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Glaucoma: HELP
Articles by Nicholas G. Strouthidis
Based on 27 articles published since 2008
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Between 2008 and 2019, N. Strouthidis wrote the following 27 articles about Glaucoma.
 
+ Citations + Abstracts
Pages: 1 · 2
1 Editorial Neuroprotection and other novel therapies for glaucoma. 2013

Nucci, Carlo / Strouthidis, Nicholas G / Khaw, Peng Tee. · ·Curr Opin Pharmacol · Pubmed #23142029.

ABSTRACT: -- No abstract --

2 Review Translating ocular biomechanics into clinical practice: current state and future prospects. 2015

Girard, Michaël J A / Dupps, William J / Baskaran, Mani / Scarcelli, Giuliano / Yun, Seok H / Quigley, Harry A / Sigal, Ian A / Strouthidis, Nicholas G. ·In Vivo Biomechanics Laboratory, Department of Biomedical Engineering, National University of Singapore , Singapore . ·Curr Eye Res · Pubmed #24832392.

ABSTRACT: Biomechanics is the study of the relationship between forces and function in living organisms and is thought to play a critical role in a significant number of ophthalmic disorders. This is not surprising, as the eye is a pressure vessel that requires a delicate balance of forces to maintain its homeostasis. Over the past few decades, basic science research in ophthalmology mostly confirmed that ocular biomechanics could explain in part the mechanisms involved in almost all major ophthalmic disorders such as optic nerve head neuropathies, angle closure, ametropia, presbyopia, cataract, corneal pathologies, retinal detachment and macular degeneration. Translational biomechanics in ophthalmology, however, is still in its infancy. It is believed that its use could make significant advances in diagnosis and treatment. Several translational biomechanics strategies are already emerging, such as corneal stiffening for the treatment of keratoconus, and more are likely to follow. This review aims to cultivate the idea that biomechanics plays a major role in ophthalmology and that the clinical translation, lead by collaborative teams of clinicians and biomedical engineers, will benefit our patients. Specifically, recent advances and future prospects in corneal, iris, trabecular meshwork, crystalline lens, scleral and lamina cribrosa biomechanics are discussed.

3 Review Recent advances in OCT imaging of the lamina cribrosa. 2014

Sigal, Ian A / Wang, Bo / Strouthidis, Nicholas G / Akagi, Tadamichi / Girard, Michael J A. ·Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. · NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore. · Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore In vivo Biomechanics Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore. ·Br J Ophthalmol · Pubmed #24934221.

ABSTRACT: The lamina cribrosa (LC) is believed to be the site of injury to retinal ganglion cell axons in glaucoma. The ability to visualise this structure has the potential to help increase our understanding of the disease and be useful in the early detection of glaucoma. While for many years the research on the LC was essentially dependent on histology and modelling, a number of recent advances in optical coherence tomography (OCT) have dramatically improved the ability to visualise the LC, such that it is now possible to image the LC in vivo in humans and animals. In this review, we highlight recent advances in OCT imaging of the LC, in the technology, processing and analysis, and discuss the impact that these will have on the ability to diagnose and monitor glaucoma, as well as to expand our understanding of its pathophysiology. With this manuscript, we aspire to share our excitement on the achievements and potential of recent developments as well as advise caution regarding the challenges that remain before imaging of the LC and optic nerve can be used routinely in clinical practice.

4 Review Teleglaucoma: ready to go? 2014

Strouthidis, N G / Chandrasekharan, G / Diamond, J P / Murdoch, I E. ·NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK Singapore Eye Research Institute, Singapore, Singapore. · Institute of Ophthalmology, London, UK. · Bristol Eye Hospital, Bristol, UK. ·Br J Ophthalmol · Pubmed #24723617.

ABSTRACT: Telemedicine technologies and services allow today's ophthalmic clinicians to remotely diagnose, manage and monitor several ophthalmic conditions from a distance. But is this the case for glaucomas? There has been a proliferation of telemedicine friendly devices in recent years that improves the capabilities of the clinician in managing glaucomas. The existing instruments still need to align themselves with accepted industry standards. There are successful programmes running in several areas of the world. The safety and efficacy of these programmes needs further exploration. The inability of a single device or test to diagnose glaucomas satisfactorily has also hampered progress in remotely diagnosing these conditions. There is, however, significant potential for telemedicine-friendly devices to remotely monitor the progress of glaucoma and, thereby, reduce some of the workload on an overstretched health service.

5 Review Imaging of the lamina cribrosa in glaucoma: perspectives of pathogenesis and clinical applications. 2013

Kim, Tae-Woo / Kagemann, Larry / Girard, Michaël J A / Strouthidis, Nicholas G / Sung, Kyung Rim / Leung, Christopher K / Schuman, Joel S / Wollstein, Gadi. ·Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea. ·Curr Eye Res · Pubmed #23768229.

ABSTRACT: The lamina cribrosa (LC) is a sieve-like structure in the sclera where retinal ganglion cell axons exit from the eye. The LC has been known to play a critical role in the pathogenesis of glaucoma. With the advent of imaging technologies, such as enhanced depth imaging, spectral-domain optical coherence tomography (OCT) enables us to unveil the LC in vivo features. The application of adaptive optics technology and a compensatory image-processing algorithm has further improved the visualization of the beams and pores and neural pathways of the LC and the scleral insertion sites. Monitoring the changes of these structures in relation to acute and chronic elevation of intraocular pressure would be germane to decipher the relationship between the stress and strain response of the LC and optic nerve damage and improve our understanding of glaucoma pathophysiology. While the impact of investigating the integrity of LC is substantive, considerable challenges remain for imaging the LC. Nevertheless, with the rapid development of the OCT technology, it is expected that some of these limitations can be overcome and the potentials of LC imaging will be unraveled.

6 Review Altering the way the optic nerve head responds to intraocular pressure-a potential approach to glaucoma therapy. 2013

Strouthidis, Nicholas G / Girard, Michael J A. ·NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, EC1 V 2PD, UK. nick.strouthidis@moorfields.nhs.uk ·Curr Opin Pharmacol · Pubmed #22999652.

