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Reliable automatic diagnosis of Diabetic Retinopathy (DR) and Macular Edema (ME) is an invaluable asset in improving the rate of monitored patients among at-risk populations and in enabling earlier treatments before the pathology progresses and threatens vision. However, the explainability of screening models is still an open question, and specifically designed datasets are required to support the research. We present MAPLES-DR (MESSIDOR Anatomical and Pathological Labels for Explainable Screening of Diabetic Retinopathy), which contains, for 198 images of the MESSIDOR public fundus dataset, new diagnoses for DR and ME as well as new pixel-wise segmentation maps for 10 anatomical and pathological biomarkers related to DR. This paper documents the design choices and the annotation procedure that produced MAPLES-DR, discusses the interobserver variability and the overall quality of the annotations, and provides guidelines on using the dataset in a machine learning context., (© 2024. The Author(s).)

Background: Code-free deep learning (CFDL) is a novel tool in artificial intelligence (AI). This study directly compared the discriminative performance of CFDL models designed by ophthalmologists without coding experience against bespoke models designed by AI experts in detecting retinal pathologies from optical coherence tomography (OCT) videos and fovea-centered images., Methods: Using the same internal dataset of 1,173 OCT macular videos and fovea-centered images, model development was performed simultaneously but independently by an ophthalmology resident (CFDL models) and a postdoctoral researcher with expertise in AI (bespoke models). We designed a multi-class model to categorize video and fovea-centered images into five labels: normal retina, macular hole, epiretinal membrane, wet age-related macular degeneration and diabetic macular edema. We qualitatively compared point estimates of the performance metrics of the CFDL and bespoke models., Results: For videos, the CFDL model demonstrated excellent discriminative performance, even outperforming the bespoke models for some metrics: area under the precision-recall curve was 0.984 (vs. 0.901), precision and sensitivity were both 94.1% (vs. 94.2%) and accuracy was 94.1% (vs. 96.7%). The fovea-centered CFDL model overall performed better than video-based model and was as accurate as the best bespoke model., Conclusion: This comparative study demonstrated that code-free models created by clinicians without coding expertise perform as accurately as expert-designed bespoke models at classifying various retinal pathologies from OCT videos and images. CFDL represents a step forward towards the democratization of AI in medicine, although its numerous limitations must be carefully addressed to ensure its effective application in healthcare., (© 2024. The Author(s).)

