WorldWideScience

Sample records for non-mydriatic digital fundus

  1. Non-mydriatic, wide field, fundus video camera

    Science.gov (United States)

    Hoeher, Bernhard; Voigtmann, Peter; Michelson, Georg; Schmauss, Bernhard

    2014-02-01

    We describe a method we call "stripe field imaging" that is capable of capturing wide field color fundus videos and images of the human eye at pupil sizes of 2mm. This means that it can be used with a non-dilated pupil even with bright ambient light. We realized a mobile demonstrator to prove the method and we could acquire color fundus videos of subjects successfully. We designed the demonstrator as a low-cost device consisting of mass market components to show that there is no major additional technical outlay to realize the improvements we propose. The technical core idea of our method is breaking the rotational symmetry in the optical design that is given in many conventional fundus cameras. By this measure we could extend the possible field of view (FOV) at a pupil size of 2mm from a circular field with 20° in diameter to a square field with 68° by 18° in size. We acquired a fundus video while the subject was slightly touching and releasing the lid. The resulting video showed changes at vessels in the region of the papilla and a change of the paleness of the papilla.

  2. Feasibility of Non-Mydriatic Ocular Fundus Photography in the Emergency Department: Phase I of the FOTO-ED Study

    Science.gov (United States)

    Bruce, Beau B.; Lamirel, Cédric; Biousse, Valérie; Ward, Antionette; Heilpern, Katherine L.; Newman, Nancy J.; Wright, David W.

    2011-01-01

    Objectives Examination of the ocular fundus is imperative in many acute medical and neurologic conditions, but direct ophthalmoscopy by non-ophthalmologists is underutilized, poorly performed, and difficult without pharmacologic pupillary dilation. The objective was to examine the feasibility of non-mydriatic fundus photography as a clinical alternative to direct ophthalmoscopy by emergency physicians (EPs). Methods Adult patients presenting to the emergency department (ED) with headache, acute focal neurologic deficit, diastolic blood pressure ≥ 120 mmHg, or acute visual change had ocular fundus photographs taken by nurse practitioners using a non-mydriatic fundus camera. Photographs were reviewed by a neuro-ophthalmologist within 24 hours for findings relevant to acute ED patient care. Nurse practitioners and patients rated ease, comfort, and speed of non-mydriatic fundus photography on a 10-point Likert scale (10 best). Timing of visit and photography were recorded by automated electronic systems. Results Three hundred fifty patients were enrolled. There were 1,734 photographs taken during 230 nurse practitioner shifts. Eighty-three percent of the 350 patients had at least one eye with a high quality photograph, while only 3% of patients had no photographs of diagnostic value. Mean ratings were ≥ 8.7 (standard deviation [SD] ≤ 1.9) for all measures. The median photography session lasted 1.9 minutes (interquartile range [IQR] 1.3 to 2.9 minutes), typically accounting for less that 0.5% of the patient’s total ED visit. Conclusions Non-mydriatic fundus photography taken by nurse practitioners is a feasible alternative to direct ophthalmoscopy in the ED. It is performed well by non-physician staff, is well-received by staff and patients, and requires a trivial amount of time to perform. PMID:21906202

  3. 应用免散瞳眼底照相技术筛查糖尿病视网膜病变临床分析%Clinical analysis of the application of non-mydriatic fundus photography for diabetic retinopathy screening

    Institute of Scientific and Technical Information of China (English)

    夏伟; 王利; 李蓬秋; 张学军; 杨艳; 杨毅

    2013-01-01

    目的:应用免散瞳眼底照相技术对糖尿病( diabetes mellitus,DM)患者糖尿病视网膜病变( diabetic retinopathy , DR)的患病情况进行筛查,并探讨DR的相关危险因素。方法:纳入2010-11/2011-12期间在我院内分泌科门诊就诊的768例2型DM患者。对所有患者采用免散瞳眼底照相机进行双侧眼底照相,并根据2002年DR国际临床分期标准将患者分为两组:DR组和非糖尿病视网膜病变组( non-diabetic retinopathy group , NDR)。采集病史,测量身高、体质量和血压,测定空腹静脉血浆葡萄糖( fasting plasma glucose , FPG )、血脂、糖化血红蛋白(glycated hemoglobin A1c,HbA1c)和尿酸(uric acid,UA)。结果:选取768例DM患者中DR患者317例,检出率为41.3%,女性DM 患者DR的检出率明显高于男性患者(45.2%vs 37.6%, P<0.05)。与NDR组相比,DR组年龄较大,病程较长,收缩压( systolic blood pressure , SBP )、FPG、甘油三酯(TG)、HbA1c、UA水平较高(P<0.05)。二项 Logistic 回归分析进一步显示,病程、性别、SBP 和HbA1 c为DM患者发生DR的独立危险因素。结论:DM患者常常并发DR,其发生与病程、性别、血压和血糖关系密切。免散瞳眼底照相技术是一种较理想的DR筛查方法。%AIM: To screen diabetic retinopathy ( DR ) in diabetes mellitus ( DM ) patients by non -mydriatic fundus photography, and to investigate the risk factors in DM patients for DR. METHODS:A total of 768 patients with DM type 2 treated in the department of endocrinology in our hospital from November 2010 to December 2011 were enrolled in this study. All patients underwent non -mydriatic fundus photography, and were divided into two groups: non-diabetic retinopathy group ( NDR group) and DR group, in accordance with the international clinical staging standard of DR released in 2002.Weight, height, blood pressure and

  4. The investigation of chromatic aberration correction for digital eye fundus images

    OpenAIRE

    Jakstys, V.; Marcinkevicius, V.; Treigys, P.

    2016-01-01

    This paper focuses on the lateral chromatic aberration correction in images captured with Optomed SmartScope M5 camera. This portable non-mydriatic eye fundus orbital camera does not have chromatic lenses. When photo camera system is designed without chromatic lenses, it is necessary to apply image processing algorithms for lateral chromatic aberration effect correction. These algorithms try to scale the fringed colour channels so that all channels spatially overlap each other ...

  5. Ophthalmoscopy versus non-mydriatic fundus photography in the ...

    African Journals Online (AJOL)

    1990-09-01

    Sep 1, 1990 ... detection of diabetic retinopathy before and after dilatation of th~ pU~i1s in black diabetics was .... patient's retina, the camera also provides excellent material for student education. We are indebted to Mr R. Taylor for taking ...

  6. An evaluation of fundus photography and fundus autofluorescence in the diagnosis of cuticular drusen

    DEFF Research Database (Denmark)

    Høeg, Tracy B; Moldow, Birgitte; Klein, Ronald

    2016-01-01

    PURPOSE: To examine non-mydriatic fundus photography (FP) and fundus autofluorescence (FAF) as alternative non-invasive imaging modalities to fluorescein angiography (FA) in the detection of cuticular drusen (CD). METHODS: Among 2953 adults from the Danish Rural Eye Study (DRES) with gradable FP...

  7. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Charles; Veras, Rodrigo; Ramalho, Geraldo; Medeiros, Fatima; Ushizima, Daniela

    2008-08-29

    Ocular fundus images can provide information about retinal, ophthalmic, and even systemic diseases such as diabetes. Microaneurysms (MAs) are the earliest sign of Diabetic Retinopathy, a frequently observed complication in both type 1 and type 2 diabetes. Robust detection of MAs in digital color fundus images is critical in the development of automated screening systems for this kind of disease. Automatic grading of these images is being considered by health boards so that the human grading task is reduced. In this paper we describe segmentation and the feature extraction methods for candidate MAs detection.We show that the candidate MAs detected with the methodology have been successfully classified by a MLP neural network (correct classification of 84percent).

  8. Comparison between Early Treatment Diabetic Retinopathy Study 7-field retinal photos and non-mydriatic, mydriatic and mydriatic steered widefield scanning laser ophthalmoscopy for assessment of diabetic retinopathy

    DEFF Research Database (Denmark)

    Rasmussen, Malin Lundberg; Broe, Rebecca; Frydkjaer-Olsen, Ulrik;

    2015-01-01

    AIMS: To compare non-mydriatic, mydriatic and steered mydriatic widefield retinal images with mydriatic 7-field Early Treatment Diabetic Retinopathy Study (ETDRS)-standards in grading diabetic retinopathy (DR). METHODS: We examined 95 patients (190 eyes) with type 1 diabetes. A non-mydriatic, a m...

  9. Quality Enhancement and Nerve Fibre Layer Artefacts Removal in Retina Fundus Images by Off Axis Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relative low cost, these cameras are employed worldwide by retina specialists to diagnose diabetic retinopathy and other degenerative diseases. Even with relative ease of use, the images produced by these systems sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or other camera lens related reflections. We propose a technique that employs multiple fundus images acquired from the same patient to obtain a single higher quality image without these reflectance artefacts. The removal of bright artefacts, and particularly of NFL reflectance, can have great benefits for the reduction of false positives in the detection of retinal lesions such as exudate, drusens and cotton wool spots by automatic systems or manual inspection. If enough redundant information is provided by the multiple images, this technique also compensates for a suboptimal illumination. The fundus images are acquired in straightforward but unorthodox manner, i.e. the stare point of the patient is changed between each shot but the camera is kept fixed. Between each shot, the apparent shape and position of all the retinal structures that do not exhibit isotropic reflectance (e.g. bright artefacts) change. This physical effect is exploited by our algorithm in order to extract the pixels belonging to the inner layers of the retina, hence obtaining a single artefacts-free image.

  10. Comparison of non-mydriatic retinal photography with ophthalmoscopy in 2159 patients: mobile retinal camera study.

    Science.gov (United States)

    Taylor, R; Lovelock, L; Tunbridge, W M; Alberti, K G; Brackenridge, R G; Stephenson, P; Young, E

    1990-01-01

    OBJECTIVE--To determine whether non-mydriatic Polaroid retinal photography was comparable to ophthalmoscopy with mydriasis in routine clinic screening for early, treatable diabetic retinopathy. DESIGN--Prospective study of ophthalmoscopic findings according to retinal camera screening and ophthalmoscopy and outcome of referral to ophthalmologist. SETTING--Outpatient diabetic clinics of three teaching hospitals and three district general hospitals. PATIENTS--2159 Adults selected randomly from the diabetic clinics, excluding only those registered as blind or those in wheelchairs and unable to enter the screening vehicle. MAIN OUTCOME MEASURES--Numbers of patients and eyes correctly identified by each technique as requiring referral with potentially treatable retinopathy (new vessel formation and maculopathy) and congruence in numbers of microaneurysms, haemorrhages, and exudates reported. RESULTS--Camera screening missed two cases of new vessel formation and did not identify a further 12 but indicated a need for referral. Ophthalmoscopy missed five cases of new vessel formation and indicated a need for referral in another four for other reasons. Maculopathy was reported in 147 eyes with camera screening alone and 95 eyes by ophthalmoscopy only (chi 2 = 11.2; p less than 0.001), in 66 and 29 of which respectively maculopathy was subsequently confirmed. Overall, 38 eyes received laser treatment for maculopathy after detection by camera screening compared with 17 after ophthalmoscopic detection (chi 2 = 8.0; p less than 0.01). Camera screening underestimated numbers of microaneurysms (chi 2 = 12.9; p less than 0.001) and haemorrhages (chi 2 = 7.4; p less than 0.01) and ophthalmoscopy underestimated hard exudates (chi 2 = 48.2; p less than 0.001). CONCLUSIONS--Non-mydriatic Polaroid retinal photography is at least as good as ophthalmoscopy with mydriasis in routine diabetic clinics in identifying new vessel formation and absence of retinopathy and is significantly better

  11. Automated Detection and Differentiation of Drusen, Exudates, and Cotton-wool Spots in Digital Color Fundus Photographs for Early Diagnosis of Diabetic Retinopathy IOVS-06-0996 accepted version

    Science.gov (United States)

    Niemeijer, Meindert; van Ginneken, Bram; Russell, Stephen R.; Suttorp-Schulten, Maria S.A.

    2008-01-01

    Purpose To describe and evaluate a machine learning based, automated system to detect exudates and cotton-wool spots in digital color fundus photographs, and differentiate them from drusen, for early diagnosis of diabetic retinopathy. Methods Three hundred retinal images from one eye of three hundred patients with diabetes were selected from a diabetic retinopathy telediagnosis database (non-mydriatic camera two field photography); 100 with previously diagnosed ‘bright’ lesions, and 200 without. A machine learning computer program was developed that can identify and differentiate among drusen, (hard) exudates, and cotton-wool spots. A human expert standard for the 300 images was obtained by consensus annotation by two retinal specialists. Sensitivities and specificities of the annotations on the 300 images by the automated system and a third retinal specialist were determined. Results The system achieved an area under the ROC curve of 0.95 and sensitivity/specificity pairs of 0.95/0.88 for the detection of ‘bright’ lesions of any type, and 0.95/0.86, 0.70/0.93 and 0.77/0.88 for the detection of exudates, cotton-wool spots and drusen, respectively. The third retinal specialist achieved pairs of 0.95/0.74 for ‘bright’ lesions, and 0.90/0.98, 0.87/0.98 and 0.92/0.79 per lesion type. Conclusions An machine learning based, automated system capable of detecting exudates and cotton-wool spots and differentiating them from drusen in color images obtained in community based diabetic patients has been developed and approaches the performance level of that of retinal experts. If the machine learning can be improved with additional training datasets, it may be useful to detect clinically important ‘bright’ lesions, enhance early diagnosis and reduce suffering from visual loss in patients with diabetes. PMID:17460289

  12. Retinopathy online challenge: automatic detection of microaneurysms in digital color fundus photographs.

    NARCIS (Netherlands)

    Niemeijer, M.; Ginneken, B. van; Cree, M.J.; Mizutani, A.; Quellec, G.; Sanchez, C.I.; Zhang, B.; Hornero, R.; Lamard, M.; Muramatsu, C.; Wu, X.; Cazuguel, G.; You, J.; Mayo, A.; Li, Q.; Hatanaka, Y.; Cochener, B.; Roux, C.; Karray, F.; Garcia, M.; Fujita, H.; Abramoff, M.D.

    2010-01-01

    The detection of microaneurysms in digital color fundus photographs is a critical first step in automated screening for diabetic retinopathy (DR), a common complication of diabetes. To accomplish this detection numerous methods have been published in the past but none of these was compared with each

  13. An image based auto-focusing algorithm for digital fundus photography.

    Science.gov (United States)

    Moscaritolo, Michele; Jampel, Henry; Knezevich, Frederick; Zeimer, Ran

    2009-11-01

    In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpness of an image. The AF algorithm was tested in the prototype of a semi-automated nonmydriatic fundus camera designed to screen in the primary care environment for major eye diseases. A series of images was acquired in volunteers while focusing the camera on the fundus. The image with the best focus was determined by the AF algorithm and compared to the assessment of two masked readers. A set of fundus images was obtained in 26 eyes of 20 normal subjects and 42 eyes of 28 glaucoma patients. The 95% limits of agreement between the readers and the AF algorithm were -2.56 to 2.93 and -3.7 to 3.84 diopter and the bias was 0.09 and 0.71 diopter, for the two readers respectively. On average, the readers agreed with the AF algorithm on the best correction within less than 3/4 diopter. The intraobserver repeatability was 0.94 and 1.87 diopter, for the two readers respectively, indicating that the limit of agreement with the AF algorithm was determined predominantly by the repeatability of each reader. An auto-focus algorithm for digital fundus photography can identify the best focus reliably and objectively. It may improve the quality of fundus images by easing the task of the photographer.

  14. A Web-based telemedicine system for diabetic retinopathy screening using digital fundus photography.

    Science.gov (United States)

    Wei, Jack C; Valentino, Daniel J; Bell, Douglas S; Baker, Richard S

    2006-02-01

    The purpose was to design and implement a Web-based telemedicine system for diabetic retinopathy screening using digital fundus cameras and to make the software publicly available through Open Source release. The process of retinal imaging and case reviewing was modeled to optimize workflow and implement use of computer system. The Web-based system was built on Java Servlet and Java Server Pages (JSP) technologies. Apache Tomcat was chosen as the JSP engine, while MySQL was used as the main database and Laboratory of Neuro Imaging (LONI) Image Storage Architecture, from the LONI-UCLA, as the platform for image storage. For security, all data transmissions were carried over encrypted Internet connections such as Secure Socket Layer (SSL) and HyperText Transfer Protocol over SSL (HTTPS). User logins were required and access to patient data was logged for auditing. The system was deployed at Hubert H. Humphrey Comprehensive Health Center and Martin Luther King/Drew Medical Center of Los Angeles County Department of Health Services. Within 4 months, 1500 images of more than 650 patients were taken at Humphrey's Eye Clinic and successfully transferred to King/Drew's Department of Ophthalmology. This study demonstrates an effective architecture for remote diabetic retinopathy screening.

  15. Diabetic Retinopathy Screening Ratio Is Improved When Using a Digital, Nonmydriatic Fundus Camera Onsite in a Diabetes Outpatient Clinic

    Directory of Open Access Journals (Sweden)

    Pia Roser

    2016-01-01

    Full Text Available Objective. To evaluate the effect of onsite screening with a nonmydriatic, digital fundus camera for diabetic retinopathy (DR at a diabetes outpatient clinic. Research Design and Methods. This cross-sectional study included 502 patients, 112 with type 1 and 390 with type 2 diabetes. Patients attended screenings for microvascular complications, including diabetic nephropathy (DN, diabetic polyneuropathy (DP, and DR. Single-field retinal imaging with a digital, nonmydriatic fundus camera was used to assess DR. Prevalence and incidence of microvascular complications were analyzed and the ratio of newly diagnosed to preexisting complications for all entities was calculated in order to differentiate natural progress from missed DRs. Results. For both types of diabetes, prevalence of DR was 25.0% (n=126 and incidence 6.4% (n=32 (T1DM versus T2DM: prevalence: 35.7% versus 22.1%, incidence 5.4% versus 6.7%. 25.4% of all DRs were newly diagnosed. Furthermore, the ratio of newly diagnosed to preexisting DR was higher than those for DN (p=0.12 and DP (p=0.03 representing at least 13 patients with missed DR. Conclusions. The results indicate that implementing nonmydriatic, digital fundus imaging in a diabetes outpatient clinic can contribute to improved early diagnosis of diabetic retinopathy.

  16. Retinopathy online challenge: automatic detection of microaneurysms in digital color fundus photographs.

    Science.gov (United States)

    Niemeijer, Meindert; van Ginneken, Bram; Cree, Michael J; Mizutani, Atsushi; Quellec, Gwénolé; Sanchez, Clara I; Zhang, Bob; Hornero, Roberto; Lamard, Mathieu; Muramatsu, Chisako; Wu, Xiangqian; Cazuguel, Guy; You, Jane; Mayo, Agustín; Li, Qin; Hatanaka, Yuji; Cochener, Béatrice; Roux, Christian; Karray, Fakhri; Garcia, María; Fujita, Hiroshi; Abramoff, Michael D

    2010-01-01

    The detection of microaneurysms in digital color fundus photographs is a critical first step in automated screening for diabetic retinopathy (DR), a common complication of diabetes. To accomplish this detection numerous methods have been published in the past but none of these was compared with each other on the same data. In this work we present the results of the first international microaneurysm detection competition, organized in the context of the Retinopathy Online Challenge (ROC), a multiyear online competition for various aspects of DR detection. For this competition, we compare the results of five different methods, produced by five different teams of researchers on the same set of data. The evaluation was performed in a uniform manner using an algorithm presented in this work. The set of data used for the competition consisted of 50 training images with available reference standard and 50 test images where the reference standard was withheld by the organizers (M. Niemeijer, B. van Ginneken, and M. D. Abràmoff). The results obtained on the test data was submitted through a website after which standardized evaluation software was used to determine the performance of each of the methods. A human expert detected microaneurysms in the test set to allow comparison with the performance of the automatic methods. The overall results show that microaneurysm detection is a challenging task for both the automatic methods as well as the human expert. There is room for improvement as the best performing system does not reach the performance of the human expert. The data associated with the ROC microaneurysm detection competition will remain publicly available and the website will continue accepting submissions.

  17. Automated measurement of the arteriolar-to-venular width ratio in digital color fundus photographs.

    Science.gov (United States)

    Niemeijer, Meindert; Xu, Xiayu; Dumitrescu, Alina V; Gupta, Priya; van Ginneken, Bram; Folk, James C; Abramoff, Michael D

    2011-11-01

    A decreased ratio of the width of retinal arteries to veins [arteriolar-to-venular diameter ratio (AVR)], is well established as predictive of cerebral atrophy, stroke and other cardiovascular events in adults. Tortuous and dilated arteries and veins, as well as decreased AVR are also markers for plus disease in retinopathy of prematurity. This work presents an automated method to estimate the AVR in retinal color images by detecting the location of the optic disc, determining an appropriate region of interest (ROI), classifying vessels as arteries or veins, estimating vessel widths, and calculating the AVR. After vessel segmentation and vessel width determination, the optic disc is located and the system eliminates all vessels outside the AVR measurement ROI. A skeletonization operation is applied to the remaining vessels after which vessel crossings and bifurcation points are removed, leaving a set of vessel segments consisting of only vessel centerline pixels. Features are extracted from each centerline pixel in order to assign these a soft label indicating the likelihood that the pixel is part of a vein. As all centerline pixels in a connected vessel segment should be the same type, the median soft label is assigned to each centerline pixel in the segment. Next, artery vein pairs are matched using an iterative algorithm, and the widths of the vessels are used to calculate the AVR. We trained and tested the algorithm on a set of 65 high resolution digital color fundus photographs using a reference standard that indicates for each major vessel in the image whether it is an artery or vein. We compared the AVR values produced by our system with those determined by a semi-automated reference system. We obtained a mean unsigned error of 0.06 (SD 0.04) in 40 images with a mean AVR of 0.67. A second observer using the semi-automated system obtained the same mean unsigned error of 0.06 (SD 0.05) on the set of images with a mean AVR of 0.66. The testing data and

  18. Fundus autofluorescence and colour fundus imaging compared during telemedicine screening in patients with diabetes.

    Science.gov (United States)

    Kolomeyer, Anton M; Baumrind, Benjamin R; Szirth, Bernard C; Shahid, Khadija; Khouri, Albert S

    2013-06-01

    We investigated the use of fundus autofluorescence (FAF) imaging in screening the eyes of patients with diabetes. Images were obtained from 50 patients with type 2 diabetes undergoing telemedicine screening with colour fundus imaging. The colour and FAF images were obtained with a 15.1 megapixel non-mydriatic retinal camera. Colour and FAF images were compared for pathology seen in nonproliferative and proliferative diabetic retinopathy (NPDR and PDR, respectively). A qualitative assessment was made of the ease of detecting early retinopathy changes and the extent of existing retinopathy. The mean age of the patients was 47 years, most were male (82%) and most were African American (68%). Their mean visual acuity was 20/45 and their mean intraocular pressure was 14.3 mm Hg. Thirty-eight eyes (76%) did not show any diabetic retinopathy changes on colour or FAF imaging. Seven patients (14%) met the criteria for NPDR and five (10%) for severe NPDR or PDR. The most common findings were microaneurysms, hard exudates and intra-retinal haemorrhages (IRH) (n = 6 for each). IRH, microaneurysms and chorioretinal scars were more easily visible on FAF images. Hard exudates, pre-retinal haemorrhage and fibrosis, macular oedema and Hollenhorst plaque were easier to identify on colour photographs. The value of FAF imaging as a complementary technique to colour fundus imaging in detecting diabetic retinopathy during ocular screening warrants further investigation.

  19. Automated Detection and Differentiation of Drusen, Exudates, and Cotton-Wool Spots in Digital Color Fundus Photographs for Diabetic Retinopathy Diagnosis

    NARCIS (Netherlands)

    Niemeijer, M.; van Ginneken, B.; Russel, S.R.; Suttorp-Schulten, M.S.A.; Abràmoff, M.D.

    2007-01-01

    purpose. To describe and evaluate a machine learning-based, automated system to detect exudates and cotton-wool spots in digital color fundus photographs and differentiate them from drusen, for early diagnosis of diabetic retinopathy. methods. Three hundred retinal images from one eye of 300

  20. Determining degree of optic nerve edema from color fundus photography

    Science.gov (United States)

    Agne, Jason; Wang, Jui-Kai; Kardon, Randy H.; Garvin, Mona K.

    2015-03-01

    Swelling of the optic nerve head (ONH) is subjectively assessed by clinicians using the Frisén scale. It is believed that a direct measurement of the ONH volume would serve as a better representation of the swelling. However, a direct measurement requires optic nerve imaging with spectral domain optical coherence tomography (SD-OCT) and 3D segmentation of the resulting images, which is not always available during clinical evaluation. Furthermore, telemedical imaging of the eye at remote locations is more feasible with non-mydriatic fundus cameras which are less costly than OCT imagers. Therefore, there is a critical need to develop a more quantitative analysis of optic nerve swelling on a continuous scale, similar to SD-OCT. Here, we select features from more commonly available 2D fundus images and use them to predict ONH volume. Twenty-six features were extracted from each of 48 color fundus images. The features include attributes of the blood vessels, optic nerve head, and peripapillary retina areas. These features were used in a regression analysis to predict ONH volume, as computed by a segmentation of the SD-OCT image. The results of the regression analysis yielded a mean square error of 2.43 mm3 and a correlation coefficient between computed and predicted volumes of R = 0:771, which suggests that ONH volume may be predicted from fundus features alone.

  1. Comparison of film and digital fundus photographs in eyes of individuals with diabetes mellitus

    DEFF Research Database (Denmark)

    Gangaputra, Sapna; Almukhtar, Talat; Glassman, Adam R

    2011-01-01

    To compare grading of diabetic retinopathy (DR) and diabetic macular edema (DME) from stereoscopic film versus stereoscopic digital photographs obtained from a subset of Diabetic Retinopathy Clinical Research Network (DRCR.net) participants....

  2. [Heterotopic fundus (author's transl)].

    Science.gov (United States)

    Denden, A

    1976-07-01

    Fundus heterotopicus is the term used to describe a rare, non-hereditary curvature anomaly of the fundus in the non-myopic eye, which is characterized: 1. functionally, by a slowly increasing myopic-astigmatic refractive error, 2. by correctable bitemporal or binasal refractionscomata and 3. ophthalmoscopically by a posterior out-pouching of the nasal or temporal fundus portions, and including the optic disc and macula in the obliquely descending wall of the extasis.

  3. Prevalencia de retinopatía diabética mediante cribado con retinógrafo no midriático Prevalence of diabetic retinopathy using non-mydriatic retinography

    Directory of Open Access Journals (Sweden)

    A. Gibelalde

    2010-12-01

    Full Text Available Objetivo: Estudiar la prevalencia de retinopatía diabética mediante retinógrafo no midriático y valorar su utilidad como método de cribaje en la comarca de Donostialdea. Métodos: Se realizó un estudio prospectivo incluyendo 2.444 pacientes diabéticos derivados por su médico de atención primaria y/o endocrinólogo. Se realizó una retinografía con cámara no midriática en los 45 grados centrales, agudeza visual y tonómetro de no contacto en todos los pacientes. La información se derivó al hospital para ser evaluado por un oftalmólogo especialista en retina. Resultados: El 15,02% de los pacientes eran diabéticos en tratamiento dietético, el 62,55% eran diabéticos no insulinodependientes y el 22,43% eran diabéticos insulinodependientes. Observamos una prevalencia de retinopatía diabética del 9,36%. El 5,27% presentó retinopatía diabética no proliferativa (RDNP leve, el 2,21% RDNP moderada, el 1,67% RDNP severa y el 0,12% RD proliferativa. El 8,22% presentó hipertensión ocular. Conclusiones: Se observa una baja prevalencia de RD en los pacientes de nuestra muestra. La utilización de telemedicina con cámara no midriática es un arma importante para el diagnóstico precoz de la retinopatía diabética y puede aplicarse a otras patologías oftalmológicas como el glaucoma.Objectives: To establish the prevalence of diabetic retinopathy (RD diagnosed after non-mydriatic retinography and to evaluate its utility as a screening test in the area of San Sebastián. Methods: A prospective study including 2,444 diabetic patients sent by their primary attention doctors and/or their endocrinologists. All patients underwent non-mydriatic retinography in the central 45 degrees; visual acuity was explored, as well as IOP through non-contact tonometry. The retinographies and information obtained were sent to our hospital and were revised by an ophthalmologist from the Retina Department. Results: Fifteen point zero two (15.02% of the

  4. The fundus slit lamp.

    Science.gov (United States)

    Gellrich, Marcus-Matthias

    2015-01-01

    Fundus biomicroscopy with the slit lamp as it is practiced widely nowadays was not established until the 1980-es with the introduction of the Volk lenses +90 and +60D. Thereafter little progress has been made in retinal imaging with the slit lamp. It is the aim of this paper to fully exploit the potential of a video slit lamp for fundus documentation by using easily accessible additions. Suitable still images are easily retrieved from videorecordings of slit lamp examinations. The effects of changements in the slit lamp itself (slit beam and apertures) and its examination equipment (converging lenses from +40 to +90D) on quality and spectrum of fundus images are demonstrated. Imaging software is applied for reconstruction of larger fundus areas in a mosaic pattern (Hugin®) and to perform the flicker test in order to visualize changes in the same fundus area at different points of time (Power Point®). The three lenses +90/+60/+40D are a good choice for imaging the whole spectrum of retinal diseases. Displacement of the oblique slit light can be used to assess changes in the surface profile of the inner retina which occurs e.g. in macular holes or pigment epithelial detachment. The mosaic function in its easiest form (one strip macula adapted to one strip with the optic disc) provides an overview of the posterior pole comparable to a fundus camera's image. A reconstruction of larger fundus areas is feasible for imaging in vitreoretinal surgery or occlusive vessel disease. The flicker test is a fine tool for monitoring progressive glaucoma by changes in the optic disc, and it is also a valuable diagnostic tool in macular disease. Nearly all retinal diseases can be imaged with the slit lamp - irrespective whether they affect the posterior pole, mainly the optic nerve or the macula, the whole retina or only its periphery. Even a basic fundus controlled perimetry is possible. Therefore fundus videography with the slit lamp is a worthwhile approach especially for the

  5. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    OpenAIRE

    Haddock, Luis J.; Kim, David Y.; Shizuo Mukai

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods:. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application wh...

  6. The grey fovea sign of macular oedema or subfoveal fluid on non-stereoscopic fundus photographs

    DEFF Research Database (Denmark)

    Hasler, Pascal W; Soliman, Wael; Sander, Birgit

    2017-01-01

    PURPOSE: To describe the grey fovea sign of fovea-involving macular oedema or subretinal fluid accumulation in red-free fundus photography. METHODS: A test set of 91 digital fundus photographs of good quality from 100 consecutive eyes in 72 patients with diabetic retinopathy or central serous cho...

  7. Image analysis of ocular fundus for retinopathy characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela; Cuadros, Jorge

    2010-02-05

    Automated analysis of ocular fundus images is a common procedure in countries as England, including both nonemergency examination and retinal screening of patients with diabetes mellitus. This involves digital image capture and transmission of the images to a digital reading center for evaluation and treatment referral. In collaboration with the Optometry Department, University of California, Berkeley, we have tested computer vision algorithms to segment vessels and lesions in ground-truth data (DRIVE database) and hundreds of images of non-macular centric and nonuniform illumination views of the eye fundus from EyePACS program. Methods under investigation involve mathematical morphology (Figure 1) for image enhancement and pattern matching. Recently, we have focused in more efficient techniques to model the ocular fundus vasculature (Figure 2), using deformable contours. Preliminary results show accurate segmentation of vessels and high level of true-positive microaneurysms.

  8. Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes.

    Science.gov (United States)

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

  9. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    Directory of Open Access Journals (Sweden)

    Luis J. Haddock

    2013-01-01

    Full Text Available Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

  10. Fundus Photography in the 21st Century--A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare.

    Science.gov (United States)

    Panwar, Nishtha; Huang, Philemon; Lee, Jiaying; Keane, Pearse A; Chuan, Tjin Swee; Richhariya, Ashutosh; Teoh, Stephen; Lim, Tock Han; Agrawal, Rupesh

    2016-03-01

    The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly. Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera. Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer. In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

  11. Ocular Fundus Photography as an Educational Tool.

    Science.gov (United States)

    Mackay, Devin D; Garza, Philip S

    2015-10-01

    The proficiency of nonophthalmologists with direct ophthalmoscopy is poor, which has prompted a search for alternative technologies to examine the ocular fundus. Although ocular fundus photography has existed for decades, its use has been traditionally restricted to ophthalmology clinical care settings and textbooks. Recent research has shown a role for nonmydriatic fundus photography in nonophthalmic settings, encouraging more widespread adoption of fundus photography technology. Recent studies have also affirmed the role of fundus photography as an adjunct or alternative to direct ophthalmoscopy in undergraduate medical education. In this review, the authors examine the use of ocular fundus photography as an educational tool and suggest future applications for this important technology. Novel applications of fundus photography as an educational tool have the potential to resurrect the dying art of funduscopy.

  12. Identification and localization of fovea on colour fundus images using blur scales.

    Science.gov (United States)

    Ganesan, Karthikeyan; Acharya, Rajendra U; Chua, Chua Kuang; Laude, Augustinus

    2014-09-01

    Identification of retinal landmarks is an important step in the extraction of anomalies in retinal fundus images. In the current study, we propose a technique to identify and localize the position of macula and hence the fovea avascular zone, in colour fundus images. The proposed method, based on varying blur scales in images, is independent of the location of other anatomical landmarks present in the fundus images. Experimental results have been provided using the open database MESSIDOR by validating our segmented regions using the dice coefficient, with ground truth segmentation provided by a human expert. Apart from testing the images on the entire MESSIDOR database, the proposed technique was also validated using 50 normal and 50 diabetic retinopathy chosen digital fundus images from the same database. A maximum overlap accuracy of 89.6%-93.8% and locational accuracy of 94.7%-98.9% was obtained for identification and localization of the fovea.

  13. A novel image recuperation approach for diagnosing and ranking retinopathy disease level using diabetic fundus image.

    Science.gov (United States)

    Krishnamoorthy, Somasundaram; Alli, P

    2015-01-01

    Retinal fundus images are widely used in diagnosing and providing treatment for several eye diseases. Prior works using retinal fundus images detected the presence of exudation with the aid of publicly available dataset using extensive segmentation process. Though it was proved to be computationally efficient, it failed to create a diabetic retinopathy feature selection system for transparently diagnosing the disease state. Also the diagnosis of diseases did not employ machine learning methods to categorize candidate fundus images into true positive and true negative ratio. Several candidate fundus images did not include more detailed feature selection technique for diabetic retinopathy. To apply machine learning methods and classify the candidate fundus images on the basis of sliding window a method called, Diabetic Fundus Image Recuperation (DFIR) is designed in this paper. The initial phase of DFIR method select the feature of optic cup in digital retinal fundus images based on Sliding Window Approach. With this, the disease state for diabetic retinopathy is assessed. The feature selection in DFIR method uses collection of sliding windows to obtain the features based on the histogram value. The histogram based feature selection with the aid of Group Sparsity Non-overlapping function provides more detailed information of features. Using Support Vector Model in the second phase, the DFIR method based on Spiral Basis Function effectively ranks the diabetic retinopathy diseases. The ranking of disease level for each candidate set provides a much promising result for developing practically automated diabetic retinopathy diagnosis system. Experimental work on digital fundus images using the DFIR method performs research on the factors such as sensitivity, specificity rate, ranking efficiency and feature selection time.

  14. Coaxial fundus camera for opthalmology

    Science.gov (United States)

    de Matos, Luciana; Castro, Guilherme; Castro Neto, Jarbas C.

    2015-09-01

    A Fundus Camera for ophthalmology is a high definition device which needs to meet low light illumination of the human retina, high resolution in the retina and reflection free image1. Those constraints make its optical design very sophisticated, but the most difficult to comply with is the reflection free illumination and the final alignment due to the high number of non coaxial optical components in the system. Reflection of the illumination, both in the objective and at the cornea, mask image quality, and a poor alignment make the sophisticated optical design useless. In this work we developed a totally axial optical system for a non-midriatic Fundus Camera. The illumination is performed by a LED ring, coaxial with the optical system and composed of IR of visible LEDs. The illumination ring is projected by the objective lens in the cornea. The Objective, LED illuminator, CCD lens are coaxial making the final alignment easily to perform. The CCD + capture lens module is a CCTV camera with autofocus and Zoom built in, added to a 175 mm focal length doublet corrected for infinity, making the system easily operated and very compact.

  15. Fundus imaging with a nasal endoscope

    Directory of Open Access Journals (Sweden)

    P Mahesh Shanmugam

    2015-01-01

    Full Text Available Wide field fundus imaging is needed to diagnose, treat, and follow-up patients with retinal pathology. This is more applicable for pediatric patients as repeated evaluation is a challenge. The presently available imaging machines though provide high definition images, but carry the obvious disadvantages of either being costly or bulky or sometimes both, which limits its usage only to large centers. We hereby report a technique of fundus imaging using a nasal endoscope coupled with viscoelastic. A regular nasal endoscope with viscoelastic coupling was placed on the cornea to image the fundus of infants under general anesthesia. Wide angle fundus images of various fundus pathologies in infants could be obtained easily with readily available instruments and without the much financial investment for the institutes.

  16. Fundus Findings in Wernicke Encephalopathy

    Directory of Open Access Journals (Sweden)

    Tal Serlin

    2017-07-01

    Full Text Available Wernicke encephalopathy (WE is an acute neuropsychiatric syndrome resulting from thiamine (vitamin B1 deficiency, classically characterized by the triad of ophthalmoplegia, confusion, and ataxia. While commonly associated with chronic alcoholism, WE may also occur in the setting of poor nutrition or absorption. We present a 37-year-old woman who underwent laparoscopic sleeve gastrectomy and presented with visual disturbance with bilateral horizontal nystagmus, confusion, and postural imbalance. Fundus examination revealed bilateral optic disc edema with a retinal hemorrhage in the left eye. Metabolic workup demonstrated thiamine deficiency. Her symptoms resolved after thiamine treatment. This case raises the awareness of the possibility of posterior segment findings in WE, which are underreported in WE.

  17. Laparoscopic retrograde (fundus first cholecystectomy

    Directory of Open Access Journals (Sweden)

    Kelly Michael D

    2009-12-01

    Full Text Available Abstract Background Retrograde ("fundus first" dissection is frequently used in open cholecystectomy and although feasible in laparoscopic cholecystectomy (LC it has not been widely practiced. LC is most simply carried out using antegrade dissection with a grasper to provide cephalad fundic traction. A series is presented to investigate the place of retrograde dissection in the hands of an experienced laparoscopic surgeon using modern instrumentation. Methods A prospective record of all LCs carried out by an experienced laparoscopic surgeon following his appointment in Bristol in 2004 was examined. Retrograde dissection was resorted to when difficulties were encountered with exposure and/or dissection of Calot's triangle. Results 1041 LCs were carried out including 148 (14% emergency operations and 131 (13% associated bile duct explorations. There were no bile duct injuries although conversion to open operation was required in six patients (0.6%. Retrograde LC was attempted successfully in 11 patients (1.1%. The age ranged from 28 to 80 years (mean 61 and there were 7 males. Indications were; fibrous, contracted gallbladder 7, Mirizzi syndrome 2 and severe kyphosis 2. Operative photographs are included to show the type of case where it was needed and the technique used. Postoperative stay was 1/2 to 5 days (mean 2.2 with no delayed sequelae on followup. Histopathology showed; chronic cholecystitis 7, xanthogranulomatous cholecystitis 3 and acute necrotising cholecystitis 1. Conclusions In this series, retrograde laparoscopic dissection was necessary in 1.1% of LCs and a liver retractor was needed in 9 of the 11 cases. This technique does have a place and should be in the armamentarium of the laparoscopic surgeon.

  18. Unique identification code for medical fundus images using blood vessel pattern for tele-ophthalmology applications.

    Science.gov (United States)

    Singh, Anushikha; Dutta, Malay Kishore; Sharma, Dilip Kumar

    2016-10-01

    Identification of fundus images during transmission and storage in database for tele-ophthalmology applications is an important issue in modern era. The proposed work presents a novel accurate method for generation of unique identification code for identification of fundus images for tele-ophthalmology applications and storage in databases. Unlike existing methods of steganography and watermarking, this method does not tamper the medical image as nothing is embedded in this approach and there is no loss of medical information. Strategic combination of unique blood vessel pattern and patient ID is considered for generation of unique identification code for the digital fundus images. Segmented blood vessel pattern near the optic disc is strategically combined with patient ID for generation of a unique identification code for the image. The proposed method of medical image identification is tested on the publically available DRIVE and MESSIDOR database of fundus image and results are encouraging. Experimental results indicate the uniqueness of identification code and lossless recovery of patient identity from unique identification code for integrity verification of fundus images. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Determining the size of retinal features in prematurely born children by fundus photography.

    Science.gov (United States)

    Knaapi, Laura; Lehtonen, Tuomo; Vesti, Eija; Leinonen, Markku T

    2015-06-01

    The purpose was to study the effect of prematurity on the macula-disc centre distance and whether it could be used as a reference tool for determining the size of retinal features in prematurely born children by fundus photography. The macula-disc centre distance of the left eye was measured in pixels from digital fundus photographs taken from 27 prematurely born children aged 10-11 years with Topcon fundus camera. A conversion factor for Topcon fundus camera (194.98 pixel/mm for a 50° lens) was used to convert the results in pixels into metric units. The macula-disc centre distance was 4.74 mm, SD 0.29. No correlation between ametropia and the macula-disc centre distance was found (r = -0.07, p > 0.05). One child (subject 20) had high myopia and retinopathy of prematurity (ROP), and the macula-disc centre distance was longer than average (6.35 mm). The macula-disc centre distance in prematurely born children at the age of 10-11 years provides an easy-to-use reference tool for evaluating the size of retinal features on fundus photographs. However, if complications of ROP, for example temporal macular dragging or high ametropia, are present, the macula-disc centre distance is potentially altered and a personal macula-disc centre distance should be determined and used as a refined reference tool. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  20. Semi-automated retinal vessel analysis in nonmydriatic fundus photography.

    Science.gov (United States)

    Schuster, Alexander Karl-Georg; Fischer, Joachim Ernst; Vossmerbaeumer, Urs

    2014-02-01

    Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. matlab software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial-venous (A/V) ratio in the central vessel equivalent on 45° digital fundus photographs. Validity and reproducibility of the results were ascertained using nonmydriatic photographs of 50 eyes from 25 subjects recorded from a 3DOCT device (Topcon Corp.). Two hundred and thirty-three eyes of 121 healthy subjects were evaluated to define normative values. A software tool was developed using image thresholds for vessel recognition and vessel width calculation in a semi-automated three-step procedure: vessel recognition on the photograph and artery/vein designation, width measurement and calculation of central retinal vessel equivalents. Mean vessel recognition rate was 78%, vessel class designation rate 75% and reproducibility between 0.78 and 0.91. Mean A/V ratio was 0.84. Application on a healthy norm cohort showed high congruence with prior published manual methods. Processing time per image was one minute. Quantitative geometrical assessment of the retinal vasculature may be performed in a semi-automated manner using dedicated software tools. Yielding reproducible numerical data within a short time leap, this may contribute additional value to mere morphological estimates in the clinical evaluation of fundus photographs. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  1. Retinal oxygen saturation evaluation by multi-spectral fundus imaging

    Science.gov (United States)

    Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

    2007-03-01

    Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work

  2. Pitfalls in colour photography of choroidal tumours.

    Science.gov (United States)

    Schalenbourg, A; Zografos, L

    2013-02-01

    Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown.

  3. Pitfalls in colour photography of choroidal tumours

    Science.gov (United States)

    Schalenbourg, A; Zografos, L

    2013-01-01

    Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown. PMID:23238442

  4. Fundus reflectance : historical and present ideas

    NARCIS (Netherlands)

    Berendschot, T.T.J.M.; Delint, P.J.; Norren, D. van

    2003-01-01

    In 1851 Helmholtz introduced the ophthalmoscope. The instrument allowed the observation of light reflected at the fundus. The development of this device was one of the major advancements in ophthalmology. Yet ophthalmoscopy allows only qualitative observation of the eye. Since 1950 attempts were mad

  5. Fundus autofluorescence applications in retinal imaging

    Directory of Open Access Journals (Sweden)

    Andrea Gabai

    2015-01-01

    Full Text Available Fundus autofluorescence (FAF is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications.

  6. Fundus changes in central retinal vein occlusion.

    Science.gov (United States)

    Hayreh, Sohan Singh; Zimmerman, M Bridget

    2015-01-01

    To investigate systematically the retinal and optic disk changes in central retinal vein occlusion (CRVO) and their natural history. This study comprised 562 consecutive patients with CRVO (492 nonischemic [NI-CRVO] and 89 ischemic CRVO [I-CRVO] eyes) seen within 3 months of onset. Ophthalmic evaluation at initial and follow-up visits included recording visual acuity, visual fields, and detailed anterior segment and fundus examinations and fluorescein fundus angiography. Retinal and subinternal limiting membrane hemorrhages and optic disk edema in I-CRVO were initially more marked (P retinal epithelial pigment degeneration, serous macular detachment, and retinal perivenous sheathing developed at a higher rate in I-CRVO than that in NI-CRVO (P retinal venous engorgement than NI-CRVO (P = 0.003). Fluorescein fundus angiography showed significantly more fluorescein leakage, retinal capillary dilatation, capillary obliteration, and broken capillary foveal arcade (P < 0.0001) in I-CRVO than NI-CRVO. Resolution time of CRVO was longer for I-CRVO than NI-CRVO (P < 0.0001). Characteristics and natural history of fundus findings in the two types of CRVO are different.

  7. Image processing based automatic diagnosis of glaucoma using wavelet features of segmented optic disc from fundus image.

    Science.gov (United States)

    Singh, Anushikha; Dutta, Malay Kishore; ParthaSarathi, M; Uher, Vaclav; Burget, Radim

    2016-02-01

    Glaucoma is a disease of the retina which is one of the most common causes of permanent blindness worldwide. This paper presents an automatic image processing based method for glaucoma diagnosis from the digital fundus image. In this paper wavelet feature extraction has been followed by optimized genetic feature selection combined with several learning algorithms and various parameter settings. Unlike the existing research works where the features are considered from the complete fundus or a sub image of the fundus, this work is based on feature extraction from the segmented and blood vessel removed optic disc to improve the accuracy of identification. The experimental results presented in this paper indicate that the wavelet features of the segmented optic disc image are clinically more significant in comparison to features of the whole or sub fundus image in the detection of glaucoma from fundus image. Accuracy of glaucoma identification achieved in this work is 94.7% and a comparison with existing methods of glaucoma detection from fundus image indicates that the proposed approach has improved accuracy of classification.

  8. Fundus Photography in the 21st Century—A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare

    Science.gov (United States)

    Panwar, Nishtha; Huang, Philemon; Lee, Jiaying; Keane, Pearse A.; Chuan, Tjin Swee; Richhariya, Ashutosh; Teoh, Stephen; Lim, Tock Han

    2016-01-01

    Abstract Background: The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly. Literature Review: Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera. Results: Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer. Conclusions: In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available. PMID:26308281

  9. Murine fundus fluorescein angiography: An alternative approach using a handheld camera.

    Science.gov (United States)

    Ehrenberg, Moshe; Ehrenberg, Scott; Schwob, Ouri; Benny, Ofra

    2016-07-01

    In today's modern pharmacologic approach to treating sight-threatening retinal vascular disorders, there is an increasing demand for a compact, mobile, lightweight and cost-effective fluorescein fundus camera to document the effects of antiangiogenic drugs on laser-induced choroidal neovascularization (CNV) in mice and other experimental animals. We have adapted the use of the Kowa Genesis Df Camera to perform Fundus Fluorescein Angiography (FFA) in mice. The 1 kg, 28 cm high camera has built-in barrier and exciter filters to allow digital FFA recording to a Compact Flash memory card. Furthermore, this handheld unit has a steady Indirect Lens Holder that firmly attaches to the main unit, that securely holds a 90 diopter lens in position, in order to facilitate appropriate focus and stability, for photographing the delicate central murine fundus. This easily portable fundus fluorescein camera can effectively record exceptional central retinal vascular detail in murine laser-induced CNV, while readily allowing the investigator to adjust the camera's position according to the variable head and eye movements that can randomly occur while the mouse is optimally anesthetized. This movable image recording device, with efficiencies of space, time, cost, energy and personnel, has enabled us to accurately document the alterations in the central choroidal and retinal vasculature following induction of CNV, implemented by argon-green laser photocoagulation and disruption of Bruch's Membrane, in the experimental murine model of exudative macular degeneration.

  10. Fundus imaging with a mobile phone: A review of techniques

    Directory of Open Access Journals (Sweden)

    Mahesh P Shanmugam

    2014-01-01

    Full Text Available Fundus imaging with a fundus camera is an essential part of ophthalmic practice. A mobile phone with its in-built camera and flash can be used to obtain fundus images of reasonable quality. The mobile phone can be used as an indirect ophthalmoscope when coupled with a condensing lens. It can be used as a direct ophthalmoscope after minimal modification, wherein the fundus can be viewed without an intervening lens in young patients with dilated pupils. Employing the ubiquitous mobile phone to obtain fundus images has the potential for mass screening, enables ophthalmologists without a fundus camera to document and share findings, is a tool for telemedicine and is rather inexpensive.

  11. Glaucoma Detection From Fundus Image Using Opencv

    Directory of Open Access Journals (Sweden)

    K. Narasimhan

    2012-12-01

    Full Text Available This study proposes a semi automated method for glaucoma detection using CDR and ISNT ratio of a fundus image. CDR (Cup to Disc Ratio is ratio of area of Optic Cup to area of Optic Disc. For a patient with glaucoma Optic Cup size increases while the Optic Disc size remains same and hence CDR will be high for glaucoma patient than normal fundus image. The ROI of green plane is taken and K-Means clustering technique is recursively applied and Optic Disc and Optic Cup is segmented. Through elliptic fiiting, area of Optic Disc and Cup is determined and hence CDR is calculated. ISNT is another parameter used for the diagnosis of glaucoma which is determined through the ratio of area of blood vessels in Inferior Superior to Nasal Temporal side. Blood vessels will shift to Nasal side for glaucoma patients, hence value will be less for glaucoma patient than normal fundus image. Matched filter and Local entropy thresholding is applied to extract blood vessels. The code is programmed in C++ using OpenCV library functions. OpenCV (Open Source Computer Vision Library is a library of programming functions developed by Intel. Core, highgui, imgproc, ml are the main libraries used from OpenCV. The optimized functions in OpenCV increase the speed of operation and is very much suitable for real time mass screening purpose. A batch of 50 retinal images (25 normal set and 25 abnormal set obtained from the Aravind Eye Hospital, is used to assess the performance of the proposed system.