ABSTRACT: Over the past decade, engineering principles have been used to explain why a mechanical load, intraocular pressure, can lead to the development of glaucomatous optic neuropathy. This has led to the 'biomechanical theory' of glaucoma, which posits that the behavior of optic nerve head connective tissues (specifically within the peripapillary sclera and lamina cribrosa) in response to intraocular pressure (regardless of its magnitude) can directly and indirectly influence the physiology and pathophysiology of the optic nerve head. Given that the biomechanics of the sclera and lamina cribrosa probably influence retinal ganglion cell loss in glaucoma, the idea that altering biomechanical behavior might be protective against glaucoma is an appealing notion. There is some evidence to suggest that stiffening the peripapillary sclera may be protective against the development of glaucoma in an animal model. It is technically possible to stiffen the sclera in vivo using collagen cross-linking techniques already applied in vivo to the cornea in the treatment of keratoconus. It has yet to be established whether scleral cross-linking is safe in humans and that it confers anything more than a theoretical advantage in terms of reducing the risk of glaucomatous damage.

7 Review New developments in Heidelberg retina tomograph for glaucoma. 2008

Strouthidis, Nicholas G / Garway-Heath, David F. ·Glaucoma Research Unit, Moorfields Eye Hospital and UCL Institute of Ophthalmology NIHR Biomedical Research Centre, London, UK. ·Curr Opin Ophthalmol · Pubmed #18301288.

ABSTRACT: PURPOSE OF REVIEW: Provides an update on research on Heidelberg retina tomograph (HRT) imaging of the optic nerve head in glaucoma. Particular reference is made to work assessing recently introduced software developments. RECENT FINDINGS: Three main areas of investigation are covered: new developments in the third major revision of the HRT operational software (HRT-3), HRT's ability to correctly classify glaucomatous optic neuropathy, and HRT's role in monitoring disease progression. The software now incorporates a larger normative database of white patients as well as new ethnic-specific databases. The main classification tools in the new software are the Moorfields regression analysis and Glaucoma Probability Score. The performance of these classification systems is influenced by the new normative databases. A number of HRT rim area progression strategies has been proposed. These appear to complement visual field progression analyses, identifying a largely different subset of progressing patients. HRT measurement variability has recently been better characterized, and promising methods of improving measurement repeatability have been described. SUMMARY: The HRT is a promising tool for monitoring patients with, or at risk of, glaucoma, although the relationship between progressive structural and visual field change has yet to be fully elucidated. Each refinement to the instrument software requires evaluation to establish whether it constitutes an improvement in our ability to manage patients.

8 Article In Vivo Three-Dimensional Lamina Cribrosa Strains in Healthy, Ocular Hypertensive, and Glaucoma Eyes Following Acute Intraocular Pressure Elevation. 2018

Beotra, Meghna R / Wang, Xiaofei / Tun, Tin A / Zhang, Liang / Baskaran, Mani / Aung, Tin / Strouthidis, Nicholas G / Girard, Michaël J A. ·Ophthalmic Engineering & Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · Duke-NUS Medical School, Singapore. · Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. · NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom. · Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, New South Wales, Australia. ·Invest Ophthalmol Vis Sci · Pubmed #29340640.

ABSTRACT: Purpose: To compare in vivo lamina cribrosa (LC) strains (deformations) following acute IOP elevation in healthy, glaucoma, and ocular hypertensive subjects. Methods: There were 20 healthy, 20 high-tension primary open-angle glaucoma (POAG), 16 primary angle-closure glaucoma (PACG), and 20 ocular hypertensive (OHT; with normal visual fields) eyes studied. For each test eye, the optic nerve head was imaged three times (at baseline IOP, following an acute elevation of IOP to approximately 35 then 45 mm Hg using an ophthalmodynamomter) using optical coherence tomography (OCT). A three-dimensional (3D) strain-mapping algorithm was applied to both sets of baseline and IOP-elevated OCT volumes to extract IOP-induced 3D strains. Octant-wise LC strains were also extracted to study the pattern of local deformation. Results: The average LC strain in OHT subjects (3.96%) was significantly lower than that measured in healthy subjects (6.81%; P < 0.05). On average, POAG subjects experienced higher strain than the PACG subjects (4.05%), healthy subjects experienced higher strains than the POAG and PACG subjects, but these difference were not statistically significant. Local LC deformations showed lowest strain in the infero-temporal and temporal octant in the POAG and OHT subjects. Conclusions: We demonstrate measurable LC strains in vivo in humans as a response to acute IOP elevation. In this population, our data suggest that OHT LCs experience lower IOP-induced strains than healthy LCs.

9 Article A Deep Learning Approach to Digitally Stain Optical Coherence Tomography Images of the Optic Nerve Head. 2018

Devalla, Sripad Krishna / Chin, Khai Sing / Mari, Jean-Martial / Tun, Tin A / Strouthidis, Nicholas G / Aung, Tin / Thiéry, Alexandre H / Girard, Michaël J A. ·Ophthalmic Engineering and Innovation Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore. · Department of Statistics and Applied Probability, National University of Singapore, Singapore. · GePaSud, Université de la Polynésie Française, Tahiti, French Polynesia. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom. · Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, New South Wales, Australia. · Yong Loo Lin School of Medicine, National University of Singapore, Singapore. ·Invest Ophthalmol Vis Sci · Pubmed #29313052.

