306 results on '"Fred K Chen"'
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2. Perspectives of people with inherited retinal diseases on ocular gene therapy in Australia: protocol for a national survey
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Fred K Chen, Alex W Hewitt, Alan Ma, John Grigg, Keith R Martin, Robyn Jamieson, Heather G Mack, Fleur O’Hare, David Mackey, John De Roach, Alexis Ceecee Britten-Jones, Myra McGuinness, Nicole Tindill, Lauren Ayton, Anai Gonzalez Cordero, Thomas L Edwards, Gladys Ho, Michael Hogden, Anthony Kwan, Tina Lamey, Terri McLaren, Benjamin Nash, Jon Ruddle, Matthew Simunovic, Ingrid Sinnerbrink, Deepa Ajay Taranath, Jen Thompson, and Jaclyn White
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Medicine - Abstract
Introduction Voretigene neparvovec-rzyl (Luxturna) was approved by the Australian Therapeutic Goods Administration on 4 August 2020 for the treatment of biallelic mutations in the RPE65 gene, a rare cause of congenital and adult-onset retinal dystrophy (predominantly Leber congenital amaurosis). Previous studies have shown that individuals who might participate in gene therapy trials overestimate clinical effect and underestimate risks. However, little is known about the perspectives of patients who may be offered approved gene therapy treatment for ocular conditions (as distinct from participating in clinical trials of gene therapy). The main objective of this study is to develop a tool to assess knowledge, attitudes and perceptions of approved and future genetic therapies among potential recipients of ocular gene therapy. In addition, we aim to assess the quality of life, attitudes towards clinical trials and vision-related quality of life among this cohort.Methods and analysis A new ‘Attitudes to Gene Therapy for the Eye’ tool will be developed following consultation with people with inherited retinal disease (IRD) and content matter experts. Australians with IRD or their guardians will be asked to complete an internet-based survey comprising existing quality of life and visual function instruments and items for the newly proposed tool. We expect to recruit 500 survey participants from patient support groups, the practices of Australian ophthalmologists who are specialists in IRD and Australian ophthalmic research institutions. Launch is anticipated early 2021. Responses will be analysed using item response theory methodology.Ethics and dissemination This study has received ethics approval from the University of Melbourne (#2057534). The results of the study will be published in a peer-reviewed journal and will be presented at relevant conferences. Organisations involved in recruitment, and the Patient Engagement Advisory committee will assist the research team with dissemination of the study outcomes.
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- 2021
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3. Rationale and protocol for the 7- and 8-year longitudinal assessments of eye health in a cohort of young adults in the Raine Study
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Seyhan Yazar, Robyn M Lucas, Mingguang He, Jeremy A Guggenheim, Jason Charng, Christopher Hammond, Gareth Lingham, Paul G Sanfilippo, Fred K Chen, Alex W Hewitt, Fletcher Ng, Leon M Straker, Peter R Eastwood, Kathryn A Rose, Seang-Mei Saw, and Minas T Coroneo
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Medicine - Abstract
Introduction Eye diseases and visual impairment more commonly affect elderly adults, thus, the majority of ophthalmic cohort studies have focused on older adults. Cohort studies on the ocular health of younger adults, on the other hand, have been few. The Raine Study is a longitudinal study that has been following a cohort since their birth in 1989–1991. As part of the 20-year follow-up of the Raine Study, participants underwent a comprehensive eye examination. As part of the 27- and 28-year follow-ups, eye assessments are being conducted and the data collected will be compared with those of the 20-year follow-up. This will provide an estimate of population incidence and updated prevalence of ocular conditions such as myopia and keratoconus, as well as longitudinal change in ocular parameters in young Australian adults. Additionally, the data will allow exploration of the environmental, health and genetic factors underlying inter-subject differential long-term ocular changes.Methods and analysis Participants are being contacted via telephone, email and/or social media and invited to participate in the eye examination. At the 27-year follow-up, participants completed a follow-up eye screening, which assessed visual acuity, autorefraction, ocular biometry and ocular sun exposure. Currently, at the 28-year follow-up, a comprehensive eye examination is being conducted which, in addition to all the eye tests performed at the 27-year follow-up visit, includes tonometry, optical coherence tomography, funduscopy and anterior segment topography, among others. Outcome measures include the incidence of refractive error and pterygium, an updated prevalence of these conditions, and the 8-year change in ocular parameters.Ethics and dissemination The Raine Study is registered in the Australian New Zealand Clinical Trials Registry. The Gen2 20-year, 27-year and 28-year follow-ups are approved by the Human Research Ethics Committee of the University of Western Australia. Findings resulting from the study will be published in health or medical journals and presented at conferences.Trial registration number ACTRN12617001599369; Active, not recruiting.
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- 2020
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4. Repeatability of retinal thickness and volume metrics in neovascular age-related macular degeneration using the topcon 3doct-1000
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Vikas Tah, Pearce A Keane, Simona Degli Esposti, Joseph Allimuthu, Fred K Chen, Lyndon Da Cruz, Adnan Tufail, and Praveen J Patel
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Glaucoma ,pressure-to-cornea index ,visual field ,Combined trabeculectomy ,glaucoma tube shunt surgery ,long-term results ,ocular perfusion pressure ,open-angle glaucoma ,systemic hypertension ,Anterior stromal opacities ,femtosecond anterior lamellar keratoplasty ,spectral domain optical coherence tomography ,Anesthesia ,cataract ,phacoemulsification ,randomized control trail ,Cataract ,intraocular lens ,optical low-coherence reflectometry ,partial coherence interferometry ,Corneal blindness ,community eye banking ,keratoplasty ,Corneal deposits ,in vivo confocal microscopy ,monoclonal gammopathy of undetermined significance ,multiple myeloma ,Imaging ,optical coherence tomography ,neovascular age-related macular degeneration ,Ophthalmology ,RE1-994 - Abstract
Introduction: Optical coherence tomography (OCT) is a commonly used imaging modality that provides detailed cross-sectional retinal images. This has revolutionised management of neovascular age-related macular degeneration. The need for repeated anti-vascular endothelial growth factor injections has led to therapy being delivered using OCT-guided retreatment strategies with both qualitative OCT features of disease activity (e.g. macular fluid) and changes in retinal thickness as triggers for retreatment The purpose of this study is to determine the intra-session repeatability of retinal thickness and volume measurements using the Topcon 3DOCT-1000 spectral-domain optical coherence tomography (SDOCT) device in patients with neovascular age-related macular degeneration (nAMD). This is the largest study to date looking specifically at the Topcon 3DOCT-1000. Materials and Methods: Two SDOCT raster scans were performed by the same blinded observer in the same sitting in consecutive patients attending for nAMD treatment as part of standard validation of a new device. Retrospective analysis was undertaken, with retinal thickness and volume measurements automatically calculated by the onboard software for each Early Treatment of Diabetic Retinopathy Study subfield for each scan. Bland-Altman methods of analysis were used to assess repeatability. Results: Data from the 73 patients were analyzed with a mean age of 78 years (standard deviation 8). The 95% coefficient of repeatability (CR) was 64 μm and 0.050 mm 3 for retinal thickness and volume respectively in the central 1 mm macular subfield. The CR did not exceed 85 μm (0.30 mm 3 ) in any subfield. The revised CR for retinal thickness and volume for the subgroup of 37 patients with no segmentation error in the central 1 mm subfield was 53 μm and 0.050 mm 3 respectively. Discussion : We report relatively modest intra-sessional repeatability of SDOCT retinal thickness and volume metrics in patients with nAMD in a clinical setting. Though useful in detecting clinical change from measurement variability in clinical practice, these results suggest the precision of macular thickness measurement does not approach the theoretical resolution of SDOCT.
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- 2014
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5. Initial clinical experience of ranibizumab therapy for neovascular age-related macular degeneration
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Tryfon Rotsos, Praveen J Patel, Fred K Chen, and et al
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Ophthalmology ,RE1-994 - Abstract
Tryfon Rotsos, Praveen J Patel, Fred K Chen, Adnan TufailMedical Retina Service, Moorfields Eye Hospital, London, UKPurpose: To describe the visual acuity and safety outcomes for the first 50 patients with neovascular age-related macular degeneration (nAMD) treated with ranibizumab at Moorfields Eye Hospital.Methods: A retrospective analysis of case notes from the first 50 consecutive patients with Primary Care Trust funding for ranibizumab therapy for nAMD. Visual acuity outcomes and adverse events were noted, as were service delivery-related indicators.Results: The mean (±standard deviation) age of the 50 patients was 81 ± 17 years. The mean follow-up of patients was 13.6 ± 2 (range 7.7–18) months. The mean change in visual acuity ± standard error was +4.6 ± 2.2 letters at the end of follow-up, with 26% gaining 15 letters or more. The mean (median) number of injections was 4.7 (4.5) per 12-month period. The mean (median) delay in Primary Care Trust funding approval was 35 days (32 days) prior to the final appraisal document from the National Institute of Health and Clinical Excellence.Conclusions: The real-world outcomes of ranibizumab therapy in this initial cohort of patients with nAMD are comparable with those reported in the pivotal, randomized, controlled trials using fewer injections and a prn strategy of retreatment to achieve the gain in visual acuity.Keywords: macular degeneration, retina, ranibizumab
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- 2010
6. Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging.