Background and Objective: The detection of retinal diseases using optical coherence tomography (OCT) images and videos is a concrete example of a data classification problem. In recent years, Transformer architectures have been successfully applied to solve a variety of real-world classification problems. Although they have shown impressive discriminative abilities compared to other state-of-the-art models, improving their performance is essential, especially in healthcare-related problems., Methods: This paper presents an effective technique named model-based transformer (MBT). It is based on popular pre-trained transformer models, particularly, vision transformer, swin transformer for OCT image classification, and multiscale vision transformer for OCT video classification. The proposed approach is designed to represent OCT data by taking advantage of an approximate sparse representation technique. Then, it estimates the optimal features, and performs data classification., Results: The experiments are carried out using three real-world retinal datasets. The experimental results on OCT image and OCT video datasets show that the proposed method outperforms existing state-of-the-art deep learning approaches in terms of classification accuracy, precision, recall, and f1-score, kappa, AUC-ROC, and AUC-PR. It can also boost the performance of existing transformer models, including Vision transformer and Swin transformer for OCT image classification, and Multiscale Vision Transformers for OCT video classification., Conclusions: This work presents an approach for the automated detection of retinal diseases. Although deep neural networks have proven great potential in ophthalmology applications, our findings demonstrate for the first time a new way to identify retinal pathologies using OCT videos instead of images. Moreover, our proposal can help researchers enhance the discriminative capacity of a variety of powerful deep learning models presented in published papers. This can be valuable for future directions in medical research and clinical practice., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Diabetic retinopathy is a leading cause of preventable blindness in Canada. Clinical guidelines recommend annual diabetic retinopathy screening for people living with diabetes to reduce the risk and progression of vision loss. However, many Canadians with diabetes do not attend screening. Screening rates are even lower in immigrants to Canada including people from China, Africa, and the Caribbean, and these groups are also at higher risk of developing diabetes complications. We aim to assess the feasibility, acceptability, and fidelity of a co-developed, linguistically and culturally tailored tele-retinopathy screening intervention for Mandarin-speaking immigrants from China and French-speaking immigrants from African-Caribbean countries living with diabetes in Ottawa, Canada, and identify how many from each population group attend screening during the pilot period., Methods: We will work with our health system and patient partners to conduct a 6-month feasibility pilot of a tele-retinopathy screening intervention in a Community Health Centre in Ottawa. We anticipate recruiting 50-150 patients and 5-10 health care providers involved in delivering the intervention for the pilot. Acceptability will be assessed via a Theoretical Framework of Acceptability-informed survey with patients and health care providers. To assess feasibility, we will use a Theoretical Domains Framework-informed interview guide and to assess fidelity, and we will use a survey informed by the National Institutes of Health framework from the perspective of health care providers. We will also collect patient demographics (i.e., age, gender, ethnicity, health insurance status, and immigration information), screening outcomes (i.e., patients with retinopathy identified, patients requiring specialist care), patient costs, and other intervention-related variables such as preferred language. Survey data will be descriptively analyzed and qualitative data will undergo content analysis., Discussion: This feasibility pilot study will capture how many people living with diabetes from each group attend the diabetic retinopathy screening, costs, and implementation processes for the tele-retinopathy screening intervention. The study will indicate the practicability and suitability of the intervention in increasing screening attendance in the target population groups. The study results will inform a patient-randomized trial, provide evidence to conduct an economic evaluation of the intervention, and optimize the community-based intervention., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Landau-Zener-Stückelberg-Majorana (LZSM) transitions occur between quantum states when parameters in the system's Hamiltonian are varied continuously and rapidly. In magnetic resonance, losses in adiabatic rapid passage can be understood using the physics of LZSM transitions. Most treatments of LZSM transitions ignore the T 2 dephasing of coherences, however. Motivated by ongoing work in magnetic resonance force microscopy, we employ the Bloch equations, coordinate transformation, and the Magnus expansion to derive expressions for the final magnetization following a rapid field sweep at fixed irradiation intensity that include T 2 losses. Our derivation introduces an inversion-function, Fourier transform method for numerically evaluating highly oscillatory integrals. Expressions for the final magnetization are given for low and high irradiation intensity, valid in the T 2 ≪T 1 limit. Analytical results are compared to numerical simulations and nuclear magnetic resonance experiments. Our relatively straightforward calculation reproduces semiquantitatively the well known LZSM result in the T 2 →0 limit., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [John A. Marohn reports financial support was provided by US Army Research Office. John A. Marohn reports financial support was provided by National Institutes of Health. John A. Marohn reports financial support was provided by Cornell University.], (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Diabetic retinopathy is a sight-threatening ocular complication of diabetes. Screening is an effective way to reduce severe complications, but screening attendance rates are often low, particularly for newcomers and immigrants to Canada and people from cultural and linguistic minority groups. Building on previous work, in partnership with patient and health system stakeholders, we co-developed a linguistically and culturally tailored tele-retinopathy screening intervention for people living with diabetes who recently immigrated to Canada from either China or African-Caribbean countries., Methods: Following an environmental scan of diabetes eye care pathways in Ottawa, we conducted co-development workshops using a nominal group technique to create and prioritize personas of individuals requiring screening and identify barriers to screening that each persona may face. Next, we used the Theoretical Domains Framework to categorize the barriers/enablers and then mapped these categories to potential evidence-informed behaviour change techniques. Finally with these techniques in mind, participants prioritized strategies and channels of delivery, developed intervention content, and clarified actions required by different actors to overcome anticipated intervention delivery barriers., Results: We carried out iterative co-development workshops with Mandarin and French-speaking individuals living with diabetes (i.e., patients in the community) who immigrated to Canada from China and African-Caribbean countries (n = 13), patient partners (n = 7), and health system partners (n = 6) recruited from community health centres in Ottawa. Patients in the community co-development workshops were conducted in Mandarin or French. Together, we prioritized five barriers to attending diabetic retinopathy screening: language (TDF Domains: skills, social influences), retinopathy familiarity (knowledge, beliefs about consequences), physician barriers regarding communication for screening (social influences), lack of publicity about screening (knowledge, environmental context and resources), and fitting screening around other activities (environmental context and resources). The resulting intervention included the following behaviour change techniques to address prioritized local barriers: information about health consequence, providing instructions on how to attend screening, prompts/cues, adding objects to the environment, social support, and restructuring the social environment. Operationalized delivery channels incorporated language support, pre-booking screening and sending reminders, social support via social media and community champions, and providing using flyers and videos as delivery channels., Conclusion: Working with intervention users and stakeholders, we co-developed a culturally and linguistically relevant tele-retinopathy intervention to address barriers to attending diabetic retinopathy screening and increase uptake among two under-served groups., (© 2023. The Author(s).)