ABSTRACT: Purpose: To develop a deep learning approach to digitally stain optical coherence tomography (OCT) images of the optic nerve head (ONH). Methods: A horizontal B-scan was acquired through the center of the ONH using OCT (Spectralis) for one eye of each of 100 subjects (40 healthy and 60 glaucoma). All images were enhanced using adaptive compensation. A custom deep learning network was then designed and trained with the compensated images to digitally stain (i.e., highlight) six tissue layers of the ONH. The accuracy of our algorithm was assessed (against manual segmentations) using the dice coefficient, sensitivity, specificity, intersection over union (IU), and accuracy. We studied the effect of compensation, number of training images, and performance comparison between glaucoma and healthy subjects. Results: For images it had not yet assessed, our algorithm was able to digitally stain the retinal nerve fiber layer + prelamina, the RPE, all other retinal layers, the choroid, and the peripapillary sclera and lamina cribrosa. For all tissues, the dice coefficient, sensitivity, specificity, IU, and accuracy (mean) were 0.84 ± 0.03, 0.92 ± 0.03, 0.99 ± 0.00, 0.89 ± 0.03, and 0.94 ± 0.02, respectively. Our algorithm performed significantly better when compensated images were used for training (P < 0.001). Besides offering a good reliability, digital staining also performed well on OCT images of both glaucoma and healthy individuals. Conclusions: Our deep learning algorithm can simultaneously stain the neural and connective tissues of the ONH, offering a framework to automatically measure multiple key structural parameters of the ONH that may be critical to improve glaucoma management.

10 Article Effect of acute intraocular pressure elevation on the minimum rim width in normal, ocular hypertensive and glaucoma eyes. 2018

Sharma, Sourabh / Tun, Tin A / Baskaran, Mani / Atalay, Eray / Thakku, Sri Gowtham / Liang, Zhang / Milea, Dan / Strouthidis, Nicholas G / Aung, Tin / Girard, Michael Ja. ·Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore. · Ophthalmic Engineering & Innovation Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore. · Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore. · NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore. · NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK. · Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia. · Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. ·Br J Ophthalmol · Pubmed #28490427.

ABSTRACT: BACKGROUND: To estimate and compare changes in the Bruch's membrane opening-minimum rim width (BMO-MRW) and area in normal, ocular hypertensive and glaucoma eyes following acute elevations in intraocular pressure (IOP). METHODS: The optic nerve heads (ONHs) of 104 subjects (31 normals, 20 ocular hypertension (OHT) and 53 with primary glaucoma) were imaged using Spectral-domain optical coherence tomography (OCT; Spectralis, Heidelberg Engineering, Germany). IOP was raised twice by applying a force (0.64 n then 0.9 n) to the anterior sclera using an ophthalmo-dynamometer. After each IOP increment, IOP was held constant, measured with a Tonopen (AVIA applanation tonometer, Reichert, Depew, New York, USA), and ONH was rescanned with OCT. In each OCT volume, BMO-MRW and area were calculated and at each IOP increment. RESULTS: The baseline MRW was significantly smaller in glaucoma subjects (174.3±54.3 µm) compared with normal (287.4±42.2 µm, p<0.001) and OHT subjects (255.4±45.3 µm, p<0.001). MRW of glaucoma subjects was significantly thinner at the first and second IOP elevations than that at baseline (both p<0.01), but no significant change was noted in normal and OHT subjects. There was no significant change of BMO area at acute IOP elevations from baseline in all diagnoses (all p>0.05). CONCLUSION: Acute IOP elevation leads to compression of the nerve fibre layers of neuroretinal rim in glaucoma subjects only without changing ONH size. This suggests that the neural and connective tissues at ONH level in glaucoma subjects are more susceptible to acute IOP episodes than OHT or normal controls.

11 Article In Vivo 3-Dimensional Strain Mapping of the Optic Nerve Head Following Intraocular Pressure Lowering by Trabeculectomy. 2016

Girard, Michaël J A / Beotra, Meghna R / Chin, Khai Sing / Sandhu, Amanjeet / Clemo, Monica / Nikita, Eleni / Kamal, Deborah S / Papadopoulos, Maria / Mari, Jean Martial / Aung, Tin / Strouthidis, Nicholas G. ·Ophthalmic Engineering & Innovation Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. Electronic address: mgirard@nus.edu.sg. · Ophthalmic Engineering & Innovation Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore. · NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom. · Université de la Polynésie française, Tahiti, French Polynesia. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom; Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia. ·Ophthalmology · Pubmed #26992836.

ABSTRACT: PURPOSE: To map the 3-dimensional (3D) strain of the optic nerve head (ONH) in vivo after intraocular pressure (IOP) lowering by trabeculectomy (TE) and to establish associations between ONH strain and retinal sensitivity. DESIGN: Observational case series. PARTICIPANTS: Nine patients with primary open-angle glaucoma (POAG) and 3 normal controls. METHODS: The ONHs of 9 subjects with POAG (pre-TE IOP: 25.3±13.9 mmHg; post-TE IOP: 11.8±8.6 mmHg) were imaged (1 eye per subject) using optical coherence tomography (OCT) (Heidelberg Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany) before (<21 days) and after (<50 days) TE. The imaging protocol was repeated for 3 controls in whom IOP was not altered. In each post-TE OCT volume, 4 tissues were manually segmented (prelamina, choroid, sclera, and lamina cribrosa [LC]). For each ONH, a 3D tracking algorithm was applied to both post- and pre-TE OCT volumes to extract IOP-induced 3D displacements at segmented nodes. Displacements were filtered, smoothed, and processed to extract 3D strain relief (the amount of tissue deformation relieved after TE). Strain relief was compared with measures of retinal sensitivity from visual field testing. MAIN OUTCOME MEASURES: Three-dimensional ONH displacements and strain relief. RESULTS: On average, strain relief (averaged or effective component) in the glaucoma ONHs (8.6%) due to TE was higher than that measured in the normal controls (1.07%). We found no associations between the magnitude of IOP decrease and the LC strain relief (P > 0.05), suggesting biomechanical variability across subjects. The LC displaced posteriorly, anteriorly, or not at all. Furthermore, we found linear associations between retinal sensitivity and LC effective strain relief (P < 0.001; high strain relief associated with low retinal sensitivity). CONCLUSIONS: We demonstrate that ONH displacements and strains can be measured in vivo and that TE can relieve ONH strains. Our data suggest a wide variability in ONH biomechanics in the subjects examined in this study. We further demonstrate associations between LC effective strain relief and retinal sensitivity.