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Danuta M Sampson, David Alonso-Caneiro, Avenell L Chew, Tina Lamey, Terri McLaren, John De Roach, and Fred K Chen
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Medicine ,Science - Abstract
To present en face optical coherence tomography (OCT) images generated by graph-search theory algorithm-based custom software and examine correlation with other imaging modalities.En face OCT images derived from high density OCT volumetric scans of 3 healthy subjects and 4 patients using a custom algorithm (graph-search theory) and commercial software (Heidelberg Eye Explorer software (Heidelberg Engineering)) were compared and correlated with near infrared reflectance, fundus autofluorescence, adaptive optics flood-illumination ophthalmoscopy (AO-FIO) and microperimetry.Commercial software was unable to generate accurate en face OCT images in eyes with retinal pigment epithelium (RPE) pathology due to segmentation error at the level of Bruch's membrane (BM). Accurate segmentation of the basal RPE and BM was achieved using custom software. The en face OCT images from eyes with isolated interdigitation or ellipsoid zone pathology were of similar quality between custom software and Heidelberg Eye Explorer software in the absence of any other significant outer retinal pathology. En face OCT images demonstrated angioid streaks, lesions of acute macular neuroretinopathy, hydroxychloroquine toxicity and Bietti crystalline deposits that correlated with other imaging modalities.Graph-search theory algorithm helps to overcome the limitations of outer retinal segmentation inaccuracies in commercial software. En face OCT images can provide detailed topography of the reflectivity within a specific layer of the retina which correlates with other forms of fundus imaging. Our results highlight the need for standardization of image reflectivity to facilitate quantification of en face OCT images and longitudinal analysis.
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- 2016
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7. mRNA transfection of mouse and human neural stem cell cultures.
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Samuel McLenachan, Dan Zhang, Ana Belén Alvarez Palomo, Michael J Edel, and Fred K Chen
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Medicine ,Science - Abstract
The use of synthetic mRNA as an alternative gene delivery vector to traditional DNA-based constructs provides an effective method for inducing transient gene expression in cell cultures without genetic modification. Delivery of mRNA has been proposed as a safer alternative to viral vectors in the induction of pluripotent cells for regenerative therapies. Although mRNA transfection of fibroblasts, dendritic and embryonic stem cells has been described, mRNA delivery to neurosphere cultures has not been previously reported. Here we sought to establish an efficient method for delivering mRNA to primary neurosphere cultures. Neurospheres derived from the subventricular zone of adult mice or from human embryonic stem cells were transfected with EGFP mRNA by lipofection and electroporation. Transfection efficiency and expression levels were monitored by flow cytometry. Cell survival following transfection was examined using live cell counting and the MTT assay. Both lipofection and electroporation provided high efficiency transfection of neurospheres. In comparison with lipofection, electroporation resulted in increased transfection efficiencies, but lower expression per cell and shorter durations of expression. Additional rounds of lipofection renewed EGFP expression in neurospheres, suggesting this method may be suitable for reprogramming applications. In summary, we have developed a protocol for achieving high efficiency transfection rates in mouse and human neurosphere cell culture that can be applied for future studies of gene function studies in neural stem cells, such as defining efficient differentiation protocols for glial and neuronal linages.
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- 2013
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8. Artificial intelligence techniques in inherited retinal diseases: A review.
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Han Trinh, Jordan Vice, Jason Charng, Zahra Tajbakhsh, Khyber Alam, Fred K. Chen, and Ajmal Mian
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- 2024
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9. Use of uncertainty quantification as a surrogate for layer segmentation error in Stargardt disease retinal OCT images.
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David Alonso-Caneiro, Jason Kugelman, Janelle Tong, Michael Kalloniatis, Fred K. Chen, Scott A. Read, and Michael J. Collins 0001
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- 2021
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10. Dual image and mask synthesis with GANs for semantic segmentation in optical coherence tomography.
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Jason Kugelman, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Fred K. Chen, and Michael J. Collins 0001
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- 2020
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11. Data augmentation for patch-based OCT chorio-retinal segmentation using generative adversarial networks.
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Jason Kugelman, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Fred K. Chen, and Michael J. Collins 0001
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- 2021
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12. Constructing Synthetic Chorio-Retinal Patches using Generative Adversarial Networks.
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Jason Kugelman, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Fred K. Chen, and Michael J. Collins 0001
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- 2019
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13. Effect of Altered OCT Image Quality on Deep Learning Boundary Segmentation.
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Jason Kugelman, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Fred K. Chen, and Michael J. Collins 0001
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- 2020
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14. Benefits of a Laser Chorioretinal Anastomosis Plus Ranibizumab vs Ranibizumab Alone for Central Retinal Vein Occlusion: 4-Year Results
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Ian L. McAllister, Lynne A. Smithies, Fred K. Chen, David A. Mackey, and Paul G. Sanfilippo
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Ophthalmology - Published
- 2023
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15. Automatic Retinal and Choroidal Boundary Segmentation in OCT Images Using Patch-Based Supervised Machine Learning Methods.
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David Alonso-Caneiro, Jason Kugelman, Jared Hamwood, Scott A. Read, Stephen J. Vincent, Fred K. Chen, and Michael J. Collins 0001
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- 2018
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16. Knockout of AMD-associated gene POLDIP2 reduces mitochondrial superoxide in human retinal pigment epithelial cells
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Tu Nguyen, Daniel Urrutia-Cabrera, Luozixian Wang, Jarmon G. Lees, Jiang-Hui Wang, Sandy S.C. Hung, Alex W. Hewitt, Thomas L. Edwards, Sam McLenachan, Fred K. Chen, Shiang Y. Lim, Chi D. Luu, Robyn Guymer, and Raymond C.B. Wong
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Aging ,Cell Biology - Published
- 2023
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17. Longitudinal Analysis of Functional and Structural Outcome Measures in PRPH2-Associated Retinal Dystrophy
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Rachael C. Heath Jeffery, Jennifer A. Thompson, Tina M. Lamey, Terri L. McLaren, John N. De Roach, Ian L. McAllister, Ian J. Constable, and Fred K. Chen
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Ophthalmology - Abstract
To establish disease progression rates in total lesion size (TLS), decreased autofluorescence (DAF) area, total macular volume (TMV), and mean macular sensitivity (MMS) in PRPH2-associated retinal dystrophy.Single-center, retrospective chart review.Patients with heterozygous pathogenic or likely pathogenic PRPH2 variants.Patients who underwent serial ultrawide-field (UWF) fundus autofluorescence (FAF), OCT, and Macular Integrity Assessment microperimetry with at least 1 year of follow-up were included. Linear correlation was performed in eyes of all patients to determine the rate of change over time.Outcome measures included changes in TLS, DAF area, TMV, and MMS.Twelve patients (mean age, 55) from 10 unrelated families attended 100 clinic visits, which spanned over a mean (SD) of 4.7 (2.0) years. Mean (SD) TLS and DAF radius expansion were 0.14 (0.12) and 0.10 (0.08) mm/year, respectively. Mean (SD) TMV change was -0.071 (0.040) mmSerial measurements of UWF-FAF-derived TLS and DAF showed slow expansion. Total macular volume might be a more sensitive measure than MMS in detecting disease progression.
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- 2023
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18. Survey of perspectives of people with inherited retinal diseases on ocular gene therapy in Australia
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Heather G. Mack, Alexis Ceecee Britten-Jones, Myra B. McGuinness, Fred K. Chen, John R. Grigg, Robyn V. Jamieson, Thomas L. Edwards, John De Roach, Fleur O’Hare, Keith R. Martin, and Lauren N. Ayton
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Genetics ,Molecular Medicine ,Molecular Biology - Abstract
Many gene therapies are in development for treating people with inherited retinal diseases (IRD). We hypothesized that potential recipients of gene therapy would have knowledge gaps regarding treatment. We aimed to assess knowledge, attitudes, and perceptions of genetic therapies among potential recipients with IRD, using a novel instrument we designed (Attitudes to Gene Therapy-Eye (AGT-Eye)) and their associations with demographic data, self-reported visual status, and tools assessing quality of life and attitudes toward clinical trials using a community-based cross-sectional survey of Australian adults with IRD. AGT-Eye, overall quality of life EQ-5D-5L, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and Patient Attitudes to Clinical Trials (PACT-22) instruments were administered. Six hundred and eighty-one people completed the study, 51.7% women of mean age 53.5 years (SD ± 15.8). Most participants (91.6%) indicated they would likely accept gene therapy if it was available to them or family members. However, only 28.3% agreed that they had good knowledge of gene therapy. Most obtained information about gene therapy from the internet (49.3%). Respondents with post-graduate degrees scored highest compared to other educational levels on methods (p p = 0.003) and were more likely to see economic value of treatment (p = 0.043). Knowledge gaps were present regarding methods and outcomes of gene therapy. This survey has shown high level of interest in the IRD community for gene therapies, and highlights areas for improved clinician and patient education.
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- 2022
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19. Deep learning: applications in retinal and optic nerve diseases
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Jason Charng, Khyber Alam, Gavin Swartz, Jason Kugelman, David Alonso-Caneiro, David A Mackey, and Fred K Chen
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Ophthalmology ,Optometry - Abstract
Deep learning (DL) represents a paradigm-shifting, burgeoning field of research with emerging clinical applications in optometry. Unlike traditional programming, which relies on human-set specific rules, DL works by exposing the algorithm to a large amount of annotated data and allowing the software to develop its own set of rules (i.e. learn) by adjusting the parameters inside the model (network) during a training process in order to complete the task on its own. One major limitation of traditional programming is that, with complex tasks, it may require an extensive set of rules to accurately complete the assignment. Additionally, traditional programming can be susceptible to human bias from programmer experience. With the dramatic increase in the amount and the complexity of clinical data, DL has been utilised to automate data analysis and thus to assist clinicians in patient management. This review will present the latest advances in DL, for managing posterior eye diseases as well as DL-based solutions for patients with vision loss.