The sensitivity of magnetic resonance force microscopy (MRFM) is limited by surface noise. Coating a thin-film polymer sample with metal has been shown to decrease, by orders of magnitude, sample-related force noise and frequency noise in MRFM experiments. Using both MRFM and inductively detected measurements of electron-spin resonance, we show that thermally evaporating a 12 nm gold layer on a 40 nm nitroxide-doped polystyrene film inactivates the nitroxide spin labels to a depth of 20 nm, making single-spin measurements difficult or impossible. We introduce a "laminated sample" protocol in which the gold layer is first evaporated on a sacrificial polymer. The sample is deposited on the room-temperature gold layer, removed using solvent lift-off, and placed manually on a coplanar waveguide. Electron spin resonance (ESR) of such a laminated sample was detected via MRFM at cryogenic temperatures using a high-compliance cantilever with an integrated 100-nm-scale cobalt tip. A 20-fold increase of spin signal was observed relative to a thin-film sample prepared instead with an evaporated metal coating. The observed signal is still somewhat smaller than expected, and we discuss possible remaining sources of signal loss.

Vision Transformers have recently emerged as a competitive architecture in image classification. The tremendous popularity of this model and its variants comes from its high performance and its ability to produce interpretable predictions. However, both of these characteristics remain to be assessed in depth on retinal images. This study proposes a thorough performance evaluation of several Transformers compared to traditional Convolutional Neural Network (CNN) models for retinal disease classification. Special attention is given to multi-modality imaging (fundus and OCT) and generalization to external data. In addition, we propose a novel mechanism to generate interpretable predictions via attribution maps. Existing attribution methods from Transformer models have the disadvantage of producing low-resolution heatmaps. Our contribution, called Focused Attention, uses iterative conditional patch resampling to tackle this issue. By means of a survey involving four retinal specialists, we validated both the superior interpretability of Vision Transformers compared to the attribution maps produced from CNNs and the relevance of Focused Attention as a lesion detector., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Clément Playout reports financial support was provided by Diabetes Action Canada., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: The COVID-19 pandemic is an event that deeply impacts our personal, professional, and collective lives. How do we teach in these times of great upheaval? What are the main changes that have occurred?, Method: Using the Cartel logic, four professors and a qualitative researcher carried out an autoethnographic research aimed at documenting the main changes that have occurred in the teaching of family medicine in their respective practices located in four different academic family medicine groups at the University of Sherbrooke., Results: Five key moments in teaching that occurred during a pandemic were identified: a) the declaration of a pandemic, b) the approach with the graduating/advanced cohort of residents, c) the anticipation and preparation for the arrival of new residents, d) arrival of first year residents and e) adaptation to the second wave. For each moment, we present the issues encountered in our care and teaching practices under three transversal relational axes: the relationship of humans to their cultural context, the patient-doctor relationship, and the teacher-resident relationship., Conclusion: Our analysis shows that the transmission of medical knowledge and the art of medicine cannot take place without specific attention to the overall cultural context, the contextual relationship of clinical care, and the teaching relationship. Our study also makes it possible to recommend the opening of spaces for reflection and dialogue in our teaching environments., (© 2022 Dubé, Boucher, Champagne, Garand, Rinfret; licensee Synergies Partners.)

Background: With the high prevalence of diabetic retinopathy and its significant visual consequences if untreated, timely identification and management of diabetic retinopathy is essential. Teleophthalmology programs have assisted in screening a large number of individuals at risk for vision loss from diabetic retinopathy. Training nonophthalmological readers to assess remote fundus images for diabetic retinopathy may further improve the efficiency of such programs., Objective: This study aimed to evaluate the performance, safety implications, and progress of 2 ophthalmology nurses trained to read and assess diabetic retinopathy fundus images within a hospital diabetic retinopathy telescreening program., Methods: In this retrospective interobserver study, 2 ophthalmology nurses followed a specific training program within a hospital diabetic retinopathy telescreening program and were trained to assess diabetic retinopathy images at 2 levels of intervention: detection of diabetic retinopathy (level 1) and identification of referable disease (level 2). The reliability of the assessment by level 1-trained readers in 266 patients and of the identification of patients at risk of vision loss from diabetic retinopathy by level 2-trained readers in 559 more patients were measured. The learning curve, sensitivity, and specificity of the readings were evaluated using a group consensus gold standard., Results: An almost perfect agreement was measured in identifying the presence of diabetic retinopathy in both level 1 readers (κ=0.86 and 0.80) and in identifying referable diabetic retinopathy by level 2 readers (κ=0.80 and 0.83). At least substantial agreement was measured in the level 2 readers for macular edema (κ=0.79 and 0.88) for all eyes. Good screening threshold sensitivities and specificities were obtained for all level readers, with sensitivities of 90.6% and 96.9% and specificities of 95.1% and 85.1% for level 1 readers (readers A and B) and with sensitivities of 86.8% and 91.2% and specificities of 91.7% and 97.0% for level 2 readers (readers A and B). This performance was achieved immediately after training and remained stable throughout the study., Conclusions: Notwithstanding the small number of trained readers, this study validates the screening performance of level 1 and level 2 diabetic retinopathy readers within this training program, emphasizing practical experience, and allows the establishment of an ongoing assessment clinic. This highlights the importance of supervised, hands-on experience and may help set parameters to further calibrate the training of diabetic retinopathy readers for safe screening programs., (©Marie Carole Boucher, Michael Trong Duc Nguyen, Jenny Qian. Originally published in JMIR Diabetes (http://diabetes.jmir.org), 07.04.2020.)

Objective: The purpose of this report is to develop a consensus for Canadian national guidelines specific to a tele-medicine approach to screening for diabetic retinopathy (DR) using evidence-based and clinical data., Methods: Canadian Tele-Screening Grading Scales for DR and diabetic macular edema (DME) were created primarily based on severity grading scales outlined by the International Clinical Diabetic Retinopathy Disease Severity Scale (ICDR) and the Scottish DR Grading Scheme 2007. Other grading scales used in international screening programs and the clinical expertise of the Canadian Retina Research Network members and retina specialists nationwide were also used in the creation of the guidelines., Results: National Tele-Screening Guidelines for DR and DME with and without optical coherence tomography (OCT) images are proposed. These outline a diagnosis and management algorithm for patients presenting with different stages of DR and/or DME. General guidelines detailing the requirements for imaged retina fields, image quality, quality control, and follow-up care and the role of visual acuity, pupil dilation, OCT, ultra-wide-field imaging, and artificial intelligence are discussed., Conclusions: Tele-retina screening can help to address the need for timely and effective screening for DR, whose prevalence continues to rise. A standardized and evidence-based national approach to DR tele-screening has been proposed, based on DR/DME grading using two 45° image fields or a single widefield or ultra-wide-field image, preferable use of OCT imaging, and a focus on local quality control measures., (Copyright © 2020 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.)

Background: Although many diabetic retinopathy (DR) tele-screening projects have shown effectiveness for DR, timely follow-up care after screening is essential to achieve the expected visual benefits of screening., Objective: To better understand the possible factors of non-compliance to follow-up care in diabetics after tele-screening for DR., Method: This cross-sectional retrospective descriptive study analyses the data of 148 diabetics referred to follow-up care following screening of 1185 diabetics through an urban community-based DR Teleophthalmology Project aimed at Type 2 diabetes. A telephone survey was conducted to assess the screening program appreciation and the sociodemographic characteristics of that population., Results: This study achieved a 91,9% (n=136) compliance rate to follow-up care. Female sex, type 2 diabetes, lower general and DR education, telephone unreachability, age less than 60 years, knowledge of a visually impaired acquaintance and more severe DR were more prevalent in non-compliant patients. Age, ethnicity, economic status, level of precariousness, distance from home to the screening/examination sites, and previous adherence to the DR screening guidelines were similar in both compliants and noncompliants. A high satisfaction score (4,8/5, n=96) to the tele-screening program was measured., Conclusion: This study is applicable to other screening programs and suggests that an increase in the number of recall letters and a greater flexibility in the organization of follow-up care appointments as well as the addition of multilingual members to the recalling team may have further improved compliance to follow-up care. It measures a high level of satisfaction provided by this model of urban teleophthalmology screening., (Copyright © 2019 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.)

Objective: To assess real-world results and the impact on a hospital service corridor for screening for DR through an urban community teleophthalmology service., Methods: Retrospective analysis at the hospital service corridor of 148 diabetics referred to it following DR teleophthalmology screening of 1185 type II diabetics., Results: Of the screened diabetics, 87.4% (n = 1036) were exempted from face-to-face clinical examination (FFCE) in a traditional hospital eye care pathway and continued monitoring through teleophthalmology under a watch-and-wait attitude, while 12.5% (n = 148) were recommended for an FFCE. The FFCEs revealed that significant DR was present in 48.2% or in 5.6% of this screened diabetic population. Reasons for referral were findings of significant DR in 40.5%, of which diabetic macular edema (DME) represented 86.6%, other incidental significant sight-threatening findings represented 32.4% (4% of the screened diabetics), and insufficient image quality was obtained for the other 27.0%. Optical coherence tomography (OCT) imaging at FFCE confirmed DME in 26.4% and led to treatment. Patients referred for insufficient image quality showed significant pathology in 90.2%, of whom 63.4% underwent further monitoring or treatment. The readers requested the FFCEs for 148 patients within 1 month of the reading in 19.6%, 3 months in 26.3%, 4-12 months in 47.3%, and 12 months in 6.7% over the 34 months of the study. Compliance with FFCEs was 91.9%, absolute in 78.4% and relative in 21.5%. The availability of OCT at the imaging site would have impacted 4.5% of the screened diabetics by enabling teleophthalmology monitoring of 91.6%, identifying just-in-time interventions for DME treatments in 26.4% and reducing by 25% the need for referral of OCT-negative reader-identified DME., Conclusion: The FFCEs generated at the hospital service corridor by an urban community DR screening teleophthalmology project did not impact negatively on its services; moreover, the service corridor was exempted from providing FFCEs to 87.4% of the diabetic population it serves. This study may help provide cost-efficiency indications for a screening protocol that would include OCT availability at the imaging site and measure its positive effects. While DR of which DME was the main cause of referral for FFCE, incidental significant sight-threatening findings were significant and approached DR as a cause of referral; this supports the recommendation of continued human intervention in DR teleophthalmology screening at this time and for this population, until automatic computer-aided diagnosis systems can recognise biomarkers associated with other significant fundus diseases. As a secondary gain this project benefited individuals in need of care who were lost to the traditional eye care pathway. Good compliance with the follow-up FFCE further supports teleophthalmology in its effort to provide better access to DR screening., (Copyright © 2018 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.)

Recent advances in the therapeutic options and approaches for diabetic retinopathy (DR) and diabetic macular edema (DME) have resulted in improved visual outcomes for many patients with diabetes. Yet, they have also created many clinical dilemmas for treating ophthalmologists and retina specialists, including treatment selection, initiation, frequency and duration. With this in mind, a panel of Canadian retina specialists met and discussed the current clinical evidence as well as specific situations and scenarios commonly encountered in daily practice. They also shared their experiences and therapeutic approaches. This document, containing a consensus on treatment algorithms for various clinical scenarios, is the result of their lengthy and in-depth discussions and considerations. The intent is to provide a step-by-step approach to the treatment of DR and DME. Although clinicians are encouraged to use and refer to these algorithms as a guide for various situations, they are not meant to be a replacement for sound clinical judgment., (© 2013 S. Karger AG, Basel.)

Background: This study aimed to describe and measure the health results of a Category 3 teleophthalmology screening project for diabetic retinopathy (DR). Implemented through mobile screening imaging units located within pharmacies, the project had the goal of reaching unscreened diabetic patients in urban communities while lowering barriers to screening and saving medical resources., Methods: Image capture of both eyes of 3505 known diabetic individuals was performed in the provinces of Quebec, British Columbia, Alberta, Manitoba, and Saskatchewan. A photographer performed fundus imaging, and a nurse used mild pupil dilation only when necessary to secure image quality. Screening was provided free of cost in the context of DR health days for DR screening. Through teleophthalmology, ophthalmologists proceeded with data and image interpretation, and timely referral when indicated., Results: This project allowed the resumption of screening of over 38% of the cohort of known diabetics who reported never having undergone any eye examination with pupil dilation, and an additional 30% who reported not having been examined for over 2 years. All known diabetics were under the care of a general physician, and their mean diabetes duration, when known, was 8 years. DR pathology was found in 22.5% (20%-28%) of the cohort, 1.8% requiring urgent referral (within 30 days) as a result of the severity of the DR and 0.6% (0%-1.8%) requiring urgent referral for other reasons. An additional 8.7% (8.1%-19.5%) required ophthalmologic attention within 6 months because of DR and another 2.0% (0%-6.3%) between 6 months and 1 year. Incidental findings were found in 23%, the majority of which were related to cataract and dry macular degeneration. Urgent or significant incidental findings were found in 0.6% of the screened eyes. Pupil dilation with tropicamide 1% was deemed useful or necessary in 33.7% of the cohort. For 0.7% of the cohort, the images could not be interpreted because of poor image quality and for that reason had to be referred for a traditional dilated eye examination. Ophthalmologists were relieved of the examination of 85.6% of the screened diabetic individuals who benefited from screening without requiring a traditional ophthalmologic examination. On the other hand, ophthalmologists were required to provide urgent (within 30 days) services to 2% of the cohort, either because of threatening DR or because of incidental findings requiring rapid ophthalmologic attention., Interpretation: This screening strategy for DR through mobile teleophthalmology imaging units efficiently lowered barriers to screening and created new screening opportunities for a large number of known diabetic individuals who were lost to the traditional health system. It has the potential to provide better outreach to diabetic populations while identifying individuals truly in need of the services of an ophthalmologist; at the same time it maximizes the use of limited ophthalmologic resources while favouring multidisciplinary collaborations. The significant incidental findings associated with screening highlight the need for ophthalmologic competencies during DR screening within a teleophthalmology approach. Further involvement of government health authorities is pivotal in embracing the opportunities provided by emerging technologies such as teleophthalmology and translating them into better outreach services to diabetic populations and thus better visual health results.

Background: Diabetic retinopathy is a leading cause of blindness. Studies have shown the value of screening and early, timely treatment. Our aim was to measure the effectiveness and degree of acceptance of community screening for diabetic retinopathy using telemedicine., Methods: In this prospective, population-based cross-sectional study, diabetics recruited through a regional multimedia campaign were surveyed and screened for retinopathy using a nonmydriatic camera and evaluated through telemedical imaging., Results: Of the 291 diabetics recruited over a 3-week period (37% by the regional diabetes association and 30% by the media), 49.4% reported having their most recent eye examination within 1 year, 30.7% between 1 to 2 years, 9.7% over 2 years, and 10.1% had never had an exam. 98.6% found our screening method acceptable, with 95.1% wanting to return for their next screening and 91.2% stating it would increase their compliance to annual screening., Interpretation: Telemedicine provided a reliable and highly acceptable method for diabetic retinopathy screening. It can attract a significant number of people with diabetes and potentially recruit patients who would otherwise be missed by the current methods of vision screening.

Case Report: We describe the clinical presentation of a choroidal amelanotic melanoma in a 46-year-old woman with oculocutaneous albinism. Clinical aspects, investigations, and management are presented, and findings from computed tomography and magnetic resonance imaging are described. Microscopic findings and histopathological features, demonstrating a spindle B-cell melanoma of the choroid, are also reviewed., Comments: Magnetic resonance imaging may be helpful in diagnosing amelanotic melanoma in patients with oculocutaneous albinism.

Background: The use of nonmydriatic cameras, which offer ease of screening and 45 degrees immediate imaging of the fundus, is gaining increasing acceptance for screening programs tailored to diverse conditions. We performed a study to evaluate the effectiveness and safety of screening for diabetic retinopathy with two nonmydriatic camera images compared with the seven standard stereoscopic 30 degrees fields (7SF). We also wished to determine whether safe screening guidelines could be established to identify patients needing referral to an ophthalmologist., Methods: In this prospective masked cross-sectional study, we evaluated agreement in the assessment of the severity of diabetic retinopathy by means of two 45 degrees images centred on the optic disc and on the macula obtained with the Topcon CRW6 nonmydriatic camera and by means of 7SF photography and ophthalmologic slit-lamp biomicroscopy, both performed with pupil dilation. Between November 2000 and June 2001, 98 adult patients known to have type 1 or 2 diabetes mellitus who presented for the first time to the diabetic retinopathy clinic of a tertiary care centre in Montreal were enrolled consecutively. Thus, patient recruitment was weighted toward more severe retinopathy to ensure sufficient representation of less frequent but more severe levels. Each patient underwent nonmydriatic fundus photography of both eyes, followed by a complete ophthalmologic examination with pupil dilation by a single retina specialist and 7SF photography of both eyes with pupil dilation. The level of retinopathy was graded independently in each eye from the 7SF photographs according to the Early Treatment Diabetic Retinopathy Study (ETDRS) scale by two graders; an independent retina specialist adjudicated the rare instances of interreader disagreement in a masked fashion. Two months later, two graders independently graded the nonmydriatic images in a blinded fashion according to the ETDRS scale; a third observer adjudicated the rare instances of interreader disagreement. We measured concordance between grading results with the various screening techniques using the weighted and unweighted kappa statistic. We used sensitivity and specificity indices to determine safe screening guidelines to identify patients needing referral to an ophthalmologist., Results: There was substantial agreement in the grading of retinopathy with nonmydriatic camera imaging and with 7SF photography, both for all eyes (kappa = 0.626 [standard deviation (SD) 0.045]) and for the eye with more severe disease (kappa = 0.654 [SD 0.063]). With nonmydriatic camera imaging, screening thresholds for patient referral to an ophthalmologist of very mild retinopathy (ETDRS grade 20), mild retinopathy (ETDRS grade 35) and moderate retinopathy (EDTRS grade 43) had sensitivity values of 97.9%, 97.1% and 53.3% respectively and specificity values of 81.3%, 95.5% and 96.9% respectively. Screening thresholds of very mild or mild retinopathy both correctly identified 100% of eyes with severe nonproliferative or proliferative retinopathy. With a screening threshold of mild retinopathy, screening with the nonmydriatic camera would lead to referral to an ophthalmologist of 37.8% of patients because of detected disease and of an additional 17.3% because of insufficient image quality in at least one eye, for a total of 55.1%. The overall sensitivity and specificity of a two-field nonmydriatic screening strategy with a threshold of mild retinopathy for referral of patients with insufficient image quality in at least one eye are 97.7% and 84.0% respectively., Interpretation: Our results suggest that two-field nonmydriatic camera imaging is a safe screening strategy that may identify the patients with diabetes most in need of ophthalmologic care.

Background: The use of the nonmydriatic camera is gaining increasing acceptance for the detection of diabetic retinopathy when integrated into a community-tailored program. We performed a study to evaluate the optimal number and positioning of photographic fields necessary to screen for diabetic retinopathy with the Topcon CRW6 nonmydriatic camera., Methods: In this prospective masked cross-sectional comparative study, we compared the assessment of diabetic retinopathy using two, three or four 45 degrees fundus images (centred respectively on the disc and the macula; on the disc, on the macula and temporal to the macula; and on the disc, on the macula, temporal to the macula and superotemporal to the macula, including the superior temporal vein) acquired with the Topcon CRW6 nonmydriatic camera, with the grading of the seven standard stereoscopic 30 degrees field photographs (7SF). The study population consisted of 98 consecutive adult patients known to have type 1 or 2 diabetes mellitus who presented for the first time to the diabetic retinopathy clinic of a tertiary care centre in Montreal. All patients underwent four nonmydriatic fundus photography sessions of both eyes, 7SF photography with pupil dilation and a complete ophthalmologic examination with pupil dilation by a retina specialist., Results: Compared to the 7SF, the sensitivity and specificity of screening for any retinopathy (Early Treatment Diabetic Retinopathy Study [ETDRS] grade greater than 10) using the two central fields were 95.7% and 78.1% respectively. The corresponding values with three image fields were 97.6% and 71.9%, and with four image fields, 97.6% and 65.6%. The sensitivity and specificity of screening for mild or worse disease (ETDRS grade 35 or greater) using the two central fields were 87.5% and 92.3%. The corresponding values with three image fields were 88.9% and 94.6%, and with four image fields, 88.9% and 91.9%. Poor image quality occurring with the addition of extra fields resulted in an increase of 6.2% in the rate of referral to an ophthalmologist. The use of two image fields missed no cases of retinopathy., Interpretation: The use of image fields in addition to the two 45 degrees images centred on the disc and the macula on imaging with the Topcon CRW6 nonmydriatic camera did not significantly increase the sensitivity or specificity of screening for diabetic retinopathy. Contrary to the desired effect, the addition of fields resulted in diminished utility and cost-effectiveness of this screening approach.

Purpose: To estimate the misclassification rate of self-reported visual disabilities in a hospital-based population with known visual impairment., Methods: Subjects (N=570) were recruited among patients aged 50 years and more and classified to three categories of visual impairment level. The questionnaire was administered to consenting patients through a telephone interview. Data collected from questionnaires and medical records were compared regarding severity of visual impairment. Sensitivity and specificity were determined for each question. Predictive ability and misclassification rates were computed for various prevalences., Results: Questions related to near and far distance visual acuity with glasses have both a good sensitivity (82.6% and 81.8%) and a good specificity (85.6% and 88.9%) for the presence of severe visual impairment., Conclusion: The findings allow the determination of the misclassification rate and predictive ability. This could be useful to estimate the prevalence of visual impairment from health surveys.

The authors describe in detail the modalities for the selection of students applying to the ophthalmology programs in the various Canadian universities; the university of Montréal will serve as a model. The characteristics of their 5-year training assured by numerous teachers and short training rotations as well as by a compulsory research project are explained. They highlight the meticulous organization and the compulsory constraints for students, teachers and universities. In absence of evaluation criteria on the efficiency of interventionist training compared to less detailed apprenticeship-program training such as that dispensed in France, they note the differences between the two systems, a necessary precursor to the standardization of training programs which would allow more complete recognition of degrees in the context of a globalization of professional activities.

Fifty-six patients with presumed ocular histoplasmosis syndrome who exhibited a disciform macular detachment or macular scar in one fundus and one or more inactive atrophic lesions within the high-risk area of the second eye were seen at the Retina Service of Maisonneuve-Rosemont Hospital, Montreal, between 1972 and 1984. All 56 were followed for at least 10 months. Of the 56, 28 had received prophylactic argon laser photocoagulation of the inactive chorioretinal lesions. The rate of activation of the lesions was similar in the treated and untreated groups (10/28 over a mean follow-up period of 44.2 months and 11/28 over a mean period of 43.2 months respectively). In the untreated group there was an increased risk of activation with a higher number of lesions (t = 2.386). In both groups the risk of activation increased with the proximity of the lesions to the centre of the fovea (chi 2 = 29.97). Of the 10 treated eyes that showed activation, 4 did so within 1 month, which suggests that prophylactic photocoagulation may not be without risk of complications.

To study the effect of nitrous oxide on the rate of absorption of intraocular air one eye of each of 20 rabbits was injected with 4 ml of air following lensectomy and total vitrectomy. After 24 hours the eyes of the 10 rabbits anesthetized with N2O had absorbed 25% more of the air than the eyes of the 10 rabbits anesthetized without N2O. These results suggest that the use of nitrous oxide for general anesthesia when air must be injected into the eye may be inadvisable.