12 Article Trabeculectomy for normal tension glaucoma: outcomes using the Moorfields Safer Surgery technique. 2016

Jayaram, Hari / Strouthidis, Nicholas G / Kamal, Deborah S. ·Glaucoma Service, Moorfields Eye Hospital, London, UK NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK Casey Eye Institute, Portland, Oregon, USA. · Glaucoma Service, Moorfields Eye Hospital, London, UK NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK Singapore Eye Research Institute, Singapore, Singapore Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, New South Wales, Australia. · Glaucoma Service, Moorfields Eye Hospital, London, UK. ·Br J Ophthalmol · Pubmed #26198279.

ABSTRACT: AIMS: To evaluate long-term outcomes and complications of trabeculectomy for normal tension glaucoma (NTG) with contemporary surgical techniques. METHODS: Retrospective consecutive, non-comparative case series of 131 eyes of 98 patients undergoing trabeculectomy between 2007 and 2013 in a dedicated NTG clinic. Data collected during routine clinical care were analysed. Assessment of clinical outcomes included intraocular pressure (IOP) reduction, bleb function, final visual acuity, evidence of glaucoma progression, postoperative complications and further surgical intervention. Surgical failure was defined as a failure to meet specified IOP-related criteria, the need to undergo further glaucoma surgery for raised IOP or loss of light perception vision. A further analysis was also performed which considered failure as glaucoma progression following surgery. Outcomes were evaluated using Kaplan-Meier life-table analysis. RESULTS: The cumulative percentages of unqualified success as defined by a ≥30% reduction of IOP from baseline preoperative maximum (95% CI; IOP of all eyes: mean±SD) at 1, 2, 3 and 4 years after surgery were 91.1% (84.1% to 95.1%; 9.7±2.9 mm Hg), 74.1% (63.7% to 81.8%; 10.3±3.0 mm Hg), 64.8% (52.7% to 74.6%; 10.6±2.5 mm Hg) and 62.1% (49.3% to 72.6%; 10.2±2.1 mm Hg), respectively. At 2 years of follow-up there was no significant association between either previous cataract surgery or ethnicity and failure. Cumulative percentages of unqualified success at 4 years after surgery as defined by a filtering trabeculectomy bleb or absence of glaucoma progression were 91.6% (83.2% to 95.9%) and 92.3% (81.3% to 97.0%), respectively. Postoperative complications such as early (2.3%) and late (0.8%) hypotony were significantly lower than suggested by the current literature. CONCLUSIONS: Trabeculectomy in NTG patients undertaken using contemporary surgical techniques and intensive postoperative management is associated with more successful long-term outcomes and fewer complications than the currently available literature suggests.

13 Article Retinal and optic nerve changes in glaucoma: From animal study to clinical implication. 2015

Chew, Shenton S L / Martins, Alessandra / Strouthidis, Nicholas. ·NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK. · Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia; Sydney Eye Hospital, Sydney, NSW, Australia. · NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK; Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia; Singapore Eye Research Institute, Singapore, Singapore. Electronic address: nick.strouthidis@moorfields.nhs.uk. ·Prog Brain Res · Pubmed #26497790.

ABSTRACT: Animal models of experimental glaucoma provide the ability to longitudinally characterize changes in the optic nerve head and surrounding retinal nerve fiber layer with various imaging modalities and compare them to histomorphometric changes. Analysis of the optic nerve head surface by confocal scanning laser tomography and structures deep to this by spectral domain optical coherence tomography allow for the detection of the earliest structural changes seen in glaucoma. Algorithms utilizing these parameters along with retinal nerve fiber layer measurement are likely to play an important role in the future of glaucoma progression monitoring.

14 Article Measures of socioeconomic status and self-reported glaucoma in the U.K. Biobank cohort. 2015

Shweikh, Y / Ko, F / Chan, M P Y / Patel, P J / Muthy, Z / Khaw, P T / Yip, J / Strouthidis, N / Foster, P J / Anonymous6890840. ·Division of Genetics and Epidemiology, NIHR Biomedical Research Centre, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK. · Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK. · Singapore Eye Research Institute, Singapore, Singapore. · Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, NSW, Australia. ·Eye (Lond) · Pubmed #26315700.

ABSTRACT: PURPOSE: To determine ocular, demographic, and socioeconomic associations with self-reported glaucoma in the U.K. Biobank. METHODS: Biobank is a study of U.K. residents aged 40-69 years registered with the National Health Service. Data were collected on visual acuity, intraocular pressure (IOP), corneal biomechanics, and questionnaire from 112,690 participants. Relationships between ocular, demographic, and socioeconomic variables with reported diagnosis of glaucoma were examined. RESULTS: In all, 1916 (1.7%) people in U.K. Biobank reported glaucoma diagnosis. Participants reporting glaucoma were more likely to be older (mean 61.4 vs. 56.7 years, P<0.001) and male (2.1% vs. 1.4%, P=0.001). The rate of reported glaucoma was significantly higher in Black (3.28%, P<0.001) and Asian (2.14%, P=0.009) participants compared with White participants (1.62%, reference). Cases of reported glaucoma had a higher mean IOP (18 mm Hg both eyes, P<0.001), lower corneal hysteresis (9.96 right eye, 9.89 left eye, P<0.001), and lower visual acuity (0.09 logMAR right eye, 0.08 logMAR left eye, P<0.001) compared with those without (16 mm Hg both eyes, hysteresis 10.67 right eye, 10.63 left eye, 0.03 logMAR right eye, 0.02 logMAR left eye). The mean Townsend deprivation index was -0.72 for those reporting glaucoma and -0.95 for those without (P<0.001), indicating greater relative deprivation in those reporting glaucoma. Multivariable logistic regression showed that people in the lowest income group (<£18,000/year) were significantly more likely to report a diagnosis of glaucoma compared with any other income level (P<0.01). We observed increasing glaucoma risk across the full range of income categories, with highest risk among those of lowest income, and no evidence of a threshold effect. CONCLUSIONS: In a large U.K. cohort, individuals reporting glaucoma had more adverse socioeconomic characteristics. Study of the mechanisms explaining these effects may aid our understanding of health inequality and will help inform public health interventions.