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- 2022
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20. Pathogenesis and Treatment of Usher Syndrome Type IIA
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Khine Zaw, Livia S. Carvalho, May T. Aung-Htut, Sue Fletcher, Steve D. Wilton, Fred K. Chen, and Samuel McLenachan
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Ophthalmology ,General Medicine - Published
- 2022
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21. Genotypic and Phenotypic Spectrum of Foveal Hypoplasia
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Helen J. Kuht, Gail D.E. Maconachie, Jinu Han, Line Kessel, Maria M. van Genderen, Rebecca J. McLean, Michael Hisaund, Zhanhan Tu, Richard W. Hertle, Karen Gronskov, Dayong Bai, Aihua Wei, Wei Li, Yonghong Jiao, Vasily Smirnov, Jae-Hwan Choi, Martin D. Tobin, Viral Sheth, Ravi Purohit, Basu Dawar, Ayesha Girach, Sasha Strul, Laura May, Fred K. Chen, Rachael C. Heath Jeffery, Abdullah Aamir, Ronaldo Sano, Jing Jin, Brian P. Brooks, Susanne Kohl, Benoit Arveiler, Lluis Montoliu, Elizabeth C. Engle, Frank A. Proudlock, Garima Nishad, Prateek Pani, Girish Varma, Irene Gottlob, and Mervyn G. Thomas
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Ophthalmology - Published
- 2022
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22. SIBLING CONCORDANCE IN SYMPTOM ONSET AND ATROPHY GROWTH RATES IN STARGARDT DISEASE USING ULTRA-WIDEFIELD FUNDUS AUTOFLUORESCENCE
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Rachael C. Heath Jeffery, Jennifer A. Thompson, Johnny Lo, Tina M. Lamey, Terri L. McLaren, John N. De Roach, Dimitar N. Azamanov, Ian L. McAllister, Ian J. Constable, and Fred K. Chen
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Adult ,Adolescent ,Fundus Oculi ,Siblings ,Infant, Newborn ,Visual Acuity ,Infant ,General Medicine ,Macular Degeneration ,Young Adult ,Ophthalmology ,Child, Preschool ,Electroretinography ,Humans ,Stargardt Disease ,ATP-Binding Cassette Transporters ,Longitudinal Studies ,Atrophy ,Fluorescein Angiography ,Child ,Tomography, Optical Coherence ,Retrospective Studies - Abstract
To investigate concordance in symptom onset, area of dark autofluorescence (DAF), and growth rate (GR) between Stargardt disease siblings at an age-matched time point.In this retrospective longitudinal study of sibling pairs with identical biallelic ABCA4 variants, age at symptom onset, best-corrected visual acuity, atrophy area, and effective radius of DAF on ultra-widefield fundus autofluorescence were recorded. Absolute intersibling differences for both eyes were compared with absolute interocular differences using the Mann-Whitney test.Overall 39 patients from 19 families were recruited. In 16 families, age-matched best-corrected visual acuity and DAF were compared between siblings. In 8 families, DAF GR was compared. The median (range) absolute difference in age at symptom onset between siblings was 3 (0-35) years. Absolute intersibling differences in age-matched best-corrected visual acuity were greater than interocular differences ( P = 0.01). Similarly, absolute intersibling differences in DAF area and radius were greater than interocular differences ( P = 0.04 for area and P = 0.001 for radius). Differences between absolute interocular and intersibling GR were not statistically significant ( P = 0.44 for area GR and P = 0.61 for radius GR).There was significant discordance in age-matched best-corrected visual acuity and DAF beyond the expected limits of interocular asymmetry. Lack of significant intersibling differences in GR warrants further investigation.
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- 2022
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23. Analysis of the outer retinal bands in ABCA4 and PRPH2-associated retinopathy using optical coherence tomography
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Rachael C. Heath Jeffery, Johnny Lo, Jennifer A. Thompson, Tina M. Lamey, Terri L. McLaren, John N. De Roach, Lauren N. Ayton, Andrea L. Vincent, Abhishek Sharma, and Fred K. Chen
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Ophthalmology - Published
- 2023
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24. Future perspectives of uveal melanoma blood based biomarkers
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Aaron B. Beasley, Fred K. Chen, Timothy W. Isaacs, and Elin S. Gray
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Cancer Research ,Oncology - Abstract
Uveal melanoma (UM) is the most common primary intraocular malignancy affecting adults. Despite successful local treatment of the primary tumour, metastatic disease develops in up to 50% of patients. Metastatic UM carries a particularly poor prognosis, with no effective therapeutic option available to date. Genetic studies of UM have demonstrated that cytogenetic features, including gene expression, somatic copy number alterations and specific gene mutations can allow more accurate assessment of metastatic risk. Pre-emptive therapies to avert metastasis are being tested in clinical trials in patients with high-risk UM. However, current prognostic methods require an intraocular tumour biopsy, which is a highly invasive procedure carrying a risk of vision-threatening complications and is limited by sampling variability. Recently, a new diagnostic concept known as “liquid biopsy” has emerged, heralding a substantial potential for minimally invasive genetic characterisation of tumours. Here, we examine the current evidence supporting the potential of blood circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), microRNA (miRNA) and exosomes as biomarkers for UM. In particular, we discuss the potential of these biomarkers to aid clinical decision making throughout the management of UM patients.
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- 2022
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25. Localised relative scotoma in cuticular drusen
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Jason Charng, Chandrakumar Balaratnasingam, Mary S. Attia, Rachael C. Heath Jeffery, and Fred K. Chen
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genetic structures ,Eye Diseases, Hereditary ,Retinal Drusen ,Middle Aged ,eye diseases ,Sensory Systems ,Cellular and Molecular Neuroscience ,Ophthalmology ,Humans ,Bruch Membrane ,sense organs ,Scotoma ,Tomography, Optical Coherence ,Retrospective Studies - Abstract
Purpose To investigate retinal sensitivity changes in eyes with pure cuticular drusen. Methods Multimodal imaging and microperimetry (37-loci grid) data were examined retrospectively to evaluate functional changes in eyes with pure cuticular drusen. Mean sensitivity in the cuticular drusen cohort was compared to age-matched normals. An age- and loci-specific normative reference was created to analyse localised sensitivity deviation. Results The mean number loci with relative scotoma in the cuticular drusen cohort (n = 27, mean [SD] age: 48.5 [12.4] years) referenced to normal eyes (n = 80, 53.5 [14.6] years) was 5.5 (95% confidence interval 3.0 to 8.1). However, mean sensitivity was not statistically different to the age-matched normal cohort (95% CI, − 2.3 to + 3.4 dB). The 37-loci grid was stratified into three rings of the approximately same number of loci, and the percentage of cuticular drusen eyes with pointwise deviation was significantly lower in the inner compared to the middle ring (12.3 [5.3]% vs. 17.3 [5.1]%, p Conclusions Eyes with cuticular drusen demonstrated relative scotoma, but mean sensitivity was not affected. Pointwise sensitivity provides a more robust measure of retinal sensitivity than mean sensitivity in cuticular drusen and should be assessed both in the clinic and in future clinical trials.
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- 2022
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26. Incidence and mortality of uveal melanoma in Australia (1982–2014)
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Aaron B Beasley, David B Preen, Samuel McLenachan, Elin S Gray, and Fred K Chen
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Cellular and Molecular Neuroscience ,Ophthalmology ,Sensory Systems - Abstract
AimsWe aimed to estimate the incidence and mortality of uveal melanoma (UM) in Australia from 1982 to 2014.MethodsDeidentified unit data for all cases of ocular melanoma were extracted from the Australian Cancer Database from 1 January 1982 to 31 December 2014. UM cases were extracted and trends in incidence and disease-specific mortality were calculated. Incidence rates were age-standardised against the 2001 Australian Standard Population. Mortality was assessed using Cox regression.ResultsFrom 1982 to 2014, there were 5087 cases of ocular melanoma in Australia, of which 4617 were classified as UM. The average age-standardised incidence rate of UM was 7.6 (95% CI 7.3 to 7.9) per million. There was an increase (p=0.0502) in the incidence of UM from 1982 to 1993 with an annual percent change (APC) of +2.5%, followed by a significant decrease in the incidence of UM from 1993 to 2014 (APC −1.2%). The average 5-year survival from 1982 to 2011 did not significantly change from an average of 81%, with an average APC (AAPC) of +0.1%. A multivariate Cox regression revealed that residence in Western Australia (p=0.001) or Tasmania (p=0.05), age ≥60 years (pConclusionIn conclusion, we found that the incidence of UM peaked in the 1990s. Although treatment for primary UM has improved in the last 30 years, overall survival did not change significantly in the last 30 years.