  12. GANGRENE OF THE FUNDUS OF STOMACH

    Directory of Open Access Journals (Sweden)

    Sribatsa Kumar

    2014-10-01

    Full Text Available : The stomach is well known for its rich vascular network which generally protects it from ischemia. So gangrene of the fundus of stomach is a rare event, Its cause has been attributed to gastric volvules, intrathoracic herniation of stomach through the diaphragm, psychogenic polyphagia resulting in massive gastric dilation, ingestion of corrosive materials, embolization of atherosclerotic plague, thrombosis of major arterial supply occlusion of gastric vessels by therapeutically injected foreign bodies and necrotizing gastritis caused by organisms. We report a case of gangrene of funds of stomach that appears to be caused by intake of bhanga. (cannabis sativa

  13. South African Medical Journal - Vol 78, No 9 (1990)

    African Journals Online (AJOL)

    Detecting asymptomatic coronary artery disease using routine exercise testing and exercise thallium ... Ophthalmoscopy versus non-mydriatic fundus photography in the detection of diabetic retinopathy in black .... Current Issue Atom logo

  14. Do it yourself smartphone fundus camera – DIYretCAM

    Directory of Open Access Journals (Sweden)

    Biju Raju

    2016-01-01

    Full Text Available This article describes the method to make a do it yourself smartphone-based fundus camera which can image the central retina as well as the peripheral retina up to the pars plana. It is a cost-effective alternative to the fundus camera.

  15. Incorporating privileged genetic information for fundus image based glaucoma detection.

    Science.gov (United States)

    Duan, Lixin; Xu, Yanwu; Li, Wen; Chen, Lin; Wing, Damon Wing Kee; Wong, Tien Yin; Liu, Jiang

    2014-01-01

    Visual features extracted from retinal fundus images have been increasingly used for glaucoma detection, as those images are generally easy to acquire. In recent years, genetic researchers have found that some single nucleic polymorphisms (SNPs) play important roles in the manifestation of glaucoma and also show superiority over fundus images for glaucoma detection. In this work, we propose to use the SNPs to form the so-called privileged information and deal with a practical problem where both fundus images and privileged genetic information exist for the training subjects, while the test objects only have fundus images. To solve this problem, we present an effective approach based on the learning using privileged information (LUPI) paradigm to train a predictive model for the image visual features. Extensive experiments demonstrate the usefulness of our approach in incorporating genetic information for fundus image based glaucoma detection.

  16. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    Processes of digitization have for years represented a major trend in the developments of modern society but have only recently been related to processes of mediatization. The purpose of this article is to look into the relation between the concepts of mediatization and digitization and to clarify...... what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...... not anticipated in previous conceptualizations of media and mediatization. If digital media are to be included, the concept of mediatization has to be revised and new parameters are to be built into the concept of media. At the same time it is argued that the concept of mediatization still provides a variety...

  17. Interoperative fundus image and report sharing in compliance with integrating the healthcare enterprise conformance and web access todigital imaging and communication in medicinepersistent object protocol

    Directory of Open Access Journals (Sweden)

    Hui-Qun Wu

    2013-12-01

    Full Text Available AIM:To address issues in interoperability between different fundus image systems, we proposed a web eye-picture archiving and communication system (PACS framework in conformance with digital imaging and communication in medicine (DICOM and health level 7 (HL7 protocol to realize fundus images and reports sharing and communication through internet.METHODS: Firstly, a telemedicine-based eye care work flow was established based on integrating the healthcare enterprise (IHE Eye Care technical framework. Then, a browser/server architecture eye-PACS system was established in conformance with the web access to DICOM persistent object (WADO protocol, which contains three tiers.RESULTS:In any client system installed with web browser, clinicians could log in the eye-PACS to observe fundus images and reports. Multipurpose internet mail extensions (MIME type of a structured report is saved as pdf/html with reference link to relevant fundus image using the WADO syntax could provide enough information for clinicians. Some functions provided by open-source Oviyam could be used to query, zoom, move, measure, view DICOM fundus images.CONCLUSION:Such web eye-PACS in compliance to WADO protocol could be used to store and communicate fundus images and reports, therefore is of great significance for teleophthalmology.

  18. Fundus albipunctatus associated with compound heterozygous mutations in RPE65

    DEFF Research Database (Denmark)

    Schatz, Patrik; Preising, Markus; Lorenz, Birgit

    2011-01-01

    To describe a family with an 18-year-old woman with fundus albipunctatus and compound heterozygous mutations in RPE65 whose unaffected parents and 1 female sibling harbored single heterozygous RPE65 mutations.......To describe a family with an 18-year-old woman with fundus albipunctatus and compound heterozygous mutations in RPE65 whose unaffected parents and 1 female sibling harbored single heterozygous RPE65 mutations....

  19. Learning deep similarity in fundus photography

    Science.gov (United States)

    Chudzik, Piotr; Al-Diri, Bashir; Caliva, Francesco; Ometto, Giovanni; Hunter, Andrew

    2017-02-01

    Similarity learning is one of the most fundamental tasks in image analysis. The ability to extract similar images in the medical domain as part of content-based image retrieval (CBIR) systems has been researched for many years. The vast majority of methods used in CBIR systems are based on hand-crafted feature descriptors. The approximation of a similarity mapping for medical images is difficult due to the big variety of pixel-level structures of interest. In fundus photography (FP) analysis, a subtle difference in e.g. lesions and vessels shape and size can result in a different diagnosis. In this work, we demonstrated how to learn a similarity function for image patches derived directly from FP image data without the need of manually designed feature descriptors. We used a convolutional neural network (CNN) with a novel architecture adapted for similarity learning to accomplish this task. Furthermore, we explored and studied multiple CNN architectures. We show that our method can approximate the similarity between FP patches more efficiently and accurately than the state-of- the-art feature descriptors, including SIFT and SURF using a publicly available dataset. Finally, we observe that our approach, which is purely data-driven, learns that features such as vessels calibre and orientation are important discriminative factors, which resembles the way how humans reason about similarity. To the best of authors knowledge, this is the first attempt to approximate a visual similarity mapping in FP.

  20. GCaMP expression in retinal ganglion cells characterized using a low-cost fundus imaging system

    Science.gov (United States)

    Chang, Yao-Chuan; Walston, Steven T.; Chow, Robert H.; Weiland, James D.

    2017-10-01

    Objective. Virus-transduced, intracellular-calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. Due to the existence of an optimal time window for the expression of calcium indicators, a suitable tool for tracking GECI expression in vivo following transduction is highly desirable. Approach. We developed a noninvasive imaging approach based on a custom-modified, low-cost fundus viewing system that allowed us to monitor and characterize in vivo bright-field and fluorescence images of the mouse retina. AAV2-CAG-GCaMP6f was injected into a mouse eye. The fundus imaging system was used to measure fluorescence at several time points post injection. At defined time points, we prepared wholemount retina mounted on a transparent multielectrode array and used calcium imaging to evaluate the responsiveness of retinal ganglion cells (RGCs) to external electrical stimulation. Main results. The noninvasive fundus imaging system clearly resolves individual (RGCs and axons. RGC fluorescence intensity and the number of observable fluorescent cells show a similar rising trend from week 1 to week 3 after viral injection, indicating a consistent increase of GCaMP6f expression. Analysis of the in vivo fluorescence intensity trend and in vitro neurophysiological responsiveness shows that the slope of intensity versus days post injection can be used to estimate the optimal time for calcium imaging of RGCs in response to external electrical stimulation. Significance. The proposed fundus imaging system enables high-resolution digital fundus imaging in the mouse eye, based on off-the-shelf components. The long-term tracking experiment with in vitro calcium imaging validation demonstrates the system can serve as a powerful tool monitoring the level of genetically-encoded calcium indicator expression, further determining the optimal time window for following experiment.

  1. Diagnostic fundus autofluorescence patterns in achromatopsia.

    Science.gov (United States)

    Fahim, Abigail T; Khan, Naheed W; Zahid, Sarwar; Schachar, Ira H; Branham, Kari; Kohl, Susanne; Wissinger, Bernd; Elner, Victor M; Heckenlively, John R; Jayasundera, Thiran

    2013-12-01

    To describe the unique diagnostic fundus autofluorescence (FAF) patterns in patients with achromatopsia and the associated findings on optical coherence tomography (OCT). Observational case series. We evaluated 10 patients with achromatopsia by means of best-corrected visual acuity (BCVA), ophthalmoscopy, Goldmann visual field, full-field electroretinography (ffERG), OCT, and FAF photography. FAF patterns were compared with patient age and foveal changes on OCT. Patients fell into two dichotomous age groups at the time of evaluation: six patients ranged from 11 to 23 years of age, and 3 patients ranged from 52 to 63 years of age. All patients had severely reduced photopic ffERG responses, including those exhibiting preserved foveal structure on OCT. The younger patients had absent to mild foveal atrophy on OCT, and four of the six demonstrated foveal and parafoveal hyperfluorescence on FAF. In addition, a 7-month-old child with compound heterozygous mutations in CNGA3 demonstrated similar foveal hyperfluorescence. The older patients demonstrated advanced foveal atrophy and punched-out foveal hypofluorescence with discrete borders on FAF imaging corresponding to the area of outer retinal cavitation on OCT. Foveal hyperfluorescence is an early sign of achromatopsia that can aid in clinical diagnosis. In our cohort, patients with achromatopsia demonstrated age-dependent changes in FAF, which are likely to be progressive and to correlate with foveal atrophy and cavitation on OCT. This finding may be useful in charting the natural course of the disease and in defining a therapeutic window for treatment. Copyright © 2013. Published by Elsevier Inc.

  2. A Method of Drusen Measurement Based on the Geometry of Fundus Reflectance

    Directory of Open Access Journals (Sweden)

    Barbazetto Irene

    2003-04-01

    Full Text Available Abstract Background The hallmarks of age-related macular degeneration, the leading cause of blindness in the developed world, are the subretinal deposits known as drusen. Drusen identification and measurement play a key role in clinical studies of this disease. Current manual methods of drusen measurement are laborious and subjective. Our purpose was to expedite clinical research with an accurate, reliable digital method. Methods An interactive semi-automated procedure was developed to level the macular background reflectance for the purpose of morphometric analysis of drusen. 12 color fundus photographs of patients with age-related macular degeneration and drusen were analyzed. After digitizing the photographs, the underlying background pattern in the green channel was leveled by an algorithm based on the elliptically concentric geometry of the reflectance in the normal macula: the gray scale values of all structures within defined elliptical boundaries were raised sequentially until a uniform background was obtained. Segmentation of drusen and area measurements in the central and middle subfields (1000 μm and 3000 μm diameters were performed by uniform thresholds. Two observers using this interactive semi-automated software measured each image digitally. The mean digital measurements were compared to independent stereo fundus gradings by two expert graders (stereo Grader 1 estimated the drusen percentage in each of the 24 regions as falling into one of four standard broad ranges; stereo Grader 2 estimated drusen percentages in 1% to 5% intervals. Results The mean digital area measurements had a median standard deviation of 1.9%. The mean digital area measurements agreed with stereo Grader 1 in 22/24 cases. The 95% limits of agreement between the mean digital area measurements and the more precise stereo gradings of Grader 2 were -6.4 % to +6.8 % in the central subfield and -6.0 % to +4.5 % in the middle subfield. The mean absolute

  3. Weighted ensemble based automatic detection of exudates in fundus photographs.

    Science.gov (United States)

    Prentasic, Pavle; Loncaric, Sven

    2014-01-01

    Diabetic retinopathy (DR) is a visual complication of diabetes, which has become one of the leading causes of preventable blindness in the world. Exudate detection is an important problem in automatic screening systems for detection of diabetic retinopathy using color fundus photographs. In this paper, we present a method for detection of exudates in color fundus photographs, which combines several preprocessing and candidate extraction algorithms to increase the exudate detection accuracy. The first stage of the method consists of an ensemble of several exudate candidate extraction algorithms. In the learning phase, simulated annealing is used to determine weights for combining the results of the ensemble candidate extraction algorithms. The second stage of the method uses a machine learning-based classification for detection of exudate regions. The experimental validation was performed using the DRiDB color fundus image set. The validation has demonstrated that the proposed method achieved higher accuracy in comparison to state-of-the art methods.

  4. Fundus Findings in Dengue Fever: A Case Report.

    Science.gov (United States)

    Şahan, Berna; Tatlıpınar, Sinan; Marangoz, Deniz; Çiftçi, Ferda

    2015-10-01

    Dengue fever is a flavivirus infection transmitted through infected mosquitoes, and is endemic in Southeast Asia, Central and South America, the Pacific, Africa and the Eastern Mediterranean region. A 41-year-old male patient had visual impairment after travelling to Thailand, which is one of the endemic areas. Cotton wool spots were observed on fundus examination. Fundus fluorescein angiography showed minimal vascular leakage from areas near the cotton wool spots and dot hemorrhages in the macula. Dengue fever should be considered in patients with visual complaints who traveled to endemic areas of dengue fever.

  5. DR HAGIS-a fundus image database for the automatic extraction of retinal surface vessels from diabetic patients.

    Science.gov (United States)

    Holm, Sven; Russell, Greg; Nourrit, Vincent; McLoughlin, Niall

    2017-01-01

    A database of retinal fundus images, the DR HAGIS database, is presented. This database consists of 39 high-resolution color fundus images obtained from a diabetic retinopathy screening program in the UK. The NHS screening program uses service providers that employ different fundus and digital cameras. This results in a range of different image sizes and resolutions. Furthermore, patients enrolled in such programs often display other comorbidities in addition to diabetes. Therefore, in an effort to replicate the normal range of images examined by grading experts during screening, the DR HAGIS database consists of images of varying image sizes and resolutions and four comorbidity subgroups: collectively defined as the diabetic retinopathy, hypertension, age-related macular degeneration, and Glaucoma image set (DR HAGIS). For each image, the vasculature has been manually segmented to provide a realistic set of images on which to test automatic vessel extraction algorithms. Modified versions of two previously published vessel extraction algorithms were applied to this database to provide some baseline measurements. A method based purely on the intensity of images pixels resulted in a mean segmentation accuracy of 95.83% ([Formula: see text]), whereas an algorithm based on Gabor filters generated an accuracy of 95.71% ([Formula: see text]).

  6. Referral system for hard exudates in eye fundus.

    Science.gov (United States)

    Naqvi, Syed Ali Gohar; Zafar, Muhammad Faisal; Haq, Ihsan ul

    2015-09-01

    Hard exudates are one of the most common anomalies/artifacts found in the eye fundus of patients suffering from diabetic retinopathy. These exudates are the major cause of loss of sight or blindness in people having diabetic retinopathy. Diagnosis of hard exudates requires considerable time and effort of an ophthalmologist. The ophthalmologists have become overloaded, so that there is a need for an automated diagnostic/referral system. In this paper a referral system for the hard exudates in the eye-fundus images has been presented. The proposed referral system works by combining different techniques like Scale Invariant Feature Transform (SIFT), K-means Clustering, Visual Dictionaries and Support Vector Machine (SVM). The system was also tested with Back Propagation Neural Network as a classifier. To test the performance of the system four fundus image databases were used. One publicly available image database was used to compare the performance of the system to the existing systems. To test the general performance of the system when the images are taken under different conditions and come from different sources, three other fundus image databases were mixed. The evaluation of the system was also performed on different sizes of the visual dictionaries. When using only one fundus image database the area under the curve (AUC) of maximum 0.9702 (97.02%) was achieved with accuracy of 95.02%. In case of mixed image databases an AUC of 0.9349 (93.49%) was recorded having accuracy of 87.23%. The results were compared to the existing systems and were found better/comparable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. FUNDUS CHANGES IN PREGNANCY INDUCED HYPERTENSION: A CLINICAL STUDY

    Directory of Open Access Journals (Sweden)

    Rama Bharathi

    2015-01-01

    Full Text Available PURPOSE: To estimate the prevalence of fundus changes in Pregnancy Induced Hypertension (PIH and to find the correlation of the findings with the levels of hypertension and with the severity of the disease. METHODS: This was a hospital based cross section al study conducted over a period of one year from July 2012 to June 2013. 150 patients with diagnosed PIH and admission into wards at King George Hospital, Visakhapatnam, with 36 weeks period of gestation and above, were included in the study. Those with p re - existing hypertension, coexisting diabetes mellitus, severe anaemia, renal disease and ocular diseases like cataract or corneal opacities were excluded from the study. After taking consent and ocular history, anterior segment was evaluated. Pupils were dilated with 0.5% tropicamide eye drops and fundus examination was done with direct ophthalmoscope. Information like age, para, BP etc., was noted down from case sheets. RESULTS: Total number of patients studied was 150.Mean age was 23.06+ 3.03years. 105 ( 70% were primigravidae and 45(30% were multigravidae. Fundus findings were seen in 35 cases (23.33%. 26 (17.33% had Grade I changes, 1 (0.66% had grade II changes, 6 (3.9% had grade III changes 2 (1.3% had serous retinal detachment/grade - IV. The de gree of retinopathy was correlating with the severity of the disease and levels of hypertension. CONCLUSION: The prevalence of fundus changes in PIH is 23.33%. Most of the fundus changes in PIH are underdiagnosed. Timely ophthalmoscopy should be called for in all cases of PIH as it would affect the decision of induction of delivery, thereby preventing other complications.

  8. The pathogenesis of the fundus peau d'orange and salmon spots.

    Science.gov (United States)

    Giuffrè, G

    1987-01-01

    The fundus of the eye of a patient with pseudoxanthoma elasticum showed angioid streaks, fundus peau d'orange and salmon spots, these latter unusually located in the macula. The fluorescein angiography revealed, in the arterial phase, a reticular hyperfluorescence in the areas of fundus peau d'orange and salmon spots. In the venous phase the fluorescence of the fundus peau d'orange was even, while the salmon spots showed staining and hyperfluorescent borders. These findings support the hypothesis that the fundus peau d'orange is due to degeneration of Bruch's membrane and the salmon spots are deiscences of this membrane.

  9. Evaluation of cone function by a handheld non-mydriatic flicker electroretinogram device

    Directory of Open Access Journals (Sweden)

    Nakamura N

    2016-06-01

    Full Text Available Natsuko Nakamura,1 Kaoru Fujinami,1 Yoshinobu Mizuno,2 Toru Noda,2 Kazushige Tsunoda11Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, 2Department of Ophthalmology, National Hospital Organization, National Tokyo Medical Center, Tokyo, JapanPurpose: Full-field electroretinograms (ERGs are used to evaluate retinal function in patients with various types of hereditary and acquired retinal diseases. However, ERG recordings require relatively invasive procedures, including pupillary dilation and the use of contact lens electrodes. Thus, it would be helpful to have a simpler and noninvasive screening method. The purpose of this study was to determine whether a new, handheld, portable ERG device, RETeval™, can be used to screen patients for cone dysfunction.Patients and methods: Thirty-five eyes of 35 patients who had reduced cone responses ascertained by a conventional ERG system using contact lens electrodes were studied. The causative diseases included achromatopsia, cone dystrophy, cone-rod dystrophy, retinitis pigmentosa, choroidal dystrophy, autoimmune retinopathy, and Stargardt disease. The flicker ERGs were recorded with the RETeval™ under undilated conditions with skin electrodes (stimulus strength, 3.0 cd·s/m2; frequency, 28.3 Hz, and the responses were compared to that of 50 healthy eyes. The amplitudes and implicit times of the fundamental component of the flicker ERGs were analyzed in three age groups: Group A, ≤20 years; Group B, 21–40 years; and Group C, ≥41 years.Results: In all of the age groups, the amplitudes of the ERGs were significantly smaller and the implicit times significantly longer in patients with cone dysfunction than in the control eyes. All but one of the patients had flicker amplitudes lower than the mean −2.0 standard deviation of control eyes.Conclusion: The RETeval™ has a potential of being used to screen for cone dysfunction. The entire examination takes <5 minutes and does not require pupil dilatation or a contact lens electrode. Although the flicker responses do not provide information on the scotopic functions, the RETeval™ device can be used to determine which patients require additional full-field ERG testing with dilated pupils under both scotopic and photopic conditions.Keywords: RETeval™, flicker ERG, cone dysfunction, retina

  10. Non-mydriatic video ophthalmoscope to measure fast temporal changes of the human retina

    Science.gov (United States)

    Tornow, Ralf P.; Kolář, Radim; Odstrčilík, Jan

    2015-07-01

    The analysis of fast temporal changes of the human retina can be used to get insight to normal physiological behavior and to detect pathological deviations. This can be important for the early detection of glaucoma and other eye diseases. We developed a small, lightweight, USB powered video ophthalmoscope that allows taking video sequences of the human retina with at least 25 frames per second without dilating the pupil. Short sequences (about 10 s) of the optic nerve head (20° x 15°) are recorded from subjects and registered offline using two-stage process (phase correlation and Lucas-Kanade approach) to compensate for eye movements. From registered video sequences, different parameters can be calculated. Two applications are described here: measurement of (i) cardiac cycle induced pulsatile reflection changes and (ii) eye movements and fixation pattern. Cardiac cycle induced pulsatile reflection changes are caused by changing blood volume in the retina. Waveform and pulse parameters like amplitude and rise time can be measured in any selected areas within the retinal image. Fixation pattern ΔY(ΔX) can be assessed from eye movements during video acquisition. The eye movements ΔX[t], ΔY[t] are derived from image registration results with high temporal (40 ms) and spatial (1,86 arcmin) resolution. Parameters of pulsatile reflection changes and fixation pattern can be affected in beginning glaucoma and the method described here may support early detection of glaucoma and other eye disease.

  11. Evaluation of retinal illumination in coaxial fundus camera

    Science.gov (United States)

    de Oliveira, André O.; de Matos, Luciana; Castro Neto, Jarbas C.

    2016-09-01

    Retinal images are obtained by simultaneously illuminating and imaging the retina, which is achieved using a fundus camera. This device meets low light illumination of the fundus with high resolution and reflection free images. Although the current equipment presents a sophisticated solution, it is complex to align due to the high number of off-axis components. In this work, we substitute the complex illumination system by a ring of LEDs mounted coaxially to the imaging optical system, positioning it in the place of the holed mirror of the traditional optical design. We evaluated the impact of this substitution regarding to image quality (measured through the modulation transfer function) and illumination uniformity produced by this system on the retina. The results showed there is no change in image quality and no problem was detected concerning uniformity compared to the traditional equipment. Consequently, we avoided off-axis components, easing the alignment of the equipment without reducing both image quality and illumination uniformity.

  12. Case Report of Bullous Pemphigoid following Fundus Fluorescein Angiography

    Directory of Open Access Journals (Sweden)

    Goktug Demirci

    2010-05-01

    Full Text Available Purpose: To report a first case of bullous pemphigoid (BP following intravenous fluorescein for fundus angiography. Clinical Features: A 70-year-old male patient was admitted to the intensive care unit with BP and sepsis. He reported a history of fundus fluorescein angiography with a pre-diagnosis of senile macular degeneration 2 months prior to presentation. At that time, fluorescein extravasated at the antecubital region. Following the procedure, pruritus and erythema began at the wrists bilaterally, and quickly spread to the entire body. The patient also reported a history of allergy to human albumin solution (Plamasteril®; Abbott 15 years before, during bypass surgery. On dermatologic examination, erythematous patches were present on the scalp, chest and anogenital region. Vesicles and bullous lesions were present on upper and lower extremities. On day 2 of hospitalization, tense bullae appeared on the upper and lower extremities. The patient was treated with oral methylprednisolone 48 mg (Prednol®; Mustafa Nevzat, topical clobetasol dipropionate 0.05% cream (Dermovate®; Glaxo SmithKline, and topical 4% urea lotion (Excipial Lipo®; Orva for presumptive bullous pemphigoid. Skin punch biopsy provided tissue for histopathology, direct immunofluorescence examination, and salt extraction, which were all consistent with BP. After 1 month, the patient was transferred to the intensive care unit with sepsis secondary to urinary tract infection; he died 2 weeks later from sepsis and cardiac failure. Conclusions: To our knowledge, this is the first reported case of BP following fundus fluorescein angiography in a patient with known human albumin solution allergy. Consideration should be made to avoid fluorescein angiography, change administration route, or premedicate with antihistamines in patients with known human albumin solution allergy. The association between fundus fluorescein angiography and BP should be further investigated.

  13. Fundus artery occlusion caused by cosmetic facial injections

    Institute of Scientific and Technical Information of China (English)

    Chen Yanyun; Wang Wenying; Li Jipeng; Yu Yajie; Li Lin; Lu Ning

    2014-01-01

    Background With the increasing popularity of cosmetic facial filler injections in recent years,more and more associated complications have been reported.However,the causative surgical procedures and preventative measures have not been studied well up to now.The aim of this stady was to investigate the clinical characteristics and visual prognosis of fundus artery occlusion resulting from cosmetic facial filler injections.Methods Thirteen consecutive patients with fundus artery occlusion caused by facial filler injections were included.Main outcome measures were filler materials,injection sites,best-corrected visual acuity (BCVA),fundus fluorescein angiography,and associated ocular and systemic manifestations.Results Eleven patients had ophthalmic artery occlusion (OAO) and one patient each had central retinal artery occlusion (CRAO) and anterior ischemic optic neuropathy (AION).Injected materials included autologous fat (seven cases),hyaluronic acid (five cases),and bone collagen (one case).Injection sites were the frontal area (five cases),periocular area (two cases),temple area (two cases),and nose area and nasal area (4 cases).Injected autologous fat was associated with worse final BCVA than hyaluronic acid.The BCVA of seven patients with autologous fat injection in frontal area and temple area was no light perception.Most of the patients with OAO had ocular pain,headache,ptosis,ophthalmoplegia,and no improvement in final BCVA.Conclusions Cosmetic facial injections can cause fundus artery occlusion.Autologous fat injection tends to be associated with painful blindness,ptosis,ophthalmoplegia,and poor visual outcomes.The prognosis is much worse with autologous fat injection than hyaluronic acid injection.

  14. [Therapy of fundus oculi vascular pathology by solcoseryl].

    Science.gov (United States)

    Eliseeva, E G; Vorob'eva, O K; Astaf'eva, N V

    1999-01-01

    Long (for more than 17 years) therapy of 2331 patients (3122 eyes) with vascular conditions of the fundus oculi by a retinotropic drug solcoseryl showed its high efficacy as a monotherapy and in complex with other traditional and symptomatic treatments. Solcoseryl improved the visual function and hemodynamics of retinal vessels, promoted a more stable and longer stabilization of the treatment results, and accelerated the rehabilitation of patients.

  15. Feasibility and quality of nonmydriatic fundus photography in children

    Science.gov (United States)

    Toffoli, Daniela; Bruce, Beau B.; Lamirel, Cédric; Henderson, Amanda D.; Newman, Nancy J.; Biousse, Valérie

    2011-01-01

    Purpose Ocular funduscopic examination is difficult in young children and is rarely attempted by nonophthalmologists. Our objective was to determine the feasibility of reliably obtaining high-quality nonmydriatic fundus photographs in children. Methods Nonmydriatic fundus photographs were obtained in both eyes of children seen in a pediatric ophthalmology clinic. Ease of fundus photography was recorded on a 10-point Likert scale (10 = very easy). Quality was graded from 1 to 5 (1, inadequate for any diagnostic purpose; 2, unable to exclude all emergent findings; 3, only able to exclude emergent findings; 4, not ideal, but still able to exclude subtle findings; and 5, ideal quality). The primary outcome measure was image quality by age. Results A total of 878 photographs of 212 children (median age, 6 years; range,1-18 years) were included. Photographs of at least one eye were obtained in 190 children (89.6%) and in both eyes in 181 (85.3%). Median rating for ease of photography was 7. Photographs of some clinical value (grade ≥2) were obtained in 33% of children 3 years. High-quality photographs (grade 4 or 5) were obtained in both eyes in 7% of children <3 years, 57% of children ≥3 to <7 years, 85% of children ≥7 to <9 years, and 65% of children ≥9 years. The youngest patient with high-quality photographs in both eyes was 22 months. Conclusions Nonmydriatic fundus photographs of adequate quality can be obtained in children over age 3 and in some children as young as 22 months. PMID:22153402

  16. Interactive segmentation for geographic atrophy in retinal fundus images

    OpenAIRE

    Lee, Noah; SMITH, R. THEODORE; Laine, Andrew F.

    2008-01-01

    Fundus auto-fluorescence (FAF) imaging is a non-invasive technique for in vivo ophthalmoscopic inspection of age-related macular degeneration (AMD), the most common cause of blindness in developed countries. Geographic atrophy (GA) is an advanced form of AMD and accounts for 12–21% of severe visual loss in this disorder [3]. Automatic quantification of GA is important for determining disease progression and facilitating clinical diagnosis of AMD. The problem of automatic segmentation of patho...

  17. High-Procession Eye Tracking Using Fundus Images

    Science.gov (United States)

    Mulligan, Jeffrey B.

    1996-01-01

    Fundus images provide high optical gain for eye movement tracking, i.e. large image displacements occur as a result of small eye rotations. Subpixel registration techniques can provide resolution better than 1 arc minute using images acquired with a CCD camera. Ocular torsion may also be estimated, with a precision of approximately 0.1 degree. This talk will discuss the software algorithms used to attain this performance.

  18. In vivo diffuse correlation spectroscopy investigation of the ocular fundus

    Science.gov (United States)

    Cattini, Stefano; Staurenghi, Giovanni; Gatti, Antonietta; Rovati, Luigi

    2013-05-01

    Diffuse correlation spectroscopy (DCS) measurements in vivo recorded from rabbits' ocular fundus are presented. Despite the complexity of these ocular tissues, we provide a clear and simple demonstration of the DCS abilities to analyze variations in physiological quantities of clinical interest. Indeed, the reported experimental activities demonstrate that DCS can reveal both choroidal-flow and temperature variations and detect nano- and micro-aggregates in ocular fundus circulation. Such abilities can be of great interest both in fundamental research and practical clinical applications. The proposed measuring system can be useful in: (a) monitoring choroidal blood flow variations, (b) determining the end-point for photo-dynamic therapy and transpupillary thermo therapy and, (c) managing the dye injection and determining an end-point for dye-enhanced photothrombosis. Moreover, it could allow both diagnoses when the presence of nano- and micro-aggregates is related to specific diseases and verifying the effects of nanoparticle injection in nanomedicine. Even though the reported results demonstrate the applicability of DCS to investigate ocular fundus, a detailed and accurate investigation of the limits of detection is beyond the scope of this article.

  19. Effect of Resected Gastric Fundus Fat on Ghrelin Tissue Levels: A Prospective Study.

    Science.gov (United States)

    Durmuş, Ali; Durmuş, Ilgim; Abahuni, Melis; Karatepe, Oguzhan

    2017-01-01

    Introduction: Obesity is currently an important health problem that is rapidly increasing worldwide. In recent years, the number of obesity-related surgeries has increased. The most common type of obesity-related surgery is laparoscopic sleeve gastrectomy (LSG). The aim of this study was to compare the genetic expression of the hormone ghrelin in different parts of the stomach. Materials and Methods: Nineteen obese patients who underwent LSG were examined in this study. Fat tissue from two different parts of the stomach, the fundus and the upper part of the fundus, were analysed by enzyme-linked immunosorbent assay (ELISA). The ribonucleic acid (RNA) isolation, complementary DNA (cDNA) and real-time quantitative polymerase chain reaction (RQ-PCR) techniques were applied. Additionally, a human ghrelin ELISA kit was used to measure ghrelin in obese patients. The ghrelin levels of fat tissue from the fundus and upper part of the fundus were statistically compared. Results: In all 19 patients, the average ghrelin level in the fundus was greater than 30. The average ghrelin level of the fat pad, which is located in the upper part of the fundus, was greater than 30 for 4 patients; the average level was approximately 5 in the remaining patients. A statistically significant difference in the ghrelin level was found between the fundus and the fundus fat tissue. Collection of fundus fat tissue is not routinely performed during LSG. However, ghrelin hormone elevation in this tissue may require collection of fundus tissue during surgery. Celsius.

  20. Automated detection of optic disk in retinal fundus images using intuitionistic fuzzy histon segmentation.

    Science.gov (United States)

    Mookiah, Muthu Rama Krishnan; Acharya, U Rajendra; Chua, Chua Kuang; Min, Lim Choo; Ng, E Y K; Mushrif, Milind M; Laude, Augustinus

    2013-01-01

    The human eye is one of the most sophisticated organs, with perfectly interrelated retina, pupil, iris cornea, lens, and optic nerve. Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Uncontrolled diabetic retinopathy (DR) and glaucoma may lead to blindness. The identification of retinal anatomical regions is a prerequisite for the computer-aided diagnosis of several retinal diseases. The manual examination of optic disk (OD) is a standard procedure used for detecting different stages of DR and glaucoma. In this article, a novel automated, reliable, and efficient OD localization and segmentation method using digital fundus images is proposed. General-purpose edge detection algorithms often fail to segment the OD due to fuzzy boundaries, inconsistent image contrast, or missing edge features. This article proposes a novel and probably the first method using the Attanassov intuitionistic fuzzy histon (A-IFSH)-based segmentation to detect OD in retinal fundus images. OD pixel intensity and column-wise neighborhood operation are employed to locate and isolate the OD. The method has been evaluated on 100 images comprising 30 normal, 39 glaucomatous, and 31 DR images. Our proposed method has yielded precision of 0.93, recall of 0.91, F-score of 0.92, and mean segmentation accuracy of 93.4%. We have also compared the performance of our proposed method with the Otsu and gradient vector flow (GVF) snake methods. Overall, our result shows the superiority of proposed fuzzy segmentation technique over other two segmentation methods.

  1. Application of 3-dimensional printing technology to construct an eye model for fundus viewing study.

    Directory of Open Access Journals (Sweden)

    Ping Xie

    Full Text Available To construct a life-sized eye model using the three-dimensional (3D printing technology for fundus viewing study of the viewing system.We devised our schematic model eye based on Navarro's eye and redesigned some parameters because of the change of the corneal material and the implantation of intraocular lenses (IOLs. Optical performance of our schematic model eye was compared with Navarro's schematic eye and other two reported physical model eyes using the ZEMAX optical design software. With computer aided design (CAD software, we designed the 3D digital model of the main structure of the physical model eye, which was used for three-dimensional (3D printing. Together with the main printed structure, polymethyl methacrylate(PMMA aspherical cornea, variable iris, and IOLs were assembled to a physical eye model. Angle scale bars were glued from posterior to periphery of the retina. Then we fabricated other three physical models with different states of ammetropia. Optical parameters of these physical eye models were measured to verify the 3D printing accuracy.In on-axis calculations, our schematic model eye possessed similar size of spot diagram compared with Navarro's and Bakaraju's model eye, much smaller than Arianpour's model eye. Moreover, the spherical aberration of our schematic eye was much less than other three model eyes. While in off- axis simulation, it possessed a bit higher coma and similar astigmatism, field curvature and distortion. The MTF curves showed that all the model eyes diminished in resolution with increasing field of view, and the diminished tendency of resolution of our physical eye model was similar to the Navarro's eye. The measured parameters of our eye models with different status of ametropia were in line with the theoretical value.The schematic eye model we designed can well simulate the optical performance of the human eye, and the fabricated physical one can be used as a tool in fundus range viewing research.

  2. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing

    OpenAIRE

    Peishan Dai; Hanwei Sheng; Jianmei Zhang; Ling Li; Jing Wu; Min Fan

    2016-01-01

    Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new ...

  3. [Top ten progressions of clinical research in fundus diseases in China].

    Science.gov (United States)

    2014-11-01

    Ten research items in the past five years representing the progression of clinical research in fundus diseases in China were voted by specialists from the Ocular Fundus Disease Group of Ophthalmology Society of Chinese Medical Association. Choroidal neovascular disease, pediatric retinal disease, polypoidal choroidal vasculopathy, intraocular malignant tumor, and intraocular infection caused by specific pathogens are covered. Novel treatment, like anti-VEGF medication, PDT, minimally invasive vitrectomy, and intraocular injection, establishment of the Clinical Research Center of New Drug Development, and the epidemiologic study of fundus diseases are also included. These landmark research progressions represent the power and influence of Chinese fundus disease scholars in the world.

  4. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing.

    Science.gov (United States)

    Dai, Peishan; Sheng, Hanwei; Zhang, Jianmei; Li, Ling; Wu, Jing; Fan, Min

    2016-01-01

    Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new retinal fundus image enhancement method is proposed. First, the original retinal fundus image was processed by the normalized convolution algorithm with a domain transform to obtain an image with the basic information of the background. Then, the image with the basic information of the background was fused with the original retinal fundus image to obtain an enhanced fundus image. Lastly, the fused image was denoised by a two-stage denoising method including the fourth order PDEs and the relaxed median filter. The retinal image databases, including the DRIVE database, the STARE database, and the DIARETDB1 database, were used to evaluate image enhancement effects. The results show that the method can enhance the retinal fundus image prominently. And, different from some other fundus image enhancement methods, the proposed method can directly enhance color images.

  5. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing

    Directory of Open Access Journals (Sweden)

    Peishan Dai

    2016-01-01

    Full Text Available Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new retinal fundus image enhancement method is proposed. First, the original retinal fundus image was processed by the normalized convolution algorithm with a domain transform to obtain an image with the basic information of the background. Then, the image with the basic information of the background was fused with the original retinal fundus image to obtain an enhanced fundus image. Lastly, the fused image was denoised by a two-stage denoising method including the fourth order PDEs and the relaxed median filter. The retinal image databases, including the DRIVE database, the STARE database, and the DIARETDB1 database, were used to evaluate image enhancement effects. The results show that the method can enhance the retinal fundus image prominently. And, different from some other fundus image enhancement methods, the proposed method can directly enhance color images.

  6. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing

    Science.gov (United States)

    2016-01-01

    Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new retinal fundus image enhancement method is proposed. First, the original retinal fundus image was processed by the normalized convolution algorithm with a domain transform to obtain an image with the basic information of the background. Then, the image with the basic information of the background was fused with the original retinal fundus image to obtain an enhanced fundus image. Lastly, the fused image was denoised by a two-stage denoising method including the fourth order PDEs and the relaxed median filter. The retinal image databases, including the DRIVE database, the STARE database, and the DIARETDB1 database, were used to evaluate image enhancement effects. The results show that the method can enhance the retinal fundus image prominently. And, different from some other fundus image enhancement methods, the proposed method can directly enhance color images. PMID:27688745

  7. Characteristics of fundus autofluorescence in cystoid macular edema

    Institute of Scientific and Technical Information of China (English)

    PENG Xi-jia; SU Lan-ping

    2011-01-01

    Background Fundus autofluorescence (FAF) imaging is a fast and noninvasive technique developed over the last decade.The authors utilized fluorescent properties of lipofuscin to study the health and viability of the retinal pigment epithelium (RPE)-photoreceptor complex.Observing the intensity and distribution of FAF of various retinal diseases is helpful for ascertaining diagnosis and evaluating prognosis.In this study,we described the FAF characteristics of cystoid macular edema (CME).Methods Sixty-two patients (70 eyes) with CME were subjected to FAF and fundus fluorescein angiography (FFA) by a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph 2 (HRA2)).Characteristics of FAF images were compared with FFA images.Results FAF intensity in normal subjects was highest at the posterior pole and dipped at the fovea.All cases of CME showed fluorescein dye accumulated into honeycomb-like spaces in macular and formated a typical petaloid pattern or atypical petaloid pattern in the late phases of the angiography.Sixty-one eyes with CME on FAF images showed mild or moderate hyperautofluorescence petaloid pattern in fovea,the FAF patterns of these CME was perfectly corresponding with shape in their FFA images;nine eyes with CME secondary to exudative age related macular degeneration (AMD) showed expansion of the hypoautofluorescence without petaloid pattern in macula.Conclusion FAF imaging can be used as a new rapid,non-invasive and ancillary technique in the diagnosis of the majority of CME,except for AMD and small part of other fundus diseases.

  8. Fundus Autofluorescence Imaging in an Ocular Screening Program

    Directory of Open Access Journals (Sweden)

    A. M. Kolomeyer

    2012-01-01

    Full Text Available Purpose. To describe integration of fundus autofluorescence (FAF imaging into an ocular screening program. Methods. Fifty consecutive screening participants were included in this prospective pilot imaging study. Color and FAF (530/640 nm exciter/barrier filters images were obtained with a 15.1MP Canon nonmydriatic hybrid camera. A clinician evaluated the images on site to determine need for referral. Visual acuity (VA, intraocular pressure (IOP, and ocular pathology detected by color fundus and FAF imaging modalities were recorded. Results. Mean ± SD age was 47.4 ± 17.3 years. Fifty-two percent were female and 58% African American. Twenty-seven percent had a comprehensive ocular examination within the past year. Mean VA was 20/39 in the right eye and 20/40 in the left eye. Mean IOP was 15 mmHg bilaterally. Positive color and/or FAF findings were identified in nine (18% individuals with diabetic retinopathy or macular edema (n=4, focal RPE defects (n=2, age-related macular degeneration (n=1, central serous retinopathy (n=1, and ocular trauma (n=1. Conclusions. FAF was successfully integrated in our ocular screening program and aided in the identification of ocular pathology. Larger studies examining the utility of this technology in screening programs may be warranted.

  9. Fundus autofluorescence imaging in an ocular screening program.

    Science.gov (United States)

    Kolomeyer, A M; Nayak, N V; Szirth, B C; Khouri, A S

    2012-01-01

    Purpose. To describe integration of fundus autofluorescence (FAF) imaging into an ocular screening program. Methods. Fifty consecutive screening participants were included in this prospective pilot imaging study. Color and FAF (530/640 nm exciter/barrier filters) images were obtained with a 15.1MP Canon nonmydriatic hybrid camera. A clinician evaluated the images on site to determine need for referral. Visual acuity (VA), intraocular pressure (IOP), and ocular pathology detected by color fundus and FAF imaging modalities were recorded. Results. Mean ± SD age was 47.4 ± 17.3 years. Fifty-two percent were female and 58% African American. Twenty-seven percent had a comprehensive ocular examination within the past year. Mean VA was 20/39 in the right eye and 20/40 in the left eye. Mean IOP was 15 mmHg bilaterally. Positive color and/or FAF findings were identified in nine (18%) individuals with diabetic retinopathy or macular edema (n = 4), focal RPE defects (n = 2), age-related macular degeneration (n = 1), central serous retinopathy (n = 1), and ocular trauma (n = 1). Conclusions. FAF was successfully integrated in our ocular screening program and aided in the identification of ocular pathology. Larger studies examining the utility of this technology in screening programs may be warranted.

  10. Glaucoma detection based on local binary patterns in fundus photographs

    Science.gov (United States)

    Alsheh Ali, Maya; Hurtut, Thomas; Faucon, Timothée.; Cheriet, Farida

    2014-03-01

    Glaucoma, a group of diseases that lead to optic neuropathy, is one of the most common reasons for blindness worldwide. Glaucoma rarely causes symptoms until the later stages of the disease. Early detection of glaucoma is very important to prevent visual loss since optic nerve damages cannot be reversed. To detect glaucoma, purely data-driven techniques have advantages, especially when the disease characteristics are complex and when precise image-based measurements are difficult to obtain. In this paper, we present our preliminary study for glaucoma detection using an automatic method based on local texture features extracted from fundus photographs. It implements the completed modeling of Local Binary Patterns to capture representative texture features from the whole image. A local region is represented by three operators: its central pixel (LBPC) and its local differences as two complementary components, the sign (which is the classical LBP) and the magnitude (LBPM). An image texture is finally described by both the distribution of LBP and the joint-distribution of LBPM and LBPC. Our images are then classified using a nearest-neighbor method with a leave-one-out validation strategy. On a sample set of 41 fundus images (13 glaucomatous, 28 non-glaucomatous), our method achieves 95:1% success rate with a specificity of 92:3% and a sensitivity of 96:4%. This study proposes a reproducible glaucoma detection process that could be used in a low-priced medical screening, thus avoiding the inter-experts variability issue.

  11. Nonmydriatic Ocular Fundus Photography in the Emergency Department: How It Can Benefit Neurologists.

    Science.gov (United States)

    Bruce, Beau B

    2015-10-01

    Examination of the ocular fundus is a critical aspect of the neurologic examination. For example, in patients with headache the ocular fundus examination is needed to uncover "red flags" suggestive of secondary etiologies. However, ocular fundus examination is infrequently and poorly performed in clinical practice. Nonmydriatic ocular fundus photography provides an alternative to direct ophthalmoscopy that has been studied as part of the Fundus Photography versus Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) Study. Herein, the results of the FOTO-ED study are reviewed with a particular focus on the study's implications for the acute care of patients presenting with headache and focal neurologic deficits. In headache patients, not only optic disc edema and optic disc pallor were observed as would be expected, but also a large number of abnormalities associated with hypertension. Based upon subjects with focal neurologic deficits, the FOTO-ED study suggests that the ocular fundus examination may assist with the triage of patients presenting with suspected transient ischemic attack. Continued advances in the ease and portability of nonmydriatic fundus photography will hopefully help to restore ocular fundus examination as a routinely performed component of all neurologic examinations.

  12. Differential diagnosis in cases of saddle-like impression of the fundus of the stomach

    Energy Technology Data Exchange (ETDEWEB)

    Hohenberg, G.; Deimer, E.; Schmidmeier, L.

    1984-01-01

    X-ray examination of the stomach sometimes shows a saddle-like impression of the region of the fundus. This phenomenon is without any clinical importance, but there are many diseases such as hiatal hernia, benign and malignant tumours, inflammatory diseases, and varices which are localised at the fundus. Differential diagnostic problems are discussed.

  13. [Cinematography of ocular fundus with a jointed optical system and tv or cine-camera (author's transl)].

    Science.gov (United States)

    Kampik, A; Rapp, J

    1979-02-01

    A method of Cinematography of the ocular fundus is introduced which--by connecting a camera with an indirect ophthalmoscop--allows to record the monocular picture of the fundus as produced by the ophthalmic lens.

  14. Comparison of Color Fundus Photography, Infrared Fundus Photography, and Optical Coherence Tomography in Detecting Retinal Hamartoma in Patients with Tuberous Sclerosis Complex

    Institute of Scientific and Technical Information of China (English)

    Da-Yong Bai; Xu Wang; Jun-Yang Zhao; Li Li; Jun Gao; Ning-Li Wang

    2016-01-01

    Background:A sensitive method is required to detect retinal hamartomas in patients with tuberous sclerosis complex (TSC).The aim of the present study was to compare the color fundus photography,infrared imaging (IFG),and optical coherence tomography (OCT) in the detection rate of retinal hamartoma in patients with TSC.Methods:This study included 11 patients (22 eyes) with TSC,who underwent color fundus photography,IFG,and spectral-domain OCT to detect retinal hamartomas.TSC1 and TSC2 mutations were tested in eight patients.Results:The mean age of the 11 patients was 8.0 ± 2.1 years.The mean spherical equivalent was-0.55 ± 1.42 D by autorefraction with cycloplegia.In 11 patients (22 eyes),OCT,infrared fundus photography,and color fundus photography revealed 26,18,and 9 hamartomas,respectively.The predominant hamartoma was type I (55.6%).All the hamartomas that detected by color fundus photography or IFG can be detected by OCT.Conclusion:Among the methods of color fundus photography,IFG,and OCT,the OCT has higher detection rate for retinal hamartoma in TSC patients;therefore,OCT might be promising for the clinical diagnosis of TSC.

  15. Realization of the ergonomics design and automatic control of the fundus cameras

    Science.gov (United States)

    Zeng, Chi-liang; Xiao, Ze-xin; Deng, Shi-chao; Yu, Xin-ye

    2012-12-01

    The principles of ergonomics design in fundus cameras should be extending the agreeableness by automatic control. Firstly, a 3D positional numerical control system is designed for positioning the eye pupils of the patients who are doing fundus examinations. This system consists of a electronically controlled chin bracket for moving up and down, a lateral movement of binocular with the detector and the automatic refocusing of the edges of the eye pupils. Secondly, an auto-focusing device for the object plane of patient's fundus is designed, which collects the patient's fundus images automatically whether their eyes is ametropic or not. Finally, a moving visual target is developed for expanding the fields of the fundus images.

  16. Statistical Characterization and Segmentation of Drusen in Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Karnowski, Thomas Paul [ORNL; Aykac, Deniz [ORNL; Giancardo, Luca [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Nichols, Trent L [ORNL; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  17. [Systemic cardiovascular risk assessment. Conventional or eye fundus-based?].

    Science.gov (United States)

    Wolf, A; Kernt, M; Kampik, A; Neubauer, A S

    2010-09-01

    Several systemic cardiovascular (CV) risk assessment algorithms exist, of which the ESC HeartScore, Framingham and PROCAM are the most frequently applied in Germany. The risk estimates generated differ and take a number of different risk factors into consideration. Due to existing homology of retinal vessels and brain vessels, eye fundus examination is a promising approach to improving risk prediction. Large cohort studies investigated retinal vascular changes, including arteriovenous ratio, as well as signs of retinopathy such as cotton-wool spots, microaneurysms, or retinal hemorrhages for their ability to predict systemic cardiovascular events. While signs of retinopathy proved to have high predictive power (but are rarely diagnosed,) the retinal vascular changes investigated could contribute little to enhancing systemic CV risk prediction. A number of new and promising approaches based on static and dynamic retinal analysis exist, but still need to be validated prospectively.

  18. Does Fundus Fluorescein Angiography Procedure Affect Ocular Pulse Amplitude?

    Directory of Open Access Journals (Sweden)

    Gökhan Pekel

    2013-01-01

    Full Text Available Purpose. This study examines the effects of fundus fluorescein angiography (FFA procedure on ocular pulse amplitude (OPA and intraocular pressure (IOP. Materials and Methods. Sixty eyes of 30 nonproliferative diabetic retinopathy patients (15 males, 15 females were included in this cross-sectional case series. IOP and OPA were measured with the Pascal dynamic contour tonometer before and after 5 minutes of intravenous fluorescein dye injection. Results. Pre-FFA mean OPA value was  mmHg and post-FFA mean OPA value was  mmHg (. Pre-FFA mean IOP value was  mmHg and post-FFA mean IOP value was  mmHg (. Conclusion. Although both mean OPA and IOP values were decreased after FFA procedure, the difference was not statistically significant. This clinical trial is registered with Australian New Zealand Clinical Trials Registry number ACTRN12613000433707.