15 Article Long-Term Outcomes of Trabeculectomy Augmented with Mitomycin C Undertaken within the First 2 Years of Life. 2015

Jayaram, Hari / Scawn, Richard / Pooley, Francisco / Chiang, Mark / Bunce, Catey / Strouthidis, Nicholas G / Khaw, Peng Tee / Papadopoulos, Maria. ·Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom; Casey Eye Institute, Oregon Health & Science University, Portland, Oregon. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; Glaucoma Department, Fundación Oftalmológica Los Andes, Santiago, Chile. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom; Glaucoma Department, Queensland Eye Institute and City Eye Centre, Brisbane, Australia. · National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom; London School of Hygiene & Tropical Medicine, London, United Kingdom. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom; Singapore Eye Research Institute, Singapore, Republic of Singapore; Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, Australia. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom. · Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom; National Institute of Health Research Biomedical Research Centre for Ophthalmology, University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom. Electronic address: maria.papadopoulos@moorfields.nhs.uk. ·Ophthalmology · Pubmed #26315044.

ABSTRACT: PURPOSE: To evaluate the long-term effectiveness and safety of mitomycin C (MMC)-augmented trabeculectomy undertaken within the first 2 years of life for the surgical management of glaucoma. DESIGN: Retrospective, consecutive, noncomparative case series. PARTICIPANTS: All children who underwent MMC-augmented trabeculectomy within 2 years of birth between May 2002 and November 2012. METHODS: The medical records of 40 consecutive eyes of 26 children who underwent surgery by a single surgeon were reviewed. Data collected during routine clinical care were analyzed. MAIN OUTCOME MEASURES: Assessment of clinical outcomes included intraocular pressure (IOP), final visual acuity, bleb morphology, surgical complications (early and late), postoperative interventions, and further glaucoma surgery performed. Surgical success was defined as final IOP of 5 mmHg or more and of 21 mmHg or less, with anti-glaucoma medications (qualified success) and without (complete success), stable ocular dimensions and optic disc cupping, and no further glaucoma surgery (including needling) or loss of light perception. Surgical outcomes were evaluated using Kaplan-Meier life table analysis. RESULTS: Forty eyes of 26 children were studied over a mean follow-up period of 62.8 months. Most cases (80%) were of primary congenital glaucoma after failed goniotomy surgery. Cumulative probabilities of survival at 1, 5, and 7 years were 78%, 67%, and 60%, respectively. Of eyes regarded as successful, 96% (25/26 eyes) had controlled IOP without topical medication and 44% achieved visual acuity of 20/40 or better. In only 1 of the 40 eyes did a cystic avascular bleb develop, with all the other eyes being non-cystic in nature (diffuse and elevated or flat) at final follow-up. Sixty-four percent (9/14 eyes) of cases regarded as failures ultimately underwent glaucoma drainage device implantation. CONCLUSIONS: A contemporary pediatric trabeculectomy technique augmented with MMC is an effective procedure in the management of glaucoma within the first 2 years of life, as shown by the successful long-term outcomes and low incidence of sight-threatening complications. Trabeculectomy after failed goniotomy surgery or as a primary surgical intervention may offer a phakic infant with glaucoma an excellent opportunity to achieve long-term control of IOP without medications and may be associated with optimal visual outcomes.

16 Article A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes. 2015

Thakku, Sri Gowtham / Tham, Yih-Chung / Baskaran, Mani / Mari, Jean-Martial / Strouthidis, Nicholas G / Aung, Tin / Cheng, Ching-Yu / Girard, Michael J A. ·Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3Duke-National University of Singapore Graduate Medical School, Singapore. · University of French Polynesia, Tahiti, French Polynesia. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 5National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital National Health Service Foundation Trust & University College London Institute of Ophtha. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 7Department of Biomedical Engineering, National University of Singapore, Singapore. ·Invest Ophthalmol Vis Sci · Pubmed #26047047.

ABSTRACT: PURPOSE: Lamina cribrosa (LC) morphology could be implicated in the progression of glaucoma. To date, no established, quantifiable parameter to assess LC shape in vivo exists. We aim to introduce a new global shape index for the anterior LC (LC-GSI) and to identify associations with ocular factors in a healthy Indian population. METHODS: Optical coherence tomography (OCT) scans of the optic nerve head (ONH) were performed on 162 healthy subjects. Optic nerve head structures were delineated and a geometric characterization of anterior LC morphology was obtained by measuring curvature along 180 LC cross sections and representing it as LC-GSI ranging from -1 to +1. Lamina cribrosa depth and curvature were also reported. Linear regression was used to identify factors associated with LC morphology. RESULTS: The typical healthy LC had a saddle rut-like appearance, with a central ridge visible in superior-inferior cross sections. A more prominent central ridge (larger LC-GSI) was associated with shorter axial length (P < 0.001), smaller Bruch's membrane opening (BMO) area (P = 0.020), smaller vertical cup-to-disc ratio (VCDR) (P = 0.007), and larger minimum rim width (BMO-MRW) (P = 0.001). A deeper LC was associated with male sex (P < 0.001), shorter axial length (P = 0.003), larger VCDR (P < 0.001), and smaller BMO-MRW (P = 0.002). Age and IOP were not significantly associated with LC morphology in healthy eyes. CONCLUSIONS: The LC-GSI is a single index that quantifies overall LC shape in an intuitive way. Ocular determinants of LC-GSI in healthy eyes included risk factors for glaucoma (axial length, VCDR, and BMO-MRW), highlighting the potential role of LC morphological characterization in the diagnosis and monitoring of glaucoma.

17 Article Lamina cribrosa visibility using optical coherence tomography: comparison of devices and effects of image enhancement techniques. 2015

Girard, Michaël J A / Tun, Tin A / Husain, Rahat / Acharyya, Sanchalika / Haaland, Benjamin A / Wei, Xin / Mari, Jean M / Perera, Shamira A / Baskaran, Mani / Aung, Tin / Strouthidis, Nicholas G. ·In Vivo Biomechanics Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore. · Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore. · Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore Department of Statistics and Applied Probability, National University of Singapore, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore. · Department of Medical Physics and Bioengineering, UCL, London, United Kingdom. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore. · Singapore Eye Research Institute, Singapore National Eye Centre, Singapore NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, New South Wales, Australia. ·Invest Ophthalmol Vis Sci · Pubmed #25593025.