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- 2021
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27. Subthreshold Nanosecond Laser in Age-Related Macular Degeneration: Observational Extension Study of the LEAD Clinical Trial
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Robyn H. Guymer, Fred K. Chen, Lauren A.B. Hodgson, Emily Caruso, Colin A. Harper, Sanjeewa S. Wickremashinghe, Amy C. Cohn, Pyrawy Sivarajah, Nicole Tindill, Chi D. Luu, Zhichao Wu, S. Al-Qureshi, L. Busija, D. Louis, C. Harper, S. Wickremasinghe, P. Van Wijngaarden, L. Lim, S. Durkin, J. Runciman, J. Gihotra, J. Muecke, K. Haywood, C. Brko, J. Paley, M. Smith, C. Luscombe, R. Vincent, D. Lee, R.H. Guymer, C. Luu, Z. Wu, L.A.B. Hodgson, K. Brassington, E. Caruso, M. McGuinness, N. Tindill, K.Z. Aung, E. Baglin, P. Sharangan, C.A. Harper, S. Sandhu, T. Nguyen, A. Cohn, D. Qatarneh, L. Robman, G. Makeyeva, R. Tan, S. Taori, K. Creese, M. Chen, D. Ong, S. No, R. Kandasamy, S.W. Lim, M. Okada, D. Cugley, R. O'Day, P. Keller, K. Lee, E. Alessandrello, J. Alessi-Calandro, M. Kolic, T. Wu, S. Griffin, J.J. Lek, W. Heriot, X. Fagan, R. McIntosh, C. Lowe, J. Boyle, O. Shanahan, F. Chen, I. McAllister, T. Isaacs, A. Shaw, C. Balarantnasingam, Y. Chen, W. Cunningham, R. Viljoen, K. Kennelly, R. Blum, S. Arunachalam, H. Razavi, M. Adams, H. Brown, J. Bryant, R. Cowles, S. Radtke, C. Barry, E. Wong, F. Shilton, A. Soloshenko, A. Jason, A. Lin, A. McSweeney, A. King, B. Shalan, D. Xie, H. Vu, I. Tang, K. Mather, M. Cuypers, M. Cheng, R. McKeone, T. Busby, R. Matthews, G. Lingham, J. Arnold, A. Luckie, D. Chan, J. Chang, T. Tan, L. Koh, H. Cass, R. Fitzsimons, T. Forsyth, A. Nguyen, V. Ghebrial, H. Ayson, A. Graham, M. Firibaldi, U. Chakravarthy, L. Kelly, K. Gillvray, M. Williams, G. Casalino, G. Mangoris, R. Das, T. Peto, L. Toth, M. Quinn, R. Denham, N.J. Lavery, G. Sterrett, V. Silvestri, G. Young, K. Graham, J. Keenan, L. Doyle, T. Douglas, D. Burns, P. Wright, and L. Scullion
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Male ,medicine.medical_specialty ,Fundus Oculi ,Retinal Drusen ,Drusen ,Multimodal Imaging ,Macular Degeneration ,03 medical and health sciences ,0302 clinical medicine ,Risk Factors ,Ophthalmology ,Internal medicine ,Humans ,Medicine ,Fluorescein Angiography ,Lead (electronics) ,Aged ,030304 developmental biology ,0303 health sciences ,business.industry ,Hazard ratio ,Macular degeneration ,medicine.disease ,Confidence interval ,Clinical trial ,Treatment Outcome ,Cohort ,Disease Progression ,030221 ophthalmology & optometry ,Female ,Observational study ,Laser Therapy ,business - Abstract
Purpose To evaluate the long-term effect of subthreshold nanosecond laser (SNL) treatment on progression to late age-related macular degeneration (AMD). Design Observational extension study of a randomized, sham-controlled trial. Participants Two hundred twelve participants with bilateral large drusen. Methods The Laser Intervention in the Early Stages of AMD (LEAD) study was a 36-month trial where participants were randomized to receive SNL or sham treatment in 1 eye at 6-monthly intervals up to 30 months. After the completion of the LEAD study, the 2 largest recruiting sites offered remaining participants an opportunity to enroll in a 24-month observational extension study. This study thus examined all participants from these 2 sites who were enrolled in the LEAD study at baseline, including the additional observational data. Main Outcome Measures Time to develop late AMD, defined on multimodal imaging, between those randomized the SNL or sham treatment. Results Overall, no significant difference was found in the rate of progression over a 60-month period in those randomized to the SNL compared with the sham group (adjusted hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.36–1.09; P = 0.098), similar to the findings at 36 months in the LEAD Study. However, evidence of treatment effect modification continued to emerge based on the coexistence of reticular pseudodrusen (RPD; P = 0.007, adjusted interaction). Namely, progression was slowed significantly with SNL treatment for those without coexistent RPD (adjusted HR, 0.34; 95% CI, 0.16–0.71; P = 0.004), but it was not significantly different for those with RPD (adjusted HR, 1.81; 95% CI, 0.67–4.88; P = 0.239). Conclusions A 24-month observational extension study to the LEAD Study confirmed that SNL treatment did not significantly reduce the overall rate of progression to late AMD in a cohort with intermediate AMD. However, the persistence of a potential beneficial treatment effect in those without coexistent RPD over a longer follow-up duration of an additional 24 months without additional treatment is encouraging. These findings provide further justification for future trials to examine the potential value of SNL treatment for slowing progression in intermediate AMD.
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- 2021
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28. Driving with retinitis pigmentosa
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Rachael C. Heath Jeffery, Johnny Lo, Jennifer A. Thompson, Tina M. Lamey, Terri L. McLaren, John N. DeRoach, Miguel S. Kabilio, and Fred K. chen
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Ophthalmology ,Pediatrics, Perinatology and Child Health ,Genetics (clinical) - Abstract
To establish the proportion of patients with retinitis pigmentosa (RP) meeting the Australian fitness to drive (FTD) visual standards. A prospective consecutive case series of patients with a clinical or genetic diagnosis of RP. Data on age at symptom onset, current driving status, inheritance pattern, better eye visual acuity (BEVA), binocular Esterman visual field (BEVF) parameters, genotype and ability to meet the driving standards based on BEVA and BEVF were collected. Outcome measures included the proportion of RP patients overall meeting the standards and clinical predictors for passing. A sub-analysis was performed on those RP patients who reported to drive. Change in BEVA and BEVF parameters across age in specific genotype groups was assessed. Overall, 228 patients with RP had a BEVF assessment. Only 39% (89/228) met the driving standards. Younger age at the time of testing was the only significant predictor (p < 0.01) for passing. Of the 55% of RP patients who reported to drive, 52% (65/125) met the standards, decreasing to 14% in the 56- to 65-year-old age group. RP patients harbouring mutations in HK1 or RHO genes may have slower rates of decline in their VF parameters. Nearly 40% of RP patients met the driving standards. However, almost 50% of RP drivers were unaware of their failure to meet the current standards. BEVF testing is essential in the assessment of RP patients who are still driving. Phenotype and genotype predictors for passing the standards warrant further investigation. Abbreviation: FTD, fitness to drive; IRD, inherited retinal disease; RP, retinitis pigmentosa; RHO, rhodopsin; HK1, hexokinase 1; PRPF31 pre-mRNA processing factor 31; RPGR, retinitis pigmentosa GTPase regulator; VF, visual field; BEVA, better eye visual acuity; BEVF, binocular Esterman visual field.
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- 2023
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29. Serum miRNA modulations indicate changes in retinal morphology
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Riemke Aggio-Bruce, Ulrike Schumann, Adrian V. Cioanca, Fred K. Chen, Samuel McLenachan, Rachael C. Heath Jeffery, Shannon Das, and Riccardo Natoli
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Cellular and Molecular Neuroscience ,Molecular Biology - Abstract
BackgroundAge-related macular degeneration (AMD) is the leading cause of vision loss in the developed world and the detection of its onset and progression are based on retinal morphological assessments. MicroRNA (miRNA) have been explored extensively as biomarkers for a range of neurological diseases including AMD, however differences in experimental design and the complexity of human biology have resulted in little overlap between studies. Using preclinical animal models and clinical samples, this study employs a novel approach to determine a serum signature of AMD progression.MethodsSerum miRNAs were extracted from mice exposed to photo-oxidative damage (PD; 0, 1, 3 and 5 days), and clinical samples from patients diagnosed with reticular pseudodrusen or atrophic AMD. The expression of ~800 miRNAs was measured using OpenArray™, and differential abundance from controls was determined using the HTqPCR R package followed by pathway analysis with DAVID. MiRNA expression changes were compared against quantifiable retinal histological indicators. Finally, the overlap of miRNA changes observed in the mouse model and human patient samples was investigated.ResultsDifferential miRNA abundance was identified at all PD time-points and in clinical samples. Importantly, these were associated with inflammatory pathways and histological changes in the retina. Further, we were able to align findings in the mouse serum to those of clinical patients.ConclusionIn conclusion, serum miRNAs are a valid tool as diagnostics for the early detection of retinal degeneration, as they reflect key changes in retinal health. The combination of pre-clinical animal models and human patient samples led to the identification of a preliminary serum miRNA signature for AMD. This study is an important platform for the future development of a diagnostic serum miRNA panel for the early detection of retinal degeneration.