  19. Statistical characterization and segmentation of drusen in fundus images.

    Science.gov (United States)

    Santos-Villalobos, H; Karnowski, T P; Aykac, D; Giancardo, L; Li, Y; Nichols, T; Tobin, K W; Chaum, E

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  20. Bayer Filter Snapshot Hyperspectral Fundus Camera for Human Retinal Imaging.

    Science.gov (United States)

    Kaluzny, Joel; Li, Hao; Liu, Wenzhong; Nesper, Peter; Park, Justin; Zhang, Hao F; Fawzi, Amani A

    2017-04-01

    To demonstrate the versatility and performance of a compact Bayer filter snapshot hyperspectral fundus camera for in-vivo clinical applications including retinal oximetry and macular pigment optical density measurements. 12 healthy volunteers were recruited under an Institutional Review Board (IRB) approved protocol. Fundus images were taken with a custom hyperspectral camera with a spectral range of 460-630 nm. We determined retinal vascular oxygen saturation (sO2) for the healthy population using the captured spectra by least squares curve fitting. Additionally, macular pigment optical density was localized and visualized using multispectral reflectometry from selected wavelengths. We successfully determined the mean sO2 of arteries and veins of each subject (ages 21-80) with excellent intrasubject repeatability (1.4% standard deviation). The mean arterial sO2 for all subjects was 90.9% ± 2.5%, whereas the mean venous sO2 for all subjects was 64.5% ± 3.5%. The mean artery-vein (A-V) difference in sO2 varied between 20.5% and 31.9%. In addition, we were able to reveal and quantify macular pigment optical density. We demonstrated a single imaging tool capable of oxygen saturation and macular pigment density measurements in vivo. The unique combination of broad spectral range, high spectral-spatial resolution, rapid and robust imaging capability, and compact design make this system a valuable tool for multifunction spectral imaging that can be easily performed in a clinic setting.

  1. Local resolved spectroscopy at the human ocular fundus in vivo: technique and clinical examples

    Science.gov (United States)

    Hammer, Martin; Schweitzer, Dietrich; Scibor, Mateusz

    1996-01-01

    Ocular fundus reflectometry is known as a method for the determination of the optical density of pigments at the eye ground. This has been described for diagnostic investigations at single locations. The new technique of imaging spectroscopy enables the recording of one dimensional local distribution of spectra from the fundus which is illuminated confocal to the entrance slit of a spectrograph. A fundus reflectometer consisting of a Zeiss fundus camera, an imaging spectrograph, and an intensified CCD-camera are presented. The local resolved spectra gained by this apparatus are approximated by a mathematical model on the basis of the anatomy of the fundus as a structure of layers with different optical properties. Each spectrum is assumed to be described by a function of the absorption spectra of the pigments found in the retinal and choroidal tissue. Assuming the existence of parameters which are independent from the fundus location we have to approximate the measured local distribution of spectra by a system of coupled non-linear equations. By a least square fit the local distribution of the extinction of melanin, xantophyll and hemoglobin may be obtained as well as the extension of pathologic alterations at the fundus. The benefits of the method for clinical diagnostics are discussed at first measurements from physiological and pathological examples.

  2. Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes

    National Research Council Canada - National Science Library

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily...

  3. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    National Research Council Canada - National Science Library

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily...

  4. Normal color variations of the canine ocular fundus, a retrospective study in Swedish dogs

    National Research Council Canada - National Science Library

    Granar, Marie I K S; Nilsson, Bo R; Hamberg-Nyström, Helene L

    2011-01-01

    A retrospective study was made to demonstrate normal variations of the color and size of the tapetal area and color of the nontapetal area in the ocular fundus in dogs, correlating them to breed, age and coat color...

  5. Multimodal retinal vessel segmentation from spectral-domain optical coherence tomography and fundus photography.

    Science.gov (United States)

    Hu, Zhihong; Niemeijer, Meindert; Abràmoff, Michael D; Garvin, Mona K

    2012-10-01

    Segmenting retinal vessels in optic nerve head (ONH) centered spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging due to the projected neural canal opening (NCO) and relatively low visibility in the ONH center. Color fundus photographs provide a relatively high vessel contrast in the region inside the NCO, but have not been previously used to aid the SD-OCT vessel segmentation process. Thus, in this paper, we present two approaches for the segmentation of retinal vessels in SD-OCT volumes that each take advantage of complimentary information from fundus photographs. In the first approach (referred to as the registered-fundus vessel segmentation approach), vessels are first segmented on the fundus photograph directly (using a k-NN pixel classifier) and this vessel segmentation result is mapped to the SD-OCT volume through the registration of the fundus photograph to the SD-OCT volume. In the second approach (referred to as the multimodal vessel segmentation approach), after fundus-to-SD-OCT registration, vessels are simultaneously segmented with a k -NN classifier using features from both modalities. Three-dimensional structural information from the intraretinal layers and neural canal opening obtained through graph-theoretic segmentation approaches of the SD-OCT volume are used in combination with Gaussian filter banks and Gabor wavelets to generate the features. The approach is trained on 15 and tested on 19 randomly chosen independent image pairs of SD-OCT volumes and fundus images from 34 subjects with glaucoma. Based on a receiver operating characteristic (ROC) curve analysis, the present registered-fundus and multimodal vessel segmentation approaches [area under the curve (AUC) of 0.85 and 0.89, respectively] both perform significantly better than the two previous OCT-based approaches (AUC of 0.78 and 0.83, p < 0.05). The multimodal approach overall performs significantly better than the other three approaches (p < 0.05).

  6. Segmentation of choroidal neovascularization in fundus fluorescein angiograms.

    Science.gov (United States)

    Abdelmoula, Walid M; Shah, Syed M; Fahmy, Ahmed S

    2013-05-01

    Choroidal neovascularization (CNV) is a common manifestation of age-related macular degeneration (AMD). It is characterized by the growth of abnormal blood vessels in the choroidal layer causing blurring and deterioration of the vision. In late stages, these abnormal vessels can rupture the retinal layers causing complete loss of vision at the affected regions. Determining the CNV size and type in fluorescein angiograms is required for proper treatment and prognosis of the disease. Computer-aided methods for CNV segmentation is needed not only to reduce the burden of manual segmentation but also to reduce inter- and intraobserver variability. In this paper, we present a framework for segmenting CNV lesions based on parametric modeling of the intensity variation in fundus fluorescein angiograms. First, a novel model is proposed to describe the temporal intensity variation at each pixel in image sequences acquired by fluorescein angiography. The set of model parameters at each pixel are used to segment the image into regions of homogeneous parameters. Preliminary results on datasets from 21 patients with Wet-AMD show the potential of the method to segment CNV lesions in close agreement with the manual segmentation.

  7. Fundus Autofluorescence in Age-related Macular Degeneration

    Science.gov (United States)

    Ly, Angelica; Nivison-Smith, Lisa; Assaad, Nagi; Kalloniatis, Michael

    2017-01-01

    ABSTRACT Fundus autofluorescence (FAF) provides detailed insight into the health of the retinal pigment epithelium (RPE). This is highly valuable in age-related macular degeneration (AMD) as RPE damage is a hallmark of the disease. The purpose of this paper is to critically appraise current clinical descriptions regarding the appearance of AMD using FAF and to integrate these findings into a chair-side reference. A wide variety of FAF patterns have been described in AMD, which is consistent with the clinical heterogeneity of the disease. In particular, FAF imaging in early to intermediate AMD has the capacity to reveal RPE alterations in areas that appear normal on funduscopy, which aids in the stratification of cases and may have visually significant prognostic implications. It can assist in differential diagnoses and also represents a reliable, sensitive method for distinguishing reticular pseudodrusen. FAF is especially valuable in the detection, evaluation, and monitoring of geographic atrophy and has been used as an endpoint in clinical trials. In neovascular AMD, FAF reveals distinct patterns of classic choroidal neovascularization noninvasively and may be especially useful for determining which eyes are likely to benefit from therapeutic intervention. FAF represents a rapid, effective, noninvasive imaging method that has been underutilized, and incorporation into the routine assessment of AMD cases should be considered. However, the practicing clinician should also be aware of the limitations of the modality, such as in the detection of foveal involvement and in the distinction of phenotypes (hypo-autofluorescent drusen from small areas of geographic atrophy). PMID:27668639

  8. Techniques of Glaucoma Detection From Color Fundus Images: A Review

    Directory of Open Access Journals (Sweden)

    Malaya Kumar Nath

    2012-09-01

    Full Text Available Glaucoma is a generic name for a group of diseases which causes progressive optic neuropathy and vision loss due to degeneration of the optic nerves. Optic nerve cells act as transducer and convert light signal entered into the eye to electrical signal for visual processing in the brain. The main risk factors of glaucoma are elevated intraocular pressure exerted by aqueous humour, family history of glaucoma (hereditary and diabetes. It causes damages to the eye, whether intraocular pressure is high, normal or below normal. It causes the peripheral vision loss. There are different types of glaucoma. Some glaucoma occurs suddenly. So, detection of glaucoma is essential for minimizing the vision loss. Increased cup area to disc area ratio is the significant change during glaucoma. Diagnosis of glaucoma is based on measurement of intraocular pressure by tonometry, visual field examination by perimetry and measurement of cup area to disc area ratio from the color fundus images. In this paper the different signal processing techniques are discussed for detection and classification of glaucoma.

  9. Interactive segmentation for geographic atrophy in retinal fundus images.

    Science.gov (United States)

    Lee, Noah; Smith, R Theodore; Laine, Andrew F

    2008-10-01

    Fundus auto-fluorescence (FAF) imaging is a non-invasive technique for in vivo ophthalmoscopic inspection of age-related macular degeneration (AMD), the most common cause of blindness in developed countries. Geographic atrophy (GA) is an advanced form of AMD and accounts for 12-21% of severe visual loss in this disorder [3]. Automatic quantification of GA is important for determining disease progression and facilitating clinical diagnosis of AMD. The problem of automatic segmentation of pathological images still remains an unsolved problem. In this paper we leverage the watershed transform and generalized non-linear gradient operators for interactive segmentation and present an intuitive and simple approach for geographic atrophy segmentation. We compare our approach with the state of the art random walker [5] algorithm for interactive segmentation using ROC statistics. Quantitative evaluation experiments on 100 FAF images show a mean sensitivity/specificity of 98.3/97.7% for our approach and a mean sensitivity/specificity of 88.2/96.6% for the random walker algorithm.

  10. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer

    Directory of Open Access Journals (Sweden)

    Bailey Y. Shen

    2017-01-01

    Full Text Available Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm×91mm×45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

  11. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer

    Science.gov (United States)

    Shen, Bailey Y.

    2017-01-01

    Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm × 91mm × 45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

  12. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer.

    Science.gov (United States)

    Shen, Bailey Y; Mukai, Shizuo

    2017-01-01

    Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm × 91mm × 45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

  13. Change in Drusen Area Over Time Compared Using Spectral-Domain Optical Coherence Tomography and Color Fundus Imaging

    Science.gov (United States)

    Gregori, Giovanni; Yehoshua, Zohar; Garcia Filho, Carlos Alexandre de Amorim; Sadda, SriniVas R.; Portella Nunes, Renata; Feuer, William J.; Rosenfeld, Philip J.

    2014-01-01

    Purpose. To investigate the relationship between drusen areas measured with color fundus images (CFIs) and those with spectral-domain optical coherence tomography (SDOCT). Methods. Forty-two eyes from thirty patients with drusen in the absence of geographic atrophy were recruited to a prospective study. Digital color fundus images and SDOCT images were obtained at baseline and at follow-up visits at 3 and 6 months. Registered, matched circles centered on the fovea with diameters of 3 mm and 5 mm were identified on both CFIs and SDOCT images. Spectral-domain OCT drusen measurements were obtained using a commercially available proprietary algorithm. Drusen boundaries on CFIs were traced manually at the Doheny Eye Institute Image Reading Center. Results. Mean square root drusen area (SQDA) measurements for the 3-mm circles on the SDOCT images were 1.451 mm at baseline and 1.464 mm at week 26, whereas the measurements on CFIs were 1.555 mm at baseline and 1.584 mm at week 26. Mean SQDA measurements from CFIs were larger than those from the SDOCT measurements at all time points (P = 0.004 at baseline, P = 0.003 at 26 weeks). Changes in SQDA over 26 weeks measured with SDOCT were not different from those measured with CFIs (mean difference = 0.014 mm, P = 0.5). Conclusions. Spectral-domain OCT drusen area measurements were smaller than the measurements obtained from CFIs. However, there were no differences in the change in drusen area over time between the two imaging modalities. Spectral-domain OCT measurements were considerably more sensitive in assessing drusen area changes. PMID:25335982

  14. Laparoscopic resection of submucosal tumor on posterior wall of gastric fundus

    Institute of Scientific and Technical Information of China (English)

    Zhong-Wei Ke; Cheng-Zhu Zheng; Ming-Gen Hu; Dan-Lei Chen

    2004-01-01

    AIM: Laparoscopic resection of tumors on the posterior wall of gastric fundus, especially when they are next to the esophagocardiac junction (ECJ), is both difficult and timeconsuming. Furthermore, it can lead to inadvertent esophagus stenosis and injury to the spleen. In order to overcome these difficulties, laparoscopically extraluminal resection of gastric fundus was designed to manage submucosal tumors located on the posterior wall of gastric fundus and next to ECJ.METHODS: From January 2001 to September 2003,laparoscopically extraluminal resection of gastric fundus was successfully carried out on 15 patients. There were11 males and 4 females with an average age of 58 years(range, 38 to 78 years). The mean diameter of the tumors was 4.8 cm. The distance of the tumor border from ECJ was about 1.5-2.5 cm. The four-portal operation procedures were as follows: localization of the tumor, dissection of the omentum, mobilization of the gastric fundus and the upper polar of spleen, exposure of ECJ, and resection of the gastric fundus with Endo GIA.RESULTS: The laparoscopic operation time averaged(66.2±10.4) min, the average amount of bleeding was(89.4±21.7) mL. The mean post-operative hospital stay was (5.3±1.1) d. Within 36 h post-operation, 73.3% of all the patients recovered their gastrointestinal function and began to eat something and to walk. In all the operations,no apparent tumor focus was left and no complication or conversion to open surgery occurred.CONCLUSION: Our newly designed procedure,laparoscopically extraluminal resection of the gastric fundus, can avoid contamination of the abdominal cavity,injury to the spleen and esophageal stenosis. The procedure seems to be both safe and effective.

  15. Automated Measurement of the Arteriolar-to-Venular Width Ratio in Digital Color Fundus Photographs

    NARCIS (Netherlands)

    Niemeijer, M.; Xu, X.; Dumitrescu, A.V.; Gupta, P.; Ginneken, B. van; Folk, J.C.; Abramoff, M.D.

    2011-01-01

    A decreased ratio of the width of retinal arteries to veins [arteriolar-to-venular diameter ratio (AVR)], is well established as predictive of cerebral atrophy, stroke and other cardiovascular events in adults. Tortuous and dilated arteries and veins, as well as decreased AVR are also markers for

  16. Automated Measurement of the Arteriolar-to-Venular Width Ratio in Digital Color Fundus Photographs

    NARCIS (Netherlands)

    Niemeijer, M.; Xu, X.; Dumitrescu, A.V.; Gupta, P.; Ginneken, B. van; Folk, J.C.; Abramoff, M.D.

    2011-01-01

    A decreased ratio of the width of retinal arteries to veins [arteriolar-to-venular diameter ratio (AVR)], is well established as predictive of cerebral atrophy, stroke and other cardiovascular events in adults. Tortuous and dilated arteries and veins, as well as decreased AVR are also markers for pl

  17. Automatic localization of bifurcations and vessel crossings in digital fundus photographs using location regression

    Science.gov (United States)

    Niemeijer, Meindert; Dumitrescu, Alina V.; van Ginneken, Bram; Abrámoff, Michael D.

    2011-03-01

    Parameters extracted from the vasculature on the retina are correlated with various conditions such as diabetic retinopathy and cardiovascular diseases such as stroke. Segmentation of the vasculature on the retina has been a topic that has received much attention in the literature over the past decade. Analysis of the segmentation result, however, has only received limited attention with most works describing methods to accurately measure the width of the vessels. Analyzing the connectedness of the vascular network is an important step towards the characterization of the complete vascular tree. The retinal vascular tree, from an image interpretation point of view, originates at the optic disc and spreads out over the retina. The tree bifurcates and the vessels also cross each other. The points where this happens form the key to determining the connectedness of the complete tree. We present a supervised method to detect the bifurcations and crossing points of the vasculature of the retina. The method uses features extracted from the vasculature as well as the image in a location regression approach to find those locations of the segmented vascular tree where the bifurcation or crossing occurs (from here, POI, points of interest). We evaluate the method on the publicly available DRIVE database in which an ophthalmologist has marked the POI.

  18. Wnt/β-catenin promotes gastric fundus specification in mice and humans.

    Science.gov (United States)

    McCracken, Kyle W; Aihara, Eitaro; Martin, Baptiste; Crawford, Calyn M; Broda, Taylor; Treguier, Julie; Zhang, Xinghao; Shannon, John M; Montrose, Marshall H; Wells, James M

    2017-01-12

    Despite the global prevalence of gastric disease, there are few adequate models in which to study the fundus epithelium of the human stomach. We differentiated human pluripotent stem cells (hPSCs) into gastric organoids containing fundic epithelium by first identifying and then recapitulating key events in embryonic fundus development. We found that disruption of Wnt/β-catenin signalling in mouse embryos led to conversion of fundic to antral epithelium, and that β-catenin activation in hPSC-derived foregut progenitors promoted the development of human fundic-type gastric organoids (hFGOs). We then used hFGOs to identify temporally distinct roles for multiple signalling pathways in epithelial morphogenesis and differentiation of fundic cell types, including chief cells and functional parietal cells. hFGOs are a powerful model for studying the development of the human fundus and the molecular bases of human gastric physiology and pathophysiology, and also represent a new platform for drug discovery.

  19. [New Approach of Fundus Image Segmentation Evaluation Based on Topology Structure].

    Science.gov (United States)

    Sheng, Hanwei; Dai, Peishan; Liu, Zhihang; Zhang-Wen, Miaoyun; Zhao, Yali; Fan, Min

    2015-10-01

    In view of the evaluation of fundus image segmentation, a new evaluation method was proposed to make up insufficiency of the traditional evaluation method which only considers the overlap of pixels and neglects topology structure of the retinal vessel. Mathematical morphology and thinning algorithm were used to obtain the retinal vascular topology structure. Then three features of retinal vessel, including mutual information, correlation coefficient and ratio of nodes, were calculated. The features of the thinned images taken as topology structure of blood vessel were used to evaluate retinal image segmentation. The manually-labeled images and their eroded ones of STARE database were used in the experiment. The result showed that these features, including mutual information, correlation coefficient and ratio of nodes, could be used to evaluate the segmentation quality of retinal vessel on fundus image through topology structure, and the algorithm was simple. The method is of significance to the supplement of traditional segmentation evaluation of retinal vessel on fundus image.

  20. Fundus autofluorescence and optical coherence tomography findings in thiamine responsive megaloblastic anemia.

    Science.gov (United States)

    Ach, Thomas; Kardorff, Rüdiger; Rohrschneider, Klaus

    2015-01-01

    To report ophthalmologic fundus autofluorescence and spectral domain optical coherence tomography findings in a patient with thiamine responsive megaloblastic anemia (TRMA). A 13-year-old girl with genetically proven TRMA was ophthalmologically (visual acuity, funduscopy, perimetry, electroretinogram) followed up over >5 years. Fundus imaging also included autofluorescence and spectral domain optical coherence tomography. During a 5-year follow-up, visual acuity and visual field decreased, despite a special TRMA diet. Funduscopy revealed bull's eye appearance, whereas fundus autofluorescence showed central and peripheral hyperfluorescence and perifoveal hypofluorescence. Spectral domain optical coherence tomography revealed affected inner segment ellipsoid band and irregularities in the retinal pigment epithelium and choroidea. Autofluorescence and spectral domain optical coherence tomography findings in a patient with TRMA show retinitis pigmentosa-like retina, retinal pigment epithelium, and choroid alterations. These findings might progress even under special TRMA diet, indispensable to life. Ophthalmologist should consider TRMA in patients with deafness and ophthalmologic disorders.

  1. Ocular fundus pathology and chronic kidney disease in a Chinese population

    Directory of Open Access Journals (Sweden)

    Gao Bixia

    2011-11-01

    Full Text Available Abstract Background Previous study indicated a high prevalence of ocular fundus pathology among patients with chronic kidney disease (CKD, while the relationship between them has never been explored in a Chinese Population. Methods This cross-sectional study included 9 670 participants enrolled in a medical screening program. Ocular fundus examination was performed by ophthalmologists using ophthalmoscopes. The presence of eGFR less than 60 mL/min/1.73 m2 and/or proteinuria was defined as CKD. Results Compared to participants without CKD, participants with CKD had higher prevalence of retinopathy (28.5% vs. 16.3%, P Conclusions Ocular fundus pathology is common among Chinese patients with CKD. Regular eye exam among persons with proteinuria is warranted.

  2. Classification of diabetic retinopathy using fractal dimension analysis of eye fundus image

    Science.gov (United States)

    Safitri, Diah Wahyu; Juniati, Dwi

    2017-08-01

    Diabetes Mellitus (DM) is a metabolic disorder when pancreas produce inadequate insulin or a condition when body resist insulin action, so the blood glucose level is high. One of the most common complications of diabetes mellitus is diabetic retinopathy which can lead to a vision problem. Diabetic retinopathy can be recognized by an abnormality in eye fundus. Those abnormalities are characterized by microaneurysms, hemorrhage, hard exudate, cotton wool spots, and venous's changes. The diabetic retinopathy is classified depends on the conditions of abnormality in eye fundus, that is grade 1 if there is a microaneurysm only in the eye fundus; grade 2, if there are a microaneurysm and a hemorrhage in eye fundus; and grade 3: if there are microaneurysm, hemorrhage, and neovascularization in the eye fundus. This study proposed a method and a process of eye fundus image to classify of diabetic retinopathy using fractal analysis and K-Nearest Neighbor (KNN). The first phase was image segmentation process using green channel, CLAHE, morphological opening, matched filter, masking, and morphological opening binary image. After segmentation process, its fractal dimension was calculated using box-counting method and the values of fractal dimension were analyzed to make a classification of diabetic retinopathy. Tests carried out by used k-fold cross validation method with k=5. In each test used 10 different grade K of KNN. The accuracy of the result of this method is 89,17% with K=3 or K=4, it was the best results than others K value. Based on this results, it can be concluded that the classification of diabetic retinopathy using fractal analysis and KNN had a good performance.

  3. EFFECT OF FUNDUS PIGMENT ON RESPONSE OF RABBIT RETINA TO TRANSPUPILLARY THERMOTHERAPY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To study the effect of fundus pigment on the response of the retina to transpupillary thermotherapy (TTT). Methods The retina were irradiated with 810 nm diode laser in 16 eyes of 8 pigmented rabbits and 12 eyes of 6 albino rabbits. The spot size was 1.2 mm; the duration was 60 s; and powers were 50, 80, 150 and 300 mW for pigmented rabbits and 800, 1 200 and 1 500mW for albino rabbits. All of the eyes were followed up with ophthalmolscope. The fundus was photographed and examined histologically with optic microscope immediately and 1 month after TTT respectively. Results The changes of the fundus and the histological examination were not significant immediately and 1 month after TTT in 50 mW group of pigmented rabbit and 800 mW of albino rabbit. Grey spot on the retina was observed on the fundus in 80 mW group of pigmented rabbit and 1 200 mW of albino rabbit immediately after TTT. The structure of the retina remained intact and subretinal fluid was observed histologically. Grey spot was still visible on the fundus, though the fluid was absorbed after 1 month. As the power of diode laser was increased to 150 mW for pigmented rabbits and 1500 mW for albino rabbit, fundus white spots were observed and the outer retina was destroyed while photoreceptors existed immediately after TTT. Pigmentation was found in white lesions and the fibrous proliferation was found in choroid 1 month after TTT. Prominent white spot was seen on the fundus immediately after laser irradiation of 300 mW in pigmented rabbits and the structure of the retina was obscured. One month after TTT, dense pigmentation appeared at laser lesions. The retina was thinner. There was prominent fibrous proliferation in the choroid. Conclusion The fundus pigment seems to play an important role in the response of the retina to TTT. The reaction of the retina is in proportion to the intensity of laser.

  4. Non-mydriatic ultra-widefield images compared to 7-field ETDRS standard images for screening of diabetic retinopathy

    DEFF Research Database (Denmark)

    Rasmussen, Malin Lundberg; Broe, Rebecca; Peto, Tunde

    Undersøgelse af diabetisk retinopati ved to forskellige typer af kamera - et traditionelt, hvor der tages 7 fotos a 45 grader og med en ny type vidvinklet kamera, hvor et billede dækker 200 grader af nethinden. Der blev fundet god overensstemmelse mellem de to typer kamera iht. at gradere diabeti...

  5. Optic disc boundary segmentation from diffeomorphic demons registration of monocular fundus image sequences versus 3D visualization of stereo fundus image pairs for automated early stage glaucoma assessment

    Science.gov (United States)

    Gatti, Vijay; Hill, Jason; Mitra, Sunanda; Nutter, Brian

    2014-03-01

    Despite the current availability in resource-rich regions of advanced technologies in scanning and 3-D imaging in current ophthalmology practice, world-wide screening tests for early detection and progression of glaucoma still consist of a variety of simple tools, including fundus image-based parameters such as CDR (cup to disc diameter ratio) and CAR (cup to disc area ratio), especially in resource -poor regions. Reliable automated computation of the relevant parameters from fundus image sequences requires robust non-rigid registration and segmentation techniques. Recent research work demonstrated that proper non-rigid registration of multi-view monocular fundus image sequences could result in acceptable segmentation of cup boundaries for automated computation of CAR and CDR. This research work introduces a composite diffeomorphic demons registration algorithm for segmentation of cup boundaries from a sequence of monocular images and compares the resulting CAR and CDR values with those computed manually by experts and from 3-D visualization of stereo pairs. Our preliminary results show that the automated computation of CDR and CAR from composite diffeomorphic segmentation of monocular image sequences yield values comparable with those from the other two techniques and thus may provide global healthcare with a cost-effective yet accurate tool for management of glaucoma in its early stage.

  6. Ocular Fundus Photography as a Tool to Study Stroke and Dementia.

    Science.gov (United States)

    Cheung, Carol Y; Chen, Christopher; Wong, Tien Y

    2015-10-01

    Although cerebral small vessel disease has been linked to stroke and dementia, due to limitations of current neuroimaging technology, direct in vivo visualization of changes in the cerebral small vessels (e.g., cerebral arteriolar narrowing, tortuous microvessels, blood-brain barrier damage, capillary microaneurysms) is difficult to achieve. As the retina and the brain share similar embryological origin, anatomical features, and physiologic properties with the cerebral small vessels, the retinal vessels offer a unique and easily accessible "window" to study the correlates and consequences of cerebral small vessel diseases in vivo. The retinal microvasculature can be visualized, quantified and monitored noninvasively using ocular fundus photography. Recent clinic- and population-based studies have demonstrated a close link between retinal vascular changes seen on fundus photography and stroke and dementia, suggesting that ocular fundus photography may provide insights to the contribution of microvascular disease to stroke and dementia. In this review, we summarize current knowledge on retinal vascular changes, such as retinopathy and changes in retinal vascular measures with stroke and dementia as well as subclinical makers of cerebral small vessel disease, and discuss the possible clinical implications of these findings in neurology. Studying pathologic changes of retinal blood vessels may be useful for understanding the etiology of various cerebrovascular conditions; hence, ocular fundus photography can be potentially translated into clinical practice.

  7. An indirect action of dopamine on the rat fundus strip mediated by 5-hydroxytryptamine

    NARCIS (Netherlands)

    Sonneville, P.F.

    Dopamine in a concentration of 10−7 molar produces a contraction of the rat stomach fundus preparation. This effect is blocked by the 5-HT antagonist methysergide. Repeated exposure to dopamine results in tachyphylaxis, but the sensitivity to dopamine can be restored by incubating the tissue with

  8. Visual stimulus-induced changes in human near-infrared fundus reflectance

    NARCIS (Netherlands)

    Abramoff, M.D.; Kwon, Y.H.; Ts’o, D.; Soliz, P.; Zimmerman, B.; Pokorny, J.; Kardon, R.

    2006-01-01

    PURPOSE. Imaging studies from anesthetized feline, primate, and human retinas have revealed near-infrared fundus reflectance changes induced by visible light stimulation. In the present study, the spatial and temporal properties of similar changes were characterized in normal, awake humans. METHODS.

  9. An indirect action of dopamine on the rat fundus strip mediated by 5-hydroxytryptamine

    NARCIS (Netherlands)

    Sonneville, P.F.

    1968-01-01

    Dopamine in a concentration of 10−7 molar produces a contraction of the rat stomach fundus preparation. This effect is blocked by the 5-HT antagonist methysergide. Repeated exposure to dopamine results in tachyphylaxis, but the sensitivity to dopamine can be restored by incubating the tissue with 5-

  10. High K+-Induced Relaxation by Nitric Oxide in Human Gastric Fundus

    Science.gov (United States)

    Kim, Dae Hoon; Choi, Woong; Sung, Rohyun; Kim, Hun Sik; Kim, Heon; Yoo, Ra Young; Park, Seon-Mee; Yun, Sei Jin; Song, Young-Jin; Xu, Wen-Xie; Lee, Sang Jin

    2012-01-01

    This study was designed to elucidate high K+-induced relaxation in the human gastric fundus. Circular smooth muscle from the human gastric fundus greater curvature showed stretch-dependent high K+ (50 mM)-induced contractions. However, longitudinal smooth muscle produced stretch-dependent high K+-induced relaxation. We investigated several relaxation mechanisms to understand the reason for the discrepancy. Protein kinase inhibitors such as KT 5823 (1 µM) and KT 5720 (1 µM) which block protein kinases (PKG and PKA) had no effect on high K+-induced relaxation. K+ channel blockers except 4-aminopyridine (4-AP), a voltage-dependent K+ channel (KV) blocker, did not affect high K+-induced relaxation. However, N(G)-nitro-L-arginine and 1H-(1,2,4)oxadiazolo (4,3-A)quinoxalin-1-one, an inhibitors of soluble guanylate cyclase (sGC) and 4-AP inhibited relaxation and reversed relaxation to contraction. High K+-induced relaxation of the human gastric fundus was observed only in the longitudinal muscles from the greater curvature. These data suggest that the longitudinal muscle of the human gastric fundus greater curvature produced high K+-induced relaxation that was activated by the nitric oxide/sGC pathway through a KV channel-dependent mechanism. PMID:23118553

  11. Automatic Drusen Quantification and Risk Assessment of Age-related Macular Degeneration on Color Fundus Images

    NARCIS (Netherlands)

    Grinsven, M.J.J.P. van; Lechanteur, Y.T.E.; Ven, J.P.H. van de; Ginneken, B. van; Hoyng, C.B.; Theelen, T.; Sanchez, C.I.

    2013-01-01

    PURPOSE: To evaluate a machine learning algorithm that allows for computer aided diagnosis (CAD) of non-advanced age-related macular degeneration (AMD) by providing an accurate detection and quantification of drusen location, area and size. METHODS: Color fundus photographs of 407 eyes without AMD

  12. Role of M1 receptor in regulation of gastric fundus smooth muscle contraction

    Directory of Open Access Journals (Sweden)

    Marta Gajdus

    2011-09-01

    Full Text Available Background:The subject of this study is determination of the influence of drugs on gastric fundus smooth muscle contraction induced by activation of muscarinic receptors M1. Experiments tested interactions between a receptor agonist, carbachol and muscarinic receptor antagonists, atropine and pirenzepine.Material/Methods:Testing was conducted on tissues isolated from rat’s stomach. Male Wistar rats with weight between 220 g and 360 g were anesthetized by intraperitoneal injection of urethane (120 mg/kg. The stomach was dissected, and later the gastric fundus was isolated. Tissue was placed in a dish for insulated organs with 20 ml in capacity, filled with Krebs fluid. Results contained in the study are average values ± SE. In order to determine statistical significance, the principles of receptor theory were used (Kenakin modification.Results:According to tests, carbachol, in concentrations ranging between 10–8 M to 10–4 M, in a dosage-dependent way induces gastric fundus smooth muscle contraction. Presented results indicate that carbachol meets the conditions posed to full agonists. On the other hand, atropine, a non-selective muscarinic receptor antagonist, causes a concentration-dependent shift of concentration-effect curve (for carbachol to the right, maintaining maximum reaction. According to analysis of the curve determined, we can deduce that atropine meets the conditions posed to competitive antagonists. The use of pirenzepine, a competitive receptor agonist M1, causes shift of concentration-effect curve (for carbachol to the right, maintaining maximum reaction.Conclusions:From the testing conducted on the preparation of the gastric fundus we can deduce that atropine causes shift of concentration-effect curves for carbachol to the right. A similar effect is released by pirenzepine, selectively blocking muscarinic receptors of M1 type. The results indicate that in the preparation of the gastric fundus smooth muscle, M1 type

  13. Role of M1 receptor in regulation of gastric fundus smooth muscle contraction.

    Science.gov (United States)

    Gajdus, Marta; Szadujkis-Szadurska, Katarzyna; Szadujkis-Szadurski, Leszek; Glaza, Izabela; Szadujkis-Szadurski, Rafał; Olkowska, Joanna

    2011-09-14

    The subject of this study is determination of the influence of drugs on gastric fundus smooth muscle contraction induced by activation of muscarinic receptors M1. Experiments tested interactions between a receptor agonist, carbachol and muscarinic receptor antagonists, atropine and pirenzepine. Testing was conducted on tissues isolated from rat's stomach. Male Wistar rats with weight between 220 g and 360 g were anesthetized by intraperitoneal injection of urethane (120 mg/kg). The stomach was dissected, and later the gastric fundus was isolated. Tissue was placed in a dish for insulated organs with 20 ml in capacity, filled with Krebs fluid. Results contained in the study are average values ± SE. In order to determine statistical significance, the principles of receptor theory were used (Kenakin modification). According to tests, carbachol, in concentrations ranging between 10(-8) M to 10(-4) M, in a dosage-dependent way induces gastric fundus smooth muscle contraction. Presented results indicate that carbachol meets the conditions posed to full agonists. On the other hand, atropine, a non-selective muscarinic receptor antagonist, causes a concentration-dependent shift of concentration-effect curve (for carbachol) to the right, maintaining maximum reaction. According to analysis of the curve determined, we can deduce that atropine meets the conditions posed to competitive antagonists. The use of pirenzepine, a competitive receptor agonist M1, causes shift of concentration-effect curve (for carbachol) to the right, maintaining maximum reaction. From the testing conducted on the preparation of the gastric fundus we can deduce that atropine causes shift of concentration-effect curves for carbachol to the right. A similar effect is released by pirenzepine, selectively blocking muscarinic receptors of M1 type. The results indicate that in the preparation of the gastric fundus smooth muscle, M1 type receptors occur also postsynaptically.

  14. Subretinal Fibrosis in Stargardt’s Disease with Fundus Flavimaculatus and ABCA4 Gene Mutation

    Directory of Open Access Journals (Sweden)

    Settimio Rossi

    2012-12-01

    Full Text Available Purpose: To report on 4 patients affected by Stargardt’s disease (STGD with fundus flavimaculatus (FFM and ABCA4 gene mutation associated with subretinal fibrosis. Methods: Four patients with a diagnosis of STGD were clinically examined. All 4 cases underwent a full ophthalmologic evaluation, including best-corrected visual acuity measured by the Snellen visual chart, biomicroscopic examination, fundus examination, fundus photography, electroretinogram, microperimetry, optical coherence tomography and fundus autofluorescence. All patients were subsequently screened for ABCA4 gene mutations, identified by microarray genotyping and confirmed by conventional DNA sequencing of the relevant exons. Results: In all 4 patients, ophthalmologic exam showed areas of subretinal fibrosis in different retinal sectors. In only 1 case, these lesions were correlated to an ocular trauma as confirmed by biomicroscopic examination of the anterior segment that showed a nuclear cataract dislocated to the superior site and vitreous opacities along the lens capsule. The other patients reported a lifestyle characterized by competitive sport activities. The performed instrumental diagnostic investigations confirmed the diagnosis of STGD with FFM in all patients. Moreover, in all 4 affected individuals, mutations in the ABCA4 gene were found. Conclusions: Patients with the diagnosis of STGD associated with FFM can show atypical fundus findings. We report on 4 patients affected by STGD with ABCA4 gene mutation associated with subretinal fibrosis. Our findings suggest that this phenomenon can be accelerated by ocular trauma and also by ocular microtrauma caused by sport activities, highlighting that lifestyle can play a role in the onset of these lesions.

  15. Telemedicine for diabetic retinopathy screening using an ultra-widefield fundus camera

    Directory of Open Access Journals (Sweden)

    Hussain N

    2017-08-01

    Full Text Available Nazimul Hussain,1 Maryam Edraki,2 Rima Tahhan,2 Nishanth Sanalkumar,2 Sami Kenz,2 Nagwa Khalil Akasha,2 Brian Mtemererwa,2 Nahed Mohammed2 1Department of Ophthalmology, Al Zahra Hospital, Sharjah, United Arab Emirates; 2Department of Endocrinology, Al Zahra Hospital, Sharjah, United Arab Emirates Objective: Telemedicine reporting of diabetic retinopathy (DR screening using ultra-widefield (UWF fundus camera. Materials and methods: Cross-sectional study of diabetic patients who visited the endocrinology department of a private multi-specialty hospital in United Arab Emirates between April 2015 and January 2017 who underwent UWF fundus imaging. Fundus pictures are then accessed at the Retina Clinic in the Department of Ophthalmology. Primary outcome measure was incidence of any form of DR detected. The secondary outcome measure was failure to take good image and inability to grade. Results: A total of 1,024 diabetic individuals were screened for DR from April 2015 to January 2017 in the department of Endocrinology. Rate of DR was 9.27%; 165 eyes of 95 individuals were diagnosed to have some form of DR. Mild non-proliferative DR (NPDR was seen in 114 of 165 eyes (69.09%, moderate NPDR in 32 eyes (19.39%, severe NPDR in six eyes (3.64%, and proliferative DR (PDR in 13 eyes (7.88%. The secondary outcome measure of poor image acquisition was seen in one individual who had an image acquired in one eye that could not be graded due to bad picture quality. Conclusions: The present study has shown the effectiveness of DR screening using UWF fundus camera. It has shown the effectiveness of trained nursing personnel taking fundus images. This model can be replicated in any private multi-specialty hospital and reduce the burden of DR screening in the retina clinic and enhance early detection of treatable DR. Keywords: telemedicine, ultra-widefield camera, diabetic retinopathy screening

  16. Enhanced depth imaging optical coherence tomography and fundus autofluorescence findings in bilateral choroidal osteoma: a case report

    Directory of Open Access Journals (Sweden)

    Muhammet Kazim Erol

    2013-06-01

    Full Text Available The authors present enhanced depth imaging optical coherence tomography (EDI OCT and fundus autofluorescence (FAF characteristics of a patient with bilateral choroidal osteoma and try to make a correlation between two imaging techniques. Two eyes of a patient with choroidal osteoma underwent complete ophthalmic examination. Enhanced depth imaging optical coherence tomography revealed a cage-like pattern, which corresponded to the calcified region of the tumor. Fundus autofluorescence imaging of the same area showed slight hyperautofluorescence. Three different reflectivity patterns in the decalcified area were defined. In the areas of subretinal fluid, outer segment elongations similar to central serous chorioretinopathy were observed. Hyperautofluorescent spots were evident in fundus autofluorescence in the same area. Calcified and decalcified portions of choroidal osteoma as well as the atrophy of choriocapillaris demonstrated different patterns with enhanced depth imaging and fundus autofluorescence imaging. Both techniques were found to be beneficial in the diagnosis and follow-up of choroidal osteoma.

  17. Enhanced depth imaging optical coherence tomography and fundus autofluorescence findings in bilateral choroidal osteoma: a case report.

    Science.gov (United States)

    Erol, Muhammet Kazim; Coban, Deniz Turgut; Ceran, Basak Bostanci; Bulut, Mehmet

    2013-01-01

    The authors present enhanced depth imaging optical coherence tomography (EDI OCT) and fundus autofluorescence (FAF) characteristics of a patient with bilateral choroidal osteoma and try to make a correlation between two imaging techniques. Two eyes of a patient with choroidal osteoma underwent complete ophthalmic examination. Enhanced depth imaging optical coherence tomography revealed a cage-like pattern, which corresponded to the calcified region of the tumor. Fundus autofluorescence imaging of the same area showed slight hyperautofluorescence. Three different reflectivity patterns in the decalcified area were defined. In the areas of subretinal fluid, outer segment elongations similar to central serous chorioretinopathy were observed. Hyperautofluorescent spots were evident in fundus autofluorescence in the same area. Calcified and decalcified portions of choroidal osteoma as well as the atrophy of choriocapillaris demonstrated different patterns with enhanced depth imaging and fundus autofluorescence imaging. Both techniques were found to be beneficial in the diagnosis and follow-up of choroidal osteoma.

  18. Enhanced depth imaging optical coherence tomography and fundus autofluorescence findings in bilateral choroidal osteoma: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Erol, Muhammet Kazim; Coban, Deniz Turgut; Ceran, Basak Bostanci; Bulut, Mehmet, E-mail: muhammetkazimerol@gmail.com [Kazim Erol. Antalya Training and Research Hospital, Ophthalmology Department, Antalya (Turkey)

    2013-11-01

    The authors present enhanced depth imaging optical coherence tomography (EDI OCT) and fundus autofluorescence (FAF) characteristics of a patient with bilateral choroidal osteoma and try to make a correlation between two imaging techniques. Two eyes of a patient with choroidal osteoma underwent complete ophthalmic examination. Enhanced depth imaging optical coherence tomography revealed a cage-like pattern, which corresponded to the calcified region of the tumor. Fundus autofluorescence imaging of the same area showed slight hyperautofluorescence. Three different reflectivity patterns in the decalcified area were defined. In the areas of subretinal fluid, outer segment elongations similar to central serous chorioretinopathy were observed. Hyperautofluorescent spots were evident in fundus autofluorescence in the same area. Calcified and decalcified portions of choroidal osteoma as well as the atrophy of choriocapillaris demonstrated different patterns with enhanced depth imaging and fundus autofluorescence imaging. Both techniques were found to be beneficial in the diagnosis and follow-up of choroidal osteoma. (author)

  19. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    Science.gov (United States)

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-10-01

    Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  20. Ultrawide-field fundus photography of the first reported case of gyrate atrophy from Australia.

    Science.gov (United States)

    Moloney, Thomas P; O'Hagan, Stephen; Lee, Lawrence

    2014-01-01

    Gyrate atrophy of the choroid and retina is a rare chorioretinal dystrophy inherited in an autosomal recessive pattern. We describe the first documented case of gyrate atrophy from Australia in a 56-year-old woman with a history of previous diagnosis of retinitis pigmentosa and worsening night vision in her right eye over several years. She was myopic and bilaterally pseudophakic, and fundus examination revealed pale optic discs and extensive peripheral chorioretinal atrophy exposing bare sclera bilaterally with only small islands of normal-appearing retina at each posterior pole. Visual field testing showed grossly constricted fields, blood testing showed hyperornithinemia, and further questioning revealed consanguinity between the patient's parents. We then used the patient's typical retinal findings of gyrate atrophy to demonstrate the potential use of ultrawide-field fundus photography and angiography in diagnosis and monitoring response in future treatment.

  1. Detection of Glaucomatous Eye via Color Fundus Images Using Fractal Dimensions

    Directory of Open Access Journals (Sweden)

    J. Jan

    2008-09-01

    Full Text Available This paper describes a method for glaucomatous eye detection based on fractal description, followed by classification. Two methods for fractal dimensions estimation, which give a different image/tissue description, are presented. The fundus color images are used, in which the areas with retinal nerve fibers are analyzed. The presented method shows that fractal dimensions can be used as features for retinal nerve fibers losses detection, which is a sign of glaucomatous eye.

  2. Influence of antioxidant depletion on nitrergic relaxation in the pig gastric fundus

    OpenAIRE

    2002-01-01

    The hypothesis that endogenous tissue antioxidants might explain the inability of the superoxide generators 6-anilino-5,8-quinolinedione (LY83583) and hydroquinone (HQ) and of the NO-scavengers hydroxocobalamin (HC) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) to affect nitrergic neurotransmission in the porcine gastric fundus was tested by selective pharmacological depletion of respectively Cu/Zn superoxide dismutase (Cu/Zn SOD) and reduced glutathione (GSH)...

  3. Joint optic disc and cup boundary extraction from monocular fundus images.

    Science.gov (United States)

    Chakravarty, Arunava; Sivaswamy, Jayanthi

    2017-08-01

    Accurate segmentation of optic disc and cup from monocular color fundus images plays a significant role in the screening and diagnosis of glaucoma. Though optic cup is characterized by the drop in depth from the disc boundary, most existing methods segment the two structures separately and rely only on color and vessel kink based cues due to the lack of explicit depth information in color fundus images. We propose a novel boundary-based Conditional Random Field formulation that extracts both the optic disc and cup boundaries in a single optimization step. In addition to the color gradients, the proposed method explicitly models the depth which is estimated from the fundus image itself using a coupled, sparse dictionary trained on a set of image-depth map (derived from Optical Coherence Tomography) pairs. The estimated depth achieved a correlation coefficient of 0.80 with respect to the ground truth. The proposed segmentation method outperformed several state-of-the-art methods on five public datasets. The average dice coefficient was in the range of 0.87-0.97 for disc segmentation across three datasets and 0.83 for cup segmentation on the DRISHTI-GS1 test set. The method achieved a good glaucoma classification performance with an average AUC of 0.85 for five fold cross-validation on RIM-ONE v2. We propose a method to jointly segment the optic disc and cup boundaries by modeling the drop in depth between the two structures. Since our method requires a single fundus image per eye during testing it can be employed in the large-scale screening of glaucoma where expensive 3D imaging is unavailable. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Diagnostic accuracy and use of nonmydriatic ocular fundus photography by emergency physicians: phase II of the FOTO-ED study.

    Science.gov (United States)

    Bruce, Beau B; Thulasi, Praneetha; Fraser, Clare L; Keadey, Matthew T; Ward, Antoinette; Heilpern, Katherine L; Wright, David W; Newman, Nancy J; Biousse, Valérie

    2013-07-01

    During the first phase of the Fundus Photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department study, 13% (44/350; 95% confidence interval [CI] 9% to 17%) of patients had an ocular fundus finding, such as papilledema, relevant to their emergency department (ED) management found by nonmydriatic ocular fundus photography reviewed by neuro-ophthalmologists. All of these findings were missed by emergency physicians, who examined only 14% of enrolled patients by direct ophthalmoscopy. In the present study, we evaluate the sensitivity of nonmydriatic ocular fundus photography, an alternative to direct ophthalmoscopy, for relevant findings when photographs are made available for use by emergency physicians during routine clinical care. Three hundred fifty-four patients presenting to our ED with headache, focal neurologic deficit, visual change, or diastolic blood pressure greater than or equal to 120 mm Hg had nonmydriatic fundus photography obtained (Kowa nonmydriatic α-D). Photographs were placed on the electronic medical record for emergency physician review. Identification of relevant findings on photographs by emergency physicians was compared with a reference standard of neuro-ophthalmologist review. Emergency physicians reviewed photographs of 239 patients (68%). Thirty-five patients (10%; 95% CI 7% to 13%) had relevant findings identified by neuro-ophthalmologist review (6 disc edema, 6 grade III/IV hypertensive retinopathy, 7 isolated hemorrhages, 15 optic disc pallor, and 1 retinal vascular occlusion). Emergency physicians identified 16 of 35 relevant findings (sensitivity 46%; 95% CI 29% to 63%) and also identified 289 of 319 normal findings (specificity 91%; 95% CI 87% to 94%). Emergency physicians reported that photographs were helpful for 125 patients (35%). Emergency physicians used nonmydriatic fundus photographs more frequently than they performed direct ophthalmoscopy, and their detection of relevant abnormalities improved. Ocular fundus

  5. Method for Calculating the Optical Diffuse Reflection Coefficient for the Ocular Fundus

    Science.gov (United States)

    Lisenko, S. A.; Kugeiko, M. M.

    2016-07-01

    We have developed a method for calculating the optical diffuse reflection coefficient for the ocular fundus, taking into account multiple scattering of light in its layers (retina, epithelium, choroid) and multiple refl ection of light between layers. The method is based on the formulas for optical "combination" of the layers of the medium, in which the optical parameters of the layers (absorption and scattering coefficients) are replaced by some effective values, different for cases of directional and diffuse illumination of the layer. Coefficients relating the effective optical parameters of the layers and the actual values were established based on the results of a Monte Carlo numerical simulation of radiation transport in the medium. We estimate the uncertainties in retrieval of the structural and morphological parameters for the fundus from its diffuse reflectance spectrum using our method. We show that the simulated spectra correspond to the experimental data and that the estimates of the fundus parameters obtained as a result of solving the inverse problem are reasonable.

  6. Effect of lymphadenectomy extent on advanced gastric cancer located in the cardia and fundus

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To analyze the prognostic impact of lymphade- nectomy extent in advanced gastric cancer located in the cardia and fundus. METHODS: Two hundred and thirty-six patients with advanced gastric cancer located in the cardia and fundus who underwent D2 curative resection were analyzed retrospectively. Relationships between the numbers of lymph nodes (iNs) dissected and survival was analyzed among different clinical stage subgroups. RESULTS: The 5-year overall survival rate of the entire cohort was 37.5%. Multivariate prognostic variables were total LNs dissected (P<0.0001; or number of negative LNs examined, P<0.0001), number of positive INs (P < 0.0001), T category (P < 0.0001) and tumor size (P=0.015). The greatest survival differences were observed at cutoff values of 20 INs resected for stage II (P = 0.0136), 25 for stage III (P < 0.0001), 30 for stage IV (P = 0.0002), and 15 for all patients (P = 0.0024). Based on the statistically assumed linearity as best fit, linear regression showed a significant survival enhancement based on increasing negative INs for patients of stages III (P = 0.013) and IV (P = 0.035). CONCLUSION: To improve the long-term survival of patients with advanced gastric cancer located in the cardia and fundus, removing at least 20 INs for stage II, 25 INs for stage III, and 30 INs for stage 1V patients during D2 radical dissection is recommended.