ABSTRACT: PURPOSE: To compare the visibility of the lamina cribrosa (LC) in optic disc images acquired from 60 glaucoma and 60 control subjects using three optical coherence tomography (OCT) devices, with and without enhanced depth imaging (EDI) and adaptive compensation (AC). METHODS: A horizontal B-scan was acquired through the center of the disc using two spectral-domain (Spectralis and Cirrus; with and without EDI) and a swept-source (DRI) OCT. Adaptive compensation was applied post acquisition to improve image quality. To assess LC visibility, four masked observers graded the 1200 images in a randomized sequence. The anterior LC was graded from 0 to 4, the LC insertions from 0 to 2, and the posterior LC either 0 or 1. The effect of EDI, AC, glaucoma severity, and other clinical/demographic factors on LC visibility was assessed using generalized estimating equations. RESULTS: The anterior LC was the most detectable feature, followed by the LC insertions. Adaptive compensation improved anterior LC visibility independent of EDI. Cirrus+EDI+AC generated the greatest anterior LC visibility grades (2.79/4). For LC insertions visibility, DRI+AC was the best method (1.10/2). Visibility of the posterior LC was consistently poor. Neither glaucoma severity nor clinical/demographic factors consistently affected LC visibility. CONCLUSIONS: Adaptive compensation is superior to EDI in improving LC visibility. Visibility of the posterior LC remains poor suggesting impracticality in using LC thickness as a glaucoma biomarker.

18 Article Age-related differences in longitudinal structural change by spectral-domain optical coherence tomography in early experimental glaucoma. 2014

Yang, Hongli / He, Lin / Gardiner, Stuart K / Reynaud, Juan / Williams, Galen / Hardin, Christy / Strouthidis, Nicholas G / Downs, J Crawford / Fortune, Brad / Burgoyne, Claude F. ·Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Health, Portland, Oregon, United States Discoveries in Sight Research Laboratories of the Devers Eye Institute, Legacy Health, Portland, Oregon, United States. · Discoveries in Sight Research Laboratories of the Devers Eye Institute, Legacy Health, Portland, Oregon, United States. · National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital National Health Service Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom. · Ocular Biomechanics and Biotransport Program, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States. ·Invest Ophthalmol Vis Sci · Pubmed #25190652.

ABSTRACT: PURPOSE: To characterize age-related differences in the magnitude of spectral-domain optical coherence tomography (SD-OCT) structural change in early experimental glaucoma (EG). METHODS: Both eyes from four young (1.4-2.6 years) and four old (18.6-21.9 years) rhesus monkeys were imaged at least three times at baseline, and then every 2 weeks after laser-induced, chronic, unilateral IOP elevation until the onset of EG (confocal scanning laser tomographic surface change confirmed twice). Two to 20 weeks after EG onset, animals were euthanized and optic nerve axon counts for all eyes were performed. Masked operators delineated retinal and ONH landmarks in 40 radial B-scans from each eye and imaging session to quantify change from baseline in five SD-OCT neural and connective tissue parameters. The effects of EG, age, and EG × age interactions on the magnitude, rate (magnitude per postlaser time), and IOP responsiveness (magnitude per cumulative IOP insult) of postlaser parameter change were individually assessed using general estimating equation models. RESULTS: Presac SD-OCT RNFLT and minimum rim width change and postmortem axon loss was not significantly different in old compared with young EG eyes. The rate of change and IOP responsiveness of the parameters anterior lamina cribrosa surface depth relative to Bruch's membrane opening (BMO) and BMO depth relative to peripheral Bruch's membrane were significantly lower (P < 0.05) in the old compared with the young EG eyes. CONCLUSIONS: At similar postlaser times, levels of cumulative IOP insult and axonal damage, SD-OCT-detected ONH connective tissue structural change is greater in young compared with old monkey EG eyes.

19 Article Longitudinal detection of optic nerve head changes by spectral domain optical coherence tomography in early experimental glaucoma. 2014

He, Lin / Yang, Hongli / Gardiner, Stuart K / Williams, Galen / Hardin, Christy / Strouthidis, Nicholas G / Fortune, Brad / Burgoyne, Claude F. ·Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Health, Portland, Oregon. ·Invest Ophthalmol Vis Sci · Pubmed #24255047.

ABSTRACT: PURPOSE: We determined if the detection of spectral-domain optical coherence tomography (SDOCT) optic nerve head (ONH) change precedes the detection of confocal scanning laser tomography (CSLT) ONH surface, SDOCT retinal nerve fiber layer (RNFL), scanning laser perimetry (SLP), and multifocal electroretinography (mfERG) change in eight experimental glaucoma (EG) eyes. METHODS: Both eyes from eight monkeys were tested at least three times at baseline, and then every 2 weeks following laser-induced chronic unilateral IOP elevation. Event and trend-based definitions of onset in the control and EG eyes for 11 SDOCT neural and connective tissue, CSLT surface, SDOCT RNFL, SLP, and mfERG parameters were explored. The frequency and timing of onset for each parameter were compared using a logrank test. RESULTS: Maximum post-laser IOP was 18 to 42 mm Hg in the EG eyes and 12 to 20 mm Hg in the control eyes. For event- and trend-based analyses, onsets were achieved earliest and most frequently within the ONH neural and connective tissues using SDOCT, and at the ONH surface using CSLT. SDOCT ONH neural and connective tissue parameter change preceded or coincided with CSLT ONH surface change in most EG eyes. The SDOCT and SLP measures of RNFL thickness, and mfERG measures of visual function demonstrated similar onset rates, but occurred later than SDOCT ONH and CSLT surface change, and in fewer eyes. CONCLUSIONS: SDOCT ONH change detection commonly precedes or coincides with CSLT ONH surface change detection, and consistently precedes RNFLT, SLP, and mfERG change detection in monkey experimental glaucoma.