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- 2022
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30. Gene replacement therapy restores RCBTB1 expression and cilium length in patient‐derived retinal pigment epithelium
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Dan Zhang, Luke Jennings, Shang Chih Chen, Zhiqin Huang, Fred K. Chen, Sue Fletcher, Livia S. Carvalho, and Samuel McLenachan
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induced pluripotent stem cells ,Genetic enhancement ,Transgene ,Genetic Vectors ,retinal pigment epithelium ,Gene Expression ,Biology ,medicine.disease_cause ,chemistry.chemical_compound ,Transduction, Genetic ,Retinal Dystrophies ,Gene expression ,medicine ,Guanine Nucleotide Exchange Factors ,Humans ,Cilia ,Transgenes ,Induced pluripotent stem cell ,Adeno-associated virus ,Cells, Cultured ,Retinal pigment epithelium ,Cilium ,adeno‐associated virus ,Cell Differentiation ,Retinal ,Genetic Therapy ,Original Articles ,Cell Biology ,Dependovirus ,gene therapy ,Molecular biology ,eye diseases ,RCBTB1 ,medicine.anatomical_structure ,chemistry ,inherited retinal disease ,Molecular Medicine ,Original Article ,sense organs - Abstract
Biallelic mutations in the RCBTB1 gene cause retinal dystrophy. Here, we characterized the effects of RCBTB1 gene deficiency in retinal pigment epithelial (RPE) cells derived from a patient with RCBTB1‐associated retinopathy and restored RCBTB1 expression in these cells using adeno‐associated viral (AAV) vectors. Induced pluripotent stem cells derived from a patient with compound heterozygous RCBTB1 mutations (c.170delG and c.707delA) and healthy control subjects were differentiated into RPE cells. RPE cells were treated with AAV vectors carrying a RCBTB1 transgene. Patient‐derived RPE cells showed reduced expression of RCBTB1. Expression of NFE2L2 showed a non‐significant reduction in patient RPE cells compared with controls, while expression of its target genes (RXRA, IDH1 and SLC25A25) was significantly reduced. Trans‐epithelial electrical resistance, surface microvillus densities and primary cilium lengths were reduced in patient‐derived RPE cells, compared with controls. Treatment of patient RPE with AAV vectors significantly increased RCBTB1, NFE2L2 and RXRA expression and cilium lengths. Our study provides the first report examining the phenotype of RPE cells derived from a patient with RCBTB1‐associated retinopathy. Furthermore, treatment of patient‐derived RPE with AAV‐RCBTB1 vectors corrected deficits in gene expression and RPE ultrastructure, supporting the use of gene replacement therapy for treating this inherited retinal disease.
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- 2021
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31. L-arginine and aged garlic extract for the prevention of migraine: a study protocol for a randomised, double-blind, placebo-controlled, phase-II trial (LARGE trial)
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Devahuti R. Chaliha, Mauro Vaccarezza, Emily Corti, Ryusuke Takechi, Satvinder S. Dhaliwal, Peter Drummond, Eric Visser, Fred K. Chen, Jason Charng, Virginie Lam, and John C.L. Mamo
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Neurology (clinical) ,General Medicine - Abstract
IntroductionMigraine is a common and distressing neurological condition characterised by recurrent throbbing headaches, nausea and heightened sensitivity to light and sound. Accumulating evidence suggests that cerebral arteries dilate during migraine, causing distal microvessels to constrict, which could activate nociceptors and cause onset of headache pain. If so, preventing or attenuating chronic microvascular constriction, and promoting a dilatory phenotype, may reduce frequency and/or severity of migraines. The primary aim of the L-Arginine and Aged Garlic Extract (LARGE) trial is to investigate whether oral treatment with dietary nutraceuticals, L-arginine and aged garlic extract (AGE), both systemic vasodilatory agents, will alleviate migraine frequency, duration and severity in adults with chronic frequent episodic migraines.Methods and analysisThe study is a randomised double-blind placebo-controlled phase-II single-site clinical trial conducted in Perth, Australia. The target sample is to recruit 240 participants diagnosed with chronic frequent episodic migraines between 18 and 80 years of age. Participants will be randomised to one of four treatment groups for 14 weeks (placebo induction for 2 weeks, followed by 12 weeks on one of the respective treatment arms): placebo, L-arginine, AGE, or a combination of L-arginine and AGE. The doses of L-arginine and AGE are 1.5 g and 1 g daily, respectively. The primary outcome is to assess migraine response using change in migraine frequency and intensity between baseline and 12 weeks. Secondary outcomes include the impact of L-arginine and/or AGE on photosensitivity, retinal vessel changes, and blood biomarker concentrations of vascular tone, following a 12-week intervention.Ethics and disseminationThe Curtin University Human Research Ethics Committee (HREC) has approved this study (Approval number: HRE2020-0466; Version 4; 16thAugust 2021). Written consent will be obtained from all participants prior to commencing their participation in the trial. The results of the study will be disseminated in peer-reviewed publications and presented at key national and international conferences and local stakeholder events.Registration detailsThe trial is registered with the Australian New Zealand Clinical Trials RegistryACTRN12621001476820 (Universal Trial Number: U1111-1268-1117).Strengths and limitations of the studyThis is the first in-human randomised double-blind placebo-controlled phase-II clinical trial examining the efficacy, safety and tolerability of L-arginine and AGE, in preventing chronic frequent episodic migraines by assessing participant-reported pain-related outcomes, and changes in photosensitivity and retinal vessels.The double-blinded nature of the study, and the placebo run-in for 2 weeks at the beginning of the study, are strengths in trial methodology.The protocol describes the oral administration of 2 nutraceutical-based interventions as possible prophylactic treatments for chronic frequent episodic migraines, with potential for direct clinical translation of outcomes.Potential limitations of the study include the fixed-dose design of each treatment arm and thatin vivoneuroimaging methods, such as magnetic resonance imaging (MRI), will not be conducted to determine putative cerebro-vasodilatory changes to coincide with the outcome measures. Dose-response studies may be indicated.
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- 2022
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32. Peripapillary hyperreflective ovoid mass-like structures: Multimodal imaging-A review
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Rachael C. Heath Jeffery and Fred K. Chen
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Ophthalmology - Abstract
Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a laterally bulging herniation of distended axons into the peripapillary region above the level of Bruch's membrane opening. Increased use of enhanced depth imaging-optical coherence tomography (EDI-OCT) in our evaluation of the optic nerve head (ONH) and greater recognition of the vast range of optic nerve pathologies with which PHOMS is associated provides convincing evidence that PHOMS is not just buried optic disc drusen (ODD) as previously described. The frequent coexistence of PHOMS with ODD, papilloedema, anterior ischaemic optic neuropathy, tilted optic disc syndrome, inflammatory demyelinating disorders and other diseases associated with axoplasmic stasis provides insight into its underlying pathophysiology. The present review will discuss the role of key imaging modalities in the differential diagnosis of PHOMS, explore the current literature on the relationship between PHOMS and common neuro-ophthalmic conditions, and highlight the gaps in our knowledge, with respect to disease classification and prognosis, to pave the way for future directions of research.
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- 2022
33. Stargardt disease: Multimodal imaging: A review
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Fred K. Chen and Rachael C. Heath Jeffery
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0301 basic medicine ,retina ,inherited retinal diseases ,ocular coherence tomography ,Retinal dystrophy ,Time efficiency ,Reviews ,Review ,Lipofuscin ,03 medical and health sciences ,0302 clinical medicine ,Optical coherence tomography ,Pathognomonic ,Retinal Dystrophies ,Humans ,Stargardt Disease ,Medicine ,Fluorescein Angiography ,retinal dystrophy ,Multimodal imaging ,Lesion segmentation ,fundus autofluorescence ,medicine.diagnostic_test ,business.industry ,Disease progression ,medicine.disease ,Stargardt disease ,Ophthalmology ,030104 developmental biology ,030221 ophthalmology & optometry ,business ,Neuroscience ,Tomography, Optical Coherence - Abstract
Stargardt disease (STGD1) is an autosomal recessive retinal dystrophy, characterized by bilateral progressive central vision loss and subretinal deposition of lipofuscin-like substances. Recent advances in molecular diagnosis and therapeutic options are complemented by the increasing recognition of new multimodal imaging biomarkers that may predict genotype and disease progression. Unique non-invasive imaging features of STDG1 are useful for gene variant interpretation and may even provide insight into the underlying molecular pathophysiology. In addition, pathognomonic imaging features of STGD1 have been used to train neural networks to improve time efficiency in lesion segmentation and disease progression measurements. This review will discuss the role of key imaging modalities, correlate imaging signs across varied STGD1 presentations, and illustrate the use of multimodal imaging as an outcome measure in determining the efficacy of emerging STGD1 specific therapies. This article is protected by copyright. All rights reserved.
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- 2021
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34. Knowledge of ocular complications of diabetes in community-based people with type 2 diabetes: The Fremantle Diabetes Study II
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Timothy M. E. Davis, Fred K. Chen, Wendy A. Davis, and Jocelyn J. Drinkwater
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Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Eye disease ,030209 endocrinology & metabolism ,Type 2 diabetes ,Fundus (eye) ,03 medical and health sciences ,0302 clinical medicine ,Quality of life ,Diabetes mellitus ,Internal medicine ,Internal Medicine ,medicine ,Humans ,Mass Screening ,030212 general & internal medicine ,Aged ,Community based ,Diabetic Retinopathy ,Nutrition and Dietetics ,business.industry ,Australia ,Diabetic retinopathy ,medicine.disease ,eye diseases ,Diabetes Mellitus, Type 2 ,Cohort ,Quality of Life ,Female ,Family Practice ,business - Abstract
Aims To assess knowledge of diabetes-related eye disease in Australians with type 2 diabetes and its associations with diabetic retinopathy (DR), other ocular complications and vision-related quality of life. Methods A random sample from the Fremantle Diabetes Study Phase II cohort (n = 360) was invited to participate. Knowledge was assessed using 10 multiple-choice questions covering how diabetes affects the eyes, frequency of ophthalmic screening, risk factors, prevention, available treatments, and prognosis. DR was assessed from fundus photographs. Multiple linear regression was used to identify independent associates of the knowledge score (KS). Results We included 264 participants (mean ± SD age 72.1 ± 9.2 years, 56.8% male, median [IQR] diabetes duration 15.4 [11.1–22.3] years). The mean ± SD KS out of 10 was 5.3 ± 1.8. Most (67%) participants knew diabetes can affect the eye and lead to blindness. Only 13.6% knew that DR screening intervals depend on risk factors. Those with moderate non-proliferative DR (NPDR) or worse had a better knowledge score (B = 1.37,P = 0.008) after adjusting for age (B = −0.03, P = 0.004) and education beyond primary school (B = 1.75, P Conclusions Overall knowledge of diabetes-related ocular complications was suboptimal. Education targeting eye disease may benefit people with type 2 diabetes who are older, less well educated and/or who have no DR/mild NPDR.
