Accepted: 02/24/2020] [Indexed: 01/17/2023] Open
Abstract
Purpose To investigate the diagnostic capability of scleral spur length in discriminating eyes with primary open-angle glaucoma (POAG) from healthy eyes. Methods Seventy-eight eyes of 78 patients with POAG and 93 eyes of 93 age-, sex- and axial length-matched healthy subjects were included. The scleral spur length was measured using swept-source optical coherence tomography. Receiver operating characteristic (ROC) curves were derived based on the measurements. Results The scleral spur length was significantly shorter in POAG eyes compared with healthy eyes (Method I, 164.91 ± 23.36 vs. 197.60 ± 25.32 μm; Method II, 145.15 ± 16.59 vs. 166.95 ± 19.31 μm; Method III, 162.33 ± 22.83 vs. 185.12 ± 23.58 μm, respectively; all p < 0.001). The areas under ROC curves were 0.841 (Method I), 0.810 (Method II), and 0.753 (Method III) for the scleral spur length. Moreover, Schlemm’s canal area was significantly associated with the scleral spur length (Method I) in both POAG (β = 0.027; p < 0.001) and healthy (β = 0.016; p = 0.009) groups. Conclusions The scleral spur length had a good discriminating capability between POAG and healthy eyes, and it could be a novel biomarker for POAG evaluation clinically.
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17
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Xu BY, Chiang M, Pardeshi AA, Moghimi S, Varma R. Deep Neural Network for Scleral Spur Detection in Anterior Segment OCT Images: The Chinese American Eye Study. Transl Vis Sci Technol 2020; 9:18. [PMID: 32818079 PMCID: PMC7395674 DOI: 10.1167/tvst.9.2.18] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/11/2020] [Indexed: 12/20/2022] Open
Abstract
Purpose To develop a deep neural network that detects the scleral spur in anterior segment optical coherence tomography (AS-OCT) images. Methods Participants in the Chinese American Eye Study, a population-based study in Los Angeles, California, underwent complete ocular examinations, including AS-OCT imaging with the Tomey CASIA SS-1000. One human expert grader provided reference labels of scleral spur locations in all images. A convolutional neural network (CNN)-based on the ResNet-18 architecture was developed to detect the scleral spur in each image. Performance of the CNN model was assessed by calculating prediction errors, defined as the difference between the Cartesian coordinates of reference and CNN-predicted scleral spur locations. Prediction errors were compared with intragrader variability in detecting scleral spur locations by the reference grader. Results The CNN was developed using a training dataset of 17,704 images and tested using an independent dataset of 921 images. The mean absolute prediction errors of the CNN model were 49.27 ± 42.07 µm for X-coordinates and 47.73 ± 39.70 µm for Y-coordinates. The mean absolute intragrader variability was 52.31 ± 47.75 µm for X-coordinates and 45.88 ± 45.06 µm for Y-coordinates. Distributions of prediction errors for the CNN and intragrader variability for the reference grader were similar for X-coordinates (P = 0.609) and Y-coordinates (P = 0.378). The mean absolute prediction error of the CNN was 73.08 ± 52.06 µm and the mean absolute intragrader variability was 73.92 ± 60.72 µm. Conclusions A deep neural network can detect the scleral spur on AS-OCT images with performance similar to that of a human expert grader. Translational Relevance Deep learning methods that automate scleral spur detection can facilitate qualitative and quantitative assessments of AS-OCT images.
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Affiliation(s)
- Benjamin Y. Xu
- Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Michael Chiang
- Sol Price School of Public Policy, University of Southern California, Los Angeles, CA, USA
| | - Anmol A. Pardeshi
- Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Sasan Moghimi
- Hamilton Glaucoma Center, Shiley Eye Institute, Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA
| | - Rohit Varma
- Southern California Eye Institute, CHA Hollywood Presbyterian Medical Center, Los Angeles, CA, USA
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18
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Deep Learning Classifiers for Automated Detection of Gonioscopic Angle Closure Based on Anterior Segment OCT Images. Am J Ophthalmol 2019; 208:273-280. [PMID: 31445003 DOI: 10.1016/j.ajo.2019.08.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 08/07/2019] [Accepted: 08/13/2019] [Indexed: 01/27/2023]
Abstract
PURPOSE To develop and test deep learning classifiers that detect gonioscopic angle closure and primary angle closure disease (PACD) based on fully automated analysis of anterior segment OCT (AS-OCT) images. METHODS Subjects were recruited as part of the Chinese-American Eye Study (CHES), a population-based study of Chinese Americans in Los Angeles, California, USA. Each subject underwent a complete ocular examination including gonioscopy and AS-OCT imaging in each quadrant of the anterior chamber angle (ACA). Deep learning methods were used to develop 3 competing multi-class convolutional neural network (CNN) classifiers for modified Shaffer grades 0, 1, 2, 3, and 4. Binary probabilities for closed (grades 0 and 1) and open (grades 2, 3, and 4) angles were calculated by summing over the corresponding grades. Classifier performance was evaluated by 5-fold cross-validation and on an independent test dataset. Outcome measures included area under the receiver operating characteristic curve (AUC) for detecting gonioscopic angle closure and PACD, defined as either 2 or 3 quadrants of gonioscopic angle closure per eye. RESULTS A total of 4036 AS-OCT images with corresponding gonioscopy grades (1943 open, 2093 closed) were obtained from 791 CHES subjects. Three competing CNN classifiers were developed with a cross-validation dataset of 3396 images (1632 open, 1764 closed) from 664 subjects. The remaining 640 images (311 open, 329 closed) from 127 subjects were segregated into a test dataset. The best-performing classifier was developed by applying transfer learning to the ResNet-18 architecture. For detecting gonioscopic angle closure, this classifier achieved an AUC of 0.933 (95% confidence interval, 0.925-0.941) on the cross-validation dataset and 0.928 on the test dataset. For detecting PACD based on 2- and 3-quadrant definitions, the ResNet-18 classifier achieved AUCs of 0.964 and 0.952, respectively, on the test dataset. CONCLUSION Deep learning classifiers effectively detect gonioscopic angle closure and PACD based on automated analysis of AS-OCT images. These methods could be used to automate clinical evaluations of the ACA and improve access to eye care in high-risk populations.
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19
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Ang BCH, Lim SY, Dorairaj S. Intra-operative optical coherence tomography in glaucoma surgery-a systematic review. Eye (Lond) 2019; 34:168-177. [PMID: 31772380 DOI: 10.1038/s41433-019-0689-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 10/01/2019] [Accepted: 11/04/2019] [Indexed: 12/16/2022] Open
Abstract
The application of the OCT in clinical ophthalmology has expanded significantly since its introduction more than 20 years ago. There has been recent growing interest in the application of intra-operative optical coherence tomography (iOCT). The iOCT's ability to enhance visualisation and depth appreciation has the potential to be further exploited in glaucoma surgery, especially with the emergence of Minimally Invasive Glaucoma Surgery (MIGS)-to facilitate targeted device placement and fine surgical manoeuvres in the angles, the sub-conjunctival layer and the suprachoroidal space. Hence, this study aims to appraise the current literature on the applications of iOCT in glaucoma surgery. A total of 79 studies were identified following a literature search adhering to PRISMA guidelines. After full text evaluation, 10 studies discussing iOCT use in glaucoma surgery were included. Traditional glaucoma filtering procedures reviewed included trabeculectomy surgery, goniosynechiolysis, bleb needling and glaucoma drainage device implantation. MIGS procedures reviewed included canaloplasty, trabecular aspiration, ab-interno trabectome and the XEN45 gel stent. iOCT use in ophthalmic surgery is becoming increasingly prevalent and has already been applied in various surgeries and procedures in the field of glaucoma. With the greater adoption of MIGS, iOCT may further contribute in facilitating surgical techniques and improving outcomes. While iOCT offers many advantages, there are still limitations to be overcome-iOCT technology continues to evolve to optimise imaging quality and user-experience.
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Affiliation(s)
- Bryan C H Ang
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, Singapore, Singapore
| | - Sheng Yang Lim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Syril Dorairaj
- Department of Ophthalmology, Mayo Clinic, Jacksonville, Florida, USA.
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20
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Y Lin K, Mosaed S. Ab Externo Imaging of Human Episcleral Vessels Using Fiberoptic Confocal Laser Endomicroscopy. J Ophthalmic Vis Res 2019; 14:275-284. [PMID: 31660106 PMCID: PMC6815344 DOI: 10.18502/jovr.v14i3.4783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 02/18/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose There is a growing interest in targeting minimally invasive surgery devices to the aqueous outflow system to optimize treatment outcomes. However, methods to visualize functioning, large-caliber aqueous and episcleral veins in-vivo are lacking. This pilot study establishes an ex-vivo system to evaluate the use of a confocal laser microendoscope to noninvasively image episcleral vessels and quantify regional flow variation along the limbal circumference. Methods A fiber-optic confocal laser endomicroscopy (CLE) system with lateral and axial resolution of 3.5 μm and 15 μm, respectively, was used on three porcine and four human eyes. Diluted fluorescein (0.04%) was injected into eyes kept under constant infusion. The microprobe was applied to the sclera 1 mm behind the limbus to acquire real-time video. Image acquisition was performed at 15-degree intervals along the limbal circumference to quantify regional flow variation in human eyes. Results Vascular structures were visualized in whole human eyes without processing. Schlemm's canal was visualized only after a scleral flap was created. Fluorescent signal intensity and vessel diameter variation were observed along the limbal circumference, with the inferior quadrant having a statistically higher fluorescein signal compared to the other quadrants in human eyes (P < 0.05). Conclusion This study demonstrates for the first time that the fiber-optic CLE platform can visualize the episcleral vasculature with high resolution ex-vivo with minimal tissue manipulation. Intravascular signal intensities and vessel diameters were acquired in real-time; such information can help select target areas for minimally invasive glaucoma surgery (MIGS) to achieve greater intraocular pressure reduction.
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Affiliation(s)
- Ken Y Lin
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, USA
| | - Sameh Mosaed
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, USA
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Angmo D, Shakrawal J, Gupta B, Yadav S, Pandey RM, Dada T. Comparative Evaluation of Phacoemulsification Alone versus Phacoemulsification with Goniosynechialysis in Primary Angle-Closure Glaucoma: A Randomized Controlled Trial. Ophthalmol Glaucoma 2019; 2:346-356. [PMID: 32672677 DOI: 10.1016/j.ogla.2019.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 06/11/2023]
Abstract
PURPOSE Comparative evaluation of phacoemulsification (phaco) alone versus phacoemulsification combined with goniosynechialysis (phacoGSL) in primary angle-closure glaucoma (PACG). DESIGN Prospective, randomized, parallel group, active controlled trial. PARTICIPANTS Patients with PACG. METHODS A total of 120 consecutive patients with PACG were screened, of whom 80 met inclusion criteria, with PACG uncontrolled on maximal hypotensive therapy and were recruited. Patients were randomized into 2 groups and underwent phaco alone in group 1 or phacoGSL in group 2. The patients were examined at baseline and at 1 week and 1, 3, and 6 months. The anterior chamber angle parameters on swept-source anterior segment OCT (SS-ASOCT) were noted at 1 and 6 months. MAIN OUTCOME MEASURES The primary outcome measure was intraocular pressure (IOP) reduction. A reduction in IOP of ≥ 20% from baseline IOP with or without medications was considered a success. Secondary outcome measures included change in the anterior chamber angle temporal parameters, angle-opening distance, trabecular-iris space area and scleral spur angle, surgical safety, visual acuity, and reduction in the number of glaucoma medications postoperatively. RESULTS The average age of patients was 58.77±8.14 years and 56.50±9.17 years in groups 1 and 2, respectively (P = 0.31). The mean baseline IOP was 29.48±6.76 mmHg and 30.72±3.88 mmHg in groups 1 and 2, respectively (P = 0.13). Success was obtained in 93.33% of patients in group 1 and 91.18% of patients in group 2 at 6 months (P = 0.39). Mean IOP was 13.17±1.66 mmHg and 13.21±1.97 mmHg at 6 months in groups 1 and 2, respectively (P = 0.001). The reduction in IOP was 55.32% and 56.99% at 6 months in groups 1 and 2 (P = 0.48). Significant widening of the angle parameters was noted at 6 months with an increase compared with baseline values in both groups. In multivariate analysis, the significant predictor of decrease in IOP was the higher baseline IOP. CONCLUSIONS Both phaco and phacoGSL are associated with a significant reduction in IOP along with a noteworthy widening of the anterior chamber angle parameters. Both procedures succeeded in reducing the necessity of glaucoma medications postoperatively in PACG eyes. There is no additional benefit of phacoGSL over phaco in PACG.
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Affiliation(s)
- Dewang Angmo
- Glaucoma Research and Clinical Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
| | - Jyoti Shakrawal
- Glaucoma Research and Clinical Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Barkha Gupta
- Glaucoma Research and Clinical Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Suresh Yadav
- Glaucoma Research and Clinical Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - R M Pandey
- Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India
| | - Tanuj Dada
- Glaucoma Research and Clinical Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Xu BY, Pardeshi AA, Burkemper B, Richter GM, Lin SC, McKean-Cowdin R, Varma R. Quantitative Evaluation of Gonioscopic and EyeCam Assessments of Angle Dimensions Using Anterior Segment Optical Coherence Tomography. Transl Vis Sci Technol 2018; 7:33. [PMID: 30619653 PMCID: PMC6314106 DOI: 10.1167/tvst.7.6.33] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/17/2018] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To evaluate the relationship between angle dimensions assessed by gonioscopy or EyeCam and anterior segment optical coherence tomography (AS-OCT). METHODS Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES). Each subject underwent a complete ocular exam, including gonioscopy, AS-OCT, and EyeCam. Angle closure was defined as three or more quadrants in which pigmented trabecular meshwork could not be visualized. Angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA) were measured in each AS-OCT image. RESULTS 709 eyes (272 angle closure, 437 open angle) from 709 subjects were analyzed. Mean gonioscopy and EyeCam grades tended to increase as AS-OCT measurements increased. There were strong correlations overall between AS-OCT measurements and gonioscopy (r > 0.73) and EyeCam (r > 0.68) grades. However, correlations with AS-OCT measurements were weak for gonioscopy (r < 0.38) and EyeCam (r < to 0.27) among eyes with angle closure. Mean AS-OCT measurements differed for eyes with Shaffer grade 0 in all four quadrants among eyes with varying degrees of angle closure on gonioscopy (P < 0.01) but did not differ among eyes with varying degrees of angle closure on EyeCam (P > 0.27). CONCLUSIONS Angle assessments by gonioscopy and EyeCam are weakly related to angle dimensions in eyes with angle closure. TRANSLATIONAL RELEVANCE AS-OCT imaging raises concerns about current clinical methods that rely on direct visualization of ACA structures to assess the degree of angle closure.
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Affiliation(s)
- Benjamin Y Xu
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Anmol A Pardeshi
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Bruce Burkemper
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Grace M Richter
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Shan C Lin
- Beckman Vision Center, Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Roberta McKean-Cowdin
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
- Department of Preventive Medicine, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Rohit Varma
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
- Department of Preventive Medicine, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
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Postexercise Recovery of Schlemm's Canal and Intraocular Pressure in Healthy Individuals: An Observational Study Using Swept-Source Optical Coherence Tomography. J Ophthalmol 2018; 2018:8513760. [PMID: 30245872 PMCID: PMC6136586 DOI: 10.1155/2018/8513760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/08/2018] [Indexed: 12/02/2022] Open
Abstract
Purpose To observe the recovery process of postexercise Schlemm's canal (SC) and intraocular pressure (IOP) in healthy individuals. Methods Twenty healthy individuals were recruited. SC and IOP were evaluated before exercise, immediately after exercise, and 15, 30, and 60 minutes after exercise. Superior, inferior, nasal, and temporal SC quadrants were evaluated using swept-source optical coherence tomography (SS-OCT). Results Average SC area (3726.81 ± 1167.06 vs. 4660.57 ± 1284.82 µm2) and perimeter (324.11 ± 58.95 vs. 367.19 ± 73.34 µm) increased, and IOP (14.02 ± 2.33 vs. 11.65 ± 1.90 mmHg) decreased significantly during exercise (all p < 0.001). After exercise, both SC and IOP recovered to preexercise values, and the recovery time for postexercise SC dimensions (15 minutes) was shorter than that for postexercise IOP (60 minutes). After adjusting for age, gender, axial length, central corneal thickness, and spherical equivalent, postexercise changes in SC dimensions were not significantly associated with postexercise changes in IOP compared with preexercise values (all p > 0.05). There were no significant differences in the observable SC proportion before and after exercise (all p > 0.05). Conclusions The exercise-induced SC expansion and IOP reduction could recover to preexercise values after exercise, and SC recovered to preexercise values ahead of IOP. Moreover, SC might be regulated by the sympathetic nerves and could be an important causative factor of changes in IOP during and after exercise.
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24
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Yan X, Li M, Zhang H. Relationship Between Post-Exercise Changes in the Lens and Schlemm's Canal: A Swept-Source Optical Coherence Tomography Study. Curr Eye Res 2018; 43:1351-1356. [PMID: 30015521 DOI: 10.1080/02713683.2018.1498523] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
AIM To observe post-exercise changes in the lens and Schlemm's canal (SC) in healthy individuals using swept-source optical coherence tomography (SS-OCT). METHODS Thirty-five healthy, young individuals were recruited and performed aerobic exercise by jogging for 20 minutes. The SC area, SC perimeter, trabecular meshwork (TM) length, TM thickness, lens vault (LV), and lens thickness (LT) were assessed by SS-OCT before and after exercise. RESULTS Following aerobic exercise, SC area (4260.85 ± 1476.02 vs. 5158.24 ± 1527.42 μm2, p < 0.001), SC perimeter (349.21 ± 62.22 vs. 391.24 ± 71.77 μm, p < 0.001), TM length (781.16 ± 114.83 vs. 816.46 ± 121.26 μm, p < 0.001), and TM thickness (111.52 ± 19.30 vs. 116.96 ± 17.57 μm, p = 0.004) increased significantly, while LV (-0.134 ± 0.198 vs. -0.195 ± 0.198 mm, p < 0.001) decreased significantly and LT showed no significant post-exercise changes (3.86 ± 0.32 vs. 3.85 ± 0.32 mm, p = 0.801). Moreover, post-exercise changes in SC area were significantly associated with post-exercise changes in LV (β = -6487.83; p = 0.040). CONCLUSIONS Aerobic exercise induces both backward axial displacement of the lens and SC expansion. This backward axial displacement of the lens could be an important causative factor of the post-exercise SC expansion via the lens-zonular-ciliotrabecular vector and the connecting fibrils between ciliary body and SC.
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Affiliation(s)
- Xiaoqin Yan
- a Department of Ophthalmology, Tongji Hospital, Tongji Medical College , Huazhong University of Science and Technology , Wuhan , China
| | - Mu Li
- a Department of Ophthalmology, Tongji Hospital, Tongji Medical College , Huazhong University of Science and Technology , Wuhan , China
| | - Hong Zhang
- a Department of Ophthalmology, Tongji Hospital, Tongji Medical College , Huazhong University of Science and Technology , Wuhan , China
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25
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Zhao Y, Chen J, Yu X, Xu J, Sun X, Hong J. Age-Related Changes in Human Schlemm's Canal: An in Vivo Optical Coherence Tomography-Based Study. Front Physiol 2018; 9:630. [PMID: 29922169 PMCID: PMC5996748 DOI: 10.3389/fphys.2018.00630] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/09/2018] [Indexed: 11/16/2022] Open
Abstract
Purpose: To investigate age-related changes in human Schlemm’s canal (SC) using spectral-domain optical coherence tomography (SD-OCT). Methods: A total of 125 normal eyes were imaged using SD-OCT nasally and temporally. The age-related variations of SC sagittal diameter and cross-sectional area (CSA) from four age groups [A (16–20 years), B (21–40 years), C (41–60 years), and D (61–80 years)] were analyzed with Spearman correlation. Results: The positive detection rates of SC showed a significantly downward trend with age. The mean CSA was 13,296 ± 1,897 μm2 nasally and 14,552 ± 2,589 μm2 temporally. The mean CSA was significantly larger in the temporal than in the nasal region (P < 0.05). Nasal CSA values varied among the four age groups (P = 0.004). Conclusion: Our study found for the first time that SC in vivo exhibits a morphological variant with age in healthy humans. Clinicians may need to consider this phenomenon when performing examinations targeting SC for glaucoma patients.
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Affiliation(s)
- Yujin Zhao
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Junyi Chen
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiaobo Yu
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jianjiang Xu
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jiaxu Hong
- Department of Ophthalmology and Visual Science, Shanghai Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Ophthalmology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China.,Key Laboratory of Myopia, National Health Commission, Beijing, China.,Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
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26
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Römkens HC, Beckers HJ, Schouten JS, Berendschot TT, Webers CA. Reference values for anterior chamber morphometrics with swept-source optical coherence tomography in a Caucasian population. Clin Ophthalmol 2018. [PMID: 29535498 PMCID: PMC5836660 DOI: 10.2147/opth.s147364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose The aim of this study is to generate reference values for anterior chamber morphometrics to facilitate the interpretation of anterior chamber images acquired with swept-source optical coherence tomography (SS-OCT) in a Caucasian population. Materials and methods Non-glaucomatous Caucasian subjects, who were newly referred to the outpatient department of the University Eye Clinic Maastricht UMC+, were asked to undergo anterior segment assessment with SS-OCT imaging prior to routine eye examination (including visual acuity and refractive error measurements, Goldmann applanation tonometry, slit lamp examination and funduscopy). Results A total of 647 Caucasian subjects, aged 40–80 years, were included. Mean age (± standard deviation) was 61.7±10.3 years, and 294 were male (45%). Mean refractive error was −0.63±3.17 D. OCT images and measurements were obtained in all cases. The mean temporal trabecular iris angle at 500 µm (TIA500) was 27.04°±12.04°, the mean nasal TIA500 was 27.43°±11.75°, the mean anterior chamber depth (ACD) was 2.75±0.39 mm and the mean lens vault (LV) was 0.44±0.30 mm. A smaller temporal TIA500, shallower ACD and higher LV were found in female and hyperopic subjects. Conclusion Reference values for anterior chamber morphometrics in Caucasians were generated, quantified and presented. These values offer tools for the interpretation of anterior segment images of Caucasians and differentiation between presumed mechanisms of angle closure.
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Affiliation(s)
- Hellen Cs Römkens
- Department of Ophthalmology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Henny Jm Beckers
- Department of Ophthalmology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Jan Sag Schouten
- Department of Ophthalmology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Tos Tjm Berendschot
- Department of Ophthalmology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Carroll Ab Webers
- Department of Ophthalmology, Maastricht University Medical Center+, Maastricht, the Netherlands
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27
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Pasricha ND, Bhullar PK, Shieh C, Viehland C, Carrasco-Zevallos OM, Keller B, Izatt JA, Toth CA, Challa P, Kuo AN. Four-dimensional microscope- integrated optical coherence tomography to enhance visualization in glaucoma surgeries. Indian J Ophthalmol 2017; 65:57-59. [PMID: 28300743 PMCID: PMC5369296 DOI: 10.4103/ijo.ijo_412_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report the first use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT) capable of live four-dimensional (4D) (three-dimensional across time) imaging intraoperatively to directly visualize tube shunt placement and trabeculectomy surgeries in two patients with severe open-angle glaucoma and elevated intraocular pressure (IOP) that was not adequately managed by medical intervention or prior surgery. We performed tube shunt placement and trabeculectomy surgery and used SS-MIOCT to visualize and record surgical steps that benefitted from the enhanced visualization. In the case of tube shunt placement, SS-MIOCT successfully visualized the scleral tunneling, tube shunt positioning in the anterior chamber, and tube shunt suturing. For the trabeculectomy, SS-MIOCT successfully visualized the scleral flap creation, sclerotomy, and iridectomy. Postoperatively, both patients did well, with IOPs decreasing to the target goal. We found the benefit of SS-MIOCT was greatest in surgical steps requiring depth-based assessments. This technology has the potential to improve clinical outcomes.
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Affiliation(s)
- Neel Dave Pasricha
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | | | - Christine Shieh
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | | | | | - Brenton Keller
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Joseph Adam Izatt
- Department of Ophthalmology, Duke University School of Medicine; Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Cynthia Ann Toth
- Department of Ophthalmology, Duke University School of Medicine; Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Pratap Challa
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Anthony Nanlin Kuo
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
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Xu BY, Israelsen P, Pan BX, Wang D, Jiang X, Varma R. Benefit of Measuring Anterior Segment Structures Using an Increased Number of Optical Coherence Tomography Images: The Chinese American Eye Study. Invest Ophthalmol Vis Sci 2017; 57:6313-6319. [PMID: 27893097 PMCID: PMC5119487 DOI: 10.1167/iovs.16-19755] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Purpose The purpose of this study was to evaluate the benefit of analyzing an increased number of anterior segment optical coherence tomography (AS-OCT) images on measurement values of various anterior segment parameters. Methods Subjects for this cross-sectional study were recruited from the Chinese American Eye Study (CHES), a population-based study in Los Angeles, CA. Thirty-two AS-OCT images were acquired from one eye each of 83 consecutive subjects. Sixteen parameters were analyzed in each image, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), scleral spur angle (SSAngle), lens vault (LV), pupillary diameter (PD), anterior chamber depth (ACD), anterior chamber width (ACW), iris area (IA), and anterior chamber area (ACA). Data from 1, 2, 4, 8, 16, or 32 OCT images were averaged across subjects to calculate the range and mean of measurement values for each parameter. Results Anatomical variations were poorly captured with fewer OCT images for AOD, ARA, TISA, SSAngle, IA, and LV. For these parameters, the range and mean of measurement values obtained from one OCT image deviated from 32-image values by up to 43.9% and 13.3% of the 32-image mean, respectively. These deviations decreased when additional OCT images were analyzed. Deviations from 32-image range and mean values were less pronounced regardless of image number for PD, ACD, ACW, and ACA, measuring up to 3.5% and 5.0%, respectively. Conclusions A multi-image approach should be the standard in OCT-based studies of AOD, ARA, TISA, TIA, SSAngle, IA, and LV.
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Affiliation(s)
- Benjamin Y Xu
- Roski Eye Institute, Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
| | - Paul Israelsen
- Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
| | - Billy X Pan
- Roski Eye Institute, Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
| | - Dandan Wang
- Roski Eye Institute, Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
| | - Xuejuan Jiang
- Roski Eye Institute, Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
| | - Rohit Varma
- Roski Eye Institute, Keck School of Medicine at the University of Southern California Los Angeles, Los Angeles, California, United States
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Mathematical Modeling of Outflow Facility Increase With Trabecular Meshwork Bypass and Schlemm Canal Dilation. J Glaucoma 2016; 25:355-64. [PMID: 25836658 DOI: 10.1097/ijg.0000000000000248] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To mathematically model the conventional aqueous humor outflow system with trabecular meshwork (TM) bypass and Schlemm canal (SC) dilation. METHODS The SC was modeled as a rectangular channel with the TM modeled as a permeable membrane. The collector channels (CCs) were modeled as fluid sinks distributed along the outer wall of SC. Two different implants were investigated in this study. The Hydrus Microstent (scaffold) was modeled with a TM bypass and a dilated region in SC that was 7 or 15 mm long and approximately 5-fold larger than the normal height of SC (h0). The iStent trabecular microbypass was modeled with a similar structure except that the dilated region in SC was 1 mm long and 25% larger than h0. RESULTS Creation of a TM bypass structure would increase the pressure in the surrounding regions inside the SC and make it close to the intraocular pressure. SC dilation would increase the pressure more uniformly in the dilated region. The pressure increase led to higher flow rates in SC and CCs, and subsequently increased outflow facility (C). If CCs were uniformly distributed, the increase in C was the smallest after implantation of 1 microbypass, compared with that after implantation of 2 microbypasses or 1 scaffold. If CCs were nonuniformly distributed, the magnitude of increase in C was sensitive to the location of implant, and the sensitivity was higher for the microbypass than the scaffold. CONCLUSION The study showed that creation of TM bypass and SC dilation significantly increased outflow facility, and the amount of increase correlated with the length of dilated regions in SC.
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Abstract
Foreword It gives me pleasure to introduce the 4th edition of the EGS Guidelines. The Third edition proved to be extremely successful, being translated into 7 languages with over 70000 copies being distributed across Europe; it has been downloadable, free, as a pdf file for the past 4 years. As one of the main objectives of the European Glaucoma Society has been to both educate and standardize glaucoma practice within the EU, these guidelines were structured so as to play their part. Glaucoma is a living specialty, with new ideas on causation, mechanisms and treatments constantly appearing. As a number of years have passed since the publication of the last edition, changes in some if not all of these ideas would be expected. For this new edition of the guidelines a number of editorial teams were created, each with responsibility for an area within the specialty; updating where necessary, introducing new diagrams and Flowcharts and ensuring that references were up to date. Each team had writers previously involved with the last edition as well as newer and younger members being co-opted. As soon as specific sections were completed they had further editorial comment to ensure cross referencing and style continuity with other sections. Overall guidance was the responsibility of Anders Heijl and Carlo Traverso. Tribute must be made to the Task Force whose efforts made the timely publication of the new edition possible. Roger Hitchings Chairman of the EGS Foundation www.eugs.org The Guidelines Writers and Contributors Augusto Azuara Blanco Luca Bagnasco Alessandro Bagnis Keith Barton Christoph Baudouin Boel Bengtsson Alain Bron Francesca Cordeiro Barbara Cvenkel Philippe Denis Christoph Faschinger Panayiota Founti Stefano Gandolfi David Garway Heath Francisco Goni Franz Grehn Anders Heijl Roger Hitchings Gabor Hollo Tony Hommer Michele Iester Jost Jonas Yves Lachkar Giorgio Marchini Frances Meier Gibbons Stefano Miglior Marta Misiuk-Hojo Maria Musolino Jean Philippe Nordmann Norbert Pfeiffer Luis Abegao Pinto Luca Rossetti John Salmon Leo Schmetterer Riccardo Scotto Tarek Shaarawy Ingeborg Stalmans Gordana Sunaric Megevand Ernst Tamm John Thygesen Fotis Topouzis Carlo Enrico Traverso Anja Tuulonen Ananth Viswanathan Thierry Zeyen The Guidelines Task Force Luca Bagnasco Anders Heijl Carlo Enrico Traverso Augusto Azuara Blanco Alessandro Bagnis David Garway Heath Michele Iester Yves Lachkar Ingeborg Stalmans Gordana Sunaric Mégevand Fotis Topouzis Anja Tuulonen Ananth Viswanathan The EGS Executive Committee Carlo Enrico Traverso (President) Anja Tuulonen (Vice President) Roger Hitchings (Past President) Anton Hommer (Treasurer) Barbara Cvenkel Julian Garcia Feijoo David Garway Heath Norbert Pfeiffer Ingeborg Stalmans The Board of the European Glaucoma Society Foundation Roger Hitchings (Chair) Carlo E. Traverso (Vice Chair) Franz Grehn Anders Heijl John Thygesen Fotis Topouzis Thierry Zeyen The EGS Committees CME and Certification Gordana Sunaric Mégevand (Chair) Carlo Enrico Traverso (Co-chair) Delivery of Care Anton Hommer (Chair) EU Action Thierry Zeyen (Chair) Carlo E. Traverso (Co-chair) Education John Thygesen (Chair) Fotis Topouzis (Co-chair) Glaucogene Ananth Viswanathan (Chair) Fotis Topouzis (Co-chair) Industry Liaison Roger Hitchings (Chair) Information Technology Ingeborg Stalmans (Chair) Carlo E. Traverso (Co-chair) National Society Liaison Anders Heijl (Chair) Program Planning Fotis Topouzis (Chair) Ingeborg Stalmans (Co-chair) Quality and Outcomes Anja Tuulonen (Chair) Augusto Azuara Blanco (Co-chair) Scientific Franz Grehn (Chair) David Garway Heath (Co-chair)
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Affiliation(s)
- Alireza Mashaghi
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Jiaxu Hong
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Sunil K Chauhan
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
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Sng CCA, Aquino MCD, Liao J, Zheng C, Ang M, Chew PTK. Anterior segment morphology after acute primary angle closure treatment: a randomised study comparing iridoplasty and medical therapy. Br J Ophthalmol 2015; 100:542-8. [PMID: 26294102 DOI: 10.1136/bjophthalmol-2015-307087] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/26/2015] [Indexed: 11/03/2022]
Abstract
PURPOSE To compare the effect of argon laser peripheral iridoplasty (ALPI) and conventional medical therapy in the immediate treatment of acute primary angle closure (APAC) using anterior segment optical coherence tomography (ASOCT). METHODS In this single tertiary centre, prospective comparative study, we randomised 30 consecutive patients with unilateral APAC into two groups: ALPI and medical treatment (n=15 each). Immediately before and 1 h after either intervention, ASOCT imaging was performed. Custom software was used to measure pupil diameter, anterior chamber depth, iris curvature (I-Curv), iris area (I-Area), and the angle opening distance (AOD750), trabecular iris space area (TISA750) and the iris thickness at 750 µm from the scleral spur. The main outcome measure was the change in anterior segment biometrical parameters. RESULTS The mean age of the patients was 62.8±7.7 years; 13 (43.3%) were male. APAC eyes treated with ALPI had a larger increase in AOD750 (p=0.002) and TISA750 (p=0.006); a smaller increase in I-Area (p=0.004) and a decrease in I-Curv (p=0.001) after treatment compared with those eyes which received medical therapy. An optimal model consisting of age, gender, pretreatment and post-treatment pupil diameter, treatment modality and pretreatment I-Curv explained 53.2% of the variance in AOD750 change after treatment, with the treatment modality accounting for 35.0% and I-Curv accounting for 12.4% of the variability. CONCLUSIONS We observed a greater increase in angle width after ALPI compared with after medical treatment in eyes with APAC. Treatment modality and pretreatment I-Curv were the most significant predictors of angle width change after treatment.
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Affiliation(s)
- Chelvin C A Sng
- Department of Ophthalmology, National University Health System, Singapore, Singapore Singapore Eye Research Institute and Singapore National Eye Centre, Singapore, Singapore
| | | | - Jiemin Liao
- Department of Ophthalmology, National University Health System, Singapore, Singapore
| | - Ce Zheng
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Kowloon, Hong Kong
| | - Marcus Ang
- Singapore Eye Research Institute and Singapore National Eye Centre, Singapore, Singapore
| | - Paul T K Chew
- Department of Ophthalmology, National University Health System, Singapore, Singapore Singapore Eye Research Institute and Singapore National Eye Centre, Singapore, Singapore
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Swain DL, Ho J, Lai J, Gong H. Shorter scleral spur in eyes with primary open-angle glaucoma. Invest Ophthalmol Vis Sci 2015; 56:1638-48. [PMID: 25670488 DOI: 10.1167/iovs.14-15593] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We determined whether the scleral spur is shorter in primary open-angle glaucoma (POAG) eyes compared to age-matched normal eyes and whether the collapse of Schlemm's canal (SC) is more prevalent in eyes with a shorter scleral spur. METHODS The anterior segments of normal (n = 20) and POAG eyes (n = 20) were fixed and processed for light microscopy. The scleral spur length, ratio of posterior trabecular meshwork (TM) insertion into the scleral spur to the posterior TM height, and the percentage of SC collapse were measured. Analysis using an existing mathematical model was conducted to estimate the distances that the scleral spur theoretically would move in vivo and to determine if these distances would be sufficient to keep SC open in POAG compared to normal eyes. RESULTS The mean scleral spur length was significantly shorter in POAG eyes compared to normal eyes (P < 0.0001). A higher mean percentage of SC collapse was found in POAG eyes than in normal eyes (P < 0.0001). Estimated posterior movement of scleral spur in POAG eyes was less than sufficient to prevent the collapse of SC. A significant negative correlation was found between the posterior scleral spur movement and percent collapse of SC (P < 0.0001). CONCLUSIONS A shorter scleral spur found in POAG eyes was associated with a higher percent of SC collapse. Our data suggest that a shorter scleral spur may be a risk factor in the development of POAG by being insufficient to hold SC open.
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Affiliation(s)
- David L Swain
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Joseph Ho
- Department of Ophthalmology, Tufts-New England Eye Center, Boston, Massachusetts, United States
| | - Julia Lai
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States
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Abstract
The use of ocular imaging tools to estimate structural and functional damage in glaucoma has become a common clinical practice and a substantial focus of vision research. The evolution of the imaging technologies through increased scanning speed, penetration depth, image registration and development of multimodal devices has the potential to detect the pathology more reliably and in earlier stages. This review is focused on new ocular imaging modalities used for glaucoma diagnosis.
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Affiliation(s)
- Tigran Kostanyan
- Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Gadi Wollstein
- Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joel S Schuman
- Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, PA, USA
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Abstract
PURPOSE OF REVIEW Recent developments in anterior segment imaging enable high-resolution imaging with higher speeds than previous systems. This review will focus on advances in optical coherence tomography (OCT) imaging of the anterior segment with an emphasis on angle evaluation. RECENT FINDINGS Anterior segment imaging with OCT is possible with both time domain and Fourier domain devices, and with light sources of different wavelengths. Recent studies have identified new risk factors for angle closure and prediction models incorporating quantitative angle width parameters have been developed for detection of gonioscopically defined angle closure. Swept source OCT is a variation of Fourier domain OCT that allows three-dimensional imaging of the angle analogous to gonioscopy and novel quantitative parameters have been described for angle measurement with this technology. Fourier domain OCT devices have higher resolution and sampling density than time domain OCT and enable visualization of more angle structures such as the Schwalbe's line and Schlemm's canal. SUMMARY OCT technology is expanding our understanding of angle closure disease. Although it does not replace gonioscopy in angle evaluation, it may help us identify predictors of progression along the angle closure disease spectrum such that treatment may be better targeted.
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