20 Article Relationship between ganglion cell-inner plexiform layer and optic disc/retinal nerve fibre layer parameters in non-glaucomatous eyes. 2013

Tham, Yih-Chung / Cheung, Carol Y / Koh, Victor T / Cheng, Ching-Yu / Sidhartha, Elizabeth / Strouthidis, Nicholas G / Wong, Tien Y / Aung, Tin. ·Singapore Eye Research Institute, Singapore National Eye Centre, , Singapore, Singapore. ·Br J Ophthalmol · Pubmed #24123901.

ABSTRACT: AIMS: To determine the relationship between macular ganglion cell-inner plexiform layer (GC-IPL) thickness and optic disc/retinal nerve fibre layer (RNFL) parameters in non-glaucomatous eyes measured by spectral-domain optical coherence tomography (SD-OCT). METHODS: 491 non-glaucomatous Chinese aged 40-80 years were recruited from a population-based study and underwent standardised ophthalmic examination. SD-OCT was used to measure GC-IPL thickness, optic disc parameters and RNFL thickness. Univariate and multiple linear regression analyses were performed to assess the association between GC-IPL and optic disc/RNFL parameters. RESULTS: In univariate analyses, all RNFL parameters and rim area were significantly correlated with all macular GC-IPL parameters (p<0.001, r=0.12-0.56). In multiple regression analyses, after adjusting for age, gender, disc area, signal strength and axial length, average RNFL thickness (per µm decrease) was most strongly correlated with average GC-IPL thickness (β=-0.30, standardised β=-0.499, p<0.001) compared with other optic disc/RNFL parameters. CONCLUSIONS: Our study demonstrated only fair correlations between macular GC-IPL and optic disc/RNFL parameters measured by SD-OCT. This information is important for further evaluation of macular GC-IPL thickness as an additional marker in detecting glaucomatous damage and progression.

21 Article Comparison of neuroretinal rim area measurements made by the Heidelberg Retina Tomograph I and the Heidelberg Retina Tomograph II. 2013

Wang, Ya Xing / O'Leary, Neil / Strouthidis, Nicholas G / White, Edward T / Ho, Tuan A / Garway-Heath, David F. ·*NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology ‡Department of Optometry and Visual Science, City University London, London, UK †Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China §Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada. ·J Glaucoma · Pubmed #22576170.

ABSTRACT: PURPOSE: To investigate the agreement between neuroretinal rim area (RA) measurements using the Heidelberg Retina Tomograph I (HRT Classic) and Heidelberg Retina Tomograph II (HRT II). To compare apparent RA changes in follow-up series of HRT II topographies when using either an HRT Classic or HRT II mean topography as baseline. DESIGN: Cross-sectional study and "no-change," short time series study. PARTICIPANTS: Forty-three ocular hypertensive and 31 primary open angle glaucoma subjects. METHODS: Five HRT Classic and 5 HRT II examinations were acquired from 1 eye of each subject, across 2 visits within 6 weeks. For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline. The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies. Intervals between topographies were arbitrarily set at 1 year for meaningful comparisons of rates. Rates of RA change over time were calculated by linear regression. Separate analyses were performed using 3 available reference planes (RP). MAIN OUTCOME MEASURES: Global and sectoral RA measurements in HRT Classic and HRT II mean topographies; linear rates of RA change. RESULTS: HRT Classic minus HRT II mean differences (95% limits of agreement) were 0.09 (-0.17, 0.35) mm, 0.09 (-0.13, 0.32) mm, and 0.11 (-0.24, 0.46) mm for the Moorfields, 320 µm, and standard RPs, respectively (P<0.001 for all RPs, Wilcoxon rank sum test). In the time series, the mean differences (95% limits of agreement) of RA rates of change (HRT Classic baseline minus HRT II baseline) were -0.01 (-0.06, 0.03) mm/y, -0.01 (-0.06, 0.04) mm/y, and -0.0 (-0.09, 0.05) mm/y using the Moorfields, 320 µm, and standard RPs, respectively. CONCLUSION: Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

22 Article Spectral-domain optical coherence tomography enhanced depth imaging of the normal and glaucomatous nonhuman primate optic nerve head. 2012

Yang, Hongli / Qi, Jingjing / Hardin, Christy / Gardiner, Stuart K / Strouthidis, Nicholas G / Fortune, Brad / Burgoyne, Claude F. ·Devers Eye Institute, Portland, Oregon, USA. ·Invest Ophthalmol Vis Sci · Pubmed #22159003.

ABSTRACT: PURPOSE: To test whether the enhanced depth imaging (EDI) modality improves anterior and posterior lamina cribrosa surface (ALCS and PLCS) visibility compared with conventional spectral-domain optical coherence tomography (SD-OCT). METHODS: Conventional and EDI SD-OCT scans were obtained 30 minutes after IOP was manometrically lowered to 10 mm Hg in both eyes of 14 nonhuman primates (NHPs) with unilateral experimental glaucoma (EG). Thirteen horizontal and seven vertical radial B-scans of each SD-OCT data set were delineated by one operator masked to image type. Delineated ALCS and PLCS points were projected to 1 of 100 equal-sized subregions of the neural canal opening (NCO) reference plane, and the number of delineated subregions (≥2 points) was counted. Poisson regression was used to analyze the effects of image type, treatment, and quadrant. Two additional delineations were performed for three NHPs to compare reproducibility. RESULTS: EDI increased the number of subregions delineated for both the ALCS (by 28%; P < 0.0001) and PLCS (by 225%; P < 0.0001). EDI improvement in ALCS visibility was significant in the superior quadrant only and was not different in EG versus control eyes, whereas EDI improvement in PLCS visibility was significant in all four quadrants (P < 0.005) and greater in EG eyes (P < 0.001), nasally and temporally. Intradelineator reproducibility was not different between image types. EDI and standard ONH parameter values were similar except for PLCS depth which was deeper in the EDI data sets (P = 0.0002). CONCLUSIONS: ALCS and PLCS visibility within control and EG NHP ONHs increased in EDI compared to conventional SD-OCT data sets. Further study of EDI effects on PLCS parameterization is required.

23 Article Longitudinal change detected by spectral domain optical coherence tomography in the optic nerve head and peripapillary retina in experimental glaucoma. 2011

Strouthidis, Nicholas G / Fortune, Brad / Yang, Hongli / Sigal, Ian A / Burgoyne, Claude F. ·Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Health System, Portland, OR 97208-3950, USA. ·Invest Ophthalmol Vis Sci · Pubmed #21217108.

ABSTRACT: PURPOSE: To investigate whether longitudinal changes deep within the optic nerve head (ONH) are detectable by spectral domain optical coherence tomography (SDOCT) in experimental glaucoma (EG) and whether these changes are detectable at the onset of Heidelberg Retina Tomography (HRT; Heidelberg Engineering, Heidelberg, Germany)-defined surface topography depression. METHODS: Longitudinal SDOCT imaging (Spectralis; Heidelberg Engineering) was performed in both eyes of nine rhesus macaques every 1 to 3 weeks. One eye of each underwent trabecular laser-induced IOP elevation. Four masked operators delineated internal limiting membrane (ILM), retinal nerve fiber layer (RNFL), Bruch's membrane/retinal pigment epithelium (BM/RPE), neural canal opening (NCO), and anterior lamina cribrosa surface (ALCS) by using custom software. Longitudinal changes were assessed and compared between the EG and control (nonlasered) eyes at the onset of HRT-detected surface depression (follow-up 1; [FU1]) and at the most recent image (follow-up 2; [FU2]). RESULTS: Mean IOP in EG eyes was 7.1 to 24.6 mm Hg at FU1 and 13.5 to 31.9 mm Hg at FU2. In control eyes, the mean IOP was 7.2 to 12.6 mm Hg (FU1) and 8.9 to 16.0 mm Hg (FU2). At FU1, neuroretinal rim decreased and ALCS depth increased significantly (paired t-test, P < 0.01); no change in RNFL thickness was detected. At FU2, however, significant prelaminar tissue thinning, posterior displacement of NCO, and RNFL thinning were observed. CONCLUSIONS: Longitudinal SDOCT imaging can detect deep ONH changes in EG eyes, the earliest of which are present at the onset of HRT-detected ONH surface height depression. These parameters represent realistic targets for SDOCT detection of glaucomatous progression in human subjects.

24 Article The Heidelberg retina tomograph Glaucoma Probability Score: reproducibility and measurement of progression. 2010

Strouthidis, Nicholas G / Demirel, Shaban / Asaoka, Ryo / Cossio-Zuniga, Claudio / Garway-Heath, David F. ·NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom. nicholas.strouthidis@btinternet.com ·Ophthalmology · Pubmed #20045564.

ABSTRACT: PURPOSE: To evaluate the reproducibility of the Heidelberg retina tomograph (HRT) Glaucoma Probability Score (GPS) and assess its potential for monitoring progression. DESIGN: Evaluation of diagnostic tests in a randomized, controlled clinical trial. PARTICIPANTS: For reproducibility, we included 43 ocular hypertensive (OHT) and 31 glaucoma subjects. For progression, we included 198 OHT and 21 control subjects. METHODS: To study reproducibility, global GPS values were generated for HRT images acquired in a test-retest study. Images were acquired at 2 visits within 6 weeks of each other, by 2 different observers. To study progression, GPS values were generated for HRT images acquired prospectively (1993-2001). Linear regression of GPS against time was performed, with progression defined as a significant negative slope (P<0.05). Criterion specificity was estimated from the number of improving subjects (significant positive slope) and the number of progressing controls. Visual field (VF) progression in the same subjects was assessed using 3-omitting pointwise linear regression of sensitivity over time. MAIN OUTCOME MEASURES: Reproducibility of GPS was assessed using Bland-Altman analysis (mean difference, 95% limits of agreement). Progression was assessed by the number of OHT subjects identified as progressing, and by agreement with VF progression. RESULTS: Reproducibility of GPS was better at its extremes (-0.01+/-0.20 for GPS 0-0.30, and 0.02+/-0.09 for GPS 0.78-1.00) than in its mid range (0.07+/-0.54 for GPS 0.30-0.78). Estimated criterion specificity ranged from 95.2% (95% confidence interval, 76.1%-99.9%) to 96.8% (93.2%-98.5%). Twenty-five OHT subjects (12.6%) progressed by GPS, with 11 of the 25 (5.6%) also progressing by VF; 26 subjects (13.1%) progressed by VF alone. CONCLUSIONS: Changes in HRT GPS values between 0.30 and 0.78 should be interpreted with caution because the index has poorer reproducibility in this range. The global GPS progression algorithm performs at least as well as previously described rim area-based HRT progression strategies. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

25 Article Predicting progression to glaucoma in ocular hypertensive patients. 2010

Strouthidis, Nicholas G / Gardiner, Stuart K / Owen, Victoria M F / Zuniga, Claudio / Garway-Heath, David F. ·Glaucoma Research Unit, NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust, UCL Institute of Ophthalmology, London, UK. ·J Glaucoma · Pubmed #19730117.

ABSTRACT: PURPOSE: To assess the ability of Heidelberg Retina Tomograph (HRT) Moorfields Regression Analysis (MRA) and Glaucoma Probability Score (GPS) classifications at baseline to predict glaucomatous progression in ocular hypertensive eyes. METHODS: One hundred ninety-eight ocular hypertensive subjects underwent regular HRT and visual field (VF) testing from 1993 to 2001. HRT progression was assessed using linear regression of rim area/time. VF progression was assessed by pointwise linear regression of sensitivity/time. Subjects were classified as progressing or stable at the end of the study period. The relationship between baseline abnormal (outside normal limits combined with borderline classification) MRA and GPS classification and progression status was assessed by odds ratios (ORs). RESULTS: An abnormal superotemporal MRA was the only classification found to be predictive of HRT progression in isolation (OR 3.05, 1.25-7.47). Abnormal global, superotemporal, superonasal, and temporal MRA classifications were all associated with significant ORs for predicting HRT or VF progression (OR range: 1.77-2.54). Abnormal GPS classifications were not predictive of disease behavior. Combined abnormal GPS and MRA classifications were associated with higher ORs than either classification in isolation. CONCLUSIONS: Patients with an abnormal MRA and GPS classification at presentation may be at increased risk of HRT or VF change.

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