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- 2021
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35. Time spent outdoors in childhood is associated with reduced risk of myopia as an adult
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Fred K. Chen, Seyhan Yazar, Kathryn A. Rose, David A. Mackey, Elizabeth Milne, Stuart MacGregor, Mingguang He, Cathy Williams, Minas T. Coroneo, Robyn M. Lucas, Gareth Lingham, Michael W. Clarke, Christopher J Hammond, Seang-Mei Saw, Alex W. Hewitt, Jeremy A. Guggenheim, and Leon Straker
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Adult ,Male ,Reduced risk ,medicine.medical_specialty ,Adolescent ,genetic structures ,Epidemiology ,Science ,Intervention group ,Logistic regression ,Article ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Leisure Activities ,Risk Factors ,Surveys and Questionnaires ,Myopia ,Medicine ,Humans ,030212 general & internal medicine ,Social determinants of health ,Young adult ,Child ,Exercise ,Multidisciplinary ,business.industry ,Public health ,Odds ratio ,Confidence interval ,eye diseases ,Risk factors ,030221 ophthalmology & optometry ,Female ,business ,Risk Reduction Behavior ,Biomarkers ,Demography - Abstract
Myopia (near-sightedness) is an important public health issue. Spending more time outdoors can prevent myopia but the long-term association between this exposure and myopia has not been well characterised. We investigated the relationship between time spent outdoors in childhood, adolescence and young adulthood and risk of myopia in young adulthood. The Kidskin Young Adult Myopia Study (KYAMS) was a follow-up of the Kidskin Study, a sun exposure-intervention study of 1776 children aged 6–12 years. Myopia status was assessed in 303 (17.6%) KYAMS participants (aged 25–30 years) and several subjective and objective measures of time spent outdoors were collected in childhood (8–12 years) and adulthood. Index measures of total, childhood and recent time spent outdoors were developed using confirmatory factor analysis. Logistic regression was used to assess the association between a 0.1-unit change in the time outdoor indices and risk of myopia after adjusting for sex, education, outdoor occupation, parental myopia, parental education, ancestry and Kidskin Study intervention group. Spending more time outdoors during childhood was associated with reduced risk of myopia in young adulthood (multivariable odds ratio [OR] 0.82, 95% confidence interval [CI] 0.69, 0.98). Spending more time outdoors in later adolescence and young adulthood was associated with reduced risk of late-onset myopia (≥ 15 years of age, multivariable OR 0.79, 95% CI 0.64, 0.98). Spending more time outdoors in both childhood and adolescence was associated with less myopia in young adulthood.
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- 2021
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36. Blackout: Understanding transient vision loss
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Christian J. Lueck, Rachael C. Heath Jeffery, and Fred K. Chen
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Monocular ,Urgent referral ,genetic structures ,medicine.diagnostic_test ,business.industry ,Blackout ,Vision Disorders ,Neurological examination ,eye diseases ,Diagnosis, Differential ,Underlying disease ,medicine ,Optic nerve ,Humans ,Optometry ,Transient (computer programming) ,medicine.symptom ,Family Practice ,business - Abstract
BACKGROUND Transient vision loss may indicate underlying disease of the eye, optic nerve, orbit, brain or heart. Detailed history-taking followed by a complete ocular and neurological examination is therefore a crucial part of any consultation. OBJECTIVE It is important to determine whether a patient with transient vision loss can be reassured or requires urgent referral for further investigation. This review examines monocular and binocular transient vision loss and provides a structured approach to the examination of a patient with transient vision loss. The aim of this article is to provide clinicians with confidence when encountering these patients. DISCUSSION Transient vision loss can imply serious underlying pathology; therefore, accurate history-taking and astute observation are paramount. This review discusses the differential diagnosis of monocular and binocular transient vision loss and the relevant localising features of each.
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- 2021
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37. Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length
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Deepaysh D. C. S. Dutt, Seyhan Yazar, Jason Charng, David A. Mackey, Fred K. Chen, and Danuta M. Sampson
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Ophthalmology ,Health Professions (miscellaneous) - Abstract
Background To generate and validate a method to estimate axial length estimated (ALest) from spherical equivalent (SE) and corneal curvature [keratometry (K)], and to determine if this ALest can replace actual axial length (ALact) for correcting transverse magnification error in optical coherence tomography angiography (OCTA) images using the Littmann-Bennett formula. Methods Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate (n = 650) and validate (n = 651) a relationship between AL, SE, and K. The developed formula was then applied to a separate dataset of 46 participants with AL, SE, and K measurements and OCTA images to estimate and compare the performance of ALest against ALact in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area (FAZA). Results The formula for ALest yielded the equation: ALest = 2.102K − 0.4125SE + 7.268, R2 = 0.794. There was good agreement between ALest and ALact for both study cohorts. The mean difference [standard deviation (SD)] between FAZA corrected with ALest and ALact was 0.002 (0.015) mm2 with the 95% limits of agreement (LoA) of − 0.027 to 0.031 mm2. In comparison, mean difference (SD) between FAZA uncorrected and corrected with ALact was − 0.005 (0.030) mm2, with 95% LoA of − 0.064 to 0.054 mm2. Conclusions ALact is more accurate than ALest and hence should be used preferentially in magnification error correction in the clinical setting. FAZA corrected with ALest is comparable to FAZA corrected with ALact, while FAZA measurements using images corrected with ALest have a greater accuracy than measurements on uncorrected images. Hence, in the absence of ALact, clinicians should use ALest to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images.
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- 2022
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38. Eye injuries: Understanding ocular trauma
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Rachael C Heath Jeffery, Jacqueline Dobes, and Fred K Chen
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Eye Injuries ,Humans ,Family Practice ,Eye ,Foreign Bodies - Abstract
Ocular trauma may result in pathology of the ocular surface and adnexa, extraocular muscles, orbital walls, eye and optic nerve. Detailed history followed by a complete ocular and, if indicated, radiological examination is therefore a crucial part of any trauma assessment. It is important to determine whether a patient with ocular trauma can be reassured or requires immediate referral for further investigation and surgical repair.This review examines chemical eye injuries, orbital fractures, superficial corneal foreign bodies, closed globe injury and suspected open globe injury with or without intra-ocular foreign bodies. A structured approach to the history and examination is provided. The aim of this article is to enhance clinician confidence when encountering these patients.Ocular trauma can lead to serious sight‑ and eye-threatening consequences. Accurate history-taking and astute observation are paramount for timely treatment or referral that may prevent blindness. This review discusses the management and referral pathways for common presentations of ocular trauma.
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- 2022
39. Reply
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Kai Lyn Goh, Fred K. Chen, Chandrakumar Balaratnasingam, Carla J. Abbott, Lauren A.B. Hodgson, Robyn H. Guymer, and Zhichao Wu
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Ophthalmology - Published
- 2022
40. Deep clinical phenotyping and gene expression analysis in a patient with RCBTB1-associated retinopathy
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Jason Charng, Enid Chelva, Jennifer A. Thompson, Saumya Shekhar Jamuar, John N. De Roach, Carla B. Mellough, Luke Jennings, Danial Roshandel, Choi Mun Chan, Dan Zhang, Fred K. Chen, Samuel McLenachan, Terri L. McLaren, Shang Chih Chen, Tina M. Lamey, and Zhiqin Huang
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0301 basic medicine ,Pathology ,medicine.medical_specialty ,Retinal pigment epithelium ,Retinal dystrophy ,business.industry ,030105 genetics & heredity ,medicine.disease ,03 medical and health sciences ,Ophthalmology ,0302 clinical medicine ,medicine.anatomical_structure ,Pediatrics, Perinatology and Child Health ,Gene expression ,030221 ophthalmology & optometry ,medicine ,business ,Gene ,Genetics (clinical) ,Retinopathy - Abstract
Background: Mutations in the RCC1 and BTB domain-containing protein 1 (RCBTB1) gene have been implicated in a rare form of retinal dystrophy. Herein, we report the clinical features of a 45-year-ol...