  7. Detection of retinal nerve fiber layer defects in retinal fundus images using Gabor filtering

    Science.gov (United States)

    Hayashi, Yoshinori; Nakagawa, Toshiaki; Hatanaka, Yuji; Aoyama, Akira; Kakogawa, Masakatsu; Hara, Takeshi; Fujita, Hiroshi; Yamamoto, Tetsuya

    2007-03-01

    Retinal nerve fiber layer defect (NFLD) is one of the most important findings for the diagnosis of glaucoma reported by ophthalmologists. However, such changes could be overlooked, especially in mass screenings, because ophthalmologists have limited time to search for a number of different changes for the diagnosis of various diseases such as diabetes, hypertension and glaucoma. Therefore, the use of a computer-aided detection (CAD) system can improve the results of diagnosis. In this work, a technique for the detection of NFLDs in retinal fundus images is proposed. In the preprocessing step, blood vessels are "erased" from the original retinal fundus image by using morphological filtering. The preprocessed image is then transformed into a rectangular array. NFLD regions are observed as vertical dark bands in the transformed image. Gabor filtering is then applied to enhance the vertical dark bands. False positives (FPs) are reduced by a rule-based method which uses the information of the location and the width of each candidate region. The detected regions are back-transformed into the original configuration. In this preliminary study, 71% of NFLD regions are detected with average number of FPs of 3.2 per image. In conclusion, we have developed a technique for the detection of NFLDs in retinal fundus images. Promising results have been obtained in this initial study.

  8. Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus

    Directory of Open Access Journals (Sweden)

    Koprowski Robert

    2012-06-01

    Full Text Available Abstract Background The available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc. Methods The paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension. Results The proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method. Conclusions This paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number.

  9. Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus.

    Science.gov (United States)

    Koprowski, Robert; Teper, Sławomir Jan; Węglarz, Beata; Wylęgała, Edward; Krejca, Michał; Wróbel, Zygmunt

    2012-06-22

    The available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc. The paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension. The proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method. This paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number.

  10. Smartphone-based fundus camera device (MII Ret Cam) and technique with ability to image peripheral retina.

    Science.gov (United States)

    Sharma, Ashish; Subramaniam, Saranya Devi; Ramachandran, K I; Lakshmikanthan, Chinnasamy; Krishna, Soujanya; Sundaramoorthy, Selva K

    2016-01-01

    To demonstrate an inexpensive smartphone-based fundus camera device (MII Ret Cam) and technique with ability to capture peripheral retinal pictures. A fundus camera was designed in the form of a device that has slots to fit a smartphone (built-in camera and flash) and 20-D lens. With the help of the device and an innovative imaging technique, high-quality fundus videos were taken with easy extraction of images. The MII Ret Cam and innovative imaging technique was able to capture high-quality images of peripheral retina such as ora serrata and pars plana apart from central fundus pictures. Our smartphone-based fundus camera can help clinicians to monitor diseases affecting both central and peripheral retina. It can help patients understand their disease and clinicians convincing their patients regarding need of treatment especially in cases of peripheral lesions. Imaging peripheral retina has not been demonstrated in existing smartphone-based fundus imaging techniques. The device can also be an inexpensive tool for mass screening.

  11. The use of retinal photography in non-ophthalmic settings and its potential for neurology

    Science.gov (United States)

    Pérez, Mario A.; Bruce, Beau B.; Newman, Nancy J.; Biousse, Valérie

    2012-01-01

    Background Ocular fundus examination is an important element of the neurological examination. However, direct ophthalmoscopy is difficult to perform without pupillary dilation and requires extensive practice to accurately recognize optic nerve and retinal abnormalities. Recent studies have suggested that digital retinal photography can replace direct ophthalmoscopy in many settings. Review Summary Ocular fundus imaging is routinely used to document and monitor disease progression in ophthalmology. Advances in optical technology have made it easier to obtain high-quality retinal imaging, even without pupillary dilation. Retinal photography has a high sensitivity, specificity, and inter-/intra-examination agreement compared to in-person ophthalmologist examination, suggesting that photographs can be used in lieu of ophthalmoscopy in many clinical situations. Non-mydriatic retinal photography has recently gained relevance as a helpful tool for diagnosing neuro-ophthalmologic disorders in the emergency department. Additionally, several population-based studies have used retinal imaging to relate ophthalmic abnormalities to the risk of hypertension, renal dysfunction, cardiovascular mortality, subclinical and clinical stroke, and cognitive impairment. The possibility of telemedical consultation offered by digital retinal photography has already increased access to timely and accurate subspecialty care, particularly for underserved areas. Conclusion Retinal photography (even without pupillary dilation) has become increasingly available to medical fields outside of ophthalmology, allowing for faster and more accurate diagnosis of various ocular, neurologic and systemic disorders. The potential for telemedicine may provide the additional benefits of improving access to appropriate urgent consultation in both clinical and research settings. PMID:23114666

  12. Automated Brightness and Contrast Adjustment of Color Fundus Photographs for the Grading of Age-Related Macular Degeneration

    Science.gov (United States)

    Tsikata, Edem; Laíns, Inês; Gil, João; Marques, Marco; Brown, Kelsey; Mesquita, Tânia; Melo, Pedro; da Luz Cachulo, Maria; Kim, Ivana K.; Vavvas, Demetrios; Murta, Joaquim N.; Miller, John B.; Silva, Rufino; Miller, Joan W.; Chen, Teresa C.; Husain, Deeba

    2017-01-01

    Purpose The purpose of this study was to develop an algorithm to automatically standardize the brightness, contrast, and color balance of digital color fundus photographs used to grade AMD and to validate this algorithm by determining the effects of the standardization on image quality and disease grading. Methods Seven-field color photographs of patients (>50 years) with any stage of AMD and a control group were acquired at two study sites, with either the Topcon TRC-50DX or Zeiss FF-450 Plus cameras. Field 2 photographs were analyzed. Pixel brightness values in the red, green, and blue (RGB) color channels were adjusted in custom-built software to make the mean brightness and contrast of the images equal to optimal values determined by the Age-Related Eye Disease Study (AREDS) 2 group. Results Color photographs of 370 eyes were analyzed. We found a wide range of brightness and contrast values in the images at baseline, even for those taken with the same camera. After processing, image brightness variability (brightest image–dimmest image in a color channel) was reduced 69-fold, 62-fold, and 96-fold for the RGB channels. Contrast variability was reduced 6-fold, 8-fold, and 13-fold, respectively, after adjustment. Of the 23% images considered nongradable before adjustment, only 5.7% remained nongradable. Conclusions This automated software enables rapid and accurate standardization of color photographs for AMD grading. Translational Relevance This work offers the potential to be the future of assessing and grading AMD from photos for clinical research and teleimaging.

  13. Cost-effective instrumentation for quantitative depth measurement of optic nerve head using stereo fundus image pair and image cross correlation techniques

    Science.gov (United States)

    de Carvalho, Luis Alberto V.; Carvalho, Valeria

    2014-02-01

    One of the main problems with glaucoma throughout the world is that there are typically no symptoms in the early stages. Many people who have the disease do not know they have it and by the time one finds out, the disease is usually in an advanced stage. Most retinal cameras available in the market today use sophisticated optics and have several other features/capabilities (wide-angle optics, red-free and angiography filters, etc) that make them expensive for the general practice or for screening purposes. Therefore, it is important to develop instrumentation that is fast, effective and economic, in order to reach the mass public in the general eye-care centers. In this work, we have constructed the hardware and software of a cost-effective and non-mydriatic prototype device that allows fast capturing and plotting of high-resolution quantitative 3D images and videos of the optical disc head and neighboring region (30° of field of view). The main application of this device is for glaucoma screening, although it may also be useful for the diagnosis of other pathologies related to the optic nerve.

  14. Agreement of retinal nerve fiber layer defect location between red-free fundus photography and cirrus HD-OCT maps.

    Science.gov (United States)

    Hwang, Young Hoon; Kim, Yong Yeon; Kim, Hwang Ki; Sohn, Yong Ho

    2014-11-01

    To investigate the agreement of angular locations of retinal nerve fiber layer (RNFL) defect margins in glaucomatous eyes by using red-free fundus photographs and Cirrus high-definition optical coherence tomography (OCT) RNFL deviation and thickness maps. We examined 380 RNFL defects that showed clear margins in red-free fundus photographs. The OCT deviation and thickness maps were overlaid on the corresponding red-free fundus photographs. A reference line was drawn between the disc center and the macular center. Lines were also drawn between the optic disc center and the point where the RNFL defect margins crossed the OCT scan circle. The angle between the reference and defect-margin lines defined the angular location of the defect margin. Angular locations of proximal (nearest to the reference) and distal (farthest from the reference) RNFL defect margins on OCT deviation and thickness maps were compared to the locations on red-free fundus photographs. The angular locations of proximal and distal RNFL defect margins on OCT thickness maps showed good agreement with red-free fundus photographs. However, OCT deviation maps showed greater angular locations for both proximal and distal RNFL defect margins compared with red-free fundus photographs, especially in eyes with higher myopia (p < 0.05). Red-free fundus photographs and OCT thickness maps showed good agreement for the RNFL defect margin identification. However, this was not the case for deviation maps, especially in myopic eyes. This finding should be considered when evaluating RNFL defects using OCT maps.

  15. Influence of antioxidant depletion on nitrergic relaxation in the pig gastric fundus.

    Science.gov (United States)

    Colpaert, E E; Timmermans, J-P; Lefebvre, R A

    2002-02-01

    1. The hypothesis that endogenous tissue antioxidants might explain the inability of the superoxide generators 6-anilino-5,8-quinolinedione (LY83583) and hydroquinone (HQ) and of the NO-scavengers hydroxocobalamin (HC) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) to affect nitrergic neurotransmission in the porcine gastric fundus was tested by selective pharmacological depletion of respectively Cu/Zn superoxide dismutase (Cu/Zn SOD) and reduced glutathione (GSH) in circular smooth muscle preparations. 2. Diethyldithiocarbamate (DETCA; 3x10(-3) M), which almost completely abolished tissue Cu/Zn SOD activity, had no effect per se on nitrergic relaxations induced by either electrical field stimulation (EFS; 4 Hz, 10 s) or exogenous nitric oxide (NO; 10(-5) M). In these DETCA-treated tissues however, electrically-induced nitrergic relaxations became sensitive to inhibition by LY83583 (10(-5) M) or HC (10(-4) M), but not by HQ (10(-4) M) or c-PTIO (10(-4) M); only for the combination of DETCA plus LY83583, this inhibition was partially reversed by exogenous Cu/Zn SOD (1000 u ml(-1)). 3. Immunohistochemical analysis of porcine gastric fundus revealed a 100% colocalization of Cu/Zn SOD and neuronal nitric oxide synthase (nNOS) in the intrinsic neurons of the myenteric plexus. 4. Buthionine sulphoximine (BSO; 10(-3) M) in the absence or presence of LY83583 (10(-5) M) or HC (10(-4) M) did not alter nitrergic relaxations, although it reduced per se the tissue GSH content to 62% of control. 5. Pharmacological depletion studies, corroborated by immunohistochemical data, thus suggest a role for Cu/Zn SOD but not for GSH in nitrergic neurotransmission in the porcine gastric fundus.

  16. Noninvasive optoacoustic temperature determination at the fundus of the eye during laser irradiation.

    Science.gov (United States)

    Schule, Georg; Huttmann, Gereon; Framme, Carsten; Roider, Johann; Brinkmann, Ralf

    2004-01-01

    In all fundus laser treatments of the eye, the temperature increase is not exactly known. In order to optimize treatments, an online temperature determination is preferable. We investigated a noninvasive optoacoustic method to monitor the fundus temperature during pulsed laser irradiation. When laser pulses are applied to the fundus, thermoelastic pressure waves are emitted, due to thermal expansion of the heated tissue. Using a constant pulse energy, the amplitude of the pressure wave increases linearly with an increase in the base temperature of between 30 and 80 degrees C. This method was evaluated in vitro on porcine retinal pigment epithelium (RPE) cell samples and clinically during selective RPE treatment with repetitive microsecond laser pulses. During the irradiation of porcine RPE with a neodymium-doped yttrium (Nd:YLF) laser (527 nm, 1.7 micros, 500 Hz repetition rate, 160 mJ/cm(2)) an increase in the base temperature of 30+/-4 degrees C after 100 pulses was found. During patient treatments, a temperature increase of 60+/-11 degrees C after 100 pulses with a 500-Hz repetition rate and 7+/-1 degrees C after 30 pulses with 100 Hz at 520 mJ/cm(2) was found. All measured data were in good agreement with heat diffusion calculations. Optoacoustic methods can be used to noninvasively determine retinal temperatures during pulsed laser treatment of the eye. This technique can also be adapted to continuous-wave photocoagulation, photodynamic therapy and transpupillary thermotherapy, or other fields of laser-heated tissue.

  17. Differentiation of ocular fundus fluorophores by fluorescence lifetime imaging using multiple excitation and emission wavelengths

    Science.gov (United States)

    Hammer, M.; Schweitzer, D.; Schenke, S.; Becker, W.; Bergmann, A.

    2006-10-01

    Ocular fundus autofluorescence imaging has been introduced into clinical diagnostics recently. It is in use for the observation of the age pigment lipofuscin, a precursor of age - related macular degeneration (AMD). But other fluorophores may be of interest too: The redox pair FAD - FADH II provides information on the retinal energy metabolism, advanced glycation end products (AGE) indicate protein glycation associated with pathologic processes in diabetes as well as AMD, and alterations in the fluorescence of collagen and elastin in connective tissue give us the opportunity to observe fibrosis by fluorescence imaging. This, however, needs techniques able to differentiate particular fluorophores despite limited permissible ocular exposure as well as excitation wavelength (limited by the transmission of the human ocular lens to >400 nm). We present an ophthalmic laser scanning system (SLO), equipped with picosecond laser diodes (FWHM 100 ps, 446 nm or 468 nm respectively) and time correlated single photon counting (TCSPC) in two emission bands (500 - 560 nm and 560 - 700 nm). The decays were fitted by a bi-exponential model. Fluorescence spectra were measured by a fluorescence spectrometer fluorolog. Upon excitation at 446 nm, the fluorescence of AGE, FAD, and lipofuscin were found to peak at 503 nm, 525 nm, and 600 nm respectively. Accordingly, the statistical distribution of the fluorescence decay times was found to depend on the different excitation wavelengths and emission bands used. The use of multiple excitation and emission wavelengths in conjunction with fluorescence lifetime imaging allows us to discriminate between intrinsic fluorophores of the ocular fundus. Taken together with our knowledge on the anatomical structure of the fundus, these findings suggest an association of the short, middle and long fluorescence decay time to the retinal pigment epithelium, the retina, and connective tissue respectively.

  18. Evaluation of Fundus Blood Flow in Normal Individuals and Patients with Internal Carotid Artery Obstruction Using Laser Speckle Flowgraphy

    Science.gov (United States)

    Akiyama, Hideo; Shimoda, Yukitoshi; Li, Danjie; Kishi, Shoji

    2017-01-01

    Purpose We investigated whether laser speckle flowgraphy (LSFG) results are comparable in both eyes and whether it is useful in the diagnosis of disparity in ocular ischemic syndrome (OIS) patients. Methods We compared the mean blur rate (MBR) value for various fundus regions in both eyes of 41 healthy subjects and 15 internal carotid artery occlusion (ICAO) cases. We calculated the standard value of the Laterality Index (LI), which was the MBR comparison of both eyes in each of the regions, in the control subjects. We then investigated the correlation between both eyes for the LIs in the entire fundus, the degree of ICAO and visual function. Results The disparity of the LIs in both eyes was least in the entire area of the fundus in control subjects and there was a significant correlation between both eyes of the 41 healthy individuals (P = 0.019). Significant correlations were found for the LI, visual acuity and degree of ICAO. The specificity and sensitivity of LI in the entire area was 93.8% and 100%, respectively. Conclusions LSFG revealed normal individuals have symmetrical fundus blood flow. LSFG could detect OIS and might be a useful tool for detecting disparities in fundus blood flow. PMID:28056061

  19. Labor-Associated Gene Expression in the Human Uterine Fundus, Lower Segment, and Cervix

    Science.gov (United States)

    Bukowski, Radek; Hankins, Gary D. V; Saade, George R; Anderson, Garland D; Thornton, Steven

    2006-01-01

    Background Preterm labor, failure to progress, and postpartum hemorrhage are the common causes of maternal and neonatal mortality or morbidity. All result from defects in the complex mechanisms controlling labor, which coordinate changes in the uterine fundus, lower segment, and cervix. We aimed to assess labor-associated gene expression profiles in these functionally distinct areas of the human uterus by using microarrays. Methods and Findings Samples of uterine fundus, lower segment, and cervix were obtained from patients at term (mean ± SD = 39.1 ± 0.5 wk) prior to the onset of labor ( n = 6), or in active phase of labor with spontaneous onset ( n = 7). Expression of 12,626 genes was evaluated using microarrays (Human Genome U95A; Affymetrix) and compared between labor and non-labor samples. Genes with the largest labor-associated change and the lowest variability in expression are likely to be fundamental for parturition, so gene expression was ranked accordingly. From 500 genes with the highest rank we identified genes with similar expression profiles using two independent clustering techniques. Sets of genes with a probability of chance grouping by both techniques less than 0.01 represented 71.2%, 81.8%, and 79.8% of the 500 genes in the fundus, lower segment, and cervix, respectively. We identified 14, 14, and 12 those sets of genes in the fundus, lower segment, and cervix, respectively. This enabled networks of co-regulated and co-expressed genes to be discovered. Many genes within the same cluster shared similar functions or had functions pertinent to the process of labor. Conclusions Our results provide support for many of the established processes of parturition and also describe novel-to-labor genes not previously associated with this process. The elucidation of these mechanisms likely to be fundamental for controlling labor is an important prerequisite to the development of effective treatments for major obstetric problems—including prematurity

  20. Labor-associated gene expression in the human uterine fundus, lower segment, and cervix.

    Directory of Open Access Journals (Sweden)

    Radek Bukowski

    2006-06-01

    Full Text Available BACKGROUND: Preterm labor, failure to progress, and postpartum hemorrhage are the common causes of maternal and neonatal mortality or morbidity. All result from defects in the complex mechanisms controlling labor, which coordinate changes in the uterine fundus, lower segment, and cervix. We aimed to assess labor-associated gene expression profiles in these functionally distinct areas of the human uterus by using microarrays. METHODS AND FINDINGS: Samples of uterine fundus, lower segment, and cervix were obtained from patients at term (mean +/- SD = 39.1 +/- 0.5 wk prior to the onset of labor (n = 6, or in active phase of labor with spontaneous onset (n = 7. Expression of 12,626 genes was evaluated using microarrays (Human Genome U95A; Affymetrix and compared between labor and non-labor samples. Genes with the largest labor-associated change and the lowest variability in expression are likely to be fundamental for parturition, so gene expression was ranked accordingly. From 500 genes with the highest rank we identified genes with similar expression profiles using two independent clustering techniques. Sets of genes with a probability of chance grouping by both techniques less than 0.01 represented 71.2%, 81.8%, and 79.8% of the 500 genes in the fundus, lower segment, and cervix, respectively. We identified 14, 14, and 12 those sets of genes in the fundus, lower segment, and cervix, respectively. This enabled networks of co-regulated and co-expressed genes to be discovered. Many genes within the same cluster shared similar functions or had functions pertinent to the process of labor. CONCLUSIONS: Our results provide support for many of the established processes of parturition and also describe novel-to-labor genes not previously associated with this process. The elucidation of these mechanisms likely to be fundamental for controlling labor is an important prerequisite to the development of effective treatments for major obstetric problems

  1. Elliptical Local Vessel Density: a Fast and Robust Quality Metric for Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Chaum, Edward [ORNL; Karnowski, Thomas Paul [ORNL; Meriaudeau, Fabrice [ORNL; Tobin Jr, Kenneth William [ORNL; Abramoff, M.D. [University of Iowa

    2008-01-01

    A great effort of the research community is geared towards the creation of an automatic screening system able to promptly detect diabetic retinopathy with the use of fundus cameras. In addition, there are some documented approaches to the problem of automatically judging the image quality. We propose a new set of features independent of Field of View or resolution to describe the morphology of the patient's vessels. Our initial results suggest that they can be used to estimate the image quality in a time one order of magnitude shorter respect to previous techniques.

  2. Involvement of vasoactive intestinal polypeptide in nicotine-induced relaxation of the rat gastric fundus

    OpenAIRE

    1997-01-01

    Nicotine-induced relaxation and release of vasoactive intestinal polypeptide (VIP)- and peptide histidine isoleucine (PHI)-like immunoreactivity (LI) were measured in longitudinal muscle strips from the rat gastric fundus.Under non-cholinergic conditions (0.3 μM atropine), nicotine (3–300 μM) produced concentration-dependent relaxations of the 5-hydroxytryptamine (3 μM)-precontracted strips. Under non-adrenergic non-cholinergic (NANC) conditions (0.3 μM atropine+1 μM phentolamine+1 μM nadolol...

  3. Fundus Autofluorescence Captured With a Nonmydriatic Retinal Camera in Vegetarians Versus Nonvegetarians.

    Science.gov (United States)

    Kommana, Sumana S; Padgaonkar, Pooja; Mendez, Nicole; Wu, Lesley; Szirth, Bernard; Khouri, Albert S

    2015-09-09

    A baseline level of lipofuscin in the retinal pigment epithelium (RPE) is inevitable with age, but increased levels due to increased oxidative stress can result in deleterious vision loss at older ages. As earlier detection of differences in levels can lead to superior preventative management, we studied the relationship between lipofuscin accumulation and dietary lifestyle (vegetarian vs. nonvegetarian) in the younger, healthy South Asian population using retinal fundus autofluorescence (FAF) imaging. In this pilot study, we examined 37 healthy subjects (average age 23 years ± 1) all undergoing similar stress levels as medical students at Rutgers New Jersey Medical School. Levels of lipofuscin concentrations were imaged using a FAF retinal camera (Canon CX-1). Two images (color and FAF) were captured of the left eye and included in the analysis. FAF quantitative scoring was measured in 2 regions of the captured image, the papillo-macular region (P) and the macula (M), by determining the grayscale score of a 35.5 mm(2) rectangle in the respective regions. Standardized scores (corrected to remove baseline fluorescence) were then obtained. Means, standard deviations, and t tests were performed for comparisons. Fundus autofluorescence scores of regions P and M were significantly different (P vegetarians had statistically significant lower levels of autofluorescence. These findings can have potential implications regarding long-term retinal health and risk for developing certain diseases over decades in subjects at risk for vision-threatening diseases. © 2015 Diabetes Technology Society.

  4. A STUDY TO COMPARE FUNDUS FLUORESCEIN ANGIOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY IN AGE RELATED MACULAR DEGENERATION

    Directory of Open Access Journals (Sweden)

    Rani Sujatha

    2016-02-01

    Full Text Available PURPOSE To compare the diagnostic accuracy of optical coherence tomography with Fundus Fluorescein Angiography in diagnosing Age related macular degeneration. METHODS A total 25 patients newly diagnosed as Age related macular degeneration were included in the study. The study was done during the time period between August 2013 to November 2015 this is a prospective randomized hospital based study. RESULTS Maximum no of patients affected belonged to the age group of 50-70 years and 60% were females. The most common symptom was defective vision accounting for 92%. Hypertension and hyperlipidemia were the most common risk factors. 12% of the cases had unilateral disease and 88% had bilateral disease. 6% of eyes were normal in both FFA and OCT. 62% of the eyes by FFA and 61% of the eyes by OCT had dry ARMD and 32 % of the eye by FFA and 33 % by OCT had wet ARMD. CONCLUSION Fundus Fluorescein Angiography is the gold standard tool for screening ARMD and OCT is more specific in detecting early subretinal neovascular membrane and also to assess the activity of the neovascular membranes. Hence OCT is superior to FFA in diagnosing early wet ARMD and thus helps in early management of patients with ARMD.

  5. Comparative inhibitory effects of niflumic acid and novel synthetic derivatives on the rat isolated stomach fundus.

    Science.gov (United States)

    Criddle, David N; Meireles, AnaVanescaP; Macêdo, Liana B; Leal-Cardoso, José H; Scarparo, Henrique C; Jaffar, Mohammed

    2002-02-01

    Novel derivatives of 2-[3-(trifluoromethyl)-analino]nicotinic acid (niflumic acid) were synthesized. The compounds were compared for their inhibitory effects on 5-hydroxytryptamine (5-HT)- and KCI-induced contraction of the rat fundus. The aim was to assess structure-activity relationships regarding the selectivity and potency of these compounds. Niflumic acid (1-100 microM) concentration-dependently inhibited 5-HT-induced tonic contractions with an IC50 value (concentration reducing the control contractile response by 50%, calculated from semi-log graphs) of 0.24 x 10(4) M (n = 9). In contrast, it was significantly less potent at inhibiting KCl-induced responses (IC50 = 1.49 x 10(4) M, n = 9). The methyl ester (NFAme) and amido (NFAm) analogues showed no selectivity between 5-HT- and KCl-induced contractions with IC50 values of 1.64 x 10(-4) M (n = 8) and 1.87 x 10(-4) M (n = 9) for 5-HT responses, and 2.61 x 10(-4) M (n = 8) and 2.55 x 10(-4) M (n = 7) for KCl-induced responses, respectively. Our results suggest that alteration of the carboxylic acid moiety of niflumic acid reduces the selectivity and potency of its inhibitory action on 5-HT-induced contractile responses of the rat fundus, possibly via a reduced interaction with calcium-activated chloride channels.

  6. Bright Retinal Lesions Detection using Colour Fundus Images Containing Reflective Features

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Karnowski, Thomas Paul [ORNL; Chaum, Edward [ORNL; Meriaudeau, Fabrice [ORNL; Tobin Jr, Kenneth William [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK)

    2009-01-01

    In the last years the research community has developed many techniques to detect and diagnose diabetic retinopathy with retinal fundus images. This is a necessary step for the implementation of a large scale screening effort in rural areas where ophthalmologists are not available. In the United States of America, the incidence of diabetes is worryingly increasing among the young population. Retina fundus images of patients younger than 20 years old present a high amount of reflection due to the Nerve Fibre Layer (NFL), the younger the patient the more these reflections are visible. To our knowledge we are not aware of algorithms able to explicitly deal with this type of reflection artefact. This paper presents a technique to detect bright lesions also in patients with a high degree of reflective NFL. First, the candidate bright lesions are detected using image equalization and relatively simple histogram analysis. Then, a classifier is trained using texture descriptor (Multi-scale Local Binary Patterns) and other features in order to remove the false positives in the lesion detection. Finally, the area of the lesions is used to diagnose diabetic retinopathy. Our database consists of 33 images from a telemedicine network currently developed. When determining moderate to high diabetic retinopathy using the bright lesions detected the algorithm achieves a sensitivity of 100% at a specificity of 100% using hold-one-out testing.

  7. Fundus Analysis and Visual Prognosis of Macular Hemorrhage in Pathological Myopia without Choroidal Neovasculopathy

    Institute of Scientific and Technical Information of China (English)

    Haitao Li; Feng Wen; De-zheng Wu; Guangwei Luo; Shizhou Huang; Tianqin Guan; Caijiao Liu

    2004-01-01

    Purpose:To analysis and evaluate the fundus characteristics and visual prognosis of macular hemorrhage in pathological myopia without choroidal neovasculopathy. Methods:Thirty-seven patients (38 eyes) of pathological myopia with macular hemorrhage and without choroidal neovascularization (CNV) underwent color photograph and fundus fiuorescein angiography (FFA) examinations. Indocyanine green angiography (ICGA) was also performed on 11 patients (11 eyes). Follow-up ranged from 3 to 21 months.Results :The macular hemorrhage in pathological, myopia without CNV demonstrated oval, less than 1PD, without edema and exudation. Lacquer cracks appeared at the site of previous subretinal bleeding in 84.2% of the eyes. The visual acuities were improved in 81.6% of eyes during the follow-up period. ICGA revealed linear hypofluorescence in 7 of 11 eyes (63.6%), indicating a ruptured Bruch's membrance at the onset of subretinal bleeding.Conclusion: A rupture of choriocapillaris complex and Bruch's membrane causes macular hemorrhage of pathological myopia without CNV, leading to the formation of a new lacquer crack. Its prognosis is favorable. Eye Science 2004;20:57-62.

  8. Unusual optical coherence tomography and fundus autofluorescence findings of eclipse retinopathy

    Directory of Open Access Journals (Sweden)

    Kun-Hsien Li

    2012-01-01

    Full Text Available A 63-year-old female patient complained of dimness in the central field of vision in the left eye after viewing an annular partial eclipse without adequate eye protection on 22 July 2009. Fundoscopy showed a wrinkled macular surface. Fundus autofluorescence study revealed well-demarcated hyperautofluorescence at the fovea. Optical coherence tomography demonstrated tiny intraretinal cysts. Fluorescein angiography and indocyanine green angiography were unremarkable. Epimacular membrane developed in the following month with deteriorated vision. Vitrectomy, epiretinal membrane and internal limiting membrane peeling were performed. Vision was restored to 20/20 after the operation. Direct sun-gazing may damage the retinal structures resulting in macular inflammation and increased focal metabolism, which explains the hyperautofluorescence. It may also induce epimacular membrane. Fundus autofluorescence might represent a useful technique to detect subtle solar-induced injuries of the retina. The visual prognosis is favorable but prevention remains the mainstay of treatment. Public health education is mandatory in reducing visual morbidity.

  9. Ultrawide-field fundus photography of the first reported case of gyrate atrophy from Australia

    Directory of Open Access Journals (Sweden)

    Moloney TP

    2014-08-01

    Full Text Available Thomas P Moloney,1 Stephen O’Hagan,1 Lawrence Lee2,3 1Department of Ophthalmology, Cairns Hospital, Cairns, QLD, Australia; 2City Eye Centre, Brisbane, QLD, Australia; 3Associate Professor of Ophthalmology, School of Medicine, University of Queensland, Brisbane, QLD, Australia Abstract: Gyrate atrophy of the choroid and retina is a rare chorioretinal dystrophy inherited in an autosomal recessive pattern. We describe the first documented case of gyrate atrophy from Australia in a 56-year-old woman with a history of previous diagnosis of retinitis pigmentosa and worsening night vision in her right eye over several years. She was myopic and bilaterally pseudophakic, and fundus examination revealed pale optic discs and extensive peripheral chorioretinal atrophy exposing bare sclera bilaterally with only small islands of normal-appearing retina at each posterior pole. Visual field testing showed grossly constricted fields, blood testing showed hyperornithinemia, and further questioning revealed consanguinity between the patient’s parents. We then used the patient’s typical retinal findings of gyrate atrophy to demonstrate the potential use of ultrawide-field fundus photography and angiography in diagnosis and monitoring response in future treatment. Keywords: gyrate atrophy, ultrawide-field retinal photography, angiography, retinal photography, hyperornithinemia

  10. Quantitative Analysis of Fundus-Image Sequences Reveals Phase of Spontaneous Venous Pulsations

    Science.gov (United States)

    Moret, Fabrice; Reiff, Charlotte M.; Lagrèze, Wolf A.; Bach, Michael

    2015-01-01

    Purpose Spontaneous venous pulsation correlates negatively with elevated intracranial pressure and papilledema, and it relates to glaucoma. Yet, its etiology remains unclear. A key element to elucidate its underlying mechanism is the time at which collapse occurs with respect to the heart cycle, but previous reports are contradictory. We assessed this question in healthy subjects using quantitative measurements of both vein diameters and artery lateral displacements; the latter being used as the marker of the ocular systole time. Methods We recorded 5-second fundus sequences with a near-infrared scanning laser ophthalmoscope in 12 young healthy subjects. The image sequences were coregistered, cleaned from microsaccades, and filtered via a principal component analysis to remove nonpulsatile dynamic features. Time courses of arterial lateral displacement and of diameter at sites of spontaneous venous pulsation or proximal to the disk were retrieved from those image sequences and compared. Results Four subjects displayed both arterial and venous pulsatile waveforms. On those, we observed venous diameter waveforms differing markedly among the subjects, ranging from a waveform matching the typical intraocular pressure waveform to a close replica of the arterial waveform. Conclusions The heterogeneity in waveforms and arteriovenous phases suggests that the mechanism governing the venous outflow resistance differs among healthy subjects. Translational relevance Further characterizations are necessary to understand the heterogeneous mechanisms governing the venous outflow resistance as this resistance is altered in glaucoma and is instrumental when monitoring intracranial hypertension based on fundus observations. PMID:26396929

  11. Feasibility of nonmydriatic ocular fundus photography in the emergency department: Phase I of the FOTO-ED study.

    Science.gov (United States)

    Bruce, Beau B; Lamirel, Cédric; Biousse, Valérie; Ward, Antionette; Heilpern, Katherine L; Newman, Nancy J; Wright, David W

    2011-09-01

    Examination of the ocular fundus is imperative in many acute medical and neurologic conditions, but direct ophthalmoscopy by nonophthalmologists is underutilized, poorly performed, and difficult without pharmacologic pupillary dilation. The objective was to examine the feasibility of nonmydriatic fundus photography as a clinical alternative to direct ophthalmoscopy by emergency physicians (EPs). Adult patients presenting to the emergency department (ED) with headache, acute focal neurologic deficit, diastolic blood pressure ≥ 120 mm Hg, or acute visual change had ocular fundus photographs taken by nurse practitioners using a nonmydriatic fundus camera. Photographs were reviewed by a neuroophthalmologist within 24 hours for findings relevant to acute ED patient care. Nurse practitioners and patients rated ease, comfort, and speed of nonmydriatic fundus photography on a 10-point Likert scale (10 best). Timing of visit and photography were recorded by automated electronic systems. A total of 350 patients were enrolled. There were 1,734 photographs taken during 230 nurse practitioner shifts. Eighty-three percent of the 350 patients had at least one eye with a high-quality photograph, while only 3% of patients had no photographs of diagnostic value. Mean ratings were ≥ 8.7 (standard deviation [SD] ≤ 1.9) for all measures. The median photography session lasted 1.9 minutes (interquartile range [IQR] = 1.3 to 2.9 minutes), typically accounting for less that 0.5% of the patient's total ED visit. Nonmydriatic fundus photography taken by nurse practitioners is a feasible alternative to direct ophthalmoscopy in the ED. It is performed well by nonphysician staff, is well-received by staff and patients, and requires a trivial amount of time to perform. © 2011 by the Society for Academic Emergency Medicine.

  12. Prognostic impact of metastatic lymph node ratio in advanced gastric cancer from cardia and fundus

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To investigate the prognostic impact of the metastatic lymph node ratio (MLR) in advanced gastric cancer from the cardia and fundus. METHODS: Two hundred and thirty-six patients with gastric cancer from the cardia and fundus who underwent D2 curative resection were analyzed ret- rospectively. The correlations between MLR and the total lymph nodes, positive nodes and the total lymph nodes were analyzed respectively. The influence of MLR on the survival time of patients was determined with univariate Kaplan-Meier survival analysis and mul- tivariate Cox proportional hazard model analysis. And the multiple linear regression was used to identify the relation between MLR and the 5-year survival rate of the patients. RESULTS: The MLR did not correlate with the total lymph nodes resected (r = -0.093, P = 0.057). The 5-year overall survival rate of the whole cohort was 37.5%. Kaplan-Meier survival analysis identified that the following eight factors influenced the survival time of the patients postoperatively: gender (X2 = 4.26, P = 0.0389), tumor size (X2 = 18.48, P < 0.001), Borrmann type (X2 = 7.41, P = 0.0065), histological grade (X2 =5.07, P = 0.0243), pT category (X2 = 49.42, P < 0.001), pN category (X2 = 87.7, P < 0.001), total number of re- trieved lymph nodes (X2 = 8.22, P = 0.0042) and MLR (X2 = 34.3, P < 0.001). Cox proportional hazard model showed that tumor size (X2 = 7.985, P = 0.018), pT category (X2 = 30.82, P < 0.001) and MLR (X2 = 69.39, P < 0.001) independently influenced the prognosis. A linear correlation between MLR and the 5-year survival was statistically significant based on the multiple lin- ear regression (β = -0.63, P < 0.001). Hypothetically, the 5-year survival would surpass 50% when MLR was lower than 10%. CONCLUSION: The MLR is an independent prognostic factor for patients with advanced gastric cancer from the cardia and fundus. The decrease of MLR due to adequate number of total resected lymph nodes can improve the survival.

  13. Primary gastric fundus tuberculosis in immunocompetent patient: a case report and literature review

    Directory of Open Access Journals (Sweden)

    Fahmi Yousef Khan

    2008-10-01

    Full Text Available We report on a 29-year-old Pakistani man who presented to the clinic with epigastric pain, of one-month duration. He did not report fever, cough, vomiting blood, passing black stools, loss of appetite or diarrhea. However, he had lost 7 kg since his symptoms had begun. Clinical examination was unremarkable. Laboratory results were within normal limits. An abdominal CT scan showed a mass with enhancement in the stomach. Gastric endoscopy revealed an ulcerative mass in the fundus. An endoscopic-biopsy specimen revealed caseating granulomas with acid-fast bacilli. The patient was diagnosed to have primary gastric tuberculosis, and antituberculous medications were initiated. Cultures of the gastric mass subsequently grew Mycobacterium tuberculosis sensitive to isoniazid and rifampcin. Follow-up after six months showed a good response to treatment; an upper gastrointestinal tract endoscopy after six months was normal.

  14. Classification of Diabetic Macular Edema and Its Stages Using Color Fundus Image

    Institute of Scientific and Technical Information of China (English)

    Muhammad Zubair; Shoab A. Khan; Ubaid Ullah Yasin

    2014-01-01

    Diabetic macular edema (DME) is a retinal thickening involving the center of the macula. It is one of the serious eye diseases which affects the central vision and can lead to partial or even complete visual loss. The only cure is timely diagnosis, prevention, and treatment of the disease. This paper presents an automated system for the diagnosis and classification of DME using color fundus image. In the proposed technique, first the optic disc is removed by applying some preprocessing steps. The preprocessed image is then passed through a classifier for segmentation of the image to detect exudates. The classifier uses dynamic thresholding technique by using some input parameters of the image. The stage classification is done on the basis of anearly treatment diabetic retinopathy study (ETDRS) given criteria to assess the severity of disease. The proposed technique gives a sensitivity, specificity, and accuracy of 98.27%, 96.58%, and 96.54%, respectively on publically available database.

  15. Automatic differentiation of color fundus images containing drusen or exudates using a contextual spatial pyramid approach.

    Science.gov (United States)

    van Grinsven, Mark J J P; Theelen, Thomas; Witkamp, Leonard; van der Heijden, Job; van de Ven, Johannes P H; Hoyng, Carel B; van Ginneken, Bram; Sánchez, Clara I

    2016-03-01

    We developed an automatic system to identify and differentiate color fundus images containing no lesions, drusen or exudates. Drusen and exudates are lesions with a bright appearance, associated with age-related macular degeneration and diabetic retinopathy, respectively. The system consists of three lesion detectors operating at pixel-level, combining their outputs using spatial pooling and classification with a random forest classifier. System performance was compared with ratings of two independent human observers using human-expert annotations as reference. Kappa agreements of 0.89, 0.97 and 0.92 and accuracies of 0.93, 0.98 and 0.95 were obtained for the system and observers, respectively.

  16. Region-based multi-step optic disk and cup segmentation from color fundus image

    Science.gov (United States)

    Xiao, Di; Lock, Jane; Manresa, Javier Moreno; Vignarajan, Janardhan; Tay-Kearney, Mei-Ling; Kanagasingam, Yogesan

    2013-02-01

    Retinal optic cup-disk-ratio (CDR) is a one of important indicators of glaucomatous neuropathy. In this paper, we propose a novel multi-step 4-quadrant thresholding method for optic disk segmentation and a multi-step temporal-nasal segmenting method for optic cup segmentation based on blood vessel inpainted HSL lightness images and green images. The performance of the proposed methods was evaluated on a group of color fundus images and compared with the manual outlining results from two experts. Dice scores of detected disk and cup regions between the auto and manual results were computed and compared. Vertical CDRs were also compared among the three results. The preliminary experiment has demonstrated the robustness of the method for automatic optic disk and cup segmentation and its potential value for clinical application.

  17. A study of prevalence and association of fundus changes in pregnancy induced hypertension

    Directory of Open Access Journals (Sweden)

    Varija T.

    2016-05-01

    Results: Out of the total 423 patients of PIH examined, the retinal changes (hypertensive retinopathy changes were noted in 181 (42.7% patients. The prevalence of retinopathy changes was more among patients with imminent Eclampsia (76.5% and eclampsia patients (50%. As the severity of the PIH increased the Odds of women developing retinopathy also increased substantially from OR: 17.6; 95% CI: 3.1-136.3 in severe PIH to OR: 253; 95% CI: 47.2-1935 in Imminent eclampsia and this association between the severity of PIH and the development of retinopathy changes was found to be statistically significant. Conclusions: Fundus examination in cases of PIH is of paramount importance in monitoring and managing cases as it co-relates with the severity of PIH. [Int J Reprod Contracept Obstet Gynecol 2016; 5(5.000: 1375-1379

  18. DISCOVERING ABNORMAL PATCHES AND TRANSFORMATIONS OF DIABETICS RETINOPATHY IN BIG FUNDUS COLLECTIONS

    Directory of Open Access Journals (Sweden)

    Yuqian ZHOU

    2017-01-01

    Full Text Available Diabetic retinopathy (DR is one of the retinal diseases due to long-term effect of diabetes. Early detection for diabetic retinopathy is crucial since timely treatment can prevent progressive loss of vision. The most common diagnosis technique of diabetic retinopathy is to screen abnormalities through retinal fundus images by clinicians. However, limited number of well-trained clinicians increase the possibilities of misdiagnosing. In this work, we propose a big-data-driven automatic computer-aided diagnosing (CAD system for diabetic retinopathy severity regression based on transfer learning, which starts from a deep convolutional neural network pre-trained on generic images, and adapts it to large-scale DR datasets. From images in the training set, we also automatically segment the abnormal patches with an occlusion test, and model the transformations and deterioration process of DR. Our results can be widely used for fast diagnosis of DR, medical education and public-level healthcare propagation.

  19. The Effects of Histamine H3 Receptors on Contractile Responses on Rat Gastric Fundus

    Directory of Open Access Journals (Sweden)

    Aşkın Hekimoğlu

    2006-01-01

    Full Text Available The aim of this study is to determine the effects of histamine receptors on the gastrointestinal system smooth muscle contractions and the role of histamine H3 receptors on these effects. İsolated rat gastric fundus preparations were hanged on isolated organ bath and histamine receptor agonist and anthagonists were added to the bath solution and the electrical field stimulation-induced contractile responses were evaluated. In our study groups after blocking one of the histamine receptors H1, H2,H3; contractile responses were observed. Then, other two receptors were blocked one by one or combination of them to observe the changes on the contractile responses given to the electrical stimulation .To blocke histamine receptors pyrilamine (10-6м as H1 receptor blocker, famotidine (10-6м as H2 receptor blocker and thioperamide (10-5м as H3 receptor blocker and various combination of them were used. All groups were treated with H3 receptor anthagonist thioperamide (10-5м and agonist (R-α-methylhistamine (RMHA on 10-8, 10-7, 10-6 ve 10-5 molar concentrations cumulatively to observe its mediator effects on contractile responses. We suggested that (R-α-methylhistamine mediates the inhibition on the contractile effects of rat gastric fundus. This conclusion was supported by these findings: a the selective agonists (RMHA caused a dumping of the contractile effect of acetylcholine; b the effect of (RMHA was prevented by the selective H3 receptor antagonist thioperamide.

  20. Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Suetsugu T

    2016-12-01

    Full Text Available Tetsuyuki Suetsugu,1,2 Aki Kato,1 Munenori Yoshida,1 Tsutomu Yasukawa,1 Akiko Nishiwaki,1,3 Norio Hasegawa,1 Hideaki Usui,1 Yuichiro Ogura1 1Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, 2Department of Ophthalmology, General Kamiiida Daiichi Hospital, 3Nishiwaki Eye Clinic, Nagoya, Aichi, Japan Purpose: We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF in wet age-related macular degeneration (AMD using wide-field imaging instrument. Patients and methods: A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients, polypoidal choroidal vasculopathy (PCV (22 eyes/20 patients, and retinal angiomatous proliferation (RAP (seven eyes/four patients. Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments. Results: Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001. Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7% showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively than control eyes (18.8%. There were no significant differences (P=0.76 between the frequencies in untreated and treated eyes. Conclusion: Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes. Keywords: age-related macular degeneration, fundus autofluorescence, polypoidal choroidal vasculopathy, retinal

  1. Multispectral imaging of the ocular fundus using light emitting diode illumination.

    Science.gov (United States)

    Everdell, N L; Styles, I B; Calcagni, A; Gibson, J; Hebden, J; Claridge, E

    2010-09-01

    We present an imaging system based on light emitting diode (LED) illumination that produces multispectral optical images of the human ocular fundus. It uses a conventional fundus camera equipped with a high power LED light source and a highly sensitive electron-multiplying charge coupled device camera. It is able to take pictures at a series of wavelengths in rapid succession at short exposure times, thereby eliminating the image shift introduced by natural eye movements (saccades). In contrast with snapshot systems the images retain full spatial resolution. The system is not suitable for applications where the full spectral resolution is required as it uses discrete wavebands for illumination. This is not a problem in retinal imaging where the use of selected wavelengths is common. The modular nature of the light source allows new wavelengths to be introduced easily and at low cost. The use of wavelength-specific LEDs as a source is preferable to white light illumination and subsequent filtering of the remitted light as it minimizes the total light exposure of the subject. The system is controlled via a graphical user interface that enables flexible control of intensity, duration, and sequencing of sources in synchrony with the camera. Our initial experiments indicate that the system can acquire multispectral image sequences of the human retina at exposure times of 0.05 s in the range of 500-620 nm with mean signal to noise ratio of 17 dB (min 11, std 4.5), making it suitable for quantitative analysis with application to the diagnosis and screening of eye diseases such as diabetic retinopathy and age-related macular degeneration.

  2. The importance of fundus eye testing in rubella-induced deafness.

    Science.gov (United States)

    Tamayo, Marta L; García, Natalia; Bermúdez Rey, María Carolina; Morales, Lisbeth; Flórez, Silvia; Varón, Clara; Gelvez, Nancy

    2013-09-01

    The purpose of this study was to establish a new approach to improve detection of deafness due to rubella. Colombian institutes for the deaf were visited by a medical team to perform in all enrolled individuals an ophthalmological examination with emphasis in fundus eye by a retina specialist. In cases where ocular alterations compatible with CRS were found, a medical interview by a clinical geneticist analyzing pre-and postnatal history and a thorough medical examination was done. A total of 1383 deaf institutionalized individuals were evaluated in 9 Colombian cities in the period of 2005 to 2006, finding a total of 463 positive cases for salt-and-pepper retinopathy (33.5%), in which rubella could be the etiology of deafness. Medellin, Cartagena, Bucaramanga and Barranquilla were the cities with the highest percentage of Congenital rubella, corresponding to 22.8% of analyzed population. The analysis performed on cases in which reliable prenatal history was obtained in a second appointment (n=88) showed association between positive viral symptoms during pregnancy and salt-and-pepper retinopathy in 62.5% of cases, while both (retinopathy and viral symptoms) were absent in 29.5% of cases; showing a correlation in 92% of cases. The frequency of deafness by rubella obtained by this study is significantly high compared with previous Colombian studies and with international reports. It was possible to correlate the antecedent of symptoms during pregnancy with the presence of salt-and-pepper retinopathy in this deaf population when reliable prenatal history was available, therefore eye testing with emphasis in fundus examination is a good indicator of rubella induced deafness. We propose a new approach in the search of deafness causes, based on a thorough ophthalmologic examination in all deaf people. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Two-port laparoscopic cholecystectomy with modified suture retraction of the fundus: A practical approach

    Directory of Open Access Journals (Sweden)

    Ming G Tian

    2013-01-01

    Full Text Available Context: Although transumbilical single incision laparoscopic cholecystectomy (SILC has been demonstrated to be superior cosmetic, it is only limited to simple cases at present. In complex cases, the standard four- or three-port LC is still the treatment of choice. Aim: To summarize the clinical effect of a modified technique in two-port LC. Settings and Design: A consecutive series of patients with benign gallbladder diseases admitted to the provincial teaching hospital who underwent LC in the past 4 years were included. A modified two-port LC was the first choice except for those requiring laparoscopic common bile duct exploration (LCBDE. Materials and Methods: The operation was done with suture retraction of the fundus by a needle-like retractor. The patients′ data, including the operative time, time consumed by gallbladder retraction, operative bleeding, conversion rate, rate of adding trocars, and postoperative complications were recorded. Statistical Analysis: Data were expressed as percentage and mean with standard deviation. Results: Total 107 patients with chronic calculous cholecystitis (N = 61, acute calculous cholecystitis (N = 43, and cholecystic polyps (N = 3 received two-port LC. The procedure was successful in 99 out of 107 cases (success rate, 92.5%, and a third trocar was added in the remaining 8 cases (7.5% due to severe pathological changes. The operative time was 47.2 (±13.21 min. There was no conversion to open surgery. Conclusion: Two-port LC using a needle-like retractor for suture retraction of the gallbladder fundus is a practical approach when considering the safety, convenience, and indications as well as relatively minimal invasion.

  4. Spectral-domain optical coherence tomographic and fundus autofluorescence findings in eyes with primary intraocular lymphoma

    Directory of Open Access Journals (Sweden)

    Egawa M

    2014-01-01

    Full Text Available Mariko Egawa, Yoshinori Mitamura, Yuki Hayashi, Takeshi NaitoDepartment of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, JapanBackground: The purpose of this study was to evaluate the findings on spectral-domain optical coherence tomography (SD-OCT and fundus autofluorescence (FAF in three eyes with primary intraocular lymphoma (PIOL.Methods: The medical records of three eyes from three patients with biopsy-proven PIOL and retinal infiltrations were reviewed. The SD-OCT and fluorescein angiographic findings were evaluated in the three eyes and FAF images in two eyes.Results: The PIOL in the three patients was monocular. Vitreous opacities and retinal infiltrations were observed in the three eyes, and iritis was present in two eyes. The cytologic diagnosis was class V in two eyes and class III in one eye. The interleukin-10/interleukin-6 ratio was >1.0 in the vitreous and aqueous humor of the three eyes. The FAF images for two eyes showed abnormal granular hyperautofluorescence and hypoautofluorescence which were the reverse of the pattern in the fluorescein angiographic images. In all three eyes, SD-OCT showed hyper-reflective infiltrations at the level of the retinal pigment epithelium (RPE, a separation of the Bruch membrane from the RPE, damage to the RPE, disruption of the photoreceptor inner segment/outer segment junction, and multiple hyper-reflective signals in the inner retina.Conclusion: Because of the characteristic FAF and SD-OCT findings in these eyes with PIOL, we suggest that these noninvasive methods may be used for a rapid diagnosis of PIOL and also for understanding the pathology of PIOL.Keywords: spectral-domain optical coherence tomography, fundus autofluorescence, primary intraocular lymphoma

  5. Digital Preservation.

    Science.gov (United States)

    Yakel, Elizabeth

    2001-01-01

    Reviews research on digital preservation issues, including born-digital and digitally recreated documents. Discusses electronic records research; metadata and other standards; electronic mail; Web-based documents; moving images media; selection of materials for digitization, including primary sources; administrative issues; media stability…

  6. Automated Detection of Malarial Retinopathy in Digital Fundus Images for Improved Diagnosis in Malawian Children with Clinically Defined Cerebral Malaria

    Science.gov (United States)

    Joshi, Vinayak; Agurto, Carla; Barriga, Simon; Nemeth, Sheila; Soliz, Peter; MacCormick, Ian J.; Lewallen, Susan; Taylor, Terrie E.; Harding, Simon P.

    2017-02-01

    Cerebral malaria (CM), a complication of malaria infection, is the cause of the majority of malaria-associated deaths in African children. The standard clinical case definition for CM misclassifies ~25% of patients, but when malarial retinopathy (MR) is added to the clinical case definition, the specificity improves from 61% to 95%. Ocular fundoscopy requires expensive equipment and technical expertise not often available in malaria endemic settings, so we developed an automated software system to analyze retinal color images for MR lesions: retinal whitening, vessel discoloration, and white-centered hemorrhages. The individual lesion detection algorithms were combined using a partial least square classifier to determine the presence or absence of MR. We used a retrospective retinal image dataset of 86 pediatric patients with clinically defined CM (70 with MR and 16 without) to evaluate the algorithm performance. Our goal was to reduce the false positive rate of CM diagnosis, and so the algorithms were tuned at high specificity. This yielded sensitivity/specificity of 95%/100% for the detection of MR overall, and 65%/94% for retinal whitening, 62%/100% for vessel discoloration, and 73%/96% for hemorrhages. This automated system for detecting MR using retinal color images has the potential to improve the accuracy of CM diagnosis.

  7. Digital Culture and Digital Library

    Directory of Open Access Journals (Sweden)

    Yalçın Yalçınkaya

    2016-12-01

    Full Text Available In this study; digital culture and digital library which have a vital connection with each other are examined together. The content of the research consists of the interaction of culture, information, digital culture, intellectual technologies, and digital library concepts. The study is an entry work to integrity of digital culture and digital library theories and aims to expand the symmetry. The purpose of the study is to emphasize the relation between the digital culture and digital library theories acting intersection of the subjects that are examined. Also the perspective of the study is based on examining the literature and analytical evaluation in both studies (digital culture and digital library. Within this context, the methodology of the study is essentially descriptive and has an attribute for the transmission and synthesis of distributed findings produced in the field of the research. According to the findings of the study results, digital culture is an inclusive term that describes the effects of intellectual technologies in the field of information and communication. Information becomes energy and the spectrum of the information is expanding in the vertical rise through the digital culture. In this context, the digital library appears as a new living space of a new environment. In essence, the digital library is information-oriented; has intellectual technology support and digital platform; is in a digital format; combines information resources and tools in relationship/communication/cooperation by connectedness, and also it is the dynamic face of the digital culture in time and space independence. Resolved with the study is that the digital libraries are active and effective in the formation of global knowing and/or mass wisdom in the process of digital culture.

  8. 新生儿眼底筛查及其眼底疾病高危因素分析%Analysis of the High Risk Factors of Fundus Screening and Fundus Diseases in Neonates

    Institute of Scientific and Technical Information of China (English)

    叶青; 何晓平

    2016-01-01

    目的:探讨新生儿眼底筛查及其眼底疾病高危因素分析。方法:回顾性分析2013年10月-2016年6月本院11270例新生儿眼底筛查情况,根据儿科指征将新生儿分为早产儿组(n=716)、高危儿组(n=831)和正常儿组(n=9723),比较三组研究对象的眼底疾病情况。结果:检出眼底异常占13.55%(1527/11270),早产儿组眼底异常检出率为16.48%(118/716),高危儿组为17.57%(146/831),正常儿组为12.99%(1263/9723),早产儿组及高危儿组眼底异常检出率均高于正常儿组,差异均有统计学意义(P<0.05)。经Logistic回归分析可知,机械通气和自然分娩是致使新生儿出现视网膜出血的高危因素(OR=1.754、3.263,P<0.05)。结论:新生儿眼底病变呈多样性且具有严重危害性,经眼底筛查可及时发现,对高危因素强加干扰,为挽救新生儿的视力甚至生命赢得宝贵的时间。%Objective:To analyze the high risk factors of fundus screening and fundus diseases in neonates. Method:11 270 cases of neonatal ocular fundus screening in our hospital from October 2013 to June 2016 were retrospective analyzed.According to the pediatric indications,neonates were divided into preterm group(n=716), high risk group(n=831) and normal group(n=9723),and the fundus diseases were compared between the three groups.Result:Fundus abnormalities were detected in 13.55% (1527/11 270),the detection rate of fundus abnormalities in preterm group was 16.48%(118/716),the high risk group was 17.57%(146/831),and the normal group was 12.99%(1263/9723),the detection rate of abnormal fundus in premature group and high risk group were higher than that in normal group,the differences were statistically significant(P<0.05).By Logistic regression analysis,mechanical ventilation and natural delivery were the high risk factors of retinal hemorrhage in newborn infants(OR=1.754,3.263,P<0.05).Conclusion:The newborn fundus

  9. Digital photography

    National Research Council Canada - National Science Library

    Windsor, J S; Rodway, G W; Middleton, P M; McCarthy, S

    2006-01-01

    The emergence of a new generation of "point-and-shoot" digital cameras offers doctors a compact, portable and user-friendly solution to the recording of highly detailed digital photographs and video images...

  10. Microvascular findings in patients with systemic lupus erythematosus assessed by fundus photography with fluorescein angiography.

    Science.gov (United States)

    Lee, Ji-Hyun; Kim, Sang-Soo; Kim, Geun-Tae

    2013-01-01

    Although a series of trials support systemic lupus erythematosus (SLE) is associated with increased atherosclerosis and cardiovascular events, the link between microvascular structural change and the disease activity of SLE is not defined. We measured retinal microvasculature change by fundus photography with fluorescein angiography (FAG) and investigated the association between retinal vasculature and clinical parameters of SLE. Fifty SLE patients and fifty healthy controls were included. Morphometric and quantitative features of the capillary image including retinal vascular sign and vessel diameters were measured with fundus photography and FAG. Information concerning SLE duration, cumulative dose of steroids and/or immunosuppressive drug intake was recorded, and autoantibodies were checked. SLE activity was assessed by SLE disease activity index (SLEDAI). The mean central retinal arteriolar equivalent (CRAE) was 89.7±14.5 μm in SLE patients, showing narrower arteriole than that of controls (102.2±11.3 μm). The mean central retinal venular equivalents (CRVE) was 127.7±14.8 μm in SLE patients, also, narrower than that of controls (144.1±14.2 μm), but both reached no statistical significance (p=0.154, p=0.609, respectively). Retinopathy was found in 26% of SLE patients. SLE patients with retinopathy were older than those without it, but reached no statistical significance. Disease duration, antidsDNA, and complement levels had no effect on the presence of retinopathy. SLE patients with retinopathy had a tendency to have higher cumulative steroid doses, hsCRP and IgG aCL levels than those without retinopathy. With multiple regression analysis, hsCRP and IgG aCL were identified as contributing factors to the decreased CRAE, whereas no contributing factor was found to CRVE. Retinopathy and retinal arteriolar narrowing were more common in SLE patients, and retinal arteriolar diameter had significant correlation with hsCRP and IgG aCL levels. Retinal imaging is

  11. Comprehensive eye evaluation algorithm

    Science.gov (United States)

    Agurto, C.; Nemeth, S.; Zamora, G.; Vahtel, M.; Soliz, P.; Barriga, S.

    2016-03-01

    In recent years, several research groups have developed automatic algorithms to detect diabetic retinopathy (DR) in individuals with diabetes (DM), using digital retinal images. Studies have indicated that diabetics have 1.5 times the annual risk of developing primary open angle glaucoma (POAG) as do people without DM. Moreover, DM patients have 1.8 times the risk for age-related macular degeneration (AMD). Although numerous investigators are developing automatic DR detection algorithms, there have been few successful efforts to create an automatic algorithm that can detect other ocular diseases, such as POAG and AMD. Consequently, our aim in the current study was to develop a comprehensive eye evaluation algorithm that not only detects DR in retinal images, but also automatically identifies glaucoma suspects and AMD by integrating other personal medical information with the retinal features. The proposed system is fully automatic and provides the likelihood of each of the three eye disease. The system was evaluated in two datasets of 104 and 88 diabetic cases. For each eye, we used two non-mydriatic digital color fundus photographs (macula and optic disc centered) and, when available, information about age, duration of diabetes, cataracts, hypertension, gender, and laboratory data. Our results show that the combination of multimodal features can increase the AUC by up to 5%, 7%, and 8% in the detection of AMD, DR, and glaucoma respectively. Marked improvement was achieved when laboratory results were combined with retinal image features.

  12. Digital Tectonics

    DEFF Research Database (Denmark)

    Christiansen, Karl; Borup, Ruben; Søndergaard, Asbjørn;

    2014-01-01

    Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated.......Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated....

  13. Digital squares

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Kim, Chul E

    1988-01-01

    Digital squares are defined and their geometric properties characterized. A linear time algorithm is presented that considers a convex digital region and determines whether or not it is a digital square. The algorithm also determines the range of the values of the parameter set of its preimages....... The analysis involves transforming the boundary of a digital region into parameter space of slope and y-intercept...

  14. Digital Citizenship

    Science.gov (United States)

    Isman, Aytekin; Canan Gungoren, Ozlem

    2014-01-01

    Era in which we live is known and referred as digital age.In this age technology is rapidly changed and developed. In light of these technological advances in 21st century, schools have the responsibility of training "digital citizen" as well as a good citizen. Digital citizens must have extensive skills, knowledge, Internet and …

  15. Toxoplasmosis with chorioretinitis in an HIV-infected child with no visual complaints—importance of fundus examination

    Science.gov (United States)

    Pereira, Noella Maria Delia; Shah, Ira; Lala, Mamatha

    2017-01-01

    Central nervous system lesions are common in HIV-infected patients. In the combination anti-retroviral therapy (ART) era, Toxoplasma reactivation has been observed only in patients with unrecognized HIV infection or refusing therapy. We present the case of 10-year-old girl with AIDS who initially presented with pneumonia. She was treated for pneumonia and thereafter started on ART as her CD4 count was low. However, 5 days after starting ART she presented with left ptosis and right-sided monoparesis. She was diagnosed with neurotoxoplasmosis and responded successfully to pyrimethamine–sulfadoxine therapy. Though she had no vision difficulties, her fundus examination revealed chorioretinitis during the hospital stay. We emphasize the importance of routine fundus examination prior to starting ART to rule out chorioretinitis even in an older child with no visual complaints. PMID:28058107

  16. Toxoplasmosis with chorioretinitis in an HIV-infected child with no visual complaints-importance of fundus examination.

    Science.gov (United States)

    Pereira, Noella Maria Delia; Shah, Ira; Lala, Mamatha

    2017-01-01

    Central nervous system lesions are common in HIV-infected patients. In the combination anti-retroviral therapy (ART) era, Toxoplasma reactivation has been observed only in patients with unrecognized HIV infection or refusing therapy. We present the case of 10-year-old girl with AIDS who initially presented with pneumonia. She was treated for pneumonia and thereafter started on ART as her CD4 count was low. However, 5 days after starting ART she presented with left ptosis and right-sided monoparesis. She was diagnosed with neurotoxoplasmosis and responded successfully to pyrimethamine-sulfadoxine therapy. Though she had no vision difficulties, her fundus examination revealed chorioretinitis during the hospital stay. We emphasize the importance of routine fundus examination prior to starting ART to rule out chorioretinitis even in an older child with no visual complaints.

  17. Comparison of subjective and objective methods to determine the retinal arterio-venous ratio using fundus photography

    OpenAIRE

    Heitmar, Rebekka; Kalitzeos, Angelos A.; Patel, Sunni R.; Prabhu-Das, Diana; Cubbidge, Robert P.

    2015-01-01

    Purpose: To assess the inter and intra observer variability of subjective grading of the retinal arterio-venous ratio (AVR) using a visual grading and to compare the subjectively derived grades to an objective method using a semi-automated computer program. Methods: Following intraocular pressure and blood pressure measurements all subjects underwent dilated fundus photography. 86 monochromatic retinal images with the optic nerve head centred (52 healthy volunteers) were obtained using a Zeis...

  18. RISK FACTORS FOR DIABETIC RETINOPATHY IN DIABETICS SCREENED USING FUNDUS PHOTOGRAPHY AT A PRIMARY HEALTH CARE SETTING IN EAST MALAYSIA

    Directory of Open Access Journals (Sweden)

    MALLIKA PS

    2011-01-01

    Full Text Available Introduction: This study reports on the prevalence of diabetic retinopathy (DR and risk factors among diabetic patients, who underwent fundus photography screening in a primary care setting of Borneo Islands, East Malaysia. We aimed to explore the preliminary data to help in the planning of more effective preventive strategies of DR at the primary health care setting. Materials and Methods: A cross-sectional study on 738 known diabetic patients aged 19-82 years was conducted in 2004. Eye examination consists of visual acuity testing followed by fundus photography for DR assessment. The fundus pictures were reviewed by a family physician and an ophthalmologist. Fundus photographs were graded as having no DR, NPDR, PDR and maculopathy. The data of other parameters was retrieved from patient’s record. Bi-variate and multivariate analysis was used toelucidate the factors associated with DR. Results: Any DR was detected in 23.7% (95% CI=21 to 27% of the patients and 3.2% had proliferative DR. The risk factors associated with any DR was duration of DM (OR =2.5, CI=1.6 to 3.9 for duration of five to 10 years when compared to <5 yearsand lower BMI (OR=1.8, CI=1.1 to 3.0. Moderate visual loss was associated with DR (OR=2.1, CI=1.2 to 3.7. Conclusions: This study confirms associations of DR with diabetic duration, body mass index and visual loss. Our data provide preliminary findings to help to improve the screening and preventive strategies of DR at the primary health care setting.

  19. Increased fundus autofluorescence and progression of geographic atrophy secondary to age-related macular degeneration. The GAIN study.

    OpenAIRE

    Biarnés Pérez, Marc, 1973-; Arias, Luis; Alonso Caballero, Jordi; García, Míriam; Hijano, Míriam; Rodríguez, Anabel; Serrano, Anna; Badal, Josep; Muhtaseb, Hussein; Verdaguer, Paula; Monés, Jordi

    2015-01-01

    PURPOSE: To define the role of increased fundus autofluorescence (FAF), a surrogate for lipofuscin content, as a risk factor for progression of geographic atrophy (GA). DESIGN: Prospective natural history cohort study, the GAIN (Characterization of geographic atrophy progression in patients with age-related macular degeneration). METHODS: setting: Single-center study conducted in Barcelona, Spain. PATIENTS: After screening of 211 patients, 109 eyes of 82 patients with GA secondary to age-rela...

  20. Selective inhibitory effects of niflumic acid on 5-HT-induced contraction of the rat isolated stomach fundus.

    Science.gov (United States)

    Scarparo, H C; Santos, G C; Leal-Cardoso, J H; Criddle, D N

    2000-06-01

    The effects of niflumic acid (NFA), an inhibitor of calcium-activated chloride currents I(Cl(Ca)), were compared with the actions of the voltage-dependent calcium channel (VDCC) blocker nifedipine on 5-hydroxtryptamine (5-HT)- and acetylcholine (ACh)-induced contractions of the rat isolated fundus. NFA (1 - 30 microM) elicited a concentration-dependent inhibition of contractions induced by 5-HT (10 microM) with a reduction to 15. 5+/-6.0% of the control value at 30 microM. 1 microM nifedipine reduced 5-HT-induced contraction to 15.2+/-4.9% of the control, an effect not greater in the additional presence of 30 microM NFA. In contrast, the contractile response to ACh (10 microM) was not inhibited by NFA in concentrations /=10 microM. Our results show that NFA can exert selective inhibitory effects on the chloride-dependent 5-HT-induced contractions of the rat fundus. The data support the hypothesis that activation of Cl((Ca)) channels leading to calcium entry via VDCCs is a mechanism utilized by 5-HT, but not by ACh, to elicit contraction of the rat fundus.

  1. Investigation of the potential modulatory effect of biliverdin, carbon monoxide and bilirubin on nitrergic neurotransmission in the pig gastric fundus.

    Science.gov (United States)

    Colpaert, Erwin E; Timmermans, Jean-Pierre; Lefebvre, Romain A

    2002-12-20

    In porcine gastric fundus, we have investigated the colocalization of the bile pigment biosynthetic enzymes heme oxygenase-2 and biliverdin reductase with neuronal nitric oxide synthase (nNOS), the effect of carbon monoxide (CO) on fundic circular smooth muscle and the possible modulatory effect of the bile pigments biliverdin and bilirubin on CO-mediated relaxations and on nitrergic relaxation. Heme oxygenase-2 and biliverdin reductase immunoreactivity was present in all nNOS containing myenteric neurons. CO induced a concentration-dependent relaxation of fundic circular smooth muscle strips, which was completely blocked by the specific guanylate cyclase inhibitor 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ). 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), biliverdin and bilirubin strongly enhanced the amplitude of the CO-induced relaxation. Tin protoporphyrin had no effect on electrically induced nitrergic relaxation, but spectrophotometric analysis learned that incubation of porcine gastric fundus circular muscle strips with tin protoporphyrin did not influence heme oxygenase activity. In conclusion, our data suggest that nitrergic neurons in the pig gastric fundus are able to produce biliverdin and bilirubin, and that these agents potentiate the relaxant effect of CO, which is formed concomitantly with biliverdin by heme oxygenase-2.

  2. Adaptive Neuro-Fuzzy Inference System Approach for the Automatic Screening of Diabetic Retinopathy in Fundus Images

    Directory of Open Access Journals (Sweden)

    S. Kavitha

    2011-01-01

    Full Text Available Problem statement: Diabetic retinopathy is one of the most significant factors contributing to blindness and so early diagnosis and timely treatment is particularly important to prevent visual loss. Approach: An integrated approach for extraction of blood vessels and exudates detection was proposed to screen diabetic retinopathy. An automated classifier was developed based on Adaptive Neuro-Fuzzy Inference System (ANFIS to differentiate between normal and nonproliferative eyes from the quantitative assessment of monocular fundus images. Feature extraction was performed on the preprocessed fundus images. Structure of Blood vessels was extracted using Multiscale analysis. Hard Exudates were detected using CIE Color channel transformation, Entropy Thresholding and Improved Connected Component Analysis from the fundus images. Features like Wall to Lumen ratio in blood vessels, Texture, Homogeneity properties and area occupied by Hard Exudates, were given as input to ANFIS.ANFIS was trained with Back propagation in combination with the least squares method. Proposed method was evaluated on 200 real time images comprising 70 normal and 130 retinopathic eyes. Results and Conclusion: All of the results were validated with ground truths obtained from expert ophthalmologists. Quantitative performance of the method, detected exudates with an accuracy of 99.5%. Receiver operating characteristic curve evaluated for real time images produced better results compared to the other state of the art methods. ANFIS provides best classification and can be used as a screening tool in the analysis and diagnosis of retinal images.

  3. Multi-modal adaptive optics system including fundus photography and optical coherence tomography for the clinical setting.

    Science.gov (United States)

    Salas, Matthias; Drexler, Wolfgang; Levecq, Xavier; Lamory, Barbara; Ritter, Markus; Prager, Sonja; Hafner, Julia; Schmidt-Erfurth, Ursula; Pircher, Michael

    2016-05-01

    We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 µm and an axial resolution of ~5 µm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases.

  4. Fundus Photography as a Screening Method for Diabetic Retinopathy in Children With Type 1 Diabetes: Outcome of the Initial Photography.

    Science.gov (United States)

    Gräsbeck, Thomas C; Gräsbeck, Sophia V; Miettinen, Päivi J; Summanen, Paula A

    2016-09-01

    To determine the success rate of the initial fundus photography session in producing gradable images for screening diabetic retinopathy in children Photography success was classified as "complete" if both images of both eyes were gradable, "partial" if both images of 1 eye were gradable, "macula-centered image(s) only" if only the macula-centered image of one or both eyes was gradable, and "unsuccessful" if neither macula-centered image was gradable. Complete success was reached in 97 (46%; 95% confidence interval [CI], 39-52) patients, at least partial success in 153 (72%; 95% CI, 65-78) patients, success of macula-centered image(s) only in 47 (22%; 95% CI, 17-28) patients, and in 13 (6%; 95%CI, 3-10) patients fundus photography was unsuccessful. Macula-centered images were more often gradable in both eyes than optic disc-centered images (P photography did not differ between right and left eye. Sex, age at diagnosis of T1D, and the duration of diabetes, age, and glycemic control at the time of initial photography were unassociated with complete success. Partial success tended to decrease with increasing age category (P = .093), and the frequency of gradable macula-centered image(s) only increased with increasing age (P = .043). Less than half of the children achieved complete success, but in only 6% initial fundus photography was unsuccessful, indicating its value in assessing retinopathy in the pediatric setting. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Fundus white spots and acquired night blindness due to vitamin A deficiency.

    Science.gov (United States)

    Genead, Mohamed A; Fishman, Gerald A; Lindeman, Martin

    2009-12-01

    To report a successfully treated case of acquired night blindness associated with fundus white spots secondary to vitamin A deficiency. An ocular examination, electrophysiologic testing, as well as visual field and OCT examinations were obtained on a 61-year-old man with vitamin A deficiency who had previously undergone gastric bypass surgery. The patient had a re-evaluation after treatment with high doses of oral vitamin A. The patient was observed to have numerous white spots in the retina of each eye. Best-corrected visual acuity was initially 20/80 in each eye, which improved to 20/40-1 OU after oral vitamin A therapy for 2 months. Full field electroretinogram (ERG) testing, showed non-detectable rod function and a 34 and 41% reduction for 32-Hz flicker and single flash cone responses, respectively, below the lower limits of normal. Both rod and cone functions markedly improved after initiation of vitamin A therapy. Vitamin A deficiency needs to be considered in a patient with white spots of the retina in the presence of poor night vision.

  6. Exudate-based diabetic macular edema detection in fundus images using publicly available datasets

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME through the presence of exudation. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing (e.g., the classifier was trained on an independent dataset and tested on MESSIDOR). Our algorithm obtained an AUC between 0.88 and 0.94 depending on the dataset/features used. Additionally, it does not need ground truth at lesion level to reject false positives and is computationally efficient, as it generates a diagnosis on an average of 4.4 s (9.3 s, considering the optic nerve localization) per image on an 2.6 GHz platform with an unoptimized Matlab implementation.

  7. Automatic Diabetic Macular Edema Detection in Fundus Images Using Publicly Available Datasets

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing. Our algorithm is robust to segmentation uncertainties, does not need ground truth at lesion level, and is very fast, generating a diagnosis on an average of 4.4 seconds per image on an 2.6 GHz platform with an unoptimised Matlab implementation.

  8. Decision support system for the detection and grading of hard exudates from color fundus photographs.

    Science.gov (United States)

    Jaafar, Hussain F; Nandi, Asoke K; Al-Nuaimy, Waleed

    2011-11-01

    Diabetic retinopathy is a major cause of blindness, and its earliest signs include damage to the blood vessels and the formation of lesions in the retina. Automated detection and grading of hard exudates from the color fundus image is a critical step in the automated screening system for diabetic retinopathy. We propose novel methods for the detection and grading of hard exudates and the main retinal structures. For exudate detection, a novel approach based on coarse-to-fine strategy and a new image-splitting method are proposed with overall sensitivity of 93.2% and positive predictive value of 83.7% at the pixel level. The average sensitivity of the blood vessel detection is 85%, and the success rate of fovea localization is 100%. For exudate grading, a polar fovea coordinate system is adopted in accordance with medical criteria. Because of its competitive performance and ability to deal efficiently with images of variable quality, the proposed technique offers promising and efficient performance as part of an automated screening system for diabetic retinopathy.

  9. Computer Aided Diagnosis of Macular Edema Using Color Fundus Images: A Review

    Directory of Open Access Journals (Sweden)

    Devashree R. Zinjarde,

    2014-03-01

    Full Text Available Diabetic retinopathy is the leading cause of blindness in the western working age population and micro aneurysms are one of the first pathologies associated with diabetic retinopathy. Diabetic retinopathy (DR is caused by damage to the blood vessels of the retina which affects the vision. But when DR becomes severe it results into macular edema. Macula is the region near the centre of the eye that provides the vision. Blood vessels leak fluid onto the macula leading to the swelling which blurs the vision eventually leading to complete loss of vision. This paper is based on the detection of the edema affected image from the normal image. If the image is edema affected it also states its severity of the disease using a rotational asymmetry metric by examining the symmetry of the macular region. Diabetic macular edema (DME is an advanced symptom of diabetic retinopathy and can lead to irreversible vision loss. A feature extraction technique is introduced to capture the global characteristics of the fundus images and discriminate the normal from DME images.

  10. Optic Disc Segmentation by Balloon Snake with Texture from Color Fundus Image

    Directory of Open Access Journals (Sweden)

    Jinyang Sun

    2015-01-01

    Full Text Available A well-established method for diagnosis of glaucoma is the examination of the optic nerve head based on fundus image as glaucomatous patients tend to have larger cup-to-disc ratios. The difficulty of optic segmentation is due to the fuzzy boundaries and peripapillary atrophy (PPA. In this paper a novel method for optic nerve head segmentation is proposed. It uses template matching to find the region of interest (ROI. The method of vessel erasing in the ROI is based on PDE inpainting which will make the boundary smoother. A novel optic disc segmentation approach using image texture is explored in this paper. A cluster method based on image texture is employed before the optic disc segmentation step to remove the edge noise such as cup boundary and vessels. We replace image force in the snake with image texture and the initial contour of the balloon snake is inside the optic disc to avoid the PPA. The experimental results show the superior performance of the proposed method when compared to some traditional segmentation approaches. An average segmentation dice coefficient of 94% has been obtained.

  11. Microaneurysms detection with the radon cliff operator in retinal fundus images

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Tobin Jr, Kenneth William [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2010-01-01

    Diabetic Retinopathy (DR) is one of the leading causes of blindness in the industrialized world. Early detection is the key in providing effective treatment. However, the current number of trained eye care specialists is inadequate to screen the increasing number of diabetic patients. In recent years, automated and semi-automated systems to detect DR with color fundus images have been developed with encouraging, but not fully satisfactory results. In this study we present the initial results of a new technique for the detection and localization of microaneurysms, an early sign of DR. The algorithm is based on three steps: candidates selection, the actual microaneurysms detection and a final probability evaluation. We introduce the new Radon Cliff operator which is our main contribution to the field. Making use of the Radon transform, the operator is able to detect single noisy Gaussian-like circular structures regardless of their size or strength. The advantages over existing microaneurysms detectors are manifold: the size of the lesions can be unknown, it automatically distinguishes lesions from the vasculature and it provides a fair approach to microaneurysm localization even without post-processing the candidates with machine learning techniques, facilitating the training phase. The algorithm is evaluated on a publicly available dataset from the Retinopathy Online Challenge.

  12. Detection of exudates in fundus photographs using deep neural networks and anatomical landmark detection fusion.

    Science.gov (United States)

    Prentašić, Pavle; Lončarić, Sven

    2016-12-01

    Diabetic retinopathy is one of the leading disabling chronic diseases and one of the leading causes of preventable blindness in developed world. Early diagnosis of diabetic retinopathy enables timely treatment and in order to achieve it a major effort will have to be invested into automated population screening programs. Detection of exudates in color fundus photographs is very important for early diagnosis of diabetic retinopathy. We use deep convolutional neural networks for exudate detection. In order to incorporate high level anatomical knowledge about potential exudate locations, output of the convolutional neural network is combined with the output of the optic disc detection and vessel detection procedures. In the validation step using a manually segmented image database we obtain a maximum F1 measure of 0.78. As manually segmenting and counting exudate areas is a tedious task, having a reliable automated output, such as automated segmentation using convolutional neural networks in combination with other landmark detectors, is an important step in creating automated screening programs for early detection of diabetic retinopathy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. 5-Hydroxytryptamino-induced calcium sparks in cultured rat stomach fundus smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xiaoling; (张小玲); YAN; Hongtao; (阎宏涛); YAN; Yang; (闫炀)

    2003-01-01

    With a new fluorescence probe of Ca2+, STDIn-AM, 5-hydroxytryptamino (5-HT)-induced spontaneous calcium release events (calcium sparks) in cultured rat stomach fundus smooth muscle cells (SFSMC) are investigated by laser scanning confocal microscope. The mechanisms of initiation of Ca2+ sparks, propagating Ca2+ waves and their relation to E-C coupling are discussed. After the extracellular [Ca2+] is increased to 10 mmol/L, addition of 5-HT causes hot spots throughout the cytoplasm, which is brighter near the plasmalemma. The amplitude of the event is at least two times greater than the standard deviation of fluorescence intensity fluctuations measured in the neighboring region and the duration of the Ca2+ signal is over 100 ms. The results suggest that 5-HT acts by the way of 5-HT2 receptors on SFSMC, then through 5-HT2 receptors couples IP3/Ca2+ and DG/PKC double signal transduction pathways to cause Ca2+ release from intracellular Ca2+ stores and followed Ca2+ influx possibly through calcium release-activated calcium influx. The acceptor of activated 5-HT2 can also cause membrane depolarization, which then stimulates the L-type Ca2+ channels leading to Ca2+ influx. Thenthe local Ca2+ entry mentioned above activates ryanodine-sensitive Ca2+ releasechannels (RyR) on sarcoplasmic reticulum (SR) to cause local Ca2+ release events (Ca2+ sparks) through calcium-induced calcium release (CICR).

  14. Detection of retinal nerve fiber layer defects on retinal fundus images for early diagnosis of glaucoma

    Science.gov (United States)

    Muramatsu, Chisako; Hayashi, Yoshinori; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2010-01-01

    Retinal nerve fiber layer defect (NFLD) is a major sign of glaucoma, which is the second leading cause of blindness in the world. Early detection of NFLDs is critical for improved prognosis of this progressive, blinding disease. We have investigated a computerized scheme for detection of NFLDs on retinal fundus images. In this study, 162 images, including 81 images with 99 NFLDs, were used. After major blood vessels were removed, the images were transformed so that the curved paths of retinal nerves become approximately straight on the basis of ellipses, and the Gabor filters were applied for enhancement of NFLDs. Bandlike regions darker than the surrounding pixels were detected as candidates of NFLDs. For each candidate, image features were determined and the likelihood of a true NFLD was determined by using the linear discriminant analysis and an artificial neural network (ANN). The sensitivity for detecting the NFLDs was 91% at 1.0 false positive per image by using the ANN. The proposed computerized system for the detection of NFLDs can be useful to physicians in the diagnosis of glaucoma in a mass screening.

  15. Fundus auto fluorescence and spectral domain ocular coherence tomography in the early detection of chloroquine retinopathy

    Directory of Open Access Journals (Sweden)

    Megan B. Goodman

    2015-03-01

    Full Text Available Purpose: To determine the sensitivity of spectral domain ocular coherence tomography (SD-OCT and fundus auto fluorescence (FAF images as a screening test to detect early changes in the retina prior to the onset of chloroquine retinopathy.Method: The study was conducted using patients taking chloroquine (CQ, referred by the Rheumatology Department to the Ophthalmology Department at Tygerberg Academic Hospital. Group A consisted of 59 patients on CQ for less than 5 years, and Group B consisted of 53 patients on CQ for more than 5 years. A 200 × 200 macula thickness map, 5-line raster SD-OCT on a Carl Zeiss Meditec Cirrus HD-OCT and FAF images on a Carl Zeiss Meditec Visucam 500 were recorded for 223 eyes. Images were reviewed independently, and then those of Groups A and B compared.Results: There were no statistically significant differences between Groups A and B. The criteria included the internal limiting membrane and the retinal pigment epithelium (ILM-RPE thickness, interdigitation zone integrity (p = 0.891, df = 1, χ² = 0.1876, ellipsoid zone integrity (p = 0.095, df = 2, χ² = 4.699 and FAF image irregularities (p = 0.479, df = 1, χ²= 4995978.Conclusion: The inclusion of SD-OCT and FAF as objective tests into the prescribed screening guidelines does not appear to simplify the detection of subclinical injury in patients on chloroquine treatment.

  16. Automated segmentation of geographic atrophy in fundus autofluorescence images using supervised pixel classification.

    Science.gov (United States)

    Hu, Zhihong; Medioni, Gerard G; Hernandez, Matthias; Sadda, Srinivas R

    2015-01-01

    Geographic atrophy (GA) is a manifestation of the advanced or late stage of age-related macular degeneration (AMD). AMD is the leading cause of blindness in people over the age of 65 in the western world. The purpose of this study is to develop a fully automated supervised pixel classification approach for segmenting GA, including uni- and multifocal patches in fundus autofluorescene (FAF) images. The image features include region-wise intensity measures, gray-level co-occurrence matrix measures, and Gaussian filter banks. A [Formula: see text]-nearest-neighbor pixel classifier is applied to obtain a GA probability map, representing the likelihood that the image pixel belongs to GA. Sixteen randomly chosen FAF images were obtained from 16 subjects with GA. The algorithm-defined GA regions are compared with manual delineation performed by a certified image reading center grader. Eight-fold cross-validation is applied to evaluate the algorithm performance. The mean overlap ratio (OR), area correlation (Pearson's [Formula: see text]), accuracy (ACC), true positive rate (TPR), specificity (SPC), positive predictive value (PPV), and false discovery rate (FDR) between the algorithm- and manually defined GA regions are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively.

  17. Digital preservation

    CERN Document Server

    Deegan, Marilyn

    2013-01-01

    Digital preservation is an issue of huge importance to the library and information profession right now. With the widescale adoption of the internet and the rise of the world wide web, the world has been overwhelmed by digital information. Digital data is being produced on a massive scale by individuals and institutions: some of it is born, lives and dies only in digital form, and it is the potential death of this data, with its impact on the preservation of culture, that is the concern of this book. So how can information professionals try to remedy this? Digital preservation is a complex iss

  18. Digital subtraktion

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    2004-01-01

    Digital subtraktion er en metode til at fjerne uønskede oplysninger i et røntgenbillede. Subtraktionsteknikken bruges primært i forbindelse med angiografi hvor man kun er interesseret i at se selve karret. Derfor er digital subtraktion i daglig tale synonymt med DSA eller DVI – hhv. Digital...... Subtraction Angiography eller Digital Vascular Imaging. Benævnelserne er to røntgenfirmaers navn for den samme teknik. Digital subtraktion kræver speciel software, samt at apparaturet kan eksponere i serier....

  19. An analysis of surgical anatomy of the gastric fundus in bariatric surgery: why the gastric pouch expands? A point of technique.

    Science.gov (United States)

    Kassir, Radwan; Blanc, Pierre; Lointier, Patrice; Tiffet, Olivier; Breton, Christophe; Ben Amor, Imed; Iannelli, Antonio; Gugenheim, Jean

    2014-11-01

    In bariatric surgery, it is essential to completely release the Fundus in order to create a narrow gastric pouch. The upper part of the fundus is located above the omental bursa and is therefore retro-peritoneal. In order to release this completely, not only does the arterial supply to the fundus need to be divided to visualise the left diaphragmatic pillar, but the right attachment beginning at the left diaphragmatic pillar and running towards the fundus needs to be divided. This minimal dissection is compensated by further dissection at the level of the left diaphragmatic pillar and traction on the stomach from right to left during the final division stapling division process. The surgeon still has the impression of having released the posterior aspect of the Fundus, exposing the pillar of the diaphragm, although in fact part of the Fundus still remains adherent to the diaphragm and is therefore not released. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  20. Digital Natives or Digital Tribes?

    Science.gov (United States)

    Watson, Ian Robert

    2013-01-01

    This research builds upon the discourse surrounding digital natives. A literature review into the digital native phenomena was undertaken and found that researchers are beginning to identify the digital native as not one cohesive group but of individuals influenced by other factors. Primary research by means of questionnaire survey of technologies…

  1. Development, Deployment, and Cost Effectiveness of a Self-Administered Stereo Non Mydriatic Automated Retinal Camera (SNARC) Containing Automated Retinal Lesion (ARL) Detection Using Adaptive Optics

    Science.gov (United States)

    2010-10-01

    diabetes and healthy eating habits . REQ ID REQUIREMENT NAME DESCRIPTION VERS NEW VERS UPD. HealthyEating_1 Nutrition Data Entry By Category...user to track the time they ate a meal/ snack . 1.0 1.0 HealthyEating_3 Daily Nutrition Feedback Provides user feedback on their progress towards

  2. Comparison of optic area measurement using fundus photography and optical coherence tomography between optic nerve head drusen and control subjects.

    Science.gov (United States)

    Flores-Rodríguez, Patricia; Gili, Pablo; Martín-Ríos, María Dolores; Grifol-Clar, Eulalia

    2013-03-01

    To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  3. The Minnesota Grading System Using Fundus Autofluorescence of Eye Bank Eyes: A Correlation To Age-Related Macular Degeneration (An AOS Thesis)

    Science.gov (United States)

    Olsen, Timothy W.

    2008-01-01

    Purpose To establish a grading system of eye bank eyes using fundus autofluorescence (FAF) and identify a methodology that correlates FAF to age-related macular degeneration (AMD) with clinical correlation to the Age-Related Eye Disease Study (AREDS). Methods Two hundred sixty-two eye bank eyes were evaluated using a standardized analysis of FAF. Measurements were taken with the confocal scanning laser ophthalmoscope (cSLO). First, high-resolution, digital, stereoscopic, color images were obtained and graded according to AREDS criteria. With the neurosensory retina removed, mean FAF values were obtained from cSLO images using software analysis that excludes areas of atrophy and other artifact, generating an FAF value from a grading template. Age and AMD grade were compared to FAF values. An internal fluorescence reference standard was tested. Results Standardization of the cSLO machine demonstrated that reliable data could be acquired after a 1-hour warm-up. Images obtained prior to 1 hour had falsely elevated levels of FAF. In this initial analysis, there was no statistical correlation of age to mean FAF. There was a statistically significant decrease in FAF from AREDS grade 1, 2 to 3, 4 (P < .0001). An internal fluorescent standard may serve as a quantitative reference. Conclusions The Minnesota Grading System (MGS) of FAF (MGS-FAF) establishes a standardized methodology for grading eye bank tissue to quantify FAF compounds in the retinal pigment epithelium and correlate these findings to the AREDS. Future studies could then correlate specific FAF to the aging process, histopathology AMD phenotypes, and other maculopathies, as well as to analyze the biochemistry of autofluorescent fluorophores. PMID:19277247

  4. 779例新生儿眼底筛查结果及新生儿眼底疾病高危因素分析%Results of 779 cases of neonatal fundus screening and risk factors for neonatal fundus diseases

    Institute of Scientific and Technical Information of China (English)

    罗睿; 刘洁; 胡颦; 陈姝姝; 石碧珍; 朱建华; 刘玲

    2014-01-01

    ObjectiveTo determine the prevalence and risk factors of retinal diseases of preterm infants and full term for newborns small gestational age born (SGA) by using wide-angle digital retinal imaging system (RetCam3). MethodsClinical data of 779 preterm and SGA infants whose eyes were detected by RetCam3 between January and December 2013 before discharge were studied retrospectively.ResultsAmong the 779 infants, there were 69 cases of retinal hemorrhage (8.9%), 10 cases (1.3%) of retinopathy of prematurity (ROP), 9 cases of retinal exudative changes, 4 cases of retinal myelinated nerve ifbers, 2 cases of congenita cataract, 3 cases of retinal chromatosis, 2 cases of retinal crystalline changes and 1 case of retinoblastoma. Logistic regression analysis indicated that low birth weight and gestational age and the history of oxygen inhalation were risk factors for the development of ROP and that vaginal delivery and mechanical ventilation increased the risk of retinal hemorrhage.ConclusionsNeonatal fundus diseases may be so various and harmful that early fundus screening should be carried out on high-risk infants, such as preterm and SAG infants. Preventive measures should be taken against the risk factors for fundus diseases.%目的:应用广角数码视网膜成像系统(RetCam3)进行新生儿眼底筛查,了解早产儿及足月小于胎龄儿视网膜疾病的患病率及影响因素。方法回顾性分析2013年1~12月在我院新生儿病房行RetCam3眼底筛查的早产儿及足月小于胎龄儿的临床病例资料。结果779例早产儿及足月小于胎龄儿接受筛查,检出有眼底病变患儿100例(12.8%),其中视网膜出血69例(8.9%)、早产儿视网膜病(ROP)10例(1.3%)、眼底渗出9例(1.2%)、视网膜有髓神经纤维4例(0.5%)、视网膜色素沉着3例(0.4%)、先天性白内障和结晶样变性各2例(0.3%)、视网膜母细胞瘤1例(0.1%)。Logistic回归分析表明低出生体重

  5. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    , by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research......This dissertation forwards the theory of digital consumer-response as a perspective to examine how digital media practices influence consumers’ response to advertising. Digital consumer-response is a development of advertising theory that encompasses how consumers employ their knowledge...... and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising...

  6. Digital Forensics

    OpenAIRE

    Ψευτέλης, Αθανάσιος Δημήτρης

    2013-01-01

    A reprint from American Scientist the magazine of Sigma Xi, The Scientific Research Society Since the 1980s, computers have had increasing roles in all aspects of human life—including an involvement in criminal acts. This development has led to the rise of digital forensics, the uncovering and examination of evidence located on all things electronic with digital storage, including computers, cell phones, and networks. Digital forensics researchers and practitione...

  7. Automatic segmentation of blood vessels from retinal fundus images through image processing and data mining techniques

    Indian Academy of Sciences (India)

    R Geetharamani; Lakshmi Balasubramanian

    2015-09-01

    Machine Learning techniques have been useful in almost every field of concern. Data Mining, a branch of Machine Learning is one of the most extensively used techniques. The ever-increasing demands in the field of medicine are being addressed by computational approaches in which Big Data analysis, image processing and data mining are on top priority. These techniques have been exploited in the domain of ophthalmology for better retinal fundus image analysis. Blood vessels, one of the most significant retinal anatomical structures are analysed for diagnosis of many diseases like retinopathy, occlusion and many other vision threatening diseases. Vessel segmentation can also be a pre-processing step for segmentation of other retinal structures like optic disc, fovea, microneurysms, etc. In this paper, blood vessel segmentation is attempted through image processing and data mining techniques. The retinal blood vessels were segmented through color space conversion and color channel extraction, image pre-processing, Gabor filtering, image postprocessing, feature construction through application of principal component analysis, k-means clustering and first level classification using Naïve–Bayes classification algorithm and second level classification using C4.5 enhanced with bagging techniques. Association of every pixel against the feature vector necessitates Big Data analysis. The proposed methodology was evaluated on a publicly available database, STARE. The results reported 95.05% accuracy on entire dataset; however the accuracy was 95.20% on normal images and 94.89% on pathological images. A comparison of these results with the existing methodologies is also reported. This methodology can help ophthalmologists in better and faster analysis and hence early treatment to the patients.

  8. Simultaneous macula detection and optic disc boundary segmentation in retinal fundus images

    Science.gov (United States)

    Girard, Fantin; Kavalec, Conrad; Grenier, Sébastien; Ben Tahar, Houssem; Cheriet, Farida

    2016-03-01

    The optic disc (OD) and the macula are important structures in automatic diagnosis of most retinal diseases inducing vision defects such as glaucoma, diabetic or hypertensive retinopathy and age-related macular degeneration. We propose a new method to detect simultaneously the macula and the OD boundary. First, the color fundus images are processed to compute several maps highlighting the different anatomical structures such as vessels, the macula and the OD. Then, macula candidates and OD candidates are found simultaneously and independently using seed detectors identified on the corresponding maps. After selecting a set of macula/OD pairs, the top candidates are sent to the OD segmentation method. The segmentation method is based on local K-means applied to color coordinates in polar space followed by a polynomial fitting regularization step. Pair scores are updated, resulting in the final best macula/OD pair. The method was evaluated on two public image databases: ONHSD and MESSIDOR. The results show an overlapping area of 0.84 on ONHSD and 0.90 on MESSIDOR, which is better than recent state of the art methods. Our segmentation method is robust to contrast and illumination problems and outputs the exact boundary of the OD, not just a circular or elliptical model. The macula detection has an accuracy of 94%, which again outperforms other macula detection methods. This shows that combining the OD and macula detections improves the overall accuracy. The computation time for the whole process is 6.4 seconds, which is faster than other methods in the literature.

  9. Influence of bilirubin and other antioxidants on nitrergic relaxation in the pig gastric fundus.

    Science.gov (United States)

    Colpaert, E E; Lefebvre, R A

    2000-03-01

    1. The influence of several antioxidants (bilirubin, urate, ascorbate, alpha-tocopherol, glutathione (GSH), Cu/Zn superoxide dismutase (SOD) and the manganese SOD mimic EUK-8) on nitrergic relaxations induced by either exogenous nitric oxide (NO; 10(-5) M) or electrical field stimulation (4 Hz; 10 s and 3 min) was studied in the pig gastric fundus. 2. Ascorbate (5x10(-4) M), alpha-tocopherol (4x10(-4) M), SOD (300 - 1000 u ml(-1)) and EUK-8 (3x10(-4) M) did not influence the relaxations to exogenous NO. In the presence of GSH (5x10(-4) M), the short-lasting relaxation to NO became biphasic, potentiated and prolonged. Urate (4x10(-4) M) and bilirubin (2x10(-4) M) also potentiated the relaxant effect of NO. None of the antioxidants influenced the electrically evoked relaxations. 3. 6-Anilino-5,8-quinolinedione (LY83583; 10(-5) M) had no influence on nitrergic nerve stimulation but nearly abolished the relaxant response to exogenous NO. Urate and GSH completely prevented this inhibitory effect, while it was partially reversed by SOD and bilirubin. Ascorbate, alpha-tocopherol and EUK-8 were without effect. 4. Hydroquinone (10(-4) M) did not affect the electrically induced nitrergic relaxations, but markedly reduced NO-induced relaxations. The inhibition of exogenous NO by hydroquinone was completely prevented by urate and GSH. SOD and ascorbate afforded partial protection, while bilirubin, EUK-8 and alpha-tocopherol were ineffective. 5. Hydroxocobalamin (10(-4) M) inhibited relaxations to NO by 50%, but not the electrically induced responses. Full protection versus this inhibitory effect was obtained with urate, GSH and alpha-tocopherol. 6. These results strengthen the hypothesis that several endogenous antioxidant defense mechanisms, enzymatic as well as non-enzymatic, might play a role in the nitrergic neurotransmission process.

  10. Detection of the optic disc in fundus images by combining probability models.

    Science.gov (United States)

    Harangi, Balazs; Hajdu, Andras

    2015-10-01

    In this paper, we propose a combination method for the automatic detection of the optic disc (OD) in fundus images based on ensembles of individual algorithms. We have studied and adapted some of the state-of-the-art OD detectors and finally organized them into a complex framework in order to maximize the accuracy of the localization of the OD. The detection of the OD can be considered as a single-object detection problem. This object can be localized with high accuracy by several algorithms extracting single candidates for the center of the OD and the final location can be defined using a single majority voting rule. To include more information to support the final decision, we can use member algorithms providing more candidates which can be ranked based on the confidence ordered by the algorithms. In this case, a spatial weighted graph is defined where the candidates are considered as its nodes, and the final OD position is determined in terms of finding a maximum-weighted clique. Now, we examine how to apply in our ensemble-based framework all the accessible information supplied by the member algorithms by making them return confidence values for each image pixel. These confidence values inform us about the probability that a given pixel is the center point of the object. We apply axiomatic and Bayesian approaches, as in the case of aggregation of judgments of experts in decision and risk analysis, to combine these confidence values. According to our experimental study, the accuracy of the localization of OD increases further. Besides single localization, this approach can be adapted for the precise detection of the boundary of the OD. Comparative experimental results are also given for several publicly available datasets.

  11. A longitudinal comparison of spectral-domain optical coherence tomography and fundus autofluorescence in geographic atrophy.

    Science.gov (United States)

    Simader, Christian; Sayegh, Ramzi G; Montuoro, Alessio; Azhary, Malek; Koth, Anna Lucia; Baratsits, Magdalena; Sacu, Stefan; Prünte, Christian; Kreil, David P; Schmidt-Erfurth, Ursula

    2014-09-01

    To identify reliable criteria based on spectral-domain optical coherence tomography (SD OCT) to monitor disease progression in geographic atrophy attributable to age-related macular degeneration (AMD) compared with lesion size determination based on fundus autofluorescence (FAF). Prospective longitudinal observational study. setting: Institutional. study population: A total of 48 eyes in 24 patients with geographic atrophy. observation procedures: Eyes with geographic atrophy were included and examined at baseline and at months 3, 6, 9, and 12. At each study visit best-corrected visual acuity (BCVA), FAF, and SD OCT imaging were performed. FAF images were analyzed using the region overlay device. Planimetric measurements in SD OCT, including alterations or loss of outer retinal layers and the RPE, as well as choroidal signal enhancement, were performed with the OCT Toolkit. main outcome measures: Areas of interest in patients with geographic atrophy measured from baseline to month 12 by SD OCT compared with the area of atrophy measured by FAF. Geographic atrophy lesion size increased from 8.88 mm² to 11.22 mm² based on quantitative FAF evaluation. Linear regression analysis demonstrated that results similar to FAF planimetry for determining lesion progression can be obtained by measuring the areas of outer plexiform layer thinning (adjusted R(2) = 0.93), external limiting membrane loss (adjusted R(2) = 0.89), or choroidal signal enhancement (R(2) = 0.93) by SD OCT. SD OCT allows morphologic markers of disease progression to be identified in geographic atrophy and may improve understanding of the pathophysiology of atrophic AMD. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Supervised pixel classification for segmenting geographic atrophy in fundus autofluorescene images

    Science.gov (United States)

    Hu, Zhihong; Medioni, Gerard G.; Hernandez, Matthias; Sadda, SriniVas R.

    2014-03-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in people over the age of 65. Geographic atrophy (GA) is a manifestation of the advanced or late-stage of the AMD, which may result in severe vision loss and blindness. Techniques to rapidly and precisely detect and quantify GA lesions would appear to be of important value in advancing the understanding of the pathogenesis of GA and the management of GA progression. The purpose of this study is to develop an automated supervised pixel classification approach for segmenting GA including uni-focal and multi-focal patches in fundus autofluorescene (FAF) images. The image features include region wise intensity (mean and variance) measures, gray level co-occurrence matrix measures (angular second moment, entropy, and inverse difference moment), and Gaussian filter banks. A k-nearest-neighbor (k-NN) pixel classifier is applied to obtain a GA probability map, representing the likelihood that the image pixel belongs to GA. A voting binary iterative hole filling filter is then applied to fill in the small holes. Sixteen randomly chosen FAF images were obtained from sixteen subjects with GA. The algorithm-defined GA regions are compared with manual delineation performed by certified graders. Two-fold cross-validation is applied for the evaluation of the classification performance. The mean Dice similarity coefficients (DSC) between the algorithm- and manually-defined GA regions are 0.84 +/- 0.06 for one test and 0.83 +/- 0.07 for the other test and the area correlations between them are 0.99 (p < 0.05) and 0.94 (p < 0.05) respectively.

  13. Digital printing

    Science.gov (United States)

    Sobotka, Werner K.

    1997-02-01

    Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

  14. Digital displacements

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co...

  15. Digital Libraries

    CERN Document Server

    Papy, Fabrice

    2008-01-01

    Of vital interest to all librarians and information specialists, this book presents all aspects of the effects of digitization of today's and tomorrow's libraries. From social to technical issues, Digital Libraries includes chapters on the growth of the role of librarian, the reader experience, cataloging, search engines, OPAC, law, ergonomic studies, and the future of libraries.

  16. Digital Audiobooks:

    DEFF Research Database (Denmark)

    Have, Iben; Pedersen, Birgitte Stougaard

    Audiobooks are rapidly gaining popularity with widely accessible digital downloading and streaming services. The paper is framing how the digital audiobook expands and changes the target groups for book publications and how it as an everyday activity is creating new reading experiences, places...

  17. Pengaruh Senam Nifas terhadap Penurunan Tinggi Fundus Uteri pada Ibu Post Partum di RSUP DR. M. Djamil Padang

    Directory of Open Access Journals (Sweden)

    Nurniati Tianastia Rullynil

    2014-09-01

    Full Text Available AbstrakPerdarahan merupakan penyebab utama kesakitan dan kematian ibu pada masa nifas, dimana 50%-60% karena kegagalan miometrium berkontraksi secara sempurna. Salah satu asuhan untuk memaksimalkan kontraksi uterus pada masa nifas adalah dengan melaksanakan senam nifas, guna mempercepat proses involusi uteri. Tujuan penelitian ini adalah untuk mengetahui pengaruh senam nifas terhadap penurunan tinggi fundus uteri (TFU pada ibu post partum. Penelitian ini merupakan studi eksperimental dengan Post Test Only Control Group Design. Alat yang digunakan dalam penelitian berupa kaliper pelvimetri. Diberikan perlakuan senam nifas pada kelompok intervensi dan tidak senam nifas pada kelompok kontrol, kemudian dilakukan pengukuran tinggi fundus uteri hari ke-1, hari ke-3 dan hari ke-6. Data dianalisa menggunakan Uji General Linier Model (GLM. Rerata TFU hari ke-1 pada kelompok intervensi 12,37±0,72 dan 12,42±0,54 pada kelompok kontrol. Rerata TFU hari ke-3 pada kelompok intervensi 9,00±0,94 dan 9,87±0,75 pada kelompok kontrol. Sedangkan rerata TFU hari ke-6 pada kelompok intervensi 5,72±0,88 dan 7,37±0,68 pada kelompok kontrol. Terdapat perbedaan yang signifikan penurunan tinggi fundus uteri antara kedua kelompok pada hari ke-3 (p=0,00 dan hari ke 6 (p=0,00. Dari hasil penelitian dapat disimpulkan bahwa senam nifas berpengaruh terhadap penurunan tinggi fundus uteri. Penurunan tinggi fundus uteri pada kelompok intervensi lebih turun dibanding kelompok kontrol.Kata kunci: senam nifas, tinggi fundus uteri, post partumAbstractHemorrhage is a major cause of maternal morbidity and mortality in the puerperium, about 50%-60% of hemorrhage occurs due to failure of myometrium to contract completely. One care to maximaze uterine contraction during the puerperium is by implementing parturition gymnastics in order to accelarate the process of uterine involution. The purpose of this study was to determine the effect of parturition gymnastics on a decreasing of

  18. 眼底荧光血管造影的护理体会%Nursing experience of fundus fluorescein angiography

    Institute of Scientific and Technical Information of China (English)

    王宝霞

    2014-01-01

    目的:探讨眼底荧光造影检查的护理方法及意义。方法:收治眼底荧光造影检查患者178例,做好造影前的准备,造影中的配合,及造影后采取相应的护理措施,为造影检查术正常实施创造有利条件。结果:本组患者在正确的护理配合下均顺利的完成眼底荧光造影检查,未发生一例严重不良反应。结论:全面正确及时的护理配合可预防和减少不良反应的发生,并可使检查获得最佳效果。%Objective:To explore the nursing methods and significance of fundus fluorescein angiography.Methods:178 patients with fundus fluorescein angiography were selected.We made good preparation before radiography,coordination in radiography, corresponding nursing measures after radiography,in order to create favorable conditions for the implementation of the normal angiography.Results:In this group,in line with the correct nursing,all patients were successfully completed the fundus fluorescein angiography,and there was no serious adverse reaction.Conclusion:A comprehensive,correct,timely nursing cooperation can prevent and reduce the occurrence of adverse reactions,and can make the examination to obtain the best results.

  19. Detailed Morphological Changes of Foveoschisis in Patient with X-Linked Retinoschisis Detected by SD-OCT and Adaptive Optics Fundus Camera

    Directory of Open Access Journals (Sweden)

    Keiichiro Akeo

    2015-01-01

    Full Text Available Purpose. To report the morphological and functional changes associated with a regression of foveoschisis in a patient with X-linked retinoschisis (XLRS. Methods. A 42-year-old man with XLRS underwent genetic analysis and detailed ophthalmic examinations. Functional assessments included best-corrected visual acuity (BCVA, full-field electroretinograms (ERGs, and multifocal ERGs (mfERGs. Morphological assessments included fundus photography, spectral-domain optical coherence tomography (SD-OCT, and adaptive optics (AO fundus imaging. After the baseline clinical data were obtained, topical dorzolamide was applied to the patient. The patient was followed for 24 months. Results. A reported RS1 gene mutation was found (P203L in the patient. At the baseline, his decimal BCVA was 0.15 in the right and 0.3 in the left eye. Fundus photographs showed bilateral spoke wheel-appearing maculopathy. SD-OCT confirmed the foveoschisis in the left eye. The AO images of the left eye showed spoke wheel retinal folds, and the folds were thinner than those in fundus photographs. During the follow-up period, the foveal thickness in the SD-OCT images and the number of retinal folds in the AO images were reduced. Conclusions. We have presented the detailed morphological changes of foveoschisis in a patient with XLRS detected by SD-OCT and AO fundus camera. However, the findings do not indicate whether the changes were influenced by topical dorzolamide or the natural history.

  20. Nerve canals at the fundus of the internal auditory canal on high-resolution temporal bone CT

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yoon Ha; Youn, Eun Kyung; Kim, Seung Chul [Sungkyunkwan Univ., School of Medicine, Seoul (Korea, Republic of)

    2001-12-01

    To identify and evaluate the normal anatomy of nerve canals in the fundus of the internal auditory canal which can be visualized on high-resolution temporal bone CT. We retrospectively reviewed high-resolution (1 mm thickness and interval contiguous scan) temporal bone CT images of 253 ears in 150 patients who had not suffered trauma or undergone surgery. Those with a history of uncomplicated inflammatory disease were included, but those with symptoms of vertigo, sensorineural hearing loss, or facial nerve palsy were excluded. Three radiologists determined the detectability and location of canals for the labyrinthine segment of the facial, superior vestibular and cochlear nerve, and the saccular branch and posterior ampullary nerve of the inferior vestibular nerve. Five bony canals in the fundus of the internal auditory canal were identified as nerve canals. Four canals were identified on axial CT images in 100% of cases; the so-called singular canal was identified in only 68%. On coronal CT images, canals for the labyrinthine segment of the facial and superior vestibular nerve were seen in 100% of cases, but those for the cochlear nerve, the saccular branch of the inferior vestibular nerve, and the singular canal were seen in 90.1%, 87.4% and 78% of cases, respectiveIy. In all detectable cases, the canal for the labyrinthine segment of the facial nerve was revealed as one which traversed anterolateralIy, from the anterosuperior portion of the fundus of the internal auditory canal. The canal for the cochlear nerve was located just below that for the labyrinthine segment of the facial nerve, while that canal for the superior vestibular nerve was seen at the posterior aspect of these two canals. The canal for the saccular branch of the inferior vestibular nerve was located just below the canal for the superior vestibular nerve, and that for the posterior ampullary nerve, the so-called singular canal, ran laterally or posteolateralIy from the posteroinferior aspect of

  1. Fundus fluorescein angiographic findings in patients who underwent ventricular assist device implantation.

    Science.gov (United States)

    Ozturk, Taylan; Nalcaci, Serhad; Ozturk, Pelin; Engin, Cagatay; Yagdi, Tahir; Akkin, Cezmi; Ozbaran, Mustafa

    2013-09-01

    Disruption of microcirculation in various tissues as a result of deformed blood rheology due to ventricular assist device (VAD) implantation causes novel arteriovenous malformations. Capillary disturbances and related vascular leakage in the retina and choroidea may also be seen in patients supported by VADs. We aimed to evaluate retinal vasculature deteriorations after VAD implantation. The charts of 17 patients who underwent VAD implantation surgery for the treatment of end-stage heart failure were retrospectively reviewed. Eight cases (47.1%) underwent pulsatile pump implantation (Berlin Heart EXCOR, Berlin Heart Mediprodukt GmbH, Berlin, Germany); however, nine cases (52.9%) had continuous-flow pump using centrifugal design (HeartWare, HeartWare Inc., Miramar, FL, USA). Study participants were selected among the patients who had survived with a VAD for at least 6 months, and results of detailed ophthalmologic examinations including optic coherence tomography (OCT) and fundus fluorescein angiography (FA) were documented. All of the 17 patients were male, with a mean age of 48.5 ± 14.8 years (15-67 years). Detailed ophthalmologic examinations including the evaluation of retinal vascular deteriorations via FA were performed at a mean of 11.8 ± 3.7 months of follow-up (6-18 months). Mean best-corrected visual acuity and intraocular pressure were found as logMAR 0.02 ± 0.08 and 14.6 ± 1.9 mm Hg, respectively in the study population. Dilated fundoscopy revealed severe focal arteriolar narrowing in two patients (11.8%), and arteriovenous crossing changes in four patients (23.5%); however, no pathological alteration was present in macular OCT scans. In patients with continuous-flow blood pumps, mean arm-retina circulation time (ARCT) and arteriovenous transit time (AVTT) were found to be 16.8 ± 3.0 and 12.4 ± 6.2 s, respectively; whereas those with pulsatile-flow blood pumps were found to be 17.4 ± 3.6 and 14.0 ± 2.1 s in patients (P=0.526 and P=0

  2. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    . With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills.......Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media...

  3. Digital holography

    CERN Document Server

    Picart, Pascal

    2013-01-01

    This book presents a substantial description of the principles and applications of digital holography.The first part of the book deals with mathematical basics and the linear filtering theory necessary to approach the topic. The next part describes the fundamentals of diffraction theory and exhaustively details the numerical computation of diffracted fields using FFT algorithms. A thorough presentation of the principles of holography and digital holography, including digital color holography, is proposed in the third part.A special section is devoted to the algorithms and method

  4. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  5. DIGITAL ASSESSMENTS

    OpenAIRE

    Nielsen, Kurt Gammelgaard; Petersen, Lise

    2013-01-01

    In accordance with The Danish eGOVERNMENT strategy 2011-2015 digital assessment and exam should be implemented at all Danish universities by the end of 2013. University of Southern Denmark (SDU) decided to start the implementation in May 2010.By the exam term of January 2013, the implementation proved successful, and close to completion. The majority of assessments at all of the 5 faculties and 5 campuses were digital, and students had handed in a total of 17.021 digital assessments.On the ba...

  6. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media....... With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills....

  7. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising......, by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research...

  8. Digital fabrication

    CERN Document Server

    2012-01-01

    The Winter 2012 (vol. 14 no. 3) issue of the Nexus Network Journal features seven original papers dedicated to the theme “Digital Fabrication”. Digital fabrication is changing architecture in fundamental ways in every phase, from concept to artifact. Projects growing out of research in digital fabrication are dependent on software that is entirely surface-oriented in its underlying mathematics. Decisions made during design, prototyping, fabrication and assembly rely on codes, scripts, parameters, operating systems and software, creating the need for teams with multidisciplinary expertise and different skills, from IT to architecture, design, material engineering, and mathematics, among others The papers grew out of a Lisbon symposium hosted by the ISCTE-Instituto Universitario de Lisboa entitled “Digital Fabrication – A State of the Art”. The issue is completed with four other research papers which address different mathematical instruments applied to architecture, including geometric tracing system...

  9. Digital Humanities

    DEFF Research Database (Denmark)

    Brügger, Niels

    2016-01-01

    the humanities for decades, starting with research fields such as humanities computing or computational linguistics in the 1950s, and later new media studies and internet studies. The historical development of digital humanities has been characterized by a focus on three successive, but co-existing types......Digital humanities is an umbrella term for theories, methodologies, and practices related to humanities scholarship that use the digital computer as an integrated and essential part of its research and teaching activities. The computer can be used for establishing, finding, collecting......, and preserving material to study, as an object of study in its own right, as an analytical tool, or for collaborating, and for disseminating results. The term "digital humanities" was coined around 2001, and gained currency within academia in the following years. However, computers had been used within...

  10. Digital Snaps

    DEFF Research Database (Denmark)

    Sandbye, Mette; Larsen, Jonas

    The New Face of Snapshot Photography / Jonas Larsen and Mette Sandbye -- pt. I. IMAGES ON WEB 2.0 AND THE CAMERA PHONE -- ch. 1. Overlooking, Rarely Looking and Not Looking / Martin Lister -- ch. 2. The (Im)mobile Life of Digital Photographs: The Case of Tourist Photography / Jonas Larsen -- ch. 3....... Distance as the New Punctum / Mikko Villi -- pt. II. FAMILY ALBUMS IN TRANSITION -- ch. 4. How Digital Technologies Do Family Snaps, Only Better / Gillian Rose -- ch. 5. Friendship Photography: Memory, Mobility and Social Networking / Joanne Garde-Hansen -- ch. 6. Play, Process and Materiality in Japanese...... Purikura Photography / Mette Sandbye -- ch. 7. 'Buying an Instrument Does Not Necessarily Make You a Musician': Studio Photography and the Digital Revolution / Sigrid Lien -- pt. III. NEW PUBLIC FORMS -- ch. 8 Paparazzi Photography, Seriality and the Digital Photo Archive / Anne Jerslev and Mette Mortensen...

  11. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    The purpose of this paper is to examine the impact of e-government reforms on street-level bureaucrats’ professionalism and relation to citizens, thus demonstrating how the bureaucratic encounter unfolds in the digital era. Design/methodology/approach: The paper is based on an ethnographic study....... An ethnographic account of how digital reforms are implemented in practice shows how street-level bureaucrat’s classic tasks such as specialized casework are being reconfigured into educational tasks that promote the idea of “becoming digital”. In the paper, the author argues that the work of “becoming digital....... Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...

  12. Effect of indomethacin on electrical field stimulation-induced contractions of isolated transverse and longitudinal rat gastric fundus strips

    Institute of Scientific and Technical Information of China (English)

    Salimeh Afshin; Mansoor Keshavarz; Mahmood Salami; Fatemeh Mirershadi; Bijan Djahanguiri

    2005-01-01

    AIM: To study the effects of indomethacin on the isolated transverse and longitudinal rat gastric fundus strips.METHODS: The strips were suspended in an organ bath containing oxygenated Krebs solution, and contractile responses to electrical field stimulation were recorded on a physiograph in an isotonic manner after administration of cumulative concentrations of indomethacin. The effects of indomethacin on the strips pretreated with KATP channel modulators, diazoxide and glybenclamide were studied.RESULTS: Treatment of the transverse strips with indomethacin resulted in a concentration-dependent inhibitory response. In longitudinal strips, biphasic responses were seen, which included a stimulatory response at low concentrations of indomethacin, followed by an inhibitory response at higher concentrations.Diazoxide pre-treatment inhibited the stimulatory response of longitudinal strips. Glybenclamide pre-treatment not only blocked inhibitory effect of the low concentrations of indomethacin on transverse strips, but also increased the amplitude of contractions. Moreover, the drug decreased the amplitude of contractions in longitudinal strips.CONCLUSION: Responses of the isolated longitudinal and transverse rat gastric fundus strips to indomethacin are not similar, and are influenced by KATP channel modulators.

  13. A gene for late-onset fundus flavimaculatus with macular dystrophy maps to chromosome 1p13

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, S.; Rozet, J.M.; Bonneau, D.; Souied, E.; Camuzat, A.; Munnich, A.; Kaplan, J. [Hopital des Enfants Malades, Paris (France); Dufier, J.L. [Hopital Laeennec, Paris (France); Amalric, P. [Consultation d`Ophtalmologie, Albi (France); Weissenbach, J. [Genethon, Evry (France)

    1995-02-01

    Fundus flavimaculatus with macular dystrophy is an autosomal recessive disease responsible for a progressive loss of visual acuity in adulthood, with pigmentary changes of the macula, perimacular flecks, and atrophy of the retinal pigmentary epithelium. Since this condition shares several clinical features with Stargardt disease, which has been mapped to chromosome 1p21-p13, we tested the disease for linkage to chromosome 1p. We report the mapping of the disease locus to chromosome 1p13-p21, in the genetic interval defined by loci D1S435 and D1S415, in four multiplex families (maximum lod score 4.79 at recombination fraction 0 for probe AFM217xb2 at locus D1S435). Thus, despite differences in the age at onset, clinical course, and severity, fundus flavimaculatus with macular dystrophy and Stargardt disease are probably allelic disorders. This result supports the view that allelic mutations produce a continuum of macular dystrophies, with onset in early childhood to late adulthood. 16 refs., 3 figs., 1 tab.

  14. Endomorphins 1 and 2 reduce relaxant non-adrenergic, non-cholinergic neurotransmission in rat gastric fundus.

    Science.gov (United States)

    Storr, M; Gaffal, E; Schusdziarra, V; Allescher, H-D

    2002-06-14

    It is now well established that opioids modulate cholinergic excitatory neurotransmission in the gastrointestinal tract. The aim of the present study was to characterize a possible effect of endomorphins on nonadrenergic, noncholinergic (NANC) relaxant neurotransmission in the rat gastric fundus in vitro. The drugs used in the experiments were the endogenous mu-opioid receptors (MORs) endomorphin 1 and 2 and the mu-opioid receptor antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2). CTAP left the basal tonus and the spontaneous activity of the preparation unchanged. Electrical field stimulation (EFS) under NANC conditions at frequencies ranging from 0.5 to 16 Hz caused a frequency-dependent relaxant response on the 5-hydoxytryptamine (5-HT) (10(-7) M) precontracted smooth-muscle strip. Both endomorphin 1 and endomorphin 2 significantly reduced this relaxation in a concentration-dependent manner. Endomorphin 1 proved to be more potent in reducing the relaxant responses. The endomorphin effects were significantly reversed by the MOR antagonist CTAP. CTAP itself did not influence the EFS-induced relaxation. In summary, these data provide evidence that the endogenous MOR agonists endomorphin 1 and 2 can reduce nonadrenergic, noncholinergic neurotransmission in the rat gastric fundus smooth muscle via a pathway involving MORs. The physiological relevance of these findings remains to be established, since the data presented suggest that the endomorphins act as neuromodulators within NANC relaxant neurotransmission.

  15. Detection of Hard Exudates in Colour Fundus Images Using Fuzzy Support Vector Machine-Based Expert System.

    Science.gov (United States)

    Jaya, T; Dheeba, J; Singh, N Albert

    2015-12-01

    Diabetic retinopathy is a major cause of vision loss in diabetic patients. Currently, there is a need for making decisions using intelligent computer algorithms when screening a large volume of data. This paper presents an expert decision-making system designed using a fuzzy support vector machine (FSVM) classifier to detect hard exudates in fundus images. The optic discs in the colour fundus images are segmented to avoid false alarms using morphological operations and based on circular Hough transform. To discriminate between the exudates and the non-exudates pixels, colour and texture features are extracted from the images. These features are given as input to the FSVM classifier. The classifier analysed 200 retinal images collected from diabetic retinopathy screening programmes. The tests made on the retinal images show that the proposed detection system has better discriminating power than the conventional support vector machine. With the best combination of FSVM and features sets, the area under the receiver operating characteristic curve reached 0.9606, which corresponds to a sensitivity of 94.1% with a specificity of 90.0%. The results suggest that detecting hard exudates using FSVM contribute to computer-assisted detection of diabetic retinopathy and as a decision support system for ophthalmologists.

  16. Changes of fundus blood flow state of patients with open-angle glaucoma before and after the treatment

    Institute of Scientific and Technical Information of China (English)

    Huai-Jie Huang; Mei-Min Niu; Yi Yang; Ke-Qin Li

    2016-01-01

    Objective:To To study and observe the change situation of fundus blood flow state of patients with open-angle glaucoma before and after the treatment.Methods:A total of 60 patients with open-angle glaucoma treated in our hospital from October 2013 to May 2015 were selected as the observation group, and 60 healthy persons with physical examination at the same period were the control group, then the RI, PI, PSV, EDV and VM levels of ocular artery, central retinal artery and posterior ciliary artery of observation group before the treatment and at 2th, 4th, 8th and 12th week after the treatment and control group were compared.Results:The RI and PI levels of ocular artery, central retinal artery and posterior ciliary artery of observation group before the treatment and at 2th, 4th and 8th week after the treatment were higher than those of control group, while the PSV, EDV and VM levels of ocular artery, central retinal artery and posterior ciliary artery were lower than those of control group. The detection results of observation group at different time after the treatment were better than those before the treatment, and there were significant differences (P0.05).Conclusions:The changes of fundus blood flow state of patients with open-angle glaucoma before and after the treatment are great, and the various artery blood flow presents continuous improvement.

  17. Clinical Analysis of Pregnancy-induced Hypertension Disease Fundus Lesions%妊娠高血压疾病眼底病变临床分析

    Institute of Scientific and Technical Information of China (English)

    周秋云

    2015-01-01

    目的:分析妊娠高血压疾病眼底病变检查重要作用。方法选取从2014年7月~2015年7月收治的60例妊娠高血压综合征,分析其眼底病变与妊娠高血压关系。结果本组60例患者中,56例眼底病变,占93.33%;4例眼底正常,占6.67%。妊娠高血压综合征病程越长发生视网膜病变概率也就越高,17例病程>31 d,16例眼底病变(94.12%)。结论眼底检查操作方便,可为妊娠高血压综合征诊断提供参考依据。%Objective To analyze the pregnancy hypertension disease check important role in fundus lesions. Methods From July 2014 to July 2015, 60 cases of pregnancy-induced hypertension syndrome were analyze its fundus lesions relationship with gestational hypertension. Results 60 cases patients, 56 cases of fundus lesions, accounted for 93.33%; Normal fundus, 4 cases (6.67%). Pregnancy-induced hypertension syndrome, the longer the duration the higher the occurrence probability of retinopathy, 17 cases of course > 31 d, 16 cases of fundus lesions (94.12%). Conclusion The fundus examination is easy to operate, can provide the reference for diagnosis of pregnancy-induced hypertension syndrome.

  18. Digital Steganography

    OpenAIRE

    KOCIÁNOVÁ, Helena

    2009-01-01

    Digital steganography is a technique for hiding data mostly into multimedia files (images, audio, video). With the development of information technology this technique has found its use in the field of copyright protection and secret data transfer, could be even applied in places where is limited possibility of using cryptography (e. g. by law). This thesis gives insight into digital steganography and contains an application using this technique.

  19. Digital watermark

    OpenAIRE

    Jasna Maver

    2004-01-01

    The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to diffe...

  20. Digital Humanities and networked digital media

    OpenAIRE

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no ...

  1. Digital watermark

    Directory of Open Access Journals (Sweden)

    Jasna Maver

    2000-01-01

    Full Text Available The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to different criteria. A digital watermark can be categorised as visible or invisible and as robust or fragile. In contrast to the visible watermark where a visible pattern or image is embedded into the original image, the invisible watermark does not change the visual appearance of the image. The existence of such a watermark can be determined only through a watermark ex¬traction or detection algorithm. The robust watermark is used for copyright protection, while the fragile watermark is designed for authentication and integrity verification of multimedia content. A watermark must be detectable or extractable to be useful. In some watermarking schemes, a watermark can be extracted in its exact form, in other cases, we can detect only whether a specific given watermarking signal is present in an image. Digital libraries, through which cultural institutions will make multimedia contents available, should support a wide range of service models for intellectual property protection, where digital watermarking may play an important role.

  2. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  3. Digital Relationships

    DEFF Research Database (Denmark)

    Ledborg Hansen, Richard

    -­‐Jones, 2011) for increases in effectiveness and efficiency we indiscriminately embrace digital communication and digitized information dissemination with enthusiasm – at the risk of ignoring the potentially dark side of technology. However, technology also holds a promise for better understanding precisely...... of residual deposits from technology in organizations and its effect on individuals ability to connect to one another. Based on the case study the paper describes indications and suggests potential implication hereof. Given the inherent enhancement possibilities of technology our expectation for entertainment......-­rich information and highly interesting communication are sky-­high and rising. With a continuous increase in digitized communication follows a decrease in face-­to-­face encounters and our ability to engage in inter-­personal relationships are suffering for it (Davis, 2013). The behavior described in this paper...

  4. Digital Creativity

    DEFF Research Database (Denmark)

    Petersson Brooks, Eva; Brooks, Anthony Lewis

    2014-01-01

    This paper reports on a study exploring the outcomes from children’s play with technology in early childhood learning practices. The paper addresses questions related to how digital technology can foster creativity in early childhood learning environments. It consists of an analysis of children......’s interaction with the KidSmart furniture focusing on digital creativity potentials and play values suggested by the technology. The study applied a qualitative approach and included125 children (aged three to five), 10 pedagogues, and two librarians. The results suggests that educators should sensitively...... consider intervening when children are interacting with technology, and rather put emphasize into the integration of the technology into the environment and to the curriculum in order to shape playful structures for children’s digital creativity....

  5. Fotografia digital

    OpenAIRE

    Vinicius Cauduro, Flávio; Pontifícia Universidade Católica do Rio Grande do Sul

    2008-01-01

    Poderíamos talvez definir como sendo fotografia digital toda e qualquer imagem obtida a partir de uma camera obscura, com características ótico-mecânicas variáveis através de princípios puramente analógicos ou por combinação híbrida (analógico/digital), e que seja posteriormente processada em computador e exibida de forma projetada (monitor ou tela) ou imprensa (papel ou filme).

  6. Digital photogrammetry

    CERN Document Server

    Egels, Yves

    2003-01-01

    Photogrammetry is the use of photography for surveying primarily and is used for the production of maps from aerial photographs. Along with remote sensing, it represents the primary means of generating data for Geographic Information Systems (GIS). As technology develops, it is becoming easier to gain access to it. The cost of digital photogrammetric workstations are falling quickly and these new tools are therefore becoming accessible to more and more users. Digital Photogrammetry is particularly useful as a text for graduate students in geomantic and is also suitable for people with a good basic scientific knowledge who need to understand photogrammetry, and who wish to use the book as a reference.

  7. Digital literacies

    CERN Document Server

    Hockly, Nicky; Pegrum, Mark

    2014-01-01

    Dramatic shifts in our communication landscape have made it crucial for language teaching to go beyond print literacy and encompass the digital literacies which are increasingly central to learners' personal, social, educational and professional lives. By situating these digital literacies within a clear theoretical framework, this book provides educators and students alike with not just the background for a deeper understanding of these key 21st-century skills, but also the rationale for integrating these skills into classroom practice. This is the first methodology book to address not jus

  8. Digital communication

    CERN Document Server

    Das, Apurba

    2010-01-01

    ""Digital Communications"" presents the theory and application of the philosophy of Digital Communication systems in a unique but lucid form. This book inserts equal importance to the theory and application aspect of the subject whereby the authors selected a wide class of problems. The Salient features of the book are: the foundation of Fourier series, Transform and wavelets are introduces in a unique way but in lucid language; the application area is rich and resemblance to the present trend of research, as we are attached with those areas professionally; a CD is included which contains code

  9. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  10. Harvesting the weak angular reflections from the fundus of the human eye : on measuring and analyzing the light wasted by the retina

    NARCIS (Netherlands)

    Kraats, J. van der

    2007-01-01

    Summary of the thesis “Harvesting the weak angular reflections from the fundus of the human eye” by Jan van de Kraats University Medical Centre Utrecht. Defended October 16, 2007. This thesis is on the modeling of the optical reflection of the human fovea, and on the three instruments build for

  11. Nonmydriatic ultra-wide-field scanning laser ophthalmoscopy (Optomap) versus two-field fundus photography in diabetic retinopathy.

    Science.gov (United States)

    Liegl, Raffael; Liegl, Kristine; Ceklic, Lala; Haritoglou, Christos; Kampik, Anselm; Ulbig, Michael W; Kernt, Marcus; Neubauer, Aljoscha S

    2014-01-01

    The purpose of this study was to investigate the diagnostic properties of a 2-laser wavelength nonmydriatic 200° ultra-wide-field scanning laser ophthalmoscope (SLO) versus mydriatic 2-field 45° color fundus photography (EURODIAB standard) for assessing diabetic retinopathy (DR). A total of 143 consecutive eyes of patients with different levels of DR were graded regarding DR level and macular edema based on 2-field color photographs or 1 Optomap Panoramic 200 SLO image. All SLO images were nonmydriatic and all photographs mydriatic. Grading was performed masked to patient and clinical data. Based on photography, 20 eyes had no DR, 44 had mild, 18 moderate and 42 severe nonproliferative DR, and 19 eyes had proliferative DR. Overall correlation for grading DR level compared to Optomap SLO was moderate with kappa 0.54 (p photography need to be confirmed in further studies.

  12. Digitalization Boosting Novel Digital Services for Consumers

    Directory of Open Access Journals (Sweden)

    Kaisa Vehmas

    Full Text Available Digitalization has changed the world. The digital revolution has promoted the Internet, and more recently mobile network infrastructure, as the technological backbone of our society. Digital technologies have become more integrated across all sectors of o ...

  13. Correlation between peripapillary retinal nerve fiber layer thickness and fundus autofluorescence in primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Reznicek L

    2013-09-01

    Full Text Available Lukas Reznicek,* Florian Seidensticker,* Thomas Mann, Irene Hübert, Alexandra Buerger, Christos Haritoglou, Aljoscha S Neubauer, Anselm Kampik, Christoph Hirneiss, Marcus Kernt Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany *These authors contributed equally to this work Purpose: To investigate the relationship between retinal nerve fiber layer (RNFL thickness and retinal pigment epithelium alterations in patients with advanced glaucomatous visual field defects. Methods: A consecutive, prospective series of 82 study eyes with primary open-angle glaucoma and advanced glaucomatous visual field defects were included in this study. All study participants underwent a full ophthalmic examination followed by visual field testing with standard automated perimetry as well as spectral-domain optical coherence tomography (SD-OCT for peripapillary RNFL thickness and Optos wide-field fundus autofluorescence (FAF images. A pattern grid with corresponding locations between functional visual field sectors and structural peripapillary RNFL thickness was aligned to the FAF images at corresponding location. Mean FAF intensity (range: 0 = black and 255 = white of each evaluated sector (superotemporal, temporal, inferotemporal, inferonasal, nasal, superonasal was correlated with the corresponding peripapillary RNFL thickness obtained with SD-OCT. Results: Correlation analyses between sectoral RNFL thickness and standardized FAF intensity in the corresponding topographic retina segments revealed partly significant correlations with correlation coefficients ranging between 0.004 and 0.376 and were statistically significant in the temporal inferior central field (r = 0.324, P = 0.036 and the nasal field (r = 0.376, P = 0.014. Conclusion: Retinal pigment epithelium abnormalities correlate with corresponding peripapillary RNFL damage, especially in the temporal inferior sector of patients with advanced glaucomatous visual field defects. A

  14. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

    Science.gov (United States)

    Werkmeister, René M.; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A.; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

    2014-10-01

    A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%;. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats.

  15. Analysis of fundus shape in highly myopic eyes by using curvature maps constructed from optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Masahiro Miyake

    Full Text Available PURPOSE: To evaluate fundus shape in highly myopic eyes using color maps created through optical coherence tomography (OCT image analysis. METHODS: We retrospectively evaluated 182 highly myopic eyes from 113 patients. After obtaining 12 lines of 9-mm radial OCT scans with the fovea at the center, the Bruch's membrane line was plotted and its curvature was measured at 1-µm intervals in each image, which was reflected as a color topography map. For the quantitative analysis of the eye shape, mean absolute curvature and variance of curvature were calculated. RESULTS: The color maps allowed staphyloma visualization as a ring of green color at the edge and as that of orange-red color at the bottom. Analyses of mean and variance of curvature revealed that eyes with myopic choroidal neovascularization tended to have relatively flat posterior poles with smooth surfaces, while eyes with chorioretinal atrophy exhibited a steep, curved shape with an undulated surface (P<0.001. Furthermore, eyes with staphylomas and those without clearly differed in terms of mean curvature and the variance of curvature: 98.4% of eyes with staphylomas had mean curvature ≥7.8×10-5 [1/µm] and variance of curvature ≥0.26×10-8 [1/µm]. CONCLUSIONS: We established a novel method to analyze posterior pole shape by using OCT images to construct curvature maps. Our quantitative analysis revealed that fundus shape is associated with myopic complications. These values were also effective in distinguishing eyes with staphylomas from those without. This tool for the quantitative evaluation of eye shape should facilitate future research of myopic complications.

  16. Evidence for a modulatory role of orexin A on the nitrergic neurotransmission in the mouse gastric fundus.

    Science.gov (United States)

    Baccari, Maria Caterina; Bani, Daniele; Calamai, Franco

    2009-04-10

    The presence of orexins and their receptors in the gastrointestinal tract supports a local action of these peptides. Aim of the present study was to investigate the effects of orexin A (OXA) on the relaxant responses of the mouse gastric fundus. Mechanical responses of gastric strips were recorded via force-displacement transducers. The presence of orexin receptors (OX-1R) was also evaluated by immunocytochemistry. In carbachol precontracted strips and in the presence of guanethidine, electrical field stimulation (EFS) elicited a fast inhibitory response that may be followed, at the highest stimulation frequencies employed, by a sustained relaxation. All relaxant responses were abolished by TTX. The fast response was abolished by the nitric oxide (NO) synthesis inhibitor l-NNA (2x10(-4) M) as well as by the guanylate cyclase inhibitor ODQ (1x10(-6) M). OXA (3x10(-7) M) greatly increased the amplitude of the EFS-induced fast relaxation without affecting the sustained one. OXA also potentiated the amplitude of the relaxant responses elicited by the ganglionic stimulating agent DMPP (1x10(-5) M), but had no effects on the direct smooth muscle relaxant responses elicited by papaverine (1x10(-5) M) or VIP (1x10(-7) M). In the presence of l-NNA, the response to DMPP was reduced in amplitude and no longer influenced by OXA. The OX1 receptor antagonist SB-334867 (1x10(-5) M) reduced the amplitude of the EFS-induced fast relaxation without influencing neither the sustained responses nor those to papaverine and VIP. Immunocytochemistry showed the presence of neurons that co-express neuronal nitric oxide synthase and OX-1R. These results indicate that, in mouse gastric fundus, OXA exerts a modulatory action at the postganglionic level on the nitrergic neurotransmission.

  17. Regional Image Features Model for Automatic Classification between Normal and Glaucoma in Fundus and Scanning Laser Ophthalmoscopy (SLO) Images.

    Science.gov (United States)

    Haleem, Muhammad Salman; Han, Liangxiu; Hemert, Jano van; Fleming, Alan; Pasquale, Louis R; Silva, Paolo S; Song, Brian J; Aiello, Lloyd Paul

    2016-06-01

    Glaucoma is one of the leading causes of blindness worldwide. There is no cure for glaucoma but detection at its earliest stage and subsequent treatment can aid patients to prevent blindness. Currently, optic disc and retinal imaging facilitates glaucoma detection but this method requires manual post-imaging modifications that are time-consuming and subjective to image assessment by human observers. Therefore, it is necessary to automate this process. In this work, we have first proposed a novel computer aided approach for automatic glaucoma detection based on Regional Image Features Model (RIFM) which can automatically perform classification between normal and glaucoma images on the basis of regional information. Different from all the existing methods, our approach can extract both geometric (e.g. morphometric properties) and non-geometric based properties (e.g. pixel appearance/intensity values, texture) from images and significantly increase the classification performance. Our proposed approach consists of three new major contributions including automatic localisation of optic disc, automatic segmentation of disc, and classification between normal and glaucoma based on geometric and non-geometric properties of different regions of an image. We have compared our method with existing approaches and tested it on both fundus and Scanning laser ophthalmoscopy (SLO) images. The experimental results show that our proposed approach outperforms the state-of-the-art approaches using either geometric or non-geometric properties. The overall glaucoma classification accuracy for fundus images is 94.4% and accuracy of detection of suspicion of glaucoma in SLO images is 93.9 %.

  18. Digital Methods

    NARCIS (Netherlands)

    Rogers, R.

    2013-01-01

    In Digital Methods, Richard Rogers proposes a methodological outlook for social and cultural scholarly research on the Web that seeks to move Internet research beyond the study of online culture. It is not a toolkit for Internet research, or operating instructions for a software package; it deals wi

  19. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  20. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  1. Digital radiography

    DEFF Research Database (Denmark)

    Precht, H; Gerke, O; Rosendahl, K

    2012-01-01

    BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults...

  2. Digital books.

    Science.gov (United States)

    Wink, Diane M

    2011-01-01

    In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes digital books.

  3. Digital forvaltning

    DEFF Research Database (Denmark)

    Remmen, Arne; Larsen, Torben; Mosgaard, Mette

    2004-01-01

    Større effektivitet, bedre service og mere demokrai er blot nogle af forventningerne til indførelse af digital forveltning i kommunerne. Kapitlet giver bland andet svar på spørgsmålene : Hvordan lever kommunerne op hertil i dagligdagen? hvilke virkemidler anvender de? Hvilke barrierer har der været...

  4. Digital Batteries

    Science.gov (United States)

    Hubler, Alfred

    2009-03-01

    The energy density in conventional capacitors is limited by sparking. We present nano-capacitor arrays, where - like in laser diodes and quantum wells [1] - quantization prevents dielectric breakthrough. We show that the energy density and the power/weight ratio are very high, possibly larger than in hydrogen [2]. Digital batteries are a potential clean energy source for cars, laptops, and mobile devices. The technology is related to flash drives. However, because of the high energy density, safety is a concern. Digital batteries can be easily and safely charged and discharged. In the discharged state they pose no danger. Even if a charged digital battery were to explode, it would produce no radioactive waste, no long-term radiation, and probably could be designed to produce no noxious chemicals. We discuss methodologies to prevent shorts and other measures to make digital batteries safe. [1] H. Higuraskh, A. Toriumi, F. Yamaguchi, K. Kawamura, A. Hubler, Correlation Tunnel Device, U. S. Patent No. 5,679,961 (1997) [2] Alfred Hubler, http://server10.how-why.com/blog/

  5. Fokus: Digital

    DEFF Research Database (Denmark)

    2014-01-01

    sammenhænge og fra forandrede distributionsformer. Dette betyder ændrede betingelser for både produktion og reception af kunstmusik og lydkunst. Med Digital tager vi udgangspunkt i fire komponisters meget forskellige bud på hvordan teknologien spiller en rolle i arbejdet. Juliana Hodkinson beskriver hvordan...

  6. 基底型胆囊腺肌增生症的影像学特征%Imaging features of fundus adenomyomatosis of the gallbladder

    Institute of Scientific and Technical Information of China (English)

    余迅; 王均庆; 于向荣; 孙屏

    2014-01-01

    Adenomyomatosis of the gallbladder (GAM) is an acquired,benign proliferative lesion of the gallbladder which is characterized by mucosal proliferation with invaginations and diverticula penetrating into the thickened muscular layer (Rokitansky-Aschoff sinuses).GAM consists of 3 types:diffuse,segmental and fundus GAM.There is no specific presentation of GAM,and computed tomography is helpful for the diagnosis of this disease.From July 2010 to May 2013,16 patients with fundus GAM were admitted to the Second People's Hospital of Wuxi.Rokitansky-Aschoff sinuses and calotte sign at the thickened muscular layer of the fundus of the gallbladder are the typical presentation of the fundus GAM.Enhanced computed tomography examination is of great importance for the diagnosis of the fundus GAM.%胆囊腺肌增生症(GAM)是发生于胆囊的良性增生性病变,是胆囊壁黏膜增生突入增厚的胆囊壁肌层,形成憩室样病变(即罗-阿氏窦),分为弥漫型、节段型和基底型3种类型.其临床表现无特异性,CT检查表现有助于该病的诊断.2010年7月至2013年5月无锡市第二人民医院收治了16例基底型GAM患者.局限性增厚的胆囊底部壁内“罗-阿氏窦”和“小帽征”是基底型GAM的CT检查的典型表现.CT增强扫描检查对基底型GAM的诊断具有重要价值.

  7. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  8. Digital Plasmonics

    CERN Document Server

    Gjonaj, Bergin; Johnson, Patrick M; Mosk, Allard P; Kuipers, Kobus; Lagendijk, Ad

    2010-01-01

    The field of plasmonics offers a route to control light fields with metallic nanostructures through the excitation of Surface Plasmon Polaritons (SPPs). These surface waves, bound to a metal dielectric interface, tightly confine electromagnetic energy. Active control over SPPs has potential for applications in sensing, photovoltaics, quantum communication, nano circuitry, metamaterials and super-resolution microscopy. We achieve here a new level of control of plasmonic fields using a digital spatial light modulator. Optimizing the plasmonic phases via feedback we focus SPPs at a freely pre-chosen point on the surface of a nanohole array with high resolution. Digital addressing and scanning of SPPs without mechanical motion will enable novel interdisciplinary applications of advanced plasmonic devices in cell microscopy, optical data storage and sensing.

  9. Digital tachometer

    Science.gov (United States)

    Shirokov, B.

    1984-03-01

    A tachometer with digital indication was built for measuring the speed of automobile engines with only two digits in the rpm readout. It consists of a Schmitt trigger for shaping input pulses, a pulse counter, a cycle time setting multivibrator and a readout time setting multivibrator, a stabilizer, a flicker suppressor, and a capacitive transducer. The instrument operates from a 12 V battery and draws 180 mA. The transducer includes a 30 to 50 turns coil of PEL 0.5 wire wound around the conductor which connects the ignition coil to the engine distributor and its transistor is mounted on a fin-type heat sink. Tuneup of the tachometer involves matching the transducer capacitor for maximum voltage at minimum current and trimming the readout time setting multivibrator with its adjustable resistor for a 1.5 readout with a 50 Hz input signal.

  10. Digital resources

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-12-01

    Full Text Available Bibliotheca Latinitatis Mediaevalis (circa VII sec. - XIV sec. IntraText Digital Library [01/06] Corpus Scriptorum Latinorum. A digital library of Latin literature by David Camden [01/06] Fonti disponibili online concernenti la vita religiosa medievale Rete Vitae Religiosae Mediaevalis Studia Conectens [01/06] Fuentes del Medievo Hispanico Instituto de Historia, Consejo Superior de Investigaciones Científicas [01/06] Latin Literature Forum Romanum [01/06] Ludovico Antonio Muratori, Dissertazioni sopra le antichità italiane, 1751 Biblioteca dei Classici Italiani di Giuseppe Bonghi [01/06] Medieval Latin The Latin Library [01/06] Médiévales Presses Universitaires de Vincennes - Revues.org [01/06] Regesta imperii Deutsche Kommission für die Bearbeitung der Regesta Imperii e.V. [01/06] Suda On Line Byzantine Lexicography [01/06

  11. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    . Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...... that call for symmetrical and relational approaches to studying street-level bureaucracy. The argument goes beyond technological or social determinism to find a fruitful intermediary position pointing at technological change as having both constraining and enabling effects....

  12. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  13. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  14. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    A.W. (Bert) Mulder; M.W. (Martijn) Hartog

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and

  15. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    Mulder, A.W. (Bert); Hartog, M.W. (Martijn)

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and col

  16. Digital pathology

    CERN Document Server

    Sucaet, Yves

    2014-01-01

    Digital pathology has experienced exponential growth, in terms of its technology and applications, since its inception just over a decade ago. Though it has yet to be approved for primary diagnostics, its values as a teaching tool, facilitator of second opinions and quality assurance reviews and research are becoming, if not already, undeniable. It also offers the hope of providing pathology consultant and educational services to under-served areas, including regions of the world that could not possibly sustain this level of services otherwise. And this is just the beginning, as its adoption b

  17. Focus: Digital

    DEFF Research Database (Denmark)

    Technology has been an all-important and defining element within the arts throughout the 20th century, and it has fundamentally changed the ways in which we produce and consume music. With this Focus we investigate the latest developments in the digital domain – and their pervasiveness and rapid...... production and reception of contemporary music and sound art. With ‘Digital’ we present four composers' very different answers to how technology impact their work. To Juliana Hodkinson it has become an integral part of her sonic writing. Rudiger Meyer analyses the relationships between art and design and how...

  18. Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography.

    Science.gov (United States)

    Pemp, Berthold; Deák, Gábor; Prager, Sonja; Mitsch, Christoph; Lammer, Jan; Schmidinger, Gerald; Scholda, Christoph; Schmidt-Erfurth, Ursula; Bolz, Matthias

    2014-12-01

    To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema. Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography. Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.

  19. The effects of pH on the affinity of pirenzepine for muscarinic receptors in the guinea-pig ileum and rat fundus strip.

    Science.gov (United States)

    Barlow, R. B.; Chan, M.

    1982-01-01

    1 Dose-ratios obtained with pirenzepine on the guinea-pig ileum at 30 degrees C are indistinguishable from those obtained at 37 degrees C. 2. In 0.1 M NaCl at 37 degrees C the pKa of pirenzepine for the loss of its last ionizable proton is 8.2. The ionization of pirenzepine is therefore markedly affected by changes in pH in the physiological range. 3 In experiments with pirenzepine on guinea-pig ileum and rat fundus made over a range of pH, the dose-ratio increases with the proportion of the protonated form present. As expected, the slope of the graph of dose-ratio against proportion protonated depends on the concentration of antagonist. The changes in pH produce only small effects on dose-ratios obtained with pirenzepine monomethiodide. These effects of pH can account for some of the differences between estimates of the affinity of pirenzepine. 4 The logarithm of the affinity constant of the protonated form of pirenzepine for the receptors in guinea-pig ileum is estimated to be 6.93, compared with 6.94 for the receptors in rat fundus. However, for the non-protonated form the values appear to be below 5 for the ileum compared with about 6.4 for the rat fundus. PMID:6897199

  20. Sensitivity and specificity of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen and optic disc oedema: optic disc drusen and oedema.

    Science.gov (United States)

    Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

    2013-03-01

    Evaluation of the efficacy of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen (ONHD) and optic disc oedema (ODE). Sixty-six patients with ONHD, 31 patients with ODE and 70 healthy subjects were studied. Colour and monochromatic fundus photography with different filters (green, red and autofluorescence) were performed. The results were analysed blindly by two observers. The sensitivity, specificity and interobserver agreement (k) of each test were assessed. Colour photography offers 65.5 % sensitivity and 100 % specificity for the diagnosis of ONHD. Monochromatic photography improves sensitivity and specificity and provides similar results: green filter (71.20 % sensitivity, 96.70 % specificity), red filter (80.30 % sensitivity, 96.80 % specificity), and autofluorescence technique (87.8 % sensitivity, 100 % specificity). The interobserver agreement was good with all techniques used: autofluorescence (k = 0.957), green filter (k = 0.897), red filter (k = 0.818) and colour (k = 0.809). Monochromatic fundus photography permits ONHD and ODE to be differentiated, with good sensitivity and very high specificity. The best results were obtained with autofluorescence and red filter study.

  1. The Nonmydriatic Fundus Camera in Diabetic Retinopathy Screening: A Cost-Effective Study with Evaluation for Future Large-Scale Application

    Science.gov (United States)

    Scarpa, Giuseppe; Urban, Francesca; Tessarin, Michele; Gallo, Giovanni; Midena, Edoardo

    2016-01-01

    Aims. The study aimed to present the experience of a screening programme for early detection of diabetic retinopathy (DR) using a nonmydriatic fundus camera, evaluating the feasibility in terms of validity, resources absorption, and future advantages of a potential application, in an Italian local health authority. Methods. Diabetic patients living in the town of Ponzano, Veneto Region (Northern Italy), were invited to be enrolled in the screening programme. The “no prevention strategy” with the inclusion of the estimation of blindness related costs was compared with screening costs in order to evaluate a future extensive and feasible implementation of the procedure, through a budget impact approach. Results. Out of 498 diabetic patients eligible, 80% was enrolled in the screening programme. 115 patients (34%) were referred to an ophthalmologist and 9 cases required prompt treatment for either proliferative DR or macular edema. Based on the pilot data, it emerged that an extensive use of the investigated screening programme, within the Greater Treviso area, could prevent 6 cases of blindness every year, resulting in a saving of €271,543.32 (−13.71%). Conclusions. Fundus images obtained with a nonmydriatic fundus camera could be considered an effective, cost-sparing, and feasible screening tool for the early detection of DR, preventing blindness as a result of diabetes. PMID:27885337

  2. Immunohistochemical localization of the antioxidant enzymes biliverdin reductase and heme oxygenase-2 in human and pig gastric fundus.

    Science.gov (United States)

    Colpaert, Erwin E; Timmermans, Jean Pierre; Lefebvre, Romain A

    2002-04-01

    The intrinsic antioxidant capacities of the bile pigments biliverdin and bilirubin are increasingly recognized since both heme degradation products can exert beneficial cytoprotective effects due to their scavenging of oxygen free radicals and interaction with antioxidant vitamins. Several studies have been published on the localization of the carbon monoxide producing enzyme heme oxygenase-2 (HO-2), which concomitantly generates biliverdin; histochemical data on the distribution of biliverdin reductase (BVR), converting biliverdin to bilirubin, are still very scarce in large mammals including humans. The present study revealed by means of immunohistochemistry the presence of BVR and HO-2 in mucosal epithelial cells and in the endothelium of intramural vessels of both human and porcine gastric fundus. In addition, co-labeling with the specific neural marker protein-gene product 9.5 (PGP 9.5) demonstrated that both BVR and HO-2 were present in all intrinsic nerve cell bodies of both submucous and myenteric plexuses, while double labeling with c-Kit antibody confirmed their presence in intramuscular interstitial cells of Cajal (ICC). Our results substantiate the hypothesis that BVR, through the production of the potent antioxidant bilirubin, might be an essential component of normal physiologic gastrointestinal defense in man and pig.

  3. Retinopathy in severe malaria in Ghanaian children - overlap between fundus changes in cerebral and non-cerebral malaria

    DEFF Research Database (Denmark)

    Essuman, Vera A; Ntim-Amponsah, Christine T; Astrup, Birgitte S

    2010-01-01

    . Secondly, to determine any association between retinopathy and the occurrence of convulsions in patients with CM. Methods and subjects A cross-sectional study of consecutive patients on admission with severe malaria who were assessed for retinal signs, at the Department of Child Health, Korle-Bu Teaching...... Hospital, Accra, from July to August 2002 was done. All children had dilated-fundus examination by direct and indirect ophthalmoscopy. RESULTS: Fifty-eight children aged between six months and nine years were recruited. Twenty six(45%) had CM, 22 with convulsion; 26(45%) had SA and six(10%) had RD. Any...... retinopathy was seen in: CM 19(73%), SA 14(54%), RD 3(50.0%), CM with convulsion 15(68%) and CM without convulsion 4(100%). Comparison between CM versus non-CM groups showed a significant risk relationship between retinal whitening and CM(OR=11.0, CI=2.2- 56.1, p= 0.001). There was no significant association...

  4. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    overgangen fra trykkekultur til digital kultur. For det første problemstillingen omkring digitalisering af litterær kulturarv med fokus på kodning og tagging af teksten samt organisering i hypertekststrukturer. For det andet reorganiseringen af det digitale dokument i dataelementer og database. For det......, der betragter DH som forbundet med "making" og "building" af digitale objekter og former. Dette kan også karakteriseres som DH som praktisk-produktiv vending. Artiklen har valgt tre typer af digitalisering. De er valgt ud fra, at de skal repræsentere forskellige måder at håndtere digitaliseringen på...... og forskellige versioner af den praktisk-produktive vending. Artiklen undersøger tre typer digitalisering fra 1990erne til i dag ud fra denne optik. De repræsenterer forskellige former for approach til digitalisering og det digitale dokument og afspejler forskellige typer af problemstillinger i...

  5. Digital Avionics

    Science.gov (United States)

    Koelbl, Terry G.; Ponchak, Denise; Lamarche, Teresa

    2003-01-01

    Digital Avionics activities played an important role in the advancements made in civil aviation, military systems, and space applications. This document profiles advances made in each of these areas by the aerospace industry, NASA centers, and the U.S. military. Emerging communication technologies covered in this document include Internet connectivity onboard aircraft, wireless broadband communication for aircraft, and a mobile router for aircraft to communicate in multiple communication networks over the course of a flight. Military technologies covered in this document include avionics for unmanned combat air vehicles and microsatellites, and head-up displays. Other technologies covered in this document include an electronic flight bag for the Boeing 777, and surveillance systems for managing airport operations.

  6. The reading of components of diabetic retinopathy: an evolutionary approach for filtering normal digital fundus imaging in screening and population based studies.

    Science.gov (United States)

    Tang, Hongying Lilian; Goh, Jonathan; Peto, Tunde; Ling, Bingo Wing-Kuen; Al Turk, Lutfiah Ismail; Hu, Yin; Wang, Su; Saleh, George Michael

    2013-01-01

    In any diabetic retinopathy screening program, about two-thirds of patients have no retinopathy. However, on average, it takes a human expert about one and a half times longer to decide an image is normal than to recognize an abnormal case with obvious features. In this work, we present an automated system for filtering out normal cases to facilitate a more effective use of grading time. The key aim with any such tool is to achieve high sensitivity and specificity to ensure patients' safety and service efficiency. There are many challenges to overcome, given the variation of images and characteristics to identify. The system combines computed evidence obtained from various processing stages, including segmentation of candidate regions, classification and contextual analysis through Hidden Markov Models. Furthermore, evolutionary algorithms are employed to optimize the Hidden Markov Models, feature selection and heterogeneous ensemble classifiers. In order to evaluate its capability of identifying normal images across diverse populations, a population-oriented study was undertaken comparing the software's output to grading by humans. In addition, population based studies collect large numbers of images on subjects expected to have no abnormality. These studies expect timely and cost-effective grading. Altogether 9954 previously unseen images taken from various populations were tested. All test images were masked so the automated system had not been exposed to them before. This system was trained using image subregions taken from about 400 sample images. Sensitivities of 92.2% and specificities of 90.4% were achieved varying between populations and population clusters. Of all images the automated system decided to be normal, 98.2% were true normal when compared to the manual grading results. These results demonstrate scalability and strong potential of such an integrated computational intelligence system as an effective tool to assist a grading service.

  7. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    2016-01-01

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the org

  8. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the

  9. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab MissionEstablish and maintain a Digital...

  10. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab Mission Establish and maintain a Digital...

  11. Digital Marketer: Facing Digital Marketing Opportunities

    OpenAIRE

    NEGRICEA, Costel Iliuta; PURCAREA, Ioan Matei

    2015-01-01

    We are witnessing the emergence of new ecosystems thanks to digital disruption, marketers being challenged to bring marketing operations into the digital era, enhance the customer journey and shift consumer behavior with the help of the digital tools, while actively encouraging feedback from users, and building a circle of trust with the company’s audience. Recent findings showed clear differences of consumers’ preferences and of what marketers say they’re doing with digital technology. Respo...

  12. Can We Teach Digital Natives Digital Literacy?

    Science.gov (United States)

    Ng, Wan

    2012-01-01

    In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…

  13. Variance Owing to Observer, Repeat Imaging, and Fundus Camera Type on Cup-to-disc Ratio Estimates by Stereo Planimetry

    NARCIS (Netherlands)

    Kwon, Young H.; Adix, Michael; Zimmerman, M. Bridget; Piette, Scott; Greenlee, Emily C.; Alward, Wallace L. M.; Abramoff, M.D.

    2009-01-01

    Objective: To determine and compare variance components in linear cup-to-disc ratio (LCDR) estimates by computer-assisted planimetry by human experts, and automated machine algorithm (digital automated planimetry). Design: Prospective case series for evaluation of planimetry.

  14. 梅毒性后葡萄膜炎的眼底自发荧光与眼底血管荧光造影特征%Characteristics of fundus autofluorescence and fundus fluorescein angiography in syphilitic posterior uveitis

    Institute of Scientific and Technical Information of China (English)

    龙永华; 王卫峻; 宫媛媛; 孙晓东

    2013-01-01

    背景 眼底自发荧光(FAF)能反映视网膜色素上皮(RPE)细胞的功能状态,作为一种无创的检查手段,广泛应用于视网膜疾病的诊断,而其在梅毒性后葡萄膜炎中的应用国内外尚未见相关报道. 目的 观察和对比首诊于眼科的梅毒性后葡萄膜炎的FAF及荧光素眼底血管造影(FFA)和吲哚青绿血管造影(ICGA)的特征.方法 回顾性分析2010年5月至2012年10月在上海交通大学附属第一人民医眼科诊断为梅毒性后葡萄膜炎的患者18例27眼的临床资料,所有患者均经血清学检查确诊为梅毒,根据眼部的临床表现分为急性期(病程2个月内)组和慢性迁延期(病程2个月以上)组,均进行FFA、ICGA及FAF检查,对各期患者的FAF表现与FFA、ICGA特征进行对比和分析. 结果 梅毒性后葡萄膜炎患者的FFA像主要表现为后极部视网膜血管渗漏改变及视网膜的斑驳状透见荧光改变,部分患者伴有视盘着染或荧光素渗漏,急性期患者可见黄斑区渗出的低荧光,慢性迁延期患者可出现囊样水肿的高荧光.患者的ICGA显示,视网膜后极部出现弥漫性点片状低荧光,造影晚期更明显.患者的FAF像主要表现为后极部弥漫性荧光增强,尤以急性期患者更为明显,可见斑驳状荧光,局部有点片状FAF减弱;慢性迁延期患者FAF缺失更明显;伴有视盘水肿及黄斑水肿的患者表现为相应区域的低荧光. 结论 梅毒性后葡萄膜炎以眼底后极部视网膜血管炎表现为主,ICGA显示出广泛的RPE及脉络膜受累,而FAF表现提示急性期患者有RPE代谢的障碍,慢性迁延期患者为RPE萎缩或缺失.FAF是反映RPE形态变化的辅助诊断指标.%Background The fundus autofluorescence (FAF)can reflect the function of retinal pigment epithelium(RPE) cell.As an invasive examination,it has been extensive used in retina disease,but there has not any report in syphilitic posterior uveitis.Objective This study was

  15. Define Digital Vernacular

    Institute of Scientific and Technical Information of China (English)

    刘佳; 李海英; James Stevens; Rough Nelson

    2014-01-01

    As science and technology developed, the tools of humans developed from humans’hands, to mechanical and digital technologies. The tools influ-ence almost everything in the humans’world, so does vernacular. The digital vernacular could be understood as using digital technology to vernacular; the digital means technologies. It also could be understood as doing vernacular in a digital way;the digital means data and information, in other words it can be seeking truth from facts. Define digital vernacular is not only what is digital vernacular, but also about how to do the digital vernacular and what kind of attitude we should hold to-ward the digital vernacular. Define digital vernacular as both thinking and doing.

  16. Development and Validation of a Deep Learning Algorithm for Detection of Diabetic Retinopathy in Retinal Fundus Photographs.

    Science.gov (United States)

    Gulshan, Varun; Peng, Lily; Coram, Marc; Stumpe, Martin C; Wu, Derek; Narayanaswamy, Arunachalam; Venugopalan, Subhashini; Widner, Kasumi; Madams, Tom; Cuadros, Jorge; Kim, Ramasamy; Raman, Rajiv; Nelson, Philip C; Mega, Jessica L; Webster, Dale R

    2016-12-13

    Deep learning is a family of computational methods that allow an algorithm to program itself by learning from a large set of examples that demonstrate the desired behavior, removing the need to specify rules explicitly. Application of these methods to medical imaging requires further assessment and validation. To apply deep learning to create an algorithm for automated detection of diabetic retinopathy and diabetic macular edema in retinal fundus photographs. A specific type of neural network optimized for image classification called a deep convolutional neural network was trained using a retrospective development data set of 128 175 retinal images, which were graded 3 to 7 times for diabetic retinopathy, diabetic macular edema, and image gradability by a panel of 54 US licensed ophthalmologists and ophthalmology senior residents between May and December 2015. The resultant algorithm was validated in January and February 2016 using 2 separate data sets, both graded by at least 7 US board-certified ophthalmologists with high intragrader consistency. Deep learning-trained algorithm. The sensitivity and specificity of the algorithm for detecting referable diabetic retinopathy (RDR), defined as moderate and worse diabetic retinopathy, referable diabetic macular edema, or both, were generated based on the reference standard of the majority decision of the ophthalmologist panel. The algorithm was evaluated at 2 operating points selected from the development set, one selected for high specificity and another for high sensitivity. The EyePACS-1 data set consisted of 9963 images from 4997 patients (mean age, 54.4 years; 62.2% women; prevalence of RDR, 683/8878 fully gradable images [7.8%]); the Messidor-2 data set had 1748 images from 874 patients (mean age, 57.6 years; 42.6% women; prevalence of RDR, 254/1745 fully gradable images [14.6%]). For detecting RDR, the algorithm had an area under the receiver operating curve of 0.991 (95% CI, 0.988-0.993) for EyePACS-1 and 0

  17. Digital forensics digital evidence in criminal investigations

    CERN Document Server

    Marshall, Angus McKenzie

    2009-01-01

    The vast majority of modern criminal investigations involve some element of digital evidence, from mobile phones, computers, CCTV and other devices. Digital Forensics: Digital Evidence in Criminal Investigations provides the reader with a better understanding of how digital evidence complements "traditional" scientific evidence and examines how it can be used more effectively and efficiently in a range of investigations. Taking a new approach to the topic, this book presents digital evidence as an adjunct to other types of evidence and discusses how it can be deployed effectively in s

  18. Contractile action of galanin analogues on rat isolated gastric fundus strips is modified by tachyphylaxis to substance P.

    Science.gov (United States)

    Korolkiewicz, R; Sliwiński, W; Rekowski, P; Halama, A; Mucha, P; Szczurowicz, A; Guzowski, P; Korolkiewicz, K Z

    1996-06-01

    This study was undertaken to characterize the interaction of porcine galanin (Gal) and some of its analogues with their receptors on rat gastric fundus muscle strips. Gal, galantide (M15) and Gal(1-14)-[Abu8]SCY-I evoked concentration-dependent contractions of gastric smooth muscle strips. Reproducible effects were observed in concentrations of 1-300, 3-1000 and 100-3000 nM, respectively. Specific EC50 for the contractile effect equalled 13.70 and 187 nM. Hill's coefficient for Gal is 1.03 indicating an interaction of one Gal molecule with one receptor, fulfilling the criteria of classical receptor theory. For M15 and Gal(1-14)-[Abu8]SCY-I Hill's coefficients are different from 1, namely 0.73 and 1.56, pointing out that the principle of interaction of one drug molecule with one receptor may not apply. The contraction induced by 300 nM of Gal was not significantly modified by tachyphylaxis to substance P (SP). On the contrary the introduction of tachyphylaxis to SP decreased the contractile effects of M15 and Gal(1-14)-[Abu8]SCY-I by about 57.7 +/- 3% and 39.6 +/- 5%, respectively. The findings suggest that contractile actions of M15 and Gal(1-14)-[Abu8]SCY-I are probably not only due to their agonist activities at Gal receptors but may result from a subsequent stimulation of receptors for SP or release of endogenous SP.

  19. Compact Laser Doppler Flowmeter (LDF Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.

    Directory of Open Access Journals (Sweden)

    Marielle Mentek

    Full Text Available Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH, choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF.A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats.The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively. Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.

  20. Digital dannelse

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe

    2012-01-01

    I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et dannelsesspørgs......I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et...... dannelsesspørgsmål knyttet til it. Hvad er egentlig digital dannelse? Og hvad betyder det for danskfaget?...

  1. Digital platforms as enablers for digital transformation

    DEFF Research Database (Denmark)

    Hossain, Mokter; Lassen, Astrid Heidemann

    2017-01-01

    Digital platforms offer new ways for organizations to collaborate with the external environment for ideas, technologies, and knowledge. They provide new possibilities and competence but they also bring new challenges for organizations. Understanding the role of these platforms in digital...... transformation is crucial. This study aims at exploring how organizations are driven towards transformation in various ways to embrace digital platforms for ideas, technologies, and knowledge. It shows the opportunities and challenges digital platforms bring in organizations. It also highlights underlying...... mechanisms and potential outcomes of various digital platforms. The contribution of the submission is valuable for scholars to understand and further explore this area. It provides insight for practitioners to capture value through digital platforms and accelerate the pace of organizations’ digital...

  2. H. Sapiens Digital: From Digital Immigrants and Digital Natives to Digital Wisdom

    Science.gov (United States)

    Prensky, Marc

    2009-01-01

    As we move further into the 21st century, the digital native/digital immigrant paradigm created by Marc Prensky in 2001 is becoming less relevant. In this article, Prensky suggests that we should focus instead on the development of what he calls "digital wisdom." Arguing that digital technology can make us not just smarter but truly wiser, Prensky…

  3. Enabling Digital Literacy

    DEFF Research Database (Denmark)

    Ryberg, Thomas; Georgsen, Marianne

    2010-01-01

    There are some tensions between high-level policy definitions of “digital literacy” and actual teaching practice. We need to find workable definitions of digital literacy; obtain a better understanding of what digital literacy might look like in practice; and identify pedagogical approaches, which......, these operate on a meso-level mediating between high-level concepts of digital literacy and classroom practice....... support teachers in designing digital literacy learning. We suggest that frameworks such as Problem Based Learning (PBL) are approaches that enable digital literacy learning because they provide good settings for engaging with digital literacy. We illustrate this through analysis of a case. Furthermore...

  4. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  5. Digital signal processing: Handbook

    Science.gov (United States)

    Goldenberg, L. M.; Matiushkin, B. D.; Poliak, M. N.

    The fundamentals of the theory and design of systems and devices for the digital processing of signals are presented. Particular attention is given to algorithmic methods of synthesis and digital processing equipment in communication systems (e.g., selective digital filtering, spectral analysis, and variation of the signal discretization frequency). Programs for the computer-aided analysis of digital filters are described. Computational examples are presented, along with tables of transfer function coefficients for recursive and nonrecursive digital filters.

  6. Digital preservation for heritages

    CERN Document Server

    Lu, Dongming

    2011-01-01

    ""Digital Preservation for Heritages: Technologies and Applications"" provides a comprehensive and up-to-date coverage of digital technologies in the area of cultural heritage preservation, including digitalization, research aiding, conservation aiding, digital exhibition, and digital utilization. Processes, technical frameworks, key technologies, as well as typical systems and applications are discussed in the book. It is intended for researchers and students in the fields of computer science and technology, museology, and archaeology. Dr. Dongming Lu is a professor at College of Computer Sci

  7. Characteristics of Digital Sustainability

    OpenAIRE

    Stuermer, Matthias

    2014-01-01

    The concept of digital sustainability is mentioned in research on digital preservation as well as on openness topics. Both streams of literature point out the necessary discussion how to create, use, and regulate digital resources in order to maximize their value for our society today and in the future. This paper therefore reviews current work on digital sustainability, presents a list of six charac-teristics how to define digitally sustainable goods, and draws the link to aspects of e-gover...

  8. Investigation of a possible interaction between the heme oxygenase/biliverdin reductase and nitric oxide synthase pathway in murine gastric fundus and jejunum.

    Science.gov (United States)

    De Backer, Ole; Lefebvre, Romain A

    2008-08-20

    This study investigated the possible interaction between the heme oxygenase (HO)/biliverdin reductase (BVR) and nitric oxide synthase (NOS) pathway in murine gastric fundus and jejunum, since previous studies have shown that both HO-2 and BVR are expressed in interstitial cells of Cajal (ICCs) and co-localized with neuronal NOS in a large proportion of myenteric neurons along the gastrointestinal tract. Neither HO inhibition by chromium mesoporphyrin (CrMP) nor co-incubation with CO or biliverdin/bilirubin affected nitrergic neurotransmission - i.e. relaxations induced by non-adrenergic non-cholinergic (NANC) nerve stimulation or exogenous NO - under normal physiological conditions. However, biliverdin/bilirubin reversed the inhibitory effect of the superoxide generator LY83583 on exogenous NO-induced relaxations in both tissues. When gastric fundus muscle strips were depleted of the endogenous antioxidant Cu/Zn superoxide dismutase (SOD) by the Cu-chelator DETCA, electrically induced NANC relaxations were also affected by LY82583; however, biliverdin/bilirubin could not substitute for the loss of Cu/Zn SOD when this specific antioxidant enzyme was depleted. In jejunal muscle strips, the combination DETCA plus LY83583 nearly abolished contractile phasic activity and, hence, did not allow studying nitrergic relaxation in these experimental conditions. In conclusion, this study does not establish a role for HO/CO in inhibitory NANC neurotransmission in murine gastric fundus and jejunum under normal physiological conditions. However, the antioxidants biliverdin/bilirubin might play an important role in the protection of the nitrergic neurotransmitter against oxidative stress.

  9. Mechanism of relaxation and interaction with nitric oxide of the soluble guanylate cyclase stimulator BAY 41-2272 in mouse gastric fundus and colon.

    Science.gov (United States)

    Cosyns, Sarah M R; Lefebvre, Romain A

    2012-07-05

    BAY 41-2272 is a heme-dependent nitric oxide-independent soluble guanylate cyclase (sGC) stimulator, but its relaxant effect in vascular, respiratory and urogenital tissue is only partially dependent on sGC activation. As its mechanism of action has not been studied in the gastrointestinal tract, it was investigated in mouse gastric fundus and colon. Circular smooth muscle strips were mounted in organ baths under non-adrenergic non-cholinergic (NANC) conditions for isometric force recording and cGMP levels were determined using an enzyme immunoassay kit. BAY 41-2272 induced concentration-dependent relaxation in both tissues and increased cGMP levels. The sGC inhibitor ODQ totally inhibited this BAY 41-2272-induced increase of cGMP, but only partially reduced the corresponding relaxation. The PDE-5 inhibitor sildenafil had no effect on BAY 41-2272-induced responses. The NO synthase inhibitor L-NAME caused a significant decrease in BAY 41-2272-induced responses in colonic strips. Electrical field stimulation in the presence of BAY 41-2272 induced increased NANC relaxation in fundus, while in colon, rebound contraction at the end of the stimulation train was no longer visible. This suggests synergy with endogenously released NO. Responses to BAY 41-2272 were not significantly influenced by apamin, charybdotoxin or ouabain, excluding interaction with small, intermediate and large conductance Ca(2+)-activated K(+) channels and with Na(+)-K(+)-ATPase. Under depletion of intracellular calcium, CaCl(2)-induced contractions were significantly reduced by BAY 41-2272 in an ODQ-insensitive way. The present study demonstrates that BAY 41-2272 exerts its relaxing effect in mouse gastric fundus and colon partially through a cGMP-dependent mechanism and at least one additional cGMP-independent mechanism involving Ca(2+)-entry blockade.

  10. Different effects of H1 and H2 blockers on the tone and the contractile activity of guinea pig stomach fundus.

    Science.gov (United States)

    Milenov, K; Todorov, S; Vassileva, M; Zamfirova, R; Shahbazian, A

    1995-11-01

    The action of H1 and H2 blockers on the spontaneous and evoked contractile activity of gastric fundus smooth muscles as well as the effects of H2 antagonists on the release of acetylcholine (ACh) from gastric myenteric neurons were studied. The experiments were performed on smooth muscle strips (25 x 3 mm) cut out in circular direction from guinea pig fundus region. In concentrations of 1 x 10(-7) M to 1 x 10(-4) M, the H1 blockers diphenhydramine (DPH), mepyramine (MEP) and dimethpyrindene (DMPD), but not the H2 blockers ranitidine (RAN), cimetidine (CIM) and roxatidine (ROX), increased in a concentration-dependent manner the smooth muscle tone, the maximum contractions being about 50% of the contractile effects of 1 x 10(-5) M ACH and 5 x 10(-5) M histamine (HA). The concentration-dependent contractions of the stomach fundus strips in response to electrical field stimulation (EFS) were enhanced by RAN, CIM and ROX (but not by MEP and DPH), all in concentrations of 1 x 10(-7) M to 1 x 10(-4) M. EFS increased the resting [3H]-ACh release by 67.8%, the S2/S1 ratio being 0.85 +/- 0.04. ROX in a concentration of 1 x 10(-5) M significantly increased (by 16.1%) the EFS-induced release with a S2/S1 ratio of 1.22 +/- 0.04. The ROX effect on the [3H]-ACh release was reduced or even abolished by 1 x 10(-6) M tetrodotoxin (TTX) and 1 x 10(-6) M scopolamine or in Ca(2+)-free medium, while 1 x 10(-6) M hexamethonium did not change it. It might be concluded that H2 blockers have no direct myogenic effect and do not interfere with muscarinic receptors in guinea pig stomach fundus. The H2 antagonists enhance the EFS-evoked contractions of the gastric smooth muscle most probably by increasing the release of ACH.

  11. Cognitive Hacking and Digital Government: Digital Identity

    OpenAIRE

    Paul Thompson

    2004-01-01

    Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation syst...

  12. Digital Archive Policies and Trusted Digital Repositories

    Directory of Open Access Journals (Sweden)

    MacKenzie Smith

    2007-07-01

    Full Text Available The MIT Libraries, the San Diego Supercomputer Center, and the University of California San Diego Libraries are conducting the PLEDGE Project to determine the set of policies that affect operational digital preservation archives and to develop standardized means of recording and enforcing them using rules engines. This has the potential to allow for automated assessment of “trustworthiness” of digital preservation archives. We are also evaluating the completeness of other efforts to define policies for digital preservation such as the RLG/NARA Trusted Digital Repository checklist and the PREMIS metadata schema. We present our results to date.

  13. Variance Owing to Observer, Repeat Imaging, and Fundus Camera Type on Cup-to-disc Ratio Estimates by Stereo Planimetry

    NARCIS (Netherlands)

    Kwon, Young H.; Adix, Michael; Zimmerman, M. Bridget; Piette, Scott; Greenlee, Emily C.; Alward, Wallace L. M.; Abramoff, M.D.

    2009-01-01

    Objective: To determine and compare variance components in linear cup-to-disc ratio (LCDR) estimates by computer-assisted planimetry by human experts, and automated machine algorithm (digital automated planimetry). Design: Prospective case series for evaluation of planimetry. Participants: F

  14. ANALYSIS OF FUNDUS IMAGES

    DEFF Research Database (Denmark)

    2000-01-01

    A method classifying objects man image as respective arterial or venous vessels comprising: identifying pixels of the said modified image which are located on a line object, determining which of the said image points is associated with crossing point or a bifurcation of the respective line object......, wherein a crossing point is represented by an image point which is the intersection of four line segments, performing a matching operation on pairs of said line segments for each said crossing point, to determine the path of blood vessels in the image, thereby classifying the line objects in the original...... image into two arbitrary sets, and thereafter designating one of the sets as representing venous structure, the other of the sets as representing arterial structure, depending on one or more of the following criteria: (a) complexity of structure; (b) average density; (c) average width; (d) tortuosity...

  15. Logic of the digital

    CERN Document Server

    Evens, Aden

    2015-01-01

    Building a foundational understanding of the digital, Logic of the Digital reveals a unique digital ontology. Beginning from formal and technical characteristics, especially the binary code at the core of all digital technologies, Aden Evens traces the pathways along which the digital domain of abstract logic encounters the material, human world. How does a code using only 0s and 1s give rise to the vast range of applications and information that constitutes a great and growing portion of our world? Evens' analysis shows how any encounter between the actual and the digital must cross an ontolo

  16. The Antimuscarinic Effects of Anticholinesterase Drugs on Electrical Field Stimulation-Induced Contractile Responses in Rat Gastric Fundus and Ileum Smooth Muscle

    Directory of Open Access Journals (Sweden)

    Ilker Kelle

    2007-01-01

    Full Text Available Parasympathetic component of autonomic nervous system is known as involving in majority of intestinal smooth muscle contractions and motility. Acetylcholine can be released from parasympathetic nerve terminals by an excitation which is formed by a physiological or an electrical stimulation in order to elicit smooth muscle contractions. Anticholinesterase drugs are expected to increase the levels of acetylcholine in cholinergic synapses via inhibiting the enzyme acetylcholinesterase. In recent studies, it has been shown that anticholinesterase drugs may cause an antimuscarinic effect on the contrary of their usual effects such as amplifying of cholinergic transmission. In this study, we investigated the antimuscarinic effects of neostigmine, edrophonium and piridostigmine on gastric fundus and ileum smooth muscle preparations isolated from Wistar albino rats. The contactions were induced by using electrical field stimulation (EFS which is a direct stimulation technique. Both neostigmine and piridostigmine increased the E max values of contractile responses for EFS at their first three concentrations; but only the changes in gastric fundus strips has found significant as statistically. At their highest concentration such as 1000 M, both neostigmine and piridostigmine attenuated the EFS induced smooth muscle contractions and caused an antimuscarinic effect (p  0,05; paired samples Student’s t test. In contrast, edrophonium had no effect on EFS induced smooth muscle contractions, at none of its four concentrations as statistically. Our results suggest that larger doses of neostigmine and piridostigmine, but not edrophonium, may evoke antimuscarinic effects on intestinal smooth muscle contractions.

  17. Genome-wide linkage and sequence analysis challenge CCDC66 as a human retinal dystrophy candidate gene and support a distinct NMNAT1-related fundus phenotype.

    Science.gov (United States)

    Khan, A O; Budde, B S; Nürnberg, P; Kawalia, A; Lenzner, S; Bolz, H J

    2017-03-30

    To uncover the genotype underlying early-onset cone-rod dystrophy and central nummular macular atrophic lesion in 2 siblings from an endogamous Arab family, we performed targeted next-generation sequencing (NGS) of 44 retinal dystrophy genes, whole-exome sequencing (WES) and genome-wide linkage analysis. Targeted NGS and WES in the index patient highlighted 2 homozygous variants, a CCDC66 frameshift deletion and a novel missense NMNAT1 variant, c.500G>A (p.Asn167Ser). Linkage and segregation analysis excluded the CCDC66 variant and confirmed the NMNAT1 mutation. Biallelic NMNAT1 mutations cause Leber congenital amaurosis with a central nummular macular atrophic lesion (LCA9). The NMNAT1 mutation reported here underlied cone-rod dystrophy rather than LCA but the fundus lesion was compatible with that of LCA9 patients, highlighting that such a fundus appearance should raise suspicion for biallelic mutations in NMNAT1 when in the context of any retinal dystrophy. Although Ccdc66 mutations have been proposed to cause retinal disease in dogs, our results and public databases challenge CCDC66 as a candidate gene for human retinal dystrophy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. On the digital homology groups of digital images

    CERN Document Server

    Lee, Dae-Woong

    2011-01-01

    In this article we study the digital homology groups of digital images which are based on the singular homology groups of topological spaces in algebraic topology. Specifically, we define a digitally standard $n$-simplex, a digitally singular $n$-simplex, and the digital homology groups of digital images with $k$-adjacency relations. We then construct a covariant functor from a category of digital images and digitally continuous functions to the one of abelian groups and group homomorphisms, and investigate some fundamental and interesting properties of digital homology groups of digital images, such as the digital version of the dimension axiom which is one of the Eilenberg-Steenrod axioms.

  19. Digital rectal exam

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007069.htm Digital rectal exam To use the sharing features on this page, please enable JavaScript. A digital rectal exam is an examination of the lower ...

  20. Identidad visual digital

    OpenAIRE

    Pérez Villanueva, Alba

    2013-01-01

    Se estudian seis casos de empresas de diferentes sectores y la adaptación de la identidad visual digital para obtener una imagen aproximada sobre el estado de la identidad visual digital de las coporaciones

  1. Coastal California Digital Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This digital ortho-imagery dataset is a survey of coastal California. The project area consists of approximately 3774 square miles. The project design of the digital...

  2. About group digital signatures

    National Research Council Canada - National Science Library

    Adriana Cristina Enache

    2012-01-01

    ...).A group digital signature is a digital signature with enhanced privacy features that allows members of a given group to anonymously sign messages on behalf of the group, producing a group signature...

  3. Effective study in the real-world study of intravitreal anti-VEGF drugs injection in the treatment of fundus diseases

    Directory of Open Access Journals (Sweden)

    Jian-Feng Xu

    2017-09-01

    Full Text Available AIM:To understand the clinic effect of intravitreal anti-vascular endothelial growth factor(VEGFdrugs injection in the treatment of fundus disease in the real-world study(RWS. METHODS: The clinical cases treated with anti-VEGF drugs in our department from September 2012 to June 2015 were enrolled in this study. Retrospective investigation was reviewed to the kinds of diseases, frequency, usage, efficacy, adverse reaction, and the effects on visual acuity, fundus and macular thickness which were treated with intravitreal anti-VEGF drugs injection. RESULTS: In 305 patients(340 eyestreated with anti-VEGF drugs, 53 patients(60 eyes, 17.6%were wet age-related macular degeneration(AMD, polypoidal choroidal vasculopathy(PCV16 cases(18 eyes, 5.3%, diabetic macular edema(DME120 cases(134 eyes, 39.4%, branch retinal vein occlusion(BRVOsecondary macular edema 61 cases(68 eyes, 20.0%, central retinal vein occlusion(CRVOsecondary macular edema 29 cases(32 eyes, 9.4%, idiopathic choroidal neovascularization(ICNV16 cases(18 eyes, 5.3%, high myopia with choroid neovascularization 4 cases(4 eyes, 1.2%, neovascular glaucoma 4 cases(4 eyes, 1.2%, retinal angiomatous proliferation(RAP1 cases(1 eyes, 0.2%and optic papillary neovascularization 1 cases(1 eyes, 0.2%. The minimum age was 16 years old, and the maximum age 90 years old. There were 247 cases(275 eyes, 80.9%were treated with intravitreal ranibizumab injection, 58 cases(65 eyes, 19.1%intravitreal conbercept injection. The time number of all patients accepted anti-VEGF drugs treatment was 465, with an average of 1.7 times per eye. Which, the "3 + PRN" treatment method in 98 patients(109 eyes, 32.1%, "1 + PRN" treatment in 207 patients(231 eyes, 67.9%. 69 cases(77 eyes, 22.6%were used alone to receive anti-VEGF drugs therapy, 10 cases(11 eyes, 3.2%combined with intravitreal triamcinolone injection(TA, 35 cases(39 eyes, 11.5%combined with vitrectomy, 26 cases(29 eyes, 8.5%combined with photodynamic treatment

  4. 系统性红斑狼疮眼底病变的特征%Observation of the ocular fundus manifestations of systemic lupus erythematosus

    Institute of Scientific and Technical Information of China (English)

    周慧颖; 叶俊杰; 王淑然

    2015-01-01

    Objective To describe the manifestations of ocular fundus secondary to systemic lupus erythematosus (SLE).Methods This was a retrospective study.Thirty-six patients (57 eyes) who were diagnosed with SLE by the Department of Rheumatology in Peking Union Medical College Hospital during the years of 2002-2013 were enrolled in the study.These case studies from the Department of Ophthalmology were summarized.The patients included 4 males and 32 females from 14 to 71 years of age with a mean age of 32.6±11.5 years.Ocular anterior segments were examined with a slit lamp microscope.Fundus examinations were performed with papillary dilation,fundus photography and fundus fluorescein angiography.Results Twenty-four eyes showed retinal vasculitis.Eighteen eyes showed precapillary arteriole occlusion.Seventeen eyes presented with retinal vascular occlusion,10 of presented with retinal artery occlusion,5 presented with retinal vein occlusion,and 2 presented with retinal artery occlusion and vein occlusion.Six eyes presented with optic neuropathy,including 1 eye with neuropapillitis,4 eyes with retrobulbar neuritis,and 1 eye with ischemic optic neuropathy.Three eyes presented with cytomegalovirus retinitis.Conclusion Retinal vasculitis,precapillary arteriole occlusion and retinal vascular occlusion are the most common manifestations of SLE as part of ocular fundus changes.%目的 探讨系统性红斑狼疮(SLE)患者的眼底病变的临床特点.方法 回顾性系列病例研究.分析2002-2013年在北京协和医院眼科门诊就诊的36例(57眼)经免疫内科确诊为SLE患者的眼底病变情况.其中男4例,女32例;年龄14~71岁,平均(32.6±11.5)岁.常规用裂隙灯显微镜检查前节、散瞳查眼底、眼底照像及FFA.结果 57眼中视网膜血管炎24眼;毛细血管前小动脉闭塞18眼;视网膜大血管阻塞17眼,其中视网膜动脉阻塞10眼,视网膜静脉不全阻塞5眼,视网膜动静脉阻塞2眼;视神经病变6

  5. Digital Inkjet Textile Printing

    OpenAIRE

    Wang, Meichun

    2017-01-01

    Digital inkjet textile printing is an emerging technology developed with the rise of the digital world. It offers a possibility to print high-resolution images with unlimited color selection on fabrics. Digital inkjet printing brings a revolutionary chance for the textile printing industry. The history of textile printing shows the law how new technology replaces the traditional way of printing. This indicates the future of digital inkjet textile printing is relatively positive. Differen...

  6. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  7. Digital dannelse til gymnasieeleverne

    DEFF Research Database (Denmark)

    Kaarsted, Thomas; Holch Andersen, Knud

    2012-01-01

    Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene.......Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene....

  8. Digital flight control research

    Science.gov (United States)

    Potter, J. E.; Stern, R. G.; Smith, T. B.; Sinha, P.

    1974-01-01

    The results of studies which were undertaken to contribute to the design of digital flight control systems, particularly for transport aircraft are presented. In addition to the overall design considerations for a digital flight control system, the following topics are discussed in detail: (1) aircraft attitude reference system design, (2) the digital computer configuration, (3) the design of a typical digital autopilot for transport aircraft, and (4) a hybrid flight simulator.

  9. Online Digital Trading

    Directory of Open Access Journals (Sweden)

    Felician Alecu

    2013-09-01

    Full Text Available This paper summarizes the main options a digital content creator has in order to obtain money by online trading of digital works. There are multiple ways to get paid for the digital products, like licensing, for example, however this article tries to present the most successful business models targeting the online market. The exclusive rights stated by the copyright laws are helping the authors to maximize to potential advantages coming from their digital creations.

  10. Interactive Digital Signal Processor

    Science.gov (United States)

    Mish, W. H.

    1985-01-01

    Interactive Digital Signal Processor, IDSP, consists of set of time series analysis "operators" based on various algorithms commonly used for digital signal analysis. Processing of digital signal time series to extract information usually achieved by applications of number of fairly standard operations. IDSP excellent teaching tool for demonstrating application for time series operators to artificially generated signals.

  11. Digital Literacy. Research Brief

    Science.gov (United States)

    Williamson, Ronald

    2011-01-01

    21st Century students need a complex set of skills to be successful in a digital environment. Digital literacy, similar to traditional definitions of literacy, is a set of skills students use to locate, organize, understand, evaluate and create information. The difference is that it occurs in an environment where a growing set of digital tools…

  12. Personal Digital Video Stories

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Henningsen, Birgitte Sølbeck; Louw, Arnt Vestergaard

    2016-01-01

    agenda focusing on video productions in combination with digital storytelling, followed by a presentation of the digital storytelling features. The paper concludes with a suggestion to initiate research in what is identified as Personal Digital Video (PDV) Stories within longitudinal settings, while...

  13. Digital language death.

    Directory of Open Access Journals (Sweden)

    András Kornai

    Full Text Available Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide.

  14. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  15. Digitization in Maritime Industry

    DEFF Research Database (Denmark)

    Constantiou, Ioanna; Shollo, Arisa; Kreiner, Kristian

    2017-01-01

    Digitization in the maritime industry is expected to transform businesses. The recently introduced mobile technologies in inter-organizational processes is an example of digitization in an industry which moves very slowly towards digital transformation. We focus on the influence of mobile...

  16. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  17. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  18. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  19. Preparing collections for digitization

    CERN Document Server

    Bulow, Anna E

    2010-01-01

    Most libraries, archives and museums are confronting the challenges of providing digital access to their collections. This guide offers guidance covering the end-to-end process of digitizing collections, from selecting records for digitization to choosing suppliers and equipment and dealing with documents that present individual problems.

  20. Digital subtraction laryngography

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.

    1983-06-01

    Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.

  1. Digital Tectonic Tools

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due

    2005-01-01

    in particular. A model of the aspects in the term tectonics – epresentation, ontology and culture – will be presented and used to discuss the current digital tools’ ability in tectonics. Furthermore it will be discussed what a digital tectonic tool is and could be and how a connection between the digital...

  2. Ageing and digital games

    DEFF Research Database (Denmark)

    Iversen, Sara Mosberg

    2016-01-01

    Digital games are still to a great degree considered a medium mainly for young boys. However, available statistics on Western media use show that this is far from the case. Increasingly, people of all ages and genders play digital games, also older adults in their early 60s and beyond. The aim...... of the book is to examine, analyse and discuss: 1) What older adults do with digital games and what meanings the use of digital games take on in the everyday life of older adults; 2) How older adults are perceived by society in relation to digital games; 3) How play and games can be used both...

  3. Digital Living at Home

    DEFF Research Database (Denmark)

    Andersen, Pernille Viktoria Kathja; Christiansen, Ellen Tove

    2013-01-01

    Does living with digital technology inevitably lead to digital living? Users talking about a digital home control system, they have had in their homes for eight years, indicate that there is more to living with digital technology than a functional-operational grip on regulation. Our analysis...... of these user voices has directed us towards a ‘home-keeping’ design discourse, which opens new horizons for design of digital home control systems by allowing users to perform as self-determined controllers and groomers of their habitat. The paper concludes by outlining the implications of a ‘home...

  4. Digital Radiation image

    Directory of Open Access Journals (Sweden)

    Abou-Bakr Ramadan

    2012-03-01

    Full Text Available This work introduces a new way for data visualization. Its name is Digital Application name' Image. Normal digital image is created by digital camera or digital scanner but digital application name image is created by measurements of monitoring data. This work uses the data which is measured by radiation monitoring station and classifies it using fuzzy logic rules to create digital radiation image. The main unique advantage of digital radiation image is that it expresses thousands of measurements in a very clear form through only one picture while the maximum number of measurements does not exceed 100 with other conventional visualization methods. This feature gives a facility to view one year of all recorded measurements in only one photo. This picture helps the user to observe the behavior of thousands of measurements in few minutes instead of spending few hours for reviewing hundreds of charts for the same measurements.

  5. Digital gaming expertise

    DEFF Research Database (Denmark)

    Toft-Nielsen, Claus

    , to have access to the dynamic power systems in and around digital games theorized as ‘gaming capital’ (Consalvo, 2007) and who cannot? I argue, in other words, for an understanding of digital gaming competence as a reflection, negotiation, and production of gendered power relations, performed in ways......In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within...... communication and game studies there are multiple understandings of how digital expertise is expressed and performed, and subsequently how these expressions and performances can be valued, understood and theorized within the research community. Among other things expertise with and within digital games has...

  6. Digital Collections, Digital Libraries and the Digitization of Cultural Heritage Information.

    Science.gov (United States)

    Lynch, Clifford

    2002-01-01

    Discusses the development of digital collections and digital libraries. Topics include digitization of cultural heritage information; broadband issues; lack of compelling content; training issues; types of materials being digitized; sustainability; digital preservation; infrastructure; digital images; data mining; and future possibilities for…

  7. Digital rights management for digital cinema

    Science.gov (United States)

    Kirovski, Darko; Peinado, Marcus; Petitcolas, Fabien A. P.

    2001-12-01

    There is a wide consensus among the feature film production studios that the Internet era brings a new paradigm for film distribution to cinemas worldwide. The benefits of digital cinema to both producers and cinemas are numerous: significantly lower distribution and maintenance costs, immediate access to film libraries, higher presentation quality, and strong potential for developing new business models. Despite these advantages, the studios are still reluctant to jump into the digital age. The main showstopper for digital cinema is the danger of widespread piracy. Piracy already costs Hollywood an estimated two billion dollars annually and digital cinema without proper copyright enforcement could increase this number. In this paper, we present a copyright management system that aims at providing the set of necessary security tools: standard cryptographic primitives and copyright protection mechanisms that enable a reliable and secure feature film delivery system.

  8. Best of Digital British Columbia : Digitization Around the Province

    OpenAIRE

    2011-01-01

    The Online Dictionary of Library and Information Science defines digitization as “the process of converting data to digital format for processing by a computer.” We have all heard about mass digitization projects such as the Google Digitization Project and Project Gutenberg, but local ’boutique’ digitization efforts do not receive as much fanfare. Digitization projects completed in BC showcase the unique culture and history of British Columbia. The BC Digitization Coalition is a new initiativ...

  9. Fundus fluorescein angiography of familial exudative vitreoretinopathy%家族性渗出性玻璃体视网膜病变的荧光素眼底血管造影分析

    Institute of Scientific and Technical Information of China (English)

    郑志坤; 黎铧; 李娟娟; 胡竹林

    2011-01-01

    Objective To analysis the the fundus characteristics and fluorescein angiography of familial exudative vitreoretinopathy. Methods Fundus photography and fundus fluorescein angiography were analyzed exudative vitreoretinop-athy. Results Fundus examination showed: the temporal side of a disc-like folds cord where the retinal blood vessels branch-intensive with relatively large number. Peripheral retinal examination showed white lesion with clear boundary, where tortuous retinal blood vessels to expand. Angiographic characteristics: Fundus fluorescein angiography shows peripheral retinal vascular branched, tortuous expansion, with "tree-like" change and take the line straight, the fan-shaped ends and vascular leakage. Conclusion The fundus examination, fundus fluorescein angiography in patients with a history, family history is helpful to confirm the diagnosis.%目的 分析家族性渗出性玻璃体视网膜病变的眼底表现及荧光素眼底血管造影(FFA)特征.方法 收集我院诊治的家族性渗出性玻璃体视网膜病变患者,进行眼底照相及FFA检查,进行对比分析.结果 眼底特征性表现为,视盘颞侧一条索样皱襞,该部分视网膜血管分支密集、数目较多,终止与周边视网膜.周边视网膜检查可见一边界清晰的片状灰白色病灶,此处视网膜血管迂曲扩张.FFA特征为:周边视网膜FFA显示血管分支增多、迂曲扩张,呈"树枝样"改变,走行平直.血管末端发生吻合、呈扇形终止,此部分血管渗漏.结论 眼底检查、FFA结合患者病史、家族史可明确诊断家族性渗出性玻璃体视网膜病变.

  10. Crowdsourcing as a novel technique for retinal fundus photography classification: analysis of images in the EPIC Norfolk cohort on behalf of the UK Biobank Eye and Vision Consortium.

    Science.gov (United States)

    Mitry, Danny; Peto, Tunde; Hayat, Shabina; Morgan, James E; Khaw, Kay-Tee; Foster, Paul J

    2013-01-01

    Crowdsourcing is the process of outsourcing numerous tasks to many untrained individuals. Our aim was to assess the performance and repeatability of crowdsourcing for the classification of retinal fundus photography. One hundred retinal fundus photograph images with pre-determined disease criteria were selected by experts from a large cohort study. After reading brief instructions and an example classification, we requested that knowledge workers (KWs) from a crowdsourcing platform classified each image as normal or abnormal with grades of severity. Each image was classified 20 times by different KWs. Four study designs were examined to assess the effect of varying incentive and KW experience in classification accuracy. All study designs were conducted twice to examine repeatability. Performance was assessed by comparing the sensitivity, specificity and area under the receiver operating characteristic curve (AUC). Without restriction on eligible participants, two thousand classifications of 100 images were received in under 24 hours at minimal cost. In trial 1 all study designs had an AUC (95%CI) of 0.701(0.680-0.721) or greater for classification of normal/abnormal. In trial 1, the highest AUC (95%CI) for normal/abnormal classification was 0.757 (0.738-0.776) for KWs with moderate experience. Comparable results were observed in trial 2. In trial 1, between 64-86% of any abnormal image was correctly classified by over half of all KWs. In trial 2, this ranged between 74-97%. Sensitivity was ≥ 96% for normal versus severely abnormal detections across all trials. Sensitivity for normal versus mildly abnormal varied between 61-79% across trials. With minimal training, crowdsourcing represents an accurate, rapid and cost-effective method of retinal image analysis which demonstrates good repeatability. Larger studies with more comprehensive participant training are needed to explore the utility of this compelling technique in large scale medical image analysis.

  11. Crowdsourcing as a novel technique for retinal fundus photography classification: analysis of images in the EPIC Norfolk cohort on behalf of the UK Biobank Eye and Vision Consortium.

    Directory of Open Access Journals (Sweden)

    Danny Mitry

    Full Text Available AIM: Crowdsourcing is the process of outsourcing numerous tasks to many untrained individuals. Our aim was to assess the performance and repeatability of crowdsourcing for the classification of retinal fundus photography. METHODS: One hundred retinal fundus photograph images with pre-determined disease criteria were selected by experts from a large cohort study. After reading brief instructions and an example classification, we requested that knowledge workers (KWs from a crowdsourcing platform classified each image as normal or abnormal with grades of severity. Each image was classified 20 times by different KWs. Four study designs were examined to assess the effect of varying incentive and KW experience in classification accuracy. All study designs were conducted twice to examine repeatability. Performance was assessed by comparing the sensitivity, specificity and area under the receiver operating characteristic curve (AUC. RESULTS: Without restriction on eligible participants, two thousand classifications of 100 images were received in under 24 hours at minimal cost. In trial 1 all study designs had an AUC (95%CI of 0.701(0.680-0.721 or greater for classification of normal/abnormal. In trial 1, the highest AUC (95%CI for normal/abnormal classification was 0.757 (0.738-0.776 for KWs with moderate experience. Comparable results were observed in trial 2. In trial 1, between 64-86% of any abnormal image was correctly classified by over half of all KWs. In trial 2, this ranged between 74-97%. Sensitivity was ≥ 96% for normal versus severely abnormal detections across all trials. Sensitivity for normal versus mildly abnormal varied between 61-79% across trials. CONCLUSIONS: With minimal training, crowdsourcing represents an accurate, rapid and cost-effective method of retinal image analysis which demonstrates good repeatability. Larger studies with more comprehensive participant training are needed to explore the utility of this compelling

  12. Seizing the Digital

    Directory of Open Access Journals (Sweden)

    Janet Vertesi

    2016-07-01

    Full Text Available Digital systems pervade classic STS sites of interest, from connecting laboratories to mediating lay-expert divides. But STS has so far been reticent to build the theoretical and analytical perspectives necessary for embracing digital systems as an important element of contemporary fieldwork, research, and practice. This paper charts a course for bringing STS concepts to bear on digital systems and vice versa, bringing our lingering concern with questions from the sociology of knowledge to bear on digitally-enacted and mediated scientific and technical practices. It shows how we can eschew the language of technological determinism inherent to discussion about digital systems outside of STS, asking instead questions germane to STS theory and practice such as the configuration of such systems to include and exclude, the epistemic entanglements of using digital tools in research practice, and the potential to build new systems that suggest alternative arrangements.

  13. DIGITAL ERA: UTILIZE OF CLOUD COMPUTING TECHNOLOGY IN DIGITAL LIBRARY

    OpenAIRE

    T. RAGHUNADHA REDDY

    2012-01-01

    With the purpose of applying cloud computing to digital library, the paper initially describes cloud computing and analyzes current status of cloud computing in digital library. Then it proposes the architecture of cloud computing in digital library and summarises the application of cloud computing in digital library. Finally the author brings out the future improvement in digital library using cloud computing technology.

  14. Digital Natives and Digital Divide: Analysing Perspective for Emerging Pedagogy

    Science.gov (United States)

    Onye, Uriel U.; Du, Yunfei

    2016-01-01

    This paper addresses the concepts of digital natives and digital divide from the perspective of the digital outsiders (part of digital natives). It takes a critical look at the implications of available ICT in both developed and underdeveloped countries in the fight against digital divide. The major contribution to literature is by drawing…

  15. Preserving Digital Materials

    CERN Document Server

    Harvey, Ross

    2011-01-01

    This book provides a single-volume introduction to the principles, strategies and practices currently applied by librarians and recordkeeping professionals to the critical issue of preservation of digital information. It incorporates practice from both the recordkeeping and the library communities, taking stock of current knowledge about digital preservation and describing recent and current research, to provide a framework for reflecting on the issues that digital preservation raises in professional practice.

  16. The digital computer

    CERN Document Server

    Parton, K C

    2014-01-01

    The Digital Computer focuses on the principles, methodologies, and applications of the digital computer. The publication takes a look at the basic concepts involved in using a digital computer, simple autocode examples, and examples of working advanced design programs. Discussions focus on transformer design synthesis program, machine design analysis program, solution of standard quadratic equations, harmonic analysis, elementary wage calculation, and scientific calculations. The manuscript then examines commercial and automatic programming, how computers work, and the components of a computer

  17. Digital image scrambling

    Institute of Scientific and Technical Information of China (English)

    丁玮; 闫伟齐; 齐东旭

    2001-01-01

    The purpose of digital image scrambling is to transforn a given digital image into a rather scrambled one so as to make it difficult for other people to find out the true meaning of the scrambled image. This paper comes up with a certain number of approaches to scrambling digital images, which, when thus processed, cannot be reconstructed in a common way. As a result, the original image is enc yrypted and protected.

  18. Digital Textile Printing

    OpenAIRE

    Moltchanova, Julia

    2011-01-01

    Rapidly evolving technology of digital printing opens new opportunities on many markets. One of them is the printed fabric market where printing companies as well as clients benefit from new printing methods. This thesis focuses on the digital textile printing technology and its implementation for fabric-on-demand printing service in Finland. The purpose of this project was to study the technology behind digital textile printing, areas of application of this technology, the requirements ...

  19. Digitally Financed Energy

    OpenAIRE

    Waldron, Daniel; Faz, Xavier

    2016-01-01

    The expansion of digital finance systems in the developing world has altered this financial context and enabled new business models that rely on small, regular payments. In the off-grid energy sector a group of solar companies, primarily in East Africa and South Asia, are leveraging digital finance to offer pay-as-you-go (PAYG) energy. This brief explains how digital finance is enabling PA...

  20. Emergence of Digital Twins

    OpenAIRE

    Datta, Shoumen Palit Austin

    2016-01-01

    Multiple forms of digital transformation are imminent. Digital Twins represent one concept. It is gaining momentum because it may offer real-time transparency. Rapid diffusion of digital duplicates faces hurdles due to lack of semantic interoperability between architectures, standards and ontologies. The technologies necessary for automated discovery are in short supply. Progression of the field depends on convergence of information technology, operational technology and protocol-agnostic tel...

  1. Digital piracy: Theory

    OpenAIRE

    Belleflamme, Paul; Peitz, Martin

    2010-01-01

    This article reviews recent theoretical contributions on digital piracy. It starts by elaborating on the reasons for intellectual property protection, by reporting a few facts about copyright protection, and by examining reasons to become a digital pirate. Next, it provides an exploration of the consequences of digital piracy, using a base model and several extensions (with consumer sampling, network effects, and indirect appropriation). A closer look at market-structure implications of end-u...

  2. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ken D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinn, Edward L. [Technology Resources, Dana Point, CA (United States); Mauck, Jerry L. [Technology Resources, Dana Point, CA (United States); Bockhorst, Richard M. [Technology Resources, Dana Point, CA (United States)

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  3. Easy digital engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Dal Bok

    2002-02-15

    This book lists basic of digital engineering, number system and digital code, Boolean algebra and basic logic circuit, simplify of logical expression, combinational circuit, arithmetic circuit, multivibrator circuit, sequential circuit, memory unit of semiconductor and logical element for program, D/A converter and A/D converter, logic element and integrated circuit and logic circuit and micro controller. It has exercises and answers about digital engineering and summary in the end of each chapter.

  4. Digital collections and exhibits

    CERN Document Server

    Denzer, Juan

    2015-01-01

    Today's libraries are taking advantage of cutting-edge technologies such as flat panel displays using touch, sound, and hands-free motions to design amazing exhibits using everything from simple computer hardware to advanced technologies such as the Microsoft Kinect. Libraries of all types are striving to add new interactive experiences for their patrons through exciting digital exhibits, both online and off. Digital Collections and Exhibits takes away the mystery of designing stunning digital exhibits to spotlight library trea

  5. Debunking the "Digital Native": Beyond Digital Apartheid, towards Digital Democracy

    Science.gov (United States)

    Brown, C.; Czerniewicz, L.

    2010-01-01

    This paper interrogates the currently pervasive discourse of the "net generation" finding the concept of the "digital native" especially problematic, both empirically and conceptually. We draw on a research project of South African higher education students' access to and use of Information and Communication Technologies (ICTs) to show that age is…

  6. Digitally-Driven Architecture

    Directory of Open Access Journals (Sweden)

    Henriette Bier

    2014-07-01

    Full Text Available The shift from mechanical to digital forces architects to reposition themselves: Architects generate digital information, which can be used not only in designing and fabricating building components but also in embedding behaviours into buildings. This implies that, similar to the way that industrial design and fabrication with its concepts of standardisation and serial production influenced modernist architecture, digital design and fabrication influences contemporary architecture. While standardisation focused on processes of rationalisation of form, mass-customisation as a new paradigm that replaces mass-production, addresses non-standard, complex, and flexible designs. Furthermore, knowledge about the designed object can be encoded in digital data pertaining not just to the geometry of a design but also to its physical or other behaviours within an environment. Digitally-driven architecture implies, therefore, not only digitally-designed and fabricated architecture, it also implies architecture – built form – that can be controlled, actuated, and animated by digital means.In this context, this sixth Footprint issue examines the influence of digital means as pragmatic and conceptual instruments for actuating architecture. The focus is not so much on computer-based systems for the development of architectural designs, but on architecture incorporating digital control, sens­ing, actuating, or other mechanisms that enable buildings to inter­act with their users and surroundings in real time in the real world through physical or sensory change and variation.

  7. Digital Differential Geometry Processing

    Institute of Scientific and Technical Information of China (English)

    Xin-Guo Liu; Hu-Jun Bao; Qun-Sheng Peng

    2006-01-01

    The theory and methods of digital geometry processing has been a hot research area in computer graphics, as geometric models serves as the core data for 3D graphics applications. The purpose of this paper is to introduce some recent advances in digital geometry processing, particularly mesh fairing, surface parameterization and mesh editing, that heavily use differential geometry quantities. Some related concepts from differential geometry, such as normal, curvature, gradient,Laplacian and their counterparts on digital geometry are also reviewed for understanding the strength and weakness of various digital geometry processing methods.

  8. Digitization Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Fei [Los Alamos National Laboratory; Holtkamp, Irma S. [Los Alamos National Laboratory; Knudson, Frances L. [Los Alamos National Laboratory

    2012-07-31

    This project involved performing tests and documenting results to determine best practices for digitizing older print documents. The digitization process is complicated, especially when original documents exhibit non-standard fonts and are faded. Tests focused on solutions to improve high quality scanning, increase OCR accuracy, and efficiently use embedded metadata. Results are summarized. From the test results on the right sides, we know that when we plan to digitize documents, we should balance Quantity and Quality based on our expectation, and then make final decision for the digitization process.

  9. Digital Audio Legal Recorder

    Data.gov (United States)

    Department of Transportation — The Digital Audio Legal Recorder (DALR) provides the legal recording capability between air traffic controllers, pilots and ground-based air traffic control TRACONs...

  10. The digital media handbook

    CERN Document Server

    Dewdney, Andrew

    2013-01-01

    The new edition of The Digital Media Handbook presents an essential guide to the historical and theoretical development of digital media, emphasising cultural continuity alongside technological change, and highlighting the emergence of new forms of communication in contemporary networked culture.Andrew Dewdney and Peter Ride present detailed critical commentary and descriptive historical accounts, as well as a series of interviews from a range of digital media practitioners, including producers, developers, curators and artists.The Digital Media Handbook highlights key concerns of today's prac

  11. Digital security technology simplified.

    Science.gov (United States)

    Scaglione, Bernard J

    2007-01-01

    Digital security technology is making great strides in replacing analog and other traditional security systems including CCTV card access, personal identification and alarm monitoring applications. Like any new technology, the author says, it is important to understand its benefits and limitations before purchasing and installing, to ensure its proper operation and effectiveness. This article is a primer for security directors on how digital technology works. It provides an understanding of the key components which make up the foundation for digital security systems, focusing on three key aspects of the digital security world: the security network, IP cameras and IP recorders.

  12. The Digital Turn

    NARCIS (Netherlands)

    Westera, Wim

    2013-01-01

    Westera, W. (2013, 22 May). The Digital Turn. How the internet transforms our existence. Invited presentation at the symposium "Onderwijsvernieuwen in crisistijd", Heerlen, The Netherlands: Open Universiteit.

  13. Digitization Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Fei [Los Alamos National Laboratory; Holtkamp, Irma S. [Los Alamos National Laboratory; Knudson, Frances L. [Los Alamos National Laboratory

    2012-07-31

    This project involved performing tests and documenting results to determine best practices for digitizing older print documents. The digitization process is complicated, especially when original documents exhibit non-standard fonts and are faded. Tests focused on solutions to improve high quality scanning, increase OCR accuracy, and efficiently use embedded metadata. Results are summarized. From the test results on the right sides, we know that when we plan to digitize documents, we should balance Quantity and Quality based on our expectation, and then make final decision for the digitization process.

  14. Cognitive Hacking and Digital Government: Digital Identity

    Directory of Open Access Journals (Sweden)

    Paul Thompson

    2004-04-01

    Full Text Available Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation systems. Most discussion at the workshop focused on issues related to authentication of users of digital government, but, as implied by the inclusion of a scenario related to ubiquitous identity theft, there was also discussion of problems related to misinformation, including cognitive hacking. Cognitive hacking refers to a computer or information system attack that relies on changing human users' perceptions and corresponding behaviors in order to succeed. This paper describes cognitive hacking, suggests countermeasures, and discusses the implications of cognitive hacking for identity in digital government. In particular, spoofing of government websites and insider misuse are considered.

  15. Cognitive Hacking and Digital Government: Digital Identity

    Directory of Open Access Journals (Sweden)

    Paul Thompson

    2004-04-01

    Full Text Available Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation systems. Most discussion at the workshop focused on issues related to authentication of users of digital government, but, as implied by the inclusion of a scenario related to ubiquitous identity theft, there was also discussion of problems related to misinformation, including cognitive hacking. Cognitive hacking refers to a computer or information system attack that relies on changing human users' perceptions and corresponding behaviors in order to succeed. This paper describes cognitive hacking, suggests countermeasures, and discusses the implications of cognitive hacking for identity in digital government. In particular, spoofing of government websites and insider misuse are considered.

  16. Virtual Identity and Digital Reading

    OpenAIRE

    Carlos Rodríguez Gordo

    2014-01-01

    This article firstly addresses a terminological clarification of the concepts of "digital identity", "digital reputation" and "digital fingerprint". On the second hand, it tries to think about the overall online activity of the digital subject, understood through the concept of “prosumer”, to lastly focus more specifically in the practical consequences of the progressive digitalization of reading.

  17. New techniques in digital holography

    CERN Document Server

    Picart, Pascal

    2015-01-01

    A state of the art presentation of important advances in the field of digital holography, detailing advances related to fundamentals of digital holography, in-line holography applied to fluid mechanics, digital color holography, digital holographic microscopy, infrared holography, special techniques in full field vibrometry and inverse problems in digital holography

  18. Prevention and Control Mode and Practice of Diabetic Fundus Lesions Based on the Mobile Internet Fundus Imaging%基于移动互联网眼底成像的 糖尿病眼底病变防控模式与实践研究

    Institute of Scientific and Technical Information of China (English)

    梁志伟; 周丽文; 张晓阳; 徐宁; 梁倩蓉; 赖小平; 袁野; 周毅

    2016-01-01

    Objective:To provide technical support to the screening of fundus lesions of diabetics in the jurisdiction carried out by grassroots communities, remote specialized agencies and teams, and improve the prevention and control capacity of major chronic non-communicable diseases. Methods:A flow chart which can be used in the prevention and control of a single major chronic non-communicable disease and has business-information-financial flow and value co-win; 20 test objects are selected, the ophthalmoscope is carried a hand to take photos for their fundus, and then through the collaborative service platform images collected are delivered to a specialized agency and a team in a another place for study; residents are asked on site, or the follow-up is completed one week after the activity for further screening and analysis. Results:Among 20 test objects selected, 17 people accept and participate in the trial test, of which fundus lesions are found in 8 people. One has fundus bleeding with high blindness risk characterization. Conclusion:Through the collaborative healthcare service of the hand-held ophthalmoscope and the interconnected and mobile operating platform, the screening of diabetic fundus lesions of residents is carried out for the regional prevention and control. The regional healthcare collaborative win-win service mode can be build, so as to help to improve the prevention and control capacity of major chronic non-communicable diseases.%目的:为基层社区、远程专科机构和团队共同对辖区糖尿病患者眼底病变开展筛查提供技术支持,提升重大慢性非传染性疾病防控能力.方法:设计一个可用于防控某单种重大慢性非传染性疾病、具有业务-信息-金融互流,以及价值共赢的流程图;选出20名拟预试对象,采用手持眼底镜对其眼底部进行拍照,再通过协同服务平台将所采集图片远程传送到异地的专科机构和团队进行研读;对居民现场询问或活动结束一

  19. Digital Video Editing

    Science.gov (United States)

    McConnell, Terry

    2004-01-01

    Monica Adams, head librarian at Robinson Secondary in Fairfax country, Virginia, states that librarians should have the technical knowledge to support projects related to digital video editing. The process of digital video editing and the cables, storage issues and the computer system with software is described.

  20. Educating Digital Citizens

    Science.gov (United States)

    Tan, Thomas

    2011-01-01

    Digital citizenship is how educators, citizens, and parents can teach where the lines of cyber safety and ethics are in the interconnected online world their students will inhabit. Aside from keeping technology users safe, digital citizenship also prepares students to survive and thrive in an environment embedded with information, communication,…

  1. Improved digital thermometer design.

    Science.gov (United States)

    Swift, C S

    1981-01-01

    A simple digital thermometer design using a self-contained 3 1/2 digit LCD meter module is presented. The Celsius-reading (Centigrade) thermometer is powered by a single 9-V battery, has very low power drain, and uses an inexpensive NPN silicon transistor for the temperature sensor. A short bibliography on temperature measurement instrumentation is included.

  2. Handwritten Digits Recognition

    OpenAIRE

    Grand, Eric

    2000-01-01

    My work of diploma consisted in developing a Windows application for the recognition of the handwritten digits. The source images come from a pen-scanner. The user can also draw the digits directly with the mouse and do the recognition of it. In this software, I integrated the SVM Light reconizer.

  3. Digital Video in Research

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2012-01-01

    as for TED Talks, podcasting and e-learning projects hosted by universities, museums and other institutions. These new audiovisual digital storytelling practices are considered “video” texts in this paper. The increasing adaptation of video for academic purposes reflects overarching changes in digital media...

  4. Changing State Digital Libraries

    Science.gov (United States)

    Pappas, Marjorie L.

    2006-01-01

    Research has shown that state virtual or digital libraries are evolving into websites that are loaded with free resources, subscription databases, and instructional tools. In this article, the author explores these evolving libraries based on the following questions: (1) How user-friendly are the state digital libraries?; (2) How do state digital…

  5. Digital formidling af kulturarv

    DEFF Research Database (Denmark)

    En af tidens store kulturelle dagsordner drejer sig om digital tilgængeliggørelse af kulturarv. Fortidens spor dukker op i nye former på nettet - næsten alle kulturinstitutioner arbejder med, og befolkningen har fået helt nye muligheder for at se med og deltage. Digital formidling af kulturarv...

  6. Digital signage sobre IP

    OpenAIRE

    Casademont Filella, Albert

    2012-01-01

    Projecte que versa sobre el disseny i la implementació d'un sistema de Digital Signage (Cartelleria Digital) sobre IP, creant un gestor que permeti controlar de forma remota tot un conjunt de petits dispositius connectats a pantalles que emeten continguts multimèdia com vídeos, imatges, feeds rss...

  7. Scholars | Digital Representation | Publishing

    Science.gov (United States)

    Hodgson, Justin

    2014-01-01

    Understanding the current state of digital publishing means that writers can now do more and say more in more ways than ever before in human history. As modes, methods, media and mechanisms of expression mutate into newer and newer digital forms, writers find themselves at a moment when they can create, critique collaborate, and comment according…

  8. Mapping digital media: Netherlands

    NARCIS (Netherlands)

    de Waal, M.; Leurdijk, A.; Nordeman, L.; Poell, T.

    2012-01-01

    The Mapping Digital Media project examines the global opportunities and risks created by the transition from traditional to digital media. Covering 60 countries, the project examines how these changes affect the core democratic service that any media system should provide: news about political,

  9. Digital Knowledge Resources

    Science.gov (United States)

    Pandian, M. Paul

    2008-01-01

    Technology has revolutionized the concept of libraries. Networking and computing technologies have now become sufficiently advanced to support the design and deployment of large digital libraries which are capable of supporting the conventional end-user functions. Digital libraries are a natural extension of the evolution in which libraries have…

  10. Changing State Digital Libraries

    Science.gov (United States)

    Pappas, Marjorie L.

    2006-01-01

    Research has shown that state virtual or digital libraries are evolving into websites that are loaded with free resources, subscription databases, and instructional tools. In this article, the author explores these evolving libraries based on the following questions: (1) How user-friendly are the state digital libraries?; (2) How do state digital…

  11. Digitizing migration heritage

    DEFF Research Database (Denmark)

    Marselis, Randi

    2011-01-01

    Museums are increasingly digitizing their collections and making them available to the public on-line. Creating such digital resources may become means for social inclusion. For museums that acknowledge migration history and cultures of ethnic minority groups as important subjects in multiethnic...

  12. Interactive digital art

    NARCIS (Netherlands)

    Spinhoven van Oosten, Bill; van der Zwaag, B.J.; Meratnia, Nirvana; Hallnäs, L.; Hellström, A.; Landin, H.

    2011-01-01

    In this paper, we present DNArt in general, our work in DNArt’s lab including a detailed presentation of the first artwork that has come out of our lab in September 2011, entitled “ENCOUNTERS #3‿, and the use of DNArt for digital art conservation. Research into the use of DNArt for digital art

  13. The Digital Absurd

    Science.gov (United States)

    Hodges, Steve

    2010-01-01

    I believe that the concept of the absurd, as described in philosophy and reflected in works of drama and literature, provides an unusual and helpful perspective from which to view the emerging field of digital media. In my opinion, absurd principles can help us understand the mixed feelings we may have when engaging with digital media: joy and…

  14. Star photographer goes digital

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> Steve McCurry is an appointed photographer of National Geo graphic magazine. Invited bySony, he attended the Sony Cyber-shot F828 digital camera product launch. He exchanged ideas with Chinese journalists and photographers regarding digital camera technology, as well as photographic techniques and experiences.

  15. Digital Signature Management.

    Science.gov (United States)

    Hassler, Vesna; Biely, Helmut

    1999-01-01

    Describes the Digital Signature Project that was developed in Austria to establish an infrastructure for applying smart card-based digital signatures in banking and electronic-commerce applications. Discusses the need to conform to international standards, an international certification infrastructure, and security features for a public directory…

  16. The politics of digits

    DEFF Research Database (Denmark)

    Olsen, Asmus Leth

    2013-01-01

    From the concept of odd pricing, i.e., setting rightmost price digits below a whole number, this paper advances the political counterpart of odd taxation using a panel of Danish municipal taxes. First, the distribution of tax decimals is non-uniform and resembles the distribution of price...... to how policy digits are arranged to exploit voters’ cognitive biases....

  17. Digital Knowledge Resources

    Science.gov (United States)

    Pandian, M. Paul

    2008-01-01

    Technology has revolutionized the concept of libraries. Networking and computing technologies have now become sufficiently advanced to support the design and deployment of large digital libraries which are capable of supporting the conventional end-user functions. Digital libraries are a natural extension of the evolution in which libraries have…

  18. Monetizing Digital Assets

    Directory of Open Access Journals (Sweden)

    Felician ALECU

    2013-04-01

    Full Text Available This article covers the options the digital content creators have to monetize their creations. The simplest solution seems to be the winning one, so by enabling the ads, the digital content may be quickly transformed into money with no cost.

  19. Digital automatic gain control

    Science.gov (United States)

    Uzdy, Z.

    1980-01-01

    Performance analysis, used to evaluated fitness of several circuits to digital automatic gain control (AGC), indicates that digital integrator employing coherent amplitude detector (CAD) is best device suited for application. Circuit reduces gain error to half that of conventional analog AGC while making it possible to automatically modify response of receiver to match incoming signal conditions.

  20. Digital Pinhole Camera

    Science.gov (United States)

    Lancor, Rachael; Lancor, Brian

    2014-01-01

    In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

  1. Digital Media and Learning

    Science.gov (United States)

    John D. and Catherine T. MacArthur Foundation, 2012

    2012-01-01

    MacArthur launched the digital media and learning initiative in 2006 to explore how digital media are changing the way young people learn, socialize, communicate, and play. Since 2006, the Foundation has awarded grants totaling more than $100 million for research, development of innovative new technologies, new learning environments for youth,…

  2. Mapping digital media: Netherlands

    NARCIS (Netherlands)

    de Waal, M.; Leurdijk, A.; Nordeman, L.; Poell, T.

    2012-01-01

    The Mapping Digital Media project examines the global opportunities and risks created by the transition from traditional to digital media. Covering 60 countries, the project examines how these changes affect the core democratic service that any media system should provide: news about political, econ

  3. Practical digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Beverly E. [Washington Univ., Seattle, WA (United States)]|[Virginia Mason Medical Center, VA (United States)

    2008-07-01

    This book is meant for the radiologist who is facing the challenge of organizing a digital mammographic imaging center. This text is meant to be a practical book that provides information about digital mammographic physics and equipment which will allow one to intelligently compare technologies and systems. Some of the major challenges include: large expense; rapidly changing technology, and inconsistent connectivity; and finally, need for strong information technology support. The initial conversion cost to digital mammographic imaging is relatively expensive due to the cost of digital mammography hardware, software, and storage. Virtually all other imaging modalities are being converted to purely digital storage and transfer, and the digital trend in mammography is inevitable. Technical advantages of digital mammography are described. However, the improved flexibility in image display and transfer are some of its strongest features. In conclusion, although there are increasing imaging modalities that may be used to evaluate breast disease, mammography will continue to play a key role in detecting breast cancer. To be an effective imager, the radiologist should become familiar with digital mammography and understand its role within the increasing complex structure of breast imaging techniques.

  4. Digital Line Graph - Large Scale

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital line graph (DLG) data are digital representations of cartographic information. DLGs of map features are converted to digital form from maps and related...

  5. Digital Line Graph - Large Scale

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital line graph (DLG) data are digital representations of cartographic information. DLGs of map features are converted to digital form from maps and related...

  6. Digital forensic standards: international progress

    CSIR Research Space (South Africa)

    Grobler, MM

    2010-05-01

    Full Text Available With the explosion of digital crime, digital forensics is more often applied. The digital forensic discipline developed rather rapidly, but up to date very little international standardization with regard to processes, procedures or management has...

  7. Parallel digital forensics infrastructure.

    Energy Technology Data Exchange (ETDEWEB)

    Liebrock, Lorie M. (New Mexico Tech, Socorro, NM); Duggan, David Patrick

    2009-10-01

    This report documents the architecture and implementation of a Parallel Digital Forensics infrastructure. This infrastructure is necessary for supporting the design, implementation, and testing of new classes of parallel digital forensics tools. Digital Forensics has become extremely difficult with data sets of one terabyte and larger. The only way to overcome the processing time of these large sets is to identify and develop new parallel algorithms for performing the analysis. To support algorithm research, a flexible base infrastructure is required. A candidate architecture for this base infrastructure was designed, instantiated, and tested by this project, in collaboration with New Mexico Tech. Previous infrastructures were not designed and built specifically for the development and testing of parallel algorithms. With the size of forensics data sets only expected to increase significantly, this type of infrastructure support is necessary for continued research in parallel digital forensics. This report documents the implementation of the parallel digital forensics (PDF) infrastructure architecture and implementation.

  8. Digital Technology Entrepreneurship

    DEFF Research Database (Denmark)

    Giones, Ferran; Brem, Alexander

    2017-01-01

    Technology entrepreneurship is an established concept in academia. However, recent developments in the context of digital entrepreneurship call for revision and advance- ment. The multiple possible combinations of technology and entrepreneurship have res- ulted in a diversity of phenomena...... with significantly different characteristics and socio-economic impact. This article is focused on the identification and description of technology entrepreneurship in times of digitization. Based on current examples, we identify and describe characterizations of technology entrepreneurship, digital techno- logy...... entrepreneurship, and digital entrepreneurship. With this new delineation of terms, we would like to foster discussion between researchers, entrepreneurs, and policy makers on the impact of digitization on entrepreneurship, and set a future research agenda....

  9. Transformation of Digital Ecosystems

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Hedman, Jonas

    2014-01-01

    In digital ecosystems, the fusion relation between business and technology means that the decision of technical compatibility of the offering is also the decision of how to position the firm relative to the coopetive relations that characterize business ecosystems. In this article we develop...... the Digital Ecosystem Technology Transformation (DETT) framework for explaining technology-based transformation of digital ecosystems by integrating theories of business and technology ecosystems. The framework depicts ecosystem transformation as distributed and emergent from micro-, meso-, and macro- level...... coopetition. The DETT framework consists an alternative to the existing explanations of digital ecosystem transformation as the rational management of one central actor balancing ecosystem tensions. We illustrate the use of the framework by a case study of transformation in the digital payment ecosystem...

  10. Creative Digital Media Practices

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    The presentation reviews the interplay of dialogic (Bakhtin, 1981) and multimodal theories on media production practices, with attention to visual communication (Kress and van Leeuwen, 2001, 2006). This theoretical approach aids in reflecting on digital media practices as novel (new) sign systems...... on collaboration (Benkler, 2006). The shift toward visual modes and digital media practices pose many pedagogical challenges for academics. I want to raise questions on how to teach “dialogically” with and through creative, digital media practices based on my plans for a course in Fall, 2011, where students...... develop a collaborative digital storytelling showcase for their own digital stories about Roskilde University. This course is intended to bring up reflections on the wider phenomenon of contemporary media practices, such as: YouTube, DIY (do-it-yourself) filmmaking or homemade, garage cinema (Jenkins...

  11. Predictive dynamic digital holography

    Science.gov (United States)

    Sulaiman, Sennan; Gibson, Steve; Spencer, Mark

    2016-09-01

    Digital holography has received recent attention for many imaging and sensing applications, including imaging through turbulent and turbid media, adaptive optics, three dimensional projective display technology and optical tweezing. A significant obstacle for digital holography in real-time applications, such as wavefront sensing for high energy laser systems and high speed imaging for target tracking, is the fact that digital holography is computationally intensive; it requires iterative virtual wavefront propagation and hill-climbing to optimize some sharpness criteria. This paper demonstrates real-time methods for digital holography based on approaches developed recently at UCLA for optimal and adaptive identification, prediction, and control of optical wavefronts. The methods presented integrate minimum variance wavefront prediction into digital holography schemes to short-circuit the computationally intensive algorithms for iterative propagation of virtual wavefronts and hill climbing for sharpness optimization.

  12. Principles of synchronous digital hierarchy

    CERN Document Server

    Jain, Rajesh Kumar

    2012-01-01

    The book presents the current standards of digital multiplexing, called synchronous digital hierarchy, including analog multiplexing technologies. It is aimed at telecommunication professionals who want to develop an understanding of digital multiplexing and synchronous digital hierarchy in particular and the functioning of practical telecommunication systems in general. The text includes all relevant fundamentals and provides a handy reference for problem solving or defining operations and maintenance strategies. The author covers digital conversion and TDM principles, line coding and digital

  13. Computing Logarithms Digit-by-Digit

    Science.gov (United States)

    Goldberg, Mayer

    2005-01-01

    In this work, we present an algorithm for computing logarithms of positive real numbers, that bears structural resemblance to the elementary school algorithm of long division. Using this algorithm, we can compute successive digits of a logarithm using a 4-operation pocket calculator. The algorithm makes no use of Taylor series or calculus, but…

  14. The Digital Carrot, the Digital Stick

    Science.gov (United States)

    Jackson, Gregory A.

    2007-01-01

    In this article, the author asserts that technology is not the answer to digital piracy at colleges and universities. Citing the three most common explanations given for copyright infringement--that students cannot always get what they want, cannot always use what they can get, or think the price of what they can get is unfair--he asserts that the…

  15. Research on Digital Product Modeling Key Technologies of Digital Manufacturing

    Institute of Scientific and Technical Information of China (English)

    DING Guoping; ZHOU Zude; HU Yefa; ZHAO Liang

    2006-01-01

    With the globalization and diversification of the market and the rapid development of Information Technology (IT) and Artificial Intelligence (AI), the digital revolution of manufacturing is coming. One of the key technologies in digital manufacturing is product digital modeling. This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle, then researches on the three critical technologies of digital modeling in digital manufacturing-product modeling, standard for the exchange of product model data and digital product data management. And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features, applies STEP as data exchange mechanism, and establishes PDM system to manage the large amount, complicated and dynamic product data to implement the product digital model data exchange, sharing and integration.

  16. 产科应用宫底按压助产的价值分析%Value Analysis of the Application of Fundus Pressing Midwifery in Obstetric Midwifery

    Institute of Scientific and Technical Information of China (English)

    陈丽

    2016-01-01

    目的:探析宫底按压助产运用在产科助产中的临床价值。方法:选择2014年2月-2015年2月来笔者所在医院分娩的产妇150例为研究对象,将其随机分为两组,每组75例,其中对照组采用常规分娩方式,而观察组则运用宫底按压助产,对两组的分娩情况进行对比分析。结果:与对照组比较,观察组的阴道自然分娩率较高,产妇会阴撕裂率和新生儿窒息率均较低,组间比较差异均有统计学意义(P<0.05);同时,两组的第二产程分娩时间比较,差异有统计学意义(P<0.05)。结论:临床上将宫底按压助产运用在产科助产中,一方面可以使第二产程时间缩短,另一方面还能使自然分娩率提高,使新生儿窒息率降低,值得推广。%Objective:To analyze the clinical value of fundus pressing midwifery in obstetric midwifery.Method:One hundred and fifty cases of puerpera admitted to our hospital from February 2014 to February 2015 were chosen as the research objects,and randomly divided into two groups,75 cases in each group, the control group was taken conventional childbirth way,while the observation group was given fundus pressing midwifery,the delivery condition of the two groups were analyzed.Result:Compared with the control group,the vaginal delivery rate of the observation group was higher,while the perineum laceration rate and neonatal asphyxia rate of which were lower,the differences were statistically significant(P<0.05).At the same time,the time of second stage of labor between thetwo groups had statistical difference(P<0.05).Conclusion:The fundus pressing midwifery is applied in obstetric midwifery,which can shorten the time of second stage of labor on the one hand,and increase the natural delivery rate on the other hand,lower the rate of neonatal asphyxia,it is worthy of promotion.

  17. Design of optical system for catadioptric fundus camera%折反式眼底相机光学系统设计

    Institute of Scientific and Technical Information of China (English)

    李灿; 宋淑梅; 刘英; 李淳; 李小虎; 孙强

    2012-01-01

    To eliminate the scatter light and central ghost in a classical fundus camera, the optical system of a catadioptric fundus camera with a field of view 40?and a working distance of 48 mm was designed. An off-axial reflecting ophthalmic lens with free form surfaces was designed to correct the off-axial aberrations. Two free-form-surfaces were introduced in the imaging objective system to correct the residual off-axial aberrations of the reflective ophthalmic lens. In the optimization of the imaging system, an eye model with varying defocuses was proposed to eliminate the negative effect of eye aberrations as well as to accommodate the eye with different refractive errors. Three adjacent illumination rings were introduced in the illumination part to avoid the undesirable light reflected by the eye optical system. Experiments show that the accommodation range of the system is between ?0 m"1 and 10 nrT1 , the resolution at the object plane is 33 lp/mm across the entire field of view,and the maximumdistortion is less than 8. 5%. Furthermore, the illumination non-uniformity is less than 15% in the conditions without scatter light and central ghost. The designed catadioptric fundus camera with a free-form-surfaces show a satisfactory large field of view and a large working distance, and removes the undesirable scatter light and central ghost greatly.%为控制传统眼底相机的杂光和鬼像,设计了一款40°视场、48 mm工作距离的折反式眼底相机光学系统.设计了离轴反射式网膜物镜,引入了自由曲面以校正其离轴像差,成像物镜中采用两个自由曲面对网膜物镜的剩余像差进行校正.建立了一种离焦眼模型,用于优化成像光路,消除人眼像差对成像的影响,同时得到不同视度缺陷眼的成像光路.照明光路中使用3个相邻的环形光阑,减少了眼球光学系统反射的杂光.成像光学系统可在-10~+10 m-1调焦,物方各视场分辨率为33 lp/mm,系统畸变小于8.5%;

  18. Agreement in Measurement of Optic Cup-to-Disc Ratio with Stereo Biomicroscope Funduscopy and Digital Image Analysis: Results from the Nigeria National Blindness and Visual Impairment Survey.

    Science.gov (United States)

    Kyari, Fatima; Gilbert, Clare

    2017-02-01

    To determine agreement in estimations of vertical cup-to-disc ratio (VCDR) between clinical stereo-biomicroscopic funduscopy and digital fundus image analysis. Systematic sampling of 1-in-7 from a sample of 13,591 participants aged ≥40 years gave a subsample who were examined in detail. VCDR was estimated clinically by 60 diopter aspheric lens biomicroscopic funduscopy (c-VCDR) and by digital fundus images (i-VCDR) graded at the Moorfields Eye Hospital Reading Centre. Spearman's correlation coefficient, paired t-test and the Bland-Altman method to assess limits of agreement (LOA) between the two methods were applied. Of 1759 participants in the subsample, 848 participants (48%) with normal frequency doubling technology (FDT) visual fields and data for i-VCDR and c-VCDR in both eyes (n = 1696 eyes) were included in the analysis. By absolute difference of VCDR values for each eye between the two methods, 1585 eyes (94%) differed by ≤0.2. Mean i-VCDR was 0.381 (standard deviation, SD 0.156), and mean c-VCDR 0.321 (SD 0.145). i-VCDRs were significantly larger by a mean difference of 0.061 (SD 0.121; 95% confidence interval, CI, 0.055-0.066; p Digital image analysis and clinical assessment are two distinct methods to measure VCDR; with larger i-VCDRs in this survey. Applying i-VCDR cut-off values to c-VCDR measurements in the Nigeria Blindness Survey might have underestimated glaucoma prevalence. It is recommended that all participants in glaucoma surveys have VCDR by digital image measurement.

  19. Digital Enlightenment Yearbook 2012

    CERN Document Server

    Bus, J; Hildebrandt, M

    2012-01-01

    There have been many inevitable transformations in society due to digitization - the introduction of digital technology, including communication technology, through the Internet and its use via the Web.This book is the first Yearbook of the Digital Enlightenment Forum. Whilst it cannot cover all the many aspects which the forum encompasses, the book gives an impression of the broad spectrum of the forum and a clear picture of the multi-disciplinary nature of the issues at stake.The first paper in the book is a contribution from the father of the Web, Sir Tim Berners-Lee, and Harry Halpin. They

  20. Encryption for digital content

    CERN Document Server

    Kiayias, Aggelos

    2010-01-01

    Encryption for Digital Content is an area in cryptography that is widely used in commercial productions (e.g., Blu-Ray and HD-DVDs). This book provides a comprehensive mathematical treatment of combinatorial encryption techniques used in digital content distribution systems and related attack models. A complete description of broadcast encryption with various revocation and tracing functionalities is included. ""Encryption for Digital Content"" introduces the subset cover framework (currently used in AACS, Blu-Ray and HD-DVDs,) and tracking/revocation mechanisms in various attack models. Pirat

  1. In a digital mood

    DEFF Research Database (Denmark)

    Brus, Anne

    2017-01-01

    “In the Mood” is a famous Glenn Miller instrumental song from the late 1930s. The song is jazzy and swingy, and you get in a dancing mood when you listen to it. It is generally accepted knowledge that music is a mood maker but how about digital media? That is the question that Richard Coyne......, a professor at the University of Edinburgh, seeks to answer in his latest book “Mood and Mobility. Navigating the Emotional Spaces of Digital Social Networks”. Coyne has written several books on architecture but in this recent work Coyne focuses on the architecture of the Internet and how digital media affect...

  2. Advanced Digital Preservation

    CERN Document Server

    Giaretta, David

    2011-01-01

    There is growing recognition of the need to address the fragility of digital information, on which our society heavily depends for smooth operation in all aspects of daily life. This has been discussed in many books and articles on digital preservation, so why is there a need for yet one more? Because, for the most part, those other publications focus on documents, images and webpages -- objects that are normally rendered to be simply displayed by software to a human viewer. Yet there are clearly many more types of digital objects that may need to be preserved, such as databases, scientific da

  3. Digital Marketing Communication

    OpenAIRE

    Corniani, Margherita

    2006-01-01

    Digital marketing communication is directed to profiled targets, which are active in the communication process. Every communication flow can ask for an information answer from the market. This opportunity grants immediate feed-backs and feed-forwards, so that digital communication can be easily and cheaply measured; digital communication flows are diffused at costs that are getting lower and lower, but it asks specialized and deep competences to communication managers. The ease in the flowing...

  4. SHDAS Production Digitizer Evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Bion J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    The Seismo-Hydroacoustic Data Acquisition System (SHDAS) is undergoing evaluation in preparation for its engineering, development, and deployment by the U.S Navy as an ocean bottom seismic monitoring system. At the current stage of development, the production digitizers are being evaluated to confirm their performance prior to packaging and assembly for deployment. The testing of the digitizers is being conducted at Delta Group Electronics, the digitizer fabricator, in San Diego, California, performed by Sandia National Laboratories with the assistance of Leidos and Delta Group Electronics.

  5. Digital Library and Digital Reference Service: Integration and Mutual Complementarity

    Science.gov (United States)

    Liu, Jia

    2008-01-01

    Both the digital library and the digital reference service were invented and have been developed under the networked environment. Among their intersections, the fundamental thing is their symbiotic interest--serving the user in a more efficient way. The article starts by discussing the digital library and its service and the digital reference…

  6. Digitization and digital archiving a practical guide for librarians

    CERN Document Server

    Leggett, Elizabeth R

    2014-01-01

    Modern library patrons are embracing the ease with which information can be accessed digitally, and so many librarians are currently working toward making information available electronically. Digitization and Digital Archiving: A Practical Guide for Librarians is a comprehensive guide with step-by-step instructions for forming digital archives.

  7. Digital culture industry a history of digital distribution

    CERN Document Server

    Allen-Robertson, James

    2013-01-01

    How did digital media happen? Through a unique approach to digital documents, and detailed intricate histories of illicit internet piracy networks, The Digital Culture Industry goes beyond the Napster creation myth and illuminates the unseen individuals, code and events behind the turn to digital media.

  8. Digital Literacy Learning in Higher Education through Digital Storytelling Approach

    Science.gov (United States)

    Chan, Banny S. K.; Churchill, Daniel; Chiu, Thomas K. F.

    2017-01-01

    It is necessary to develop digital literacy skills with which students can communicate and express their ideas effectively using digital media. The educational sectors around the world are beginning to incorporate digital literacy into the curriculum. Digital storytelling, one of the possible classroom activities, is an approach which may help…

  9. Digital functions and data reconstruction digital-discrete methods

    CERN Document Server

    Chen, Li M

    2012-01-01

    Digital Functions and Data Reconstruction: Digital-Discrete Methods provides a solid foundation to the theory of digital functions and its applications to image data analysis, digital object deformation, and data reconstruction. This new method has a unique feature in that it is mainly built on discrete mathematics with connections to classical methods in mathematics and computer sciences. Digitally continuous functions and gradually varied functions were developed in the late 1980s. A. Rosenfeld (1986) proposed digitally continuous functions for digital image analysis, especially to describe

  10. Digital literacies at school. Students' digital profiles

    Directory of Open Access Journals (Sweden)

    Valentina Pennazio

    2013-04-01

    Full Text Available L’articolo presenta una ricerca volta a focalizzare le modalità in cui la Digital Literacy si traduce a scuola. Lo studio ha inteso sottolineare le molteplici dimensioni della Digital Literacy: Information Technology Literacy; Information Literacy; Visual Literacy e Media Literacy ed è stato effettuato nelle scuole primarie e secondarie di primo grado in Liguria. Sono state organizzate settimane di attività di ricerca, analisi e rielaborazione di informazioni, in classe e in rete, individualmente e in gruppo. Dalle autovalutazione degli studenti, svolte al termine di ogni attività, sono emersi i profili digitali che gli studenti tendono ad assumere quando utilizzano le tecnologie digitali. Tali profili possono essere utilizzati dagli insegnanti per progettare in maniera più mirata e significativa le attività con le tecnologie a scuola.

  11. NLM Digital Collections

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Library of Medicine's (NLM) Digital Collections offers a search-based Web service that provides access to the Dublin Core metadata and full-text OCR of...

  12. Creative Digital Media Practices

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    on collaboration (Benkler, 2006). The shift toward visual modes and digital media practices pose many pedagogical challenges for academics. I want to raise questions on how to teach “dialogically” with and through creative, digital media practices based on my plans for a course in Fall, 2011, where students......The presentation reviews the interplay of dialogic (Bakhtin, 1981) and multimodal theories on media production practices, with attention to visual communication (Kress and van Leeuwen, 2001, 2006). This theoretical approach aids in reflecting on digital media practices as novel (new) sign systems...... and personal levels. The discussion includes pedagogical issues in regards to the upcoming university course, such as: how to encourage dialogic reflection between students as authors and viewers of digital stories, and how to support their application and integration of visual and dialogic communication...

  13. Digital Audio Collections

    Directory of Open Access Journals (Sweden)

    Jason Tenter

    2010-11-01

    Full Text Available

    This paper is about the possibility of libraries creating digital music or audio collections based on the current state of the digital music industry, and in comparison with the difficulties librarians have found in adding e-books to collections. In comparing the e-book and digital music markets, factors such as digital rights management (DRM and the differences in both markets’ relationships with customers are examined. This juxtaposition suggests that where e-books have been difficult to include in library collections because publishers want to maintain control over their content, music publishers have had to resign some of the control over their products because of file-sharing, and so may work with libraries to develop these collections in a more constructive way than e-book venders. At the end of the paper, some models are suggested for developing these collections.

  14. Academia Leads Digital Revolution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ As the Chinese book publishing industry sits nervously on the edqe of possible market economy led reforms, one key area to address will be its ability to come to terms with the onset of digital publishing.

  15. Comprehension of digital media

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Hwan

    2008-11-15

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  16. Bridging the Digital Divide

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2002-01-01

    The article concerns the digital divide, meaning the social inequity in the access and the opportunities for gaining competencies with ICT (information and communication technologies). Problematic issues are highlighted in relation to experiences during visits to several Computer Clubhouses...

  17. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    system.   Sessions in class with active participation by the students. The time will be divided between lectures and the students solving problems, including simulating digital communication building blocks in Matlab. Combines lectures and hands-on work. Semester: E2011 Extent: 7.5 ects......The course presents the fundamental principles for digital communication, e.g. fixed-wire modems or wireless communication channels, as applied in mobile phones, wireless computer networks or wireless systems in intelligent houses. Based on the functional blocks of a digital communication system......, the fundamental principles for modulation and detection in Gaussian noise is treated. This includes the principles for the determination of the bit-error rate for a digital communication system. During the course, a selection of small Matlab exercises are prepared, for simulation of parts of a communication...

  18. Developing digital forensic governance

    CSIR Research Space (South Africa)

    Grobler, M

    2010-03-01

    Full Text Available This paper presents a Digital Forensic (DF) governance framework and its mapping on the SANS ISO/IEC 38500:2009 Corporate governance of information technology structure. DF governance assists organisations in guiding the management team...

  19. Performing Digital Literature

    Directory of Open Access Journals (Sweden)

    Jerome Fletcher

    2015-11-01

    Full Text Available Digital literature is a complex assemblage of related elements –material, spatial, linguistic, performative, textual, cultural, social– each of which is at one time interdependent and detached. This article discusses the literary creation within the cyberculture from the performativity point of view in relation to the textual apparatus. This is done through the analysis of a selection of performances where physical corporeality has a collaborative function with the body to a greater or lesser degree. Therefore, this physical feature can not only change, but stand at three possible and hybridizable axes: 1 the digital text as protagonist, 2 the digital text as counterpart, and 3 the digital text as site.

  20. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    The course presents the fundamental principles for digital communication, e.g. fixed-wire modems or wireless communication channels, as applied in mobile phones, wireless computer networks or wireless systems in intelligent houses. Based on the functional blocks of a digital communication system......, the fundamental principles for modulation and detection in Gaussian noise is treated. This includes the principles for the determination of the bit-error rate for a digital communication system. During the course, a selection of small Matlab exercises are prepared, for simulation of parts of a communication...... system. Having passed the course, the student will be able to accomplish the following, within the areas shown below: Model for Communication System. Prepare and explain the functional block in a digital communication system, corresponding to the specific course contents. Model for Communication Channel...

  1. DIGITAL TRAINING TEACHER COMPETENCIES

    National Research Council Canada - National Science Library

    Jesús Arturo Regalado Sandoval

    2013-01-01

    ...” and also a need to talk about teaching skills, digital skills, project work, learning to learn in schools of all levels, as it is in this case the high school, as our young students belong to a new...

  2. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    The course presents the fundamental principles for digital communication, e.g. fixed-wire modems or wireless communication channels, as applied in mobile phones, wireless computer networks or wireless systems in intelligent houses. Based on the functional blocks of a digital communication system...... system. Having passed the course, the student will be able to accomplish the following, within the areas shown below: Model for Communication System. Prepare and explain the functional block in a digital communication system, corresponding to the specific course contents. Model for Communication Channel....... Prepare and explain a model for a communication channel, corresponding to the specific course contents. Modulation Methods. Explain the properties of digital modulation methods, corresponding to the specific course contents. Intersymbol Interference. Explain intersymbol inteference, corresponding...

  3. Digital imaging primer

    CERN Document Server

    Parkin, Alan

    2016-01-01

    Digital Imaging targets everyyone with an interest in digital imaging, be they professional or private, who uses even quite modest equipment such as a PC, digital camera and scanner, a graphics editor such as Paint, and an inkjet printer. Uniquely, it is intended to fill the gap between highly technical texts for academics (with access to expensive equipment) and superficial introductions for amateurs. The four-part treatment spans theory, technology, programs and practice. Theory covers integer arithmetic, additive and subtractive color, greyscales, computational geometry, and a new presentation of discrete Fourier analysis; Technology considers bitmap file structures, scanners, digital cameras, graphic editors, and inkjet printers; Programs develops several processing tools for use in conjunction with a standard Paint graphics editor and supplementary processing tools; Practice discusses 1-bit, greyscale, 4-bit, 8-bit, and 24-bit images for the practice section. Relevant QBASIC code is supplied an accompa...

  4. Digital Raster Graphics

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) topographic map. The scanned image includes all map collar information. The...

  5. TV Digital Station Transmitters

    Data.gov (United States)

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Digital Television broadcasters (see Rule Part47...

  6. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    The course presents the fundamental principles for digital communication, e.g. fixed-wire modems or wireless communication channels, as applied in mobile phones, wireless computer networks or wireless systems in intelligent houses. Based on the functional blocks of a digital communication system......, the fundamental principles for modulation and detection in Gaussian noise is treated. This includes the principles for the determination of the bit-error rate for a digital communication system. During the course, a selection of small Matlab exercises are prepared, for simulation of parts of a communication...... system. Having passed the course, the student will be able to accomplish the following, within the areas shown below: Model for Communication System. Prepare and explain the functional block in a digital communication system, corresponding to the specific course contents. Model for Communication Channel...

  7. DIGITAL ERA: UTILIZE OF CLOUD COMPUTING TECHNOLOGY IN DIGITAL LIBRARY

    Directory of Open Access Journals (Sweden)

    T. RAGHUNADHA REDDY

    2012-09-01

    Full Text Available With the purpose of applying cloud computing to digital library, the paper initially describes cloud computing and analyzes current status of cloud computing in digital library. Then it proposes the architecture of cloud computing in digital library and summarises the application of cloud computing in digital library. Finally the author brings out the future improvement in digital library using cloud computing technology.

  8. Digital and analog communication systems

    Science.gov (United States)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  9. The Coevolution of Digital Ecosystems

    Science.gov (United States)

    SungYong, Um

    2016-01-01

    Digital ecosystems are