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Tan SS, Tun TA, Aung T, Nongpiur ME. Comparison of intraocular pressure and anterior segment parameters in subjects with asymmetrical primary angle closure disease. Clin Exp Ophthalmol 2024. [PMID: 38803136 DOI: 10.1111/ceo.14402] [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: 02/04/2024] [Revised: 04/17/2024] [Accepted: 05/11/2024] [Indexed: 05/29/2024]
Abstract
BACKGROUND To compare intraocular pressure (IOP) and anterior segment parameters between eyes with unilateral primary angle closure glaucoma (PACG) and their fellow eyes with primary angle closure (PAC) or primary angle closure suspect (PACS). METHODS Subjects underwent anterior segment imaging using 360-degree swept-source optical coherence tomography (SS-OCT, CASIA Tomey, Nagoya, Japan) and ocular investigations including gonioscopy and IOP measurement. Each SS-OCT scan (divided into 8 frames, 22.5 degrees apart) was analysed and an average was obtained for the following anterior segment parameters: iridotrabecular contact (ITC), angle opening distance (AOD750), iris thickness and curvature, anterior chamber width, depth and area (ACW, ACD and ACA) and lens vault (LV). RESULTS Among 132 unilateral PACG subjects (mean age: 62.91 ± 7.2 years; 59.1% male), eyes with PACG had significantly higher presenting IOP (24.81 ± 0.94 vs. 18.43 ± 0.57 mmHg, p < 0.001), smaller gonioscopic Shaffer grade (2.07 ± 0.07 vs. 2.31 ± 0.07, p < 0.001) and a greater extent of peripheral anterior synechiae (PAS, 1.21 ± 0.21 vs. 0.54 ± 0.16 clock hours, p = 0.001). PACG eyes also exhibited increased ITC, ITC area, greater LV and smaller AOD750, ACD and ACA (all p < 0.05). Using the forward stepwise regression model, an increase in 1 mmHg in presenting IOP before laser peripheral iridotomy (LPI) increases the odds of having PACG by 9% (95% confidence interval 5%-14%). CONCLUSIONS PACG eyes have higher presenting IOP, smaller anterior segment parameters, greater extent of PAS, and larger LV compared to their fellow eyes with angle closure. Narrower anterior chamber dimensions and higher presenting IOP before LPI may increase risk of chronic elevated IOP and glaucomatous optic neuropathy after LPI.
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Affiliation(s)
- Shayne S Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Tin A Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - Monisha E Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
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Yuan Y, Xiong R, Wang W, Xu BY, Liao C, Yang S, Li C, Zhang J, Yin Q, Zheng Y, Friedman DS, Foster PJ, He M. Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect. JAMA Ophthalmol 2024; 142:216-223. [PMID: 38236591 PMCID: PMC10797526 DOI: 10.1001/jamaophthalmol.2023.5286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/26/2023] [Indexed: 01/19/2024]
Abstract
Importance Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. Objective To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). Design, Setting, and Participants This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. Results The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 μm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 μm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 μm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. Conclusions and Relevance This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 μm and light-room ARA at 750 μm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.
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Affiliation(s)
- Yixiong Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Ruilin Xiong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Wei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, China
| | - Benjamin Y. Xu
- Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Chimei Liao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Shaopeng Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Cong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Jian Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Qiuxia Yin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Yingfeng Zheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - David S. Friedman
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston
| | - Paul J. Foster
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom
| | - Mingguang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Experimental Ophthalmology, The Hong Kong Polytechnic University, Hong Kong, China
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Sener H, Gulmez Sevim D, Evereklioglu C, Uludag MT, Gunay Sener AB, Polat OA, Arda H, Horozoglu F. Efficacy and Safety of Different Types of Intraocular Pressure-Lowering Surgeries in Patients with Primary Angle Closure (PAC) or PAC Glaucoma: Systematic Review and Network Meta-Analysis of Randomized Clinical Trials. Semin Ophthalmol 2024; 39:17-26. [PMID: 37296113 DOI: 10.1080/08820538.2023.2223292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 06/12/2023]
Abstract
OBJECTIVE To compare the intraocular pressure (IOP)-lowering effect of different types of surgery available in the literature using a network meta-analysis (NMA) based on a systematic review. METHODS PubMed and the Cochrane database were searched. Randomized clinical trials involving surgical interventions for high IOP for PAC (primary angle closure) or PACG (primary angle closure glaucoma) were included. Descriptive statistics and outcomes were extracted. Bayesian NMA was performed to compare the IOP-lowering effect and the change in the number of antiglaucoma drugs required between baseline and endpoint, as well as success rates. RESULTS This NMA included 21 articles with 1237 eyes with PAC or PACG. Interventions were characterised as phacoemulsification (phaco), trabeculectomy, goniosynechialysis (GSL) with viscoelastic or blunt device, goniosurgery (GS) (trabeculotomy or goniotomy), micro-bypass stent (Istent®), endocyclophotocoagulation (ECPL) or various combinations of these procedures. Phaco+GSL [-1.73 (95%CrI: -3.53 to -0.13)] and phaco+GSL+GS [-3.92 (95%CrI: -6.91 to -1.31)] provided better IOP lowering effects than phaco alone. Phaco+trabeculectomy [-3.11 (95%CrI: -5.82 to -0.44)] was inferior to phaco+GSL+GS. Phaco+trabeculectomy [-0.45 (95%CrI: -0.81 to -0.13)] provided a better outcome in terms of reducing the need for antiglaucoma drug compared to phaco alone. There were no differences between the other surgeries in terms of reduction of antiglaucoma drug number and IOP lowering effect. Success rates were similar for all surgical procedures. CONCLUSIONS Phaco+GSL+GS showed the most promising results for lowering IOP. Phaco+trabeculectomy resulted in a significant reduction in the number of antiglaucoma drugs compared to phaco alone.
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Affiliation(s)
- Hidayet Sener
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Duygu Gulmez Sevim
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Cem Evereklioglu
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Muhammed Taha Uludag
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Ayse Busra Gunay Sener
- Department of Medical Informatics and Biostatistics, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Osman Ahmet Polat
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Hatice Arda
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
| | - Fatih Horozoglu
- Department of Ophthalmology, Division of Surgical and Medical Glaucoma, Erciyes University Medical Faculty, Kayseri, Türkiye
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Hao L, Hu Y, Xu Y, Fu H, Miao H, Zheng C, Liu J. Dynamic analysis of iris changes and a deep learning system for automated angle-closure classification based on AS-OCT videos. EYE AND VISION 2022; 9:41. [PMID: 36333758 PMCID: PMC9636810 DOI: 10.1186/s40662-022-00314-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
Abstract
Background To study the association between dynamic iris change and primary angle-closure disease (PACD) with anterior segment optical coherence tomography (AS-OCT) videos and develop an automated deep learning system for angle-closure screening as well as validate its performance.
Methods A total of 369 AS-OCT videos (19,940 frames)—159 angle-closure subjects and 210 normal controls (two datasets using different AS-OCT capturing devices)—were included. The correlation between iris changes (pupil constriction) and PACD was analyzed based on dynamic clinical parameters (pupil diameter) under the guidance of a senior ophthalmologist. A temporal network was then developed to learn discriminative temporal features from the videos. The datasets were randomly split into training, and test sets and fivefold stratified cross-validation were used to evaluate the performance. Results For dynamic clinical parameter evaluation, the mean velocity of pupil constriction (VPC) was significantly lower in angle-closure eyes (0.470 mm/s) than in normal eyes (0.571 mm/s) (P < 0.001), as was the acceleration of pupil constriction (APC, 3.512 mm/s2vs. 5.256 mm/s2; P < 0.001). For our temporal network, the areas under the curve of the system using AS-OCT images, original AS-OCT videos, and aligned AS-OCT videos were 0.766 (95% CI: 0.610–0.923) vs. 0.820 (95% CI: 0.680–0.961) vs. 0.905 (95% CI: 0.802–1.000) (for Casia dataset) and 0.767 (95% CI: 0.620–0.914) vs. 0.837 (95% CI: 0.713–0.961) vs. 0.919 (95% CI: 0.831–1.000) (for Zeiss dataset). Conclusions The results showed, comparatively, that the iris of angle-closure eyes stretches less in response to illumination than in normal eyes. Furthermore, the dynamic feature of iris motion could assist in angle-closure classification. Supplementary Information The online version contains supplementary material available at 10.1186/s40662-022-00314-1.
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Multiview Volume and Temporal Difference Network for Angle-Closure Glaucoma Screening from AS-OCT Videos. JOURNAL OF HEALTHCARE ENGINEERING 2022. [DOI: 10.1155/2022/2722608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background. Precise and comprehensive characterizations from anterior segment optical coherence tomography (AS-OCT) are of great importance in facilitating the diagnosis of angle-closure glaucoma. Existing automated analysis methods focus on analyzing structural properties identified from the single AS-OCT image, which is limited to comprehensively representing the status of the anterior chamber angle (ACA). Dynamic iris changes are evidenced as a risk factor in primary angle-closure glaucoma. Method. In this work, we focus on detecting the ACA status from AS-OCT videos, which are captured in a dark-bright-dark changing environment. We first propose a multiview volume and temporal difference network (MT-net). Our method integrates the spatial structural information from multiple views of AS-OCT videos and utilizes temporal dynamics of iris regions simultaneously based on image difference. Moreover, to reduce the video jitter caused by eye movement, we employ preprocessing to align the corneal part between video frames. The regions of interest (ROIs) in appearance and dynamics are also automatically detected to intensify the related informative features. Results. In this work, we employ two AS-OCT video datasets captured by two different devices to evaluate the performance, which includes a total of 342 AS-OCT videos. For the Casia dataset, the classification accuracy for our MT-net is 0.866 with a sensitivity of 0.857 and a specificity of 0.875, which achieves superior performance compared with the results of the algorithms based on AS-OCT images with an obvious gap. For the Zeiss AS-OCT video dataset, our method also gets better performance against the methods based on AS-OCT images with a classification accuracy of 0.833, a sensitivity of 0.860, and a specificity of 0.800. Conclusions. The AS-OCT videos captured under changing environments can be a comprehended means for angle-closure classification. The effectiveness of our proposed MT-net is proved by two datasets from different manufacturers
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Association of peripheral anterior synechiae with anterior segment parameters in eyes with primary angle closure glaucoma. Sci Rep 2021; 11:13906. [PMID: 34230538 PMCID: PMC8260708 DOI: 10.1038/s41598-021-93293-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/16/2021] [Indexed: 11/09/2022] Open
Abstract
To investigate the association of peripheral anterior synechiae (PAS) with intraocular pressure (IOP) and anterior-segment parameters in subjects with primary angle-closure glaucoma (PACG). A total of 267 subjects with PACG were recruited and underwent gonioscopy and anterior-segment optical coherence tomography (ASOCT). Customized software was used to measure ASOCT parameters, including angle opening distance (AOD750) and trabecular-iris-space-area (TISA750) at 750 µm from the scleral spur, anterior chamber depth, width, area and volume (ACD, ACW, ACA, ACV), iris thickness (IT750), iris area (IAREA), and lens vault (LV). Presenting IOP was defined as the first IOP reading before the initiation of IOP-lowering treatment. The mean age of the 267 subjects was 67.0 ± 8.9 years, 140 (52.4%) were male, and 246 (92.1%) were of Chinese ethnicity. PAS was present in 122 (45.7%) subjects, and was most frequently found in the superior quadrant (79.5%). Subjects with PAS had greater presenting IOP (28.7 ± 12.9 vs 22.4 ± 9.7 mmHg, p < 0.001), narrower AOD750 (p < 0.001), smaller TISA750 (p < 0.001), ACD (p = 0.04), ACA (p = 0.02), ACV (p = 0.01) and larger LV (p = 0.01) compared to PACG eyes without PAS. No significant differences were noted for iris parameters. A multivariate logistic regression analysis showed that higher presenting IOP (β = 0.20, p < 0.001), worse visual field mean deviation (β = - 0.20, p = 0.01) and narrower AOD750 (β = - 0.25, p = 0.03) were the only parameters that significantly correlated with the extent of PAS in clock hours. Almost one-half of the subjects with PACG demonstrated PAS; these eyes were associated with higher presenting IOP, smaller anterior segment dimensions and more severe disease.
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Dai Y, Zhang S, Shen M, Jin Z, Zhou Y, Ye S, Bao C, Zhu D. Identification of peripheral anterior synechia with anterior segment optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2021; 259:2753-2759. [PMID: 33974133 DOI: 10.1007/s00417-021-05220-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022] Open
Abstract
PURPOSE To generate a model that evaluates the presence and extent of peripheral anterior synechia (PAS) based on anterior segment optical coherence tomography (AS-OCT). METHODS The extent of PAS involvement in the eyes of patients with angle closure was assessed by indentation gonioscopy, and the part of non-PAS and PAS were assigned into two groups (NPAS and PAS). Anterior chamber angles were then imaged by AS-OCT with light-emitting diode (LED) irradiation directly into the pupils, leading to pupillary constriction and increasing anterior chamber angle width. Parameters including the angle opening distance at 750 μm anterior to the scleral spur (AOD750) and trabecular-iris space area at 750 μm anterior to the scleral spur (TISA750) were then obtained. The differences before and after LED irradiation of AOD750 and TISA750 were calculated and used to generate a PAS model based on binary logistic regression. Validation data were then tested. RESULTS A total of 258 AS-OCT images in 14 eyes were assigned to the modeling data, and 120 were assigned to the validation data. There were no differences in AOD750 and TISA750 in the dark between NPAS and PAS (PAOD750 = 0.258, PTISA750 = 0.486), whereas after LED light exposure, TISA750light was larger in NPAS than in PAS (P = 0.047). The light-dark differences of both parameters showed significant differences between the two groups (PAOD750dif = 0.019, PTISA750dif < 0.001). The area under the curve of the model performance was 0.841, and the overall correct rate was 80.8% based on the validation data. CONCLUSIONS The present study demonstrates that the AS-OCT-based PAS model could be useful in the identifying of the presence of synechial angle closure and evaluating the extent of PAS in a single eye.
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Affiliation(s)
- Yingying Dai
- Zhejiang Industry and Trade Vocational College, Wenzhou, Zhejiang, China
| | - Shaodan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zi Jin
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yuheng Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shuling Ye
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chenhong Bao
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Dexi Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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Effect of Phacoemulsification on Drainage Angle Status in Angle Closure Eyes with or without Extensive Peripheral Anterior Synechiae. Eur J Ophthalmol 2018; 23:70 - 79. [DOI: 10.5301/ejo.5000191] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2012] [Indexed: 11/20/2022]
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Porporato N, Baskaran M, Aung T. Role of anterior segment optical coherence tomography in angle-closure disease: a review. Clin Exp Ophthalmol 2017; 46:147-157. [DOI: 10.1111/ceo.13120] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 11/01/2017] [Indexed: 12/01/2022]
Affiliation(s)
- Natalia Porporato
- Singapore Eye Research Institute; Singapore National Eye Centre; Singapore Singapore
| | - Mani Baskaran
- Singapore Eye Research Institute; Singapore National Eye Centre; Singapore Singapore
- Duke-NUS Graduate Medical School; Singapore Singapore
| | - Tin Aung
- Singapore Eye Research Institute; Singapore National Eye Centre; Singapore Singapore
- Duke-NUS Graduate Medical School; Singapore Singapore
- Yong Loo Lin School of Medicine; National University of Singapore; Singapore Singapore
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Quantification of trabecular-iris contact and its prevalence by optical coherence tomography in a healthy Caucasian population. Eur J Ophthalmol 2017; 27:417-422. [PMID: 28009398 DOI: 10.5301/ejo.5000919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2016] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the prevalence of trabecular-iris contact (TIC) and quantify this contact in healthy Caucasian individuals using Fourier-domain optical coherence tomography (FD-OCT). METHODS For this cross-sectional study, 2,012 eyes of 1,006 healthy subjects were recruited among individuals undergoing a routine ophthalmologic checkup. In each participant, age, sex, intraocular pressure, and spherical refractive error were first recorded along with anterior chamber depth and volume, central corneal thickness measured with the Pentacam, and axial length with the IOLMaster. Anterior chamber angle variables and the presence of TIC in the horizontal quadrants were determined by anterior segment FD-OCT (RTVue 100®). When TIC was observed, TIC length (TICL) and its percentage in relation to the length of the trabecular meshwork (TICL percentage) were also measured. RESULTS Trabecular-iris contact in the horizontal quadrants was observed in 34 eyes of 25 patients, representing 1.6% of the total number of eyes examined. In this subgroup of individuals, mean age was 55.8 years, 84% were women, and spherical refractive error ranged from -0.25 to 8.25 D. Eyes with TIC showed an angle width of less than 23.2 degrees and axial length shorter than 23.7 mm. Mean TICL was 239 ± 79 μm (103-495 μm) and mean TICL percentage was 46.9% ± 13.9% (17.2%-76.3%). CONCLUSIONS The prevalence of TIC was low in this population. Fourier-domain optical coherence tomography emerged as useful to assess its prevalence and quantify the extent of TIC.
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Phacoemulsification Versus Combined Phacoemulsification and Viscogonioplasty in Primary Angle-Closure Glaucoma. J Glaucoma 2015; 24:575-82. [DOI: 10.1097/ijg.0000000000000196] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ang M, Chong W, Huang H, Wong TY, He MG, Aung T, Mehta JS. Determinants of posterior corneal biometric measurements in a multi-ethnic Asian population. PLoS One 2014; 9:e101483. [PMID: 25006679 PMCID: PMC4090002 DOI: 10.1371/journal.pone.0101483] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 06/06/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To describe the corneal and anterior segment determinants of posterior corneal arc length (PCAL) and posterior corneal curvature (PCC). METHODS Cross-sectional, population-based study of 1069 subjects (1069 eyes) aged 40-80 years, from three major Asian ethnic groups. All underwent anterior segment optical coherence tomography imaging and analysis with Zhongshan Angle Assessment Program. Our main outcome measures were determinants of PCAL and PCC using adjusted, multivariate linear regression analysis, adjusted for confounders to obtain the estimated marginal means (EMM) with standard error (SE). RESULTS The overall mean (± SD) of PCC was: 6.51±0.39 mm; and PCAL was: 12.52±0.59 mm. Malays had a relatively longer PCAL (EMM = 12.74 mm, SE = 0.04 mm) than Chinese (EMM = 12.48 mm, SE = 0.03 mm, P<0.001), and Indians (EMM = 12.42 mm, SE = 0.03 mm, P<0.001). Anterior segment parameters had weak-moderate correlations with PCAL, which included: anterior chamber depth (ACD) (r = 0.55, P<0.001), PCC (r = 0.27, P<0.001), anterior corneal curvature (ACC) (r = 0.14, P<0.001) and central corneal thickness (CCT) (r = -0.07, P = 0.023). In multivariate analysis, anterior segment parameters explained only 37.6% of the variance of PCAL, with ACD being the most important determinant (partial R2 = 0.300; P<0.001). The determinants of PCC included ACC, PCAL and CCT (explaining 72.1% variation of PCC), with ACC being the most important determinant (partial R2 = 0.683; P<0.001). CONCLUSION There was moderate correlation of PCAL with ACD, but anterior segment parameters accounted for only a small proportion of the variation in PCAL. The significant differences in PCAL and PCC amongst different Asian ethnic groups suggests that there is a need to consider this factor when planning for anterior segment surgeries such as endothelial keratoplasty.
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Affiliation(s)
- Marcus Ang
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - Wesley Chong
- Singapore National Eye Centre, Singapore, Singapore
| | - Huiqi Huang
- Singapore Eye Research Institute, Singapore, Singapore
| | - Tien Yin Wong
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
- Office of Clinical Sciences, Duke- National University of Singapore Graduate Medical School, Singapore, Singapore
| | - Ming-Guang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangzhou, China
| | - Tin Aung
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Office of Clinical Sciences, Duke- National University of Singapore Graduate Medical School, Singapore, Singapore
- * E-mail:
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Sharma R, Sharma A, Arora T, Sharma S, Sobti A, Jha B, Chaturvedi N, Dada T. Application of anterior segment optical coherence tomography in glaucoma. Surv Ophthalmol 2013; 59:311-27. [PMID: 24138894 DOI: 10.1016/j.survophthal.2013.06.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 02/02/2023]
Abstract
Optical coherence tomography (OCT) is a cross-sectional, three-dimensional, high-resolution imaging modality that uses low coherence interferometry to achieve axial resolution in the range of 3-20 μm. Two OCT platforms have been developed: time domain (TD-OCT) and spectral (or Fourier) domain (SD/FD-OCT). Visante anterior segment OCT (Carl Zeiss Meditec) is a TD-OCT widely used for anterior segment imaging. The SD-OCT systems with both posterior and anterior segment imaging capabilities include the RTVue, iVue (Optovue), the Cirrus (Carl Zeiss Meditec), and the Spectralis (Heidelberg Engineering, Inc.). Each of the SD-OCTs has a wavelength in the range of 820-879 nm. Anterior segment OCT is a non-contact method providing high resolution tomographic cross-sectional imaging of anterior segment structures. Anterior segment OCT provides qualitative and quantitative assessment of the anterior segment structures important to the pathogenesis and the anatomical variations of glaucoma, and the approach to and success of treatment. We summarize the clinical applications of anterior segment OCT in glaucoma.
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Affiliation(s)
- Reetika Sharma
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Ajay Sharma
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Tarun Arora
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Sourabh Sharma
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Amit Sobti
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Bhaskar Jha
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Neha Chaturvedi
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Tanuj Dada
- Glaucoma Facility, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
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Smith SD, Singh K, Lin SC, Chen PP, Chen TC, Francis BA, Jampel HD. Evaluation of the Anterior Chamber Angle in Glaucoma. Ophthalmology 2013; 120:1985-97. [DOI: 10.1016/j.ophtha.2013.05.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 01/19/2023] Open
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Ang M, Chong W, Huang H, Tay WT, Wong TY, He MG, Aung T, Mehta JS. Comparison of anterior segment optical tomography parameters measured using a semi-automatic software to standard clinical instruments. PLoS One 2013; 8:e65559. [PMID: 23750265 PMCID: PMC3672133 DOI: 10.1371/journal.pone.0065559] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 04/25/2013] [Indexed: 11/26/2022] Open
Abstract
Objective To compare anterior segment parameters measured using a semi-automatic software (Zhongshan Angle Assessment Program, ZAP) applied to anterior segment optical coherence tomography (AS-OCT) images, with commonly used instruments. Methods Cross-sectional study of a total of 1069 subjects (1069 eyes) from three population-based studies of adults aged 40–80 years. All subjects underwent AS-OCT imaging and ZAP software was applied to determine anterior chamber depth (ACD), central corneal thickness (CCT), anterior and keratometry (K) – readings. These were compared to auto-refraction, keratometry and ocular biometry measured using an IOLMaster, ultrasound pachymeter and auto-refractor respectively. Agreements between AS-OCT (ZAP) and clinical instrument modalities were described using Bland-Altman, 95% limits of agreement (LOA). Results The mean age of our subjects was 56.9±9.5 years and 50.9% were male. The mean AS-OCT (ZAP) parameters of our study cohort were: ACD 3.29±0.35 mm, CCT 560.75±35.07 µm; K-reading 46.79±2.72 D. There was good agreement between the measurements from ZAP analysis and each instrument and no violations in the assumptions of the LOA; albeit with a systematic bias for each comparison: AS-OCT consistently measured a deeper ACD compared to IOLMaster (95% LOA −0.24, 0.55); and a thicker CCT for the AS-OCT compared to ultrasound pachymetry (16.8±0.53 µm 95% LOA −17.3, 50.8). AS-OCT had good agreement with auto-refractor with at least 95% of the measurements within the prediction interval (P value <0.001). Conclusion This study demonstrates that there is good agreement between the measurements from the AS-OCT (ZAP) and conventional tools. However, small systematic biases remain that suggest that these measurement tools may not be interchanged.
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Affiliation(s)
- Marcus Ang
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - Wesley Chong
- Singapore National Eye Centre, Singapore, Singapore
| | - Huiqi Huang
- Singapore Eye Research Institute, Singapore, Singapore
| | - Wan Ting Tay
- Singapore Eye Research Institute, Singapore, Singapore
| | - Tien Yin Wong
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University Health System, Singapore, Singapore
- Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Ming-Guang He
- Singapore Eye Research Institute, Singapore, Singapore
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong, China
| | - Tin Aung
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University Health System, Singapore, Singapore
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, National University Health System, Singapore, Singapore
- Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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Lee RY, Kasuga T, Cui QN, Huang G, He M, Lin SC. Association between baseline angle width and induced angle opening following prophylactic laser peripheral iridotomy. Invest Ophthalmol Vis Sci 2013; 54:3763-70. [PMID: 23661374 DOI: 10.1167/iovs.13-11597] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate the association between baseline angle width and laser peripheral iridotomy (LPI)-induced opening of the anterior chamber angle. METHODS Anterior segment optical coherence tomography images captured before and after LPI were analyzed to determine the angle opening distance at 250 μm (AOD250), 500 μm (AOD500), and 750 μm (AOD750) from the scleral spur; trabecular-iris space area at 500 μm (TISA500) and 750 μm (TISA750) from the scleral spur; angle recess area at 750 μm (ARA750) from the scleral spur; and trabecular-iris angle (TIA). Differences in preoperative and postoperative measurements for the anterior chamber angle width parameters were compared by paired Student's t-tests. Univariate and linear mixed-effects regression models were used to examine the association between baseline and LPI-induced opening of anterior chamber angle width parameters. RESULTS Eighty-four eyes of 52 primary angle closure suspects were included in the analysis. AOD250, AOD500, AOD750, TISA500, TISA750, ARA750, and TIA significantly increased following LPI by paired Student's t-tests (all P < 0.0001). Lower baseline measurements were significantly associated with greater postoperative opening in all anterior chamber angle width parameters in both univariate and linear mixed-effects regression analyses (all P < 0.05). CONCLUSIONS Our results showed significant opening of the anterior chamber angle width after LPI and demonstrated an inverse association between baseline and LPI-induced opening of the anterior chamber angle width, such that eyes with a more crowded anterior chamber angle undergoing LPI had a greater magnitude of increase in anterior chamber angle width after the procedure.
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Affiliation(s)
- Roland Y Lee
- Department of Ophthalmology, University of California, San Francisco, CA 94143-0730, USA
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Anterior chamber angle imaging with swept-source optical coherence tomography: measuring peripheral anterior synechia in glaucoma. Ophthalmology 2013; 120:1144-9. [PMID: 23522970 DOI: 10.1016/j.ophtha.2012.12.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 11/28/2012] [Accepted: 12/04/2012] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To investigate the use of swept-source optical coherence tomography (OCT) for measuring the area and degree of peripheral anterior synechia (PAS) involvement in patients with angle-closure glaucoma. DESIGN Cross-sectional study. PARTICIPANTS Twenty-three eyes with PAS (detected by indentation gonioscopy) from 20 patients with angle-closure glaucoma (20 eyes had primary angle-closure glaucoma and 3 eyes had angle-closure glaucoma secondary to chronic anterior uveitis [n = 2] and Axenfeld-Rieger syndrome [n = 1]). METHODS The anterior chamber angles were evaluated with indentation gonioscopy and imaged by swept-source OCT (Casia OCT, Tomey, Nagoya, Japan) in room light and in the dark using the "angle analysis" protocol, which was composed of 128 radial B-scans each with 512 A-scans (16-mm scan length). The area and degree of PAS involvement were measured in each eye after manual detection of the scleral spur and the anterior irido-angle adhesion by 2 masked observers. The interobserver variability of the PAS measurements was calculated. MAIN OUTCOME MEASURES The agreement of PAS assessment by gonioscopy and OCT, the area and the degree of PAS involvement, and the intraclass correlation coefficient (ICC) of interobserver PAS measurements. RESULTS The area of PAS (mean ± standard deviation) was 20.8 ± 16.9 mm(2) (range, 3.9-74.9 mm(2)), and the degree of PAS involvement was 186.5 ± 79.9 degrees (range, 42-314 degrees). There was no difference in the area of PAS (P = 0.90) and the degree of PAS involvement (P = 0.95) between images obtained in room light and in the dark. The interobserver ICCs were 0.99 (95% confidence interval [CI], 0.98-1.00) for the area of PAS and 0.99 (95% CI, 0.97-1.00) for the degree of PAS involvement. There was good agreement of PAS assessment between gonioscopy and OCT images (kappa = 0.79; 95% CI, 0.67-0.91). CONCLUSIONS Swept-source OCT allows visualization and reproducible measurements of the area and degree of PAS involvement, providing a new paradigm for evaluation of PAS progression and risk assessment for development of angle-closure glaucoma. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Reznicek L, Dabov S, Haritoglou C, Kampik A, Kernt M, Neubauer AS. Green-light fundus autofluorescence in diabetic macular edema. Int J Ophthalmol 2013; 6:75-80. [PMID: 23549658 DOI: 10.3980/j.issn.2222-3959.2013.01.16] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/30/2013] [Indexed: 01/07/2023] Open
Abstract
AIM To evaluate the role of central green-light fundus autofluorescence (FAF) in diabetic macular edema (DME). METHODS A consecutive series of 92 study eyes with diabetic retinopathy were included. Out of those, 51 diabetic eyes had DME and were compared to 41 diabetic eyes without DME. In all subjects, green-light FAF images were obtained, quantified and classified into various FAF patterns. Cross-sectional optical coherence tomography (OCT) scans were obtained for evaluation of Inner/Outer segment (IS/OS) layer integrity, measurements of central RPE-IS/OS layer thickness as well as classification of DME into various subtypes. RESULTS Mean central green-light FAF intensity of eyes with DME (1.289±0.140)log did not significantly differ from diabetic patients without DME (1.317±0.137)log. Most classifiable FAF patterns were seen in patients with cystoid DME. Mean central retinal thickness (CRT) of all study eyes with DME was (501.9±112.4)µm compared to (328.2±27.0)µm in diabetic patients without DME. Patients with DME had significantly more disrupted photoreceptor IS/OS layers than diabetic patients without DME (28/51 vs 5/41, P<0.001). Mean RPE-IS/OS thickness of patients with DME (60.7±14.1)µm was significantly (P<0.001) lower than in diabetic eyes without DME (73.5±9.4)µm. Correlation analys1s revealed non-significant correlations of green-light FAF intensity and OCT parameters in all subtypes of DME. CONCLUSION Our results indicate a poor correlation of central green-light FAF intensity with CRT, IS/OS layer integrity or RPE-IS/OS layer thickness in diabetic patients with or without DME and its various subtypes. Thus, central green-light FAF is not suitable for detection of retinal thickening in DME.
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Affiliation(s)
- Lukas Reznicek
- Department of Ophthalmology, Ludwig Maximilians University, Mathildenstr. 8, Munich 80336, Germany
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Eslami Y, Latifi G, Moghimi S, Ghaffari R, Fakhraie G, Zarei R, Jabbarvand M, Mohammadi M, Lin S. Effect of adjunctive viscogonioplasty on drainage angle status in cataract surgery: a randomized clinical trial. Clin Exp Ophthalmol 2012; 41:368-78. [DOI: 10.1111/j.1442-9071.2012.02871.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/12/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Yadollah Eslami
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Golshan Latifi
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Sasan Moghimi
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Reza Ghaffari
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Ghasem Fakhraie
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Reza Zarei
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Mahmood Jabbarvand
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Massood Mohammadi
- Farabi Eye Research Center; Tehran University of Medical Science; Tehran; Iran
| | - Shan Lin
- Department of Ophthalmology; San Francisco School of Medicine; University of California; San Francisco; California; USA
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Riau AK, Tan NYS, Angunawela RI, Htoon HM, Chaurasia SS, Mehta JS. Reproducibility and age-related changes of ocular parametric measurements in rabbits. BMC Vet Res 2012; 8:138. [PMID: 22901963 PMCID: PMC3514359 DOI: 10.1186/1746-6148-8-138] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/15/2012] [Indexed: 12/02/2022] Open
Abstract
Background The rabbit is a common animal model for ophthalmic research, especially corneal research. Ocular structures grow rapidly during the early stages of life. It is unclear when the rabbit cornea becomes mature and stabilized. We investigated the changes of keratometry, refractive state and central corneal thickness (CCT) with age. In addition, we studied the intra- and inter-observer reproducibility of anterior chamber depth (ACD) and anterior chamber width (ACW) measurements in rabbits using anterior segment-optical coherence tomography (AS-OCT). Results The growth of New Zealand White rabbits (n = 16) were monitored from age 1 to 12 months old. Corneal keratometric and refractive values were obtained using an autorefractor/keratometer, and CCT was measured using an AS-OCT. Keratometry and CCT changed rapidly from 1 to 7 months and appeared to be stabilizing after 8 months. The reduction of corneal curvature was approximately 1.36 diopter (D)/month from age 1 to 7 months, but the change decelerated to 0.30 D/month from age 8 to 12 months. An increase of 10 μm/month in CCT was observed from age 1 to 7 months, but the gain was reduced to less than 1 μm/month from age 8 to 12 months. There was a hyperopic shift over the span of 12 months, albeit the increase in spherical equivalent was slow and gradual. Rabbits of random age were then selected for 2 repeated ACD and ACW measurements by 2 independent and masked observers. Bland-Altman plots revealed a good agreement of ACD and ACW measurements inter- and intra-observer and the ranges of 95% limit of agreement were acceptable from a clinical perspective. Conclusions Corneal keratometry, spherical equivalent refraction and CCT changed significantly during the first few months of life of rabbits. Young rabbits have been used in a large number of eye research studies. In certain settings, the ocular parametric changes are an important aspect to note as they may alter the findings made in a rabbit experimental model. In this study, we have also demonstrated for the first time a good between observer reproducibility of measurements of ocular parameters in an animal model by using an AS-OCT.
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Affiliation(s)
- Andri K Riau
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
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Tan GS, He M, Tan DT, Mehta JS. Correlation of anterior segment optical coherence tomography measurements with graft trephine diameter following descemet stripping automated endothelial keratoplasty. BMC Med Imaging 2012; 12:19. [PMID: 22824516 PMCID: PMC3431259 DOI: 10.1186/1471-2342-12-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 07/05/2012] [Indexed: 11/27/2022] Open
Abstract
Background To assess repeatability of the Zhongshan Assessment Program (ZAP) software measurement of Anterior Segment Optical Coherence Tomography (ASOCT) images and correlate with graft trephine diameter following Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) Methods Retrospectively evaluated interventional case series. 121 consecutive eyes undergoing DSAEK over a 26 month period underwent ASOCT imaging 1month after their surgery. ASOCT images were processed using ZAP software which measured the graft and cornea parameters including anterior and posterior graft arc length and cord length, posterior cornea arc length (PCAL) and anterior chamber width. Results The graft measurements showed good repeatability on ASOCT using ZAP with high intra class coefficient and small variation in the coefficient of variation. On ASOCT, the mean recipient PCAL was 12.99+/−0.69mm and the anterior chamber width was 11.16+/−0.57mm. The mean Graft anterior arc length was 9.69+/−0.66mm and the mean Graft anterior cord length was 8.92+/−2.94mm. The mean graft posterior arc length was 9.24+/−0.75mm and the mean graft posterior cord length was 8.15+/−0.57mm. Graft posterior arc length (rho=0.788, p< 0.001) correlated best with intra-operative graft trephine diameter. The mean ratio of posterior graft arc length to PCAL was 0.712 +/− 0.056. Conclusions We have validated the repeatability of the ZAP software for DSAEK graft measurements from ASOCT images and shown that the graft arc length parameters calculated from the ASOCT images correlate well with the intra-operative graft trephine diameter. This software may help surgeons determine the optimal DSAEK graft size based on pre-operative ASOCT measurements of the recipient eye.
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Affiliation(s)
- Gavin S Tan
- Singapore National Eye Centre (SNEC), 11 Third Hospital Avenue, Singapore, 168751, Singapore
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Deokule S, Alencar L, Vizzeri G, Medeiros F, Weinreb RN. Comparison of Unenhanced and Enhanced Imaging Protocols for Angle Measurements With Anterior Segment Optical Coherence Tomography. Ophthalmic Surg Lasers Imaging Retina 2012; 43:39-44. [DOI: 10.3928/15428877-20111027-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 09/23/2011] [Indexed: 11/20/2022]
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Hall RC, Mohamed FK, Htoon HM, Tan DT, Mehta JS. Laser in situ keratomileusis flap measurements: Comparison between observers and between spectral-domain and time-domain anterior segment optical coherence tomography. J Cataract Refract Surg 2011; 37:544-51. [PMID: 21333877 DOI: 10.1016/j.jcrs.2010.10.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 08/31/2010] [Accepted: 10/05/2010] [Indexed: 11/19/2022]
Affiliation(s)
- Reece C Hall
- Singapore National Eye Centre, National University of Singapore, Singapore
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Diurnal intraocular pressure fluctuation and associated risk factors in eyes with angle closure. Ophthalmology 2009; 116:2300-4. [PMID: 19850348 DOI: 10.1016/j.ophtha.2009.06.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/04/2009] [Accepted: 06/08/2009] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To investigate diurnal intraocular pressure (IOP) fluctuation in eyes with angle closure in comparison with normal subjects and to look for associated risk factors for IOP fluctuation. DESIGN Prospective, cross-sectional study. PARTICIPANTS Ninety-eight eyes of 98 Asian subjects with angle closure (consisting of 32 primary angle-closure suspects [PACS], 34 subjects with primary angle closure [PAC], and 32 subjects with primary angle-closure glaucoma [PACG]) and 21 eyes of 21 normal control subjects. METHODS All angle-closure subjects were enrolled after laser peripheral iridotomy but before commencement of any medical or surgical treatment. Ophthalmic examination, including dynamic gonioscopy and automated perimetry, were performed, and diurnal IOP measurements were obtained using noncontact air-puff tonometry at hourly intervals between 8:00 am and 5:00 pm. Mean diurnal IOP, peak diurnal IOP, trough IOP, and IOP fluctuation (peak IOP-trough IOP) were compared between groups. Multiple linear regression analysis was performed to study the association of IOP fluctuation with clinical variables such as age, extent of peripheral anterior synechiae (PAS), central corneal thickness, vertical cup-to-disc ratio, and pattern standard deviation (PSD) on automated perimetry. MAIN OUTCOME MEASURES Mean diurnal IOP, peak IOP, and IOP fluctuation. RESULTS Most subjects were Chinese (89.1%) and female (61.3%). Intraocular pressure fluctuation was significantly higher in PACG (5.4+/-2.4 mmHg) and PAC (4.5+/-2.3 mmHg) subjects compared with PACS subjects (3.7+/-1.2 mmHg) and normal controls (3.8+/-1.1 mmHg; P = 0.005), with highest IOP found in the early morning. The combined PACG and PAC group had more than twice the risk (odds ratio, 2.38; 95% confidence interval, 1.1-5.1; P = 0.025) of having IOP fluctuation of more than 3 mmHg compared with the combined PACS and normal group. Extent of PAS (Pearson's correlation coefficient, r = 0.37; P = 0.0001) and visual field PSD (r = 0.34; P = 0.0002) were found to be associated with greater IOP fluctuation. CONCLUSIONS The PACG and PAC eyes showed diurnal IOP fluctuation of 4 to 5 mmHg, and this fluctuation was higher than in PACS subjects and normal controls. The degree of PAS and visual field loss were associated with IOP fluctuation in PAC and PACG eyes.
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