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- 2021
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41. A novel phenotype in a family with autosomal dominant retinal dystrophy due to c.1430A > G in retinoid isomerohydrolase (RPE65) and c.37C > T in bestrophin 1 (BEST1)
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Juanita Pappalardo, Fred K. Chen, Terri L. McLaren, Rachael C. Heath Jeffery, Jennifer A. Thompson, Quang Pham, John N. De Roach, Enid Chelva, Ian J. Constable, and Tina M. Lamey
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Proband ,medicine.medical_specialty ,genetic structures ,Vitelliform macular dystrophy ,Choroideremia ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Physiology (medical) ,Ophthalmology ,Retinitis pigmentosa ,Medicine ,biology ,business.industry ,Foveal atrophy ,Retinal ,medicine.disease ,eye diseases ,Sensory Systems ,Bestrophin 1 ,chemistry ,030221 ophthalmology & optometry ,biology.protein ,sense organs ,business ,Microperimetry ,030217 neurology & neurosurgery - Abstract
The c.1430A > G (Asp477Gly) variant in RPE65 has been reported in Irish and Scottish families with either an autosomal dominant retinal dystrophy (adRD) that resembles choroideremia, a vitelliform macular dystrophy or an isolated macular atrophy. We report novel features on multimodal imaging and the natural history of a family harbouring this variant in combination with the BEST1 c.37C > T (Arg13Cys) variant. Members of a family with an adRD were examined clinically to ascertain phenotype and underwent genetic testing. Multimodal imaging included widefield colour fundus photography, quantitative autofluorescence (qAF) and spectral domain optical coherence tomography. Electrophysiology and microperimetry were also performed. Vision loss was attributed to foveal atrophy in the proband and choroidal neovascularisation and a vitello-eruptive lesion in one affected son. Peripheral retinal white dots corresponding to subretinal deposits were seen in three patients. The median qAF8 values in the proband (I:1) were low (40 and 101 in OD and OS) at age 79. Similarly, the qAF8 values for the middle son (II:2) were also low (100 and 87 in ODS and OS) at age 60. Electrophysiology showed disproportionate reduction in Arden ratio prior to the gradual loss of full-field responses. Microperimetry demonstrated an enlarging scotoma in the proband. The coexistence of the pathogenic BEST1 c.37C > T variant may modify clinical features observed in RPE65 adRD. This study expands our understanding of RPE65 adRD as a retinoid cycle disorder supported by the reduced qAF, fine white retinal dots and corresponding subretinal deposits on OCT in affected members.
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- 2021
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42. Progressive sector retinitis pigmentosa due to c.440G>T mutation in SAG in an Australian family
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Jason Charng, Enid Chelva, Jennifer A. Thompson, Terri L. McLaren, Ian J. Constable, Juanita Pappalardo, Rachael C. Heath Jeffery, Fred K. Chen, Tina M. Lamey, and John N. De Roach
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Genetics ,congenital, hereditary, and neonatal diseases and abnormalities ,genetic structures ,Biology ,medicine.disease ,Autosomal dominant retinitis pigmentosa ,eye diseases ,Fundus autofluorescence ,Ophthalmology ,Pediatrics, Perinatology and Child Health ,Retinitis pigmentosa ,Mutation (genetic algorithm) ,Arrestin ,Rod-cone dystrophy ,medicine ,sense organs ,Genetics (clinical) - Abstract
Heterozygous c.440 G > T mutation in the S-antigen visual arrestin (SAG) gene has been described as a cause of autosomal dominant retinitis pigmentosa (adRP) in a series of patients of Hispanic ori...
- Published
- 2020
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43. Exploring microperimetry and autofluorescence endpoints for monitoring disease progression in PRPF31-associated retinopathy
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Enid Chelva, Dan Zhang, Jason Charng, David A. Mackey, Jennifer A. Thompson, Tina M. Lamey, Sue Fletcher, Terri L. McLaren, Mary S. Attia, Danial Roshandel, Sukanya Arunachalam, John N. De Roach, Steve D. Wilton, Samuel McLenachan, and Fred K. Chen
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0301 basic medicine ,Oncology ,medicine.medical_specialty ,PRPF31 ,business.industry ,Disease progression ,030105 genetics & heredity ,medicine.disease ,eye diseases ,03 medical and health sciences ,Ophthalmology ,Splicing factor ,Autofluorescence ,0302 clinical medicine ,Internal medicine ,Pediatrics, Perinatology and Child Health ,Retinitis pigmentosa ,030221 ophthalmology & optometry ,medicine ,business ,Microperimetry ,Gene ,Genetics (clinical) ,Retinopathy - Abstract
Mutations in the splicing factor pre-messenger RNA processing factor 31 (PRPF31) gene cause autosomal dominant retinitis pigmentosa 11 (RP11) through a haplo-insufficiency mechanism. We describe th...
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- 2020
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44. Choroidal Thickness in Young Adults and its Association with Visual Acuity
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Alex W. Hewitt, Seyhan Yazar, David A. Mackey, Fred K. Chen, David Alonso-Caneiro, Samantha Sze Yee Lee, and Gareth Lingham
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Adult ,Male ,Intraocular pressure ,medicine.medical_specialty ,Biometry ,Visual acuity ,genetic structures ,Visual Acuity ,Refraction, Ocular ,Cohort Studies ,Tonometry, Ocular ,Young Adult ,03 medical and health sciences ,Sex Factors ,0302 clinical medicine ,Optical coherence tomography ,Reference Values ,Interquartile range ,Ophthalmology ,Ethnicity ,Humans ,Medicine ,Young adult ,Intraocular Pressure ,030304 developmental biology ,0303 health sciences ,medicine.diagnostic_test ,Choroid ,business.industry ,Organ Size ,Healthy Volunteers ,eye diseases ,Cross-Sectional Studies ,medicine.anatomical_structure ,Cohort ,030221 ophthalmology & optometry ,Female ,sense organs ,medicine.symptom ,business ,Tomography, Optical Coherence ,Optic disc - Abstract
To describe the choroidal thickness (ChT) in a large sample of young adults with the aim of establishing a normative ChT profile reference in this demographic cohort and explore its association with best-corrected visual acuity (BCVA).Cross-sectional study.From a single center, 741 young adults (19-30 years of age, 49% male) were recruited to undergo a comprehensive ophthalmic examination, including BCVA measurement, post-cycloplegic autorefraction, ocular biometry, tonometry, and spectral-domain optical coherence tomography (SD-OCT) imaging. The enhanced depth imaging mode on the SD-OCT was used. The main outcome measure was the central macular ChT (0.5-mm radius around the fovea). The ChTs at the inner (between 0.5-mm and 1.5-mm radius) and outer macular rings (between 1.5-mm and 2.5-mm radius) were also measured.The median central macular ChT was 370 μm (interquartile range 312-406 μm). The choroid was thickest at the superior-inner, inferior-inner, and central macular regions (370-373 μm) and thinnest nasally at the outer macular region (median 256 μm). Decreased central macular ChT was associated with younger age, female sex, nonwhite ethnicities, and myopia (P ≤ .013). There was a significant association between better BCVA and increased central macular ChT (P.001), after adjusting for age, sex, ethnicity, and ocular measures. His relationship was only apparent in eyes with central macular ChTs300 μm (P = .019) and absent in eyes with ChTs300 μm.The central ChT of young adults was 370 μm. There was a significant association between worse BCVA and thinner choroids below a threshold of 300 μm, raising the possibility that ChT could be predictive of visual function.
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- 2020
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45. Western Australia Atropine for the Treatment of Myopia (WA‐ATOM) study: Rationale, methodology and participant baseline characteristics
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Julie Crewe, Fred K. Chen, Michael D. Richards, Jason Charng, James Loughman, Tan Tai Truong, Ian Flitcroft, Fletcher Ng, Augusto Azuara-Blanco, Antony Clark, Nicola S Logan, Samantha Sze Yee Lee, Gareth Lingham, David A. Mackey, Audrey Chia, and Christopher J Hammond
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Atropine ,Pediatrics ,medicine.medical_specialty ,genetic structures ,Astigmatism ,Refraction, Ocular ,Placebo ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,Myopia ,medicine ,Humans ,Child ,030304 developmental biology ,0303 health sciences ,business.industry ,Incidence (epidemiology) ,Australia ,Western Australia ,medicine.disease ,Iris colour ,Ophthalmology ,Tolerability ,Baseline characteristics ,Disease Progression ,030221 ophthalmology & optometry ,Ophthalmic Solutions ,business ,medicine.drug - Abstract
Importance Atropine eyedrops are a promising treatment for slowing myopia progression in East Asian children. However, its effects on children in Australia, including those of non-Asian background, have not been well-studied. Background The Western Australia Atropine for the Treatment of Myopia (WA-ATOM) study aims to determine the efficacy and long-term effects of low-dose atropine eyedrops in myopia control. This paper describes the study rationale, methodology and participant baseline characteristics. Design Single-centre, double-masked, randomized controlled trial. Participants Children (6-16 years) with spherical equivalent ≤-1.50 D in each eye, astigmatism ≤1.50 D and myopia progression by ≥0.50 D/year. Methods Enrolled children were randomly assigned 2:1 to receive 0.01% atropine or placebo eyedrops. Participants are examined every 6 months during first 3 years of the study (2-year treatment phase followed by a 1-year washout phase), and then at a 5-year follow-up (2 years after the end of the washout phase). Main outcome measures Annual progression rate of myopia and axial length, tolerability to eyedrops and incidence and severity of unwanted effects. Results Out of 311 children who were referred, 242 were suitable for study participation, and 153 were subsequently enrolled. The baseline characteristics of enrolled participants are presented. Conclusions and relevance Outcomes of the WA-ATOM study will inform on the efficacy, tolerability, safety and long-term effects of low-dose atropine eyedrops in myopia control in Australian children. The impact of ocular sun exposure, iris colour and parental myopia on the efficacy of low-dose atropine will also be assessed.
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- 2020
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46. Choroidal Thickening During Young Adulthood and Baseline Choroidal Thickness Predicts Refractive Error Change
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Samantha Sze-Yee Lee, David Alonso-Caneiro, Gareth Lingham, Fred K. Chen, Paul G. Sanfilippo, Seyhan Yazar, and David A. Mackey
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Adult ,Male ,Axial Length, Eye ,Young Adult ,Choroid ,Myopia ,Humans ,Female ,Refraction, Ocular ,Refractive Errors ,Tomography, Optical Coherence - Abstract
The purpose of this study was to explore the age-related change in choroidal thickness (ChT) and test the hypothesis that baseline ChT is predictive of refractive error change in healthy young adults.Participants underwent spectral-domain optical coherence tomography (SD-OCT) imaging and autorefraction at 20 (baseline) and 28 years old. The enhanced depth imaging mode on the SD-OCT was used to obtain images of the choroid. Scans were exported from the SD-OCT and analyzed with a custom software that automatically measures the central ChT. The longitudinal change in subfoveal ChT and association between baseline subfoveal ChT and 8-year change in refractive error (spherical equivalent) were determined using linear mixed models.In total, 395 eyes of 198 participants (44% men; 18-22 years at baseline) were included. Over 8 years, mean spherical equivalent decreased by 0.25 diopters (D) and axial length increased by 0.09 mm. Subfoveal choroid thickened by 1.3 µm/year (95% confidence interval [CI] = 0.6-2.0), but this was reduced by 0.9 µm/year (95% CI = 1.6-0.2) for every 1 mm increase in axial length. For every 10 µm increase in baseline ChT, average annual change in spherical equivalent and axial length reduced by 0.006 D/year and 0.003 mm/year, respectively.In a community-based cohort of young adults, the choroid continued to change during early adulthood. Choroidal thickening was less in eyes that were longer at baseline, and the choroid thinned in eyes that showed myopia progression. The association between baseline ChT and longitudinal changes in spherical equivalent and axial length supports the hypothesis that ChT may be predictive of refractive error development and/or myopia progression.
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- 2022
47. A comparison of deep learning U-Net architectures for posterior segment OCT retinal layer segmentation
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Jason Kugelman, Joseph Allman, Scott A. Read, Stephen J. Vincent, Janelle Tong, Michael Kalloniatis, Fred K. Chen, Michael J. Collins, and David Alonso-Caneiro
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Multidisciplinary ,Deep Learning ,Image Processing, Computer-Assisted ,Retina - Abstract
Deep learning methods have enabled a fast, accurate and automated approach for retinal layer segmentation in posterior segment OCT images. Due to the success of semantic segmentation methods adopting the U-Net, a wide range of variants and improvements have been developed and applied to OCT segmentation. Unfortunately, the relative performance of these methods is difficult to ascertain for OCT retinal layer segmentation due to a lack of comprehensive comparative studies, and a lack of proper matching between networks in previous comparisons, as well as the use of different OCT datasets between studies. In this paper, a detailed and unbiased comparison is performed between eight U-Net architecture variants across four different OCT datasets from a range of different populations, ocular pathologies, acquisition parameters, instruments and segmentation tasks. The U-Net architecture variants evaluated include some which have not been previously explored for OCT segmentation. Using the Dice coefficient to evaluate segmentation performance, minimal differences were noted between most of the tested architectures across the four datasets. Using an extra convolutional layer per pooling block gave a small improvement in segmentation performance for all architectures across all four datasets. This finding highlights the importance of careful architecture comparison (e.g. ensuring networks are matched using an equivalent number of layers) to obtain a true and unbiased performance assessment of fully semantic models. Overall, this study demonstrates that the vanilla U-Net is sufficient for OCT retinal layer segmentation and that state-of-the-art methods and other architectural changes are potentially unnecessary for this particular task, especially given the associated increased complexity and slower speed for the marginal performance gains observed. Given the U-Net model and its variants represent one of the most commonly applied image segmentation methods, the consistent findings across several datasets here are likely to translate to many other OCT datasets and studies. This will provide significant value by saving time and cost in experimentation and model development as well as reduced inference time in practice by selecting simpler models.
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- 2022
48. Towards standardizing retinal optical coherence tomography angiography: a review
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Danuta M. Sampson, Adam M. Dubis, Fred K. Chen, Robert J. Zawadzki, and David D. Sampson
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Detection ,screening and diagnosis ,Neurosciences ,Biomedical Imaging ,Bioengineering ,Optical Physics ,Eye ,Eye Disease and Disorders of Vision ,Atomic and Molecular Physics, and Optics ,4.1 Discovery and preclinical testing of markers and technologies ,Electronic, Optical and Magnetic Materials - Abstract
The visualization and assessment of retinal microvasculature are important in the study, diagnosis, monitoring, and guidance of treatment of ocular and systemic diseases. With the introduction of optical coherence tomography angiography (OCTA), it has become possible to visualize the retinal microvasculature volumetrically and without a contrast agent. Many lab-based and commercial clinical instruments, imaging protocols and data analysis methods and metrics, have been applied, often inconsistently, resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of disease. Open data and software sharing, and cross-comparison and pooling of data from different studies are rare. These inabilities have impeded building the large databases of annotated OCTA images of healthy and diseased retinas that are necessary to study and define characteristics of specific conditions. This paper addresses the steps needed to standardize OCTA imaging of the human retina to address these limitations. Through review of the OCTA literature, we identify issues and inconsistencies and propose minimum standards for imaging protocols, data analysis methods, metrics, reporting of findings, and clinical practice and, where this is not possible, we identify areas that require further investigation. We hope that this paper will encourage the unification of imaging protocols in OCTA, promote transparency in the process of data collection, analysis, and reporting, and facilitate increasing the impact of OCTA on retinal healthcare delivery and life science investigations.
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- 2022
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49. Mitochondrial Dysfunction and Impaired Antioxidant Responses in Retinal Pigment Epithelial Cells Derived from a Patient with RCBTB1-Associated Retinopathy
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Zhiqin Huang, Dan Zhang, Shang-Chih Chen, Di Huang, David Mackey, Fred K. Chen, and Samuel McLenachan
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General Medicine ,RCBTB1 ,inherited retinal disease ,retinal pigment epithelium ,oxidative stress ,mitochondria - Abstract
Mutations in the RCBTB1 gene cause inherited retinal disease; however, the pathogenic mechanisms associated with RCBTB1 deficiency remain poorly understood. Here, we investigated the effect of RCBTB1 deficiency on mitochondria and oxidative stress responses in induced pluripotent stem cell (iPSC)-derived retinal pigment epithelial (RPE) cells from control subjects and a patient with RCBTB1-associated retinopathy. Oxidative stress was induced with tert-butyl hydroperoxide (tBHP). RPE cells were characterized by immunostaining, transmission electron microscopy (TEM), CellROX assay, MitoTracker assay, quantitative PCR and immunoprecipitation assay. Patient-derived RPE cells displayed abnormal mitochondrial ultrastructure and reduced MitoTracker fluorescence compared with controls. Patient RPE cells displayed increased levels of reactive oxygen species (ROS) and were more sensitive to tBHP-induced ROS generation than control RPE. Control RPE upregulated RCBTB1 and NFE2L2 expression in response to tBHP treatment; however, this response was highly attenuated in patient RPE. RCBTB1 was co-immunoprecipitated from control RPE protein lysates by antibodies for either UBE2E3 or CUL3. Together, these results demonstrate that RCBTB1 deficiency in patient-derived RPE cells is associated with mitochondrial damage, increased oxidative stress and an attenuated oxidative stress response.
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- 2023
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50. Measurement Properties of the Attitudes to Gene Therapy for the Eye (AGT-Eye) Instrument for People With Inherited Retinal Diseases
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Myra B. McGuinness, Alexis Ceecee Britten-Jones, Lauren N. Ayton, Robert P. Finger, Fred K. Chen, John Grigg, and Heather G. Mack
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Adult ,Aged, 80 and over ,Male ,Adolescent ,Psychometrics ,Biomedical Engineering ,Australia ,Reproducibility of Results ,Genetic Therapy ,Middle Aged ,Ophthalmology ,Young Adult ,Cross-Sectional Studies ,Attitude ,Retinal Diseases ,Humans ,Female ,Aged - Abstract
To assess the measurement properties of the Attitudes to Gene Therapy for the Eye (AGT-Eye) instrument among Australian adults with inherited retinal diseases (IRDs) and parents/caregivers of people with IRDs. Constructs of interest included sources of information, knowledge of treatment methods, awareness of treatment outcomes, and perceived value of gene therapy for IRDs.A cross-sectional, self-reported, 30-item questionnaire was administered in English from January to June 2021. It was predominantly conducted online with phone and paper alternatives available. Rating scale models were generated separately for each of the four subscales to assess fit, discrimination, and differential item functioning of the items, as well as targeting, reliability, and precision of the subscales. Principal components analysis was used to assess dimensionality.Responses from 681 participants (87.1% online, 12.9% phone/mail) were included (ages 18-93 years; 51.7% female). Removal of two poorly performing items slightly improved subscale properties. Item reliability was high for each of the subscales; however, person reliability was suboptimal, with limited ability to stratify participants according to traits (person separation coefficient1.8 for each subscale). There was no evidence of differential item functioning by gender, online completion, or patient/caregiver status. Evidence of multidimensionality was detected for two subscales.Four subscales of the AGT-Eye will be used to analyze operational knowledge and perceived value of ocular gene therapy in Australia. Measurement properties may be improved with the generation of additional items.Physicians can use the AGT-Eye to assess knowledge and expectations of potential recipients of ocular gene therapy for IRDs.
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- 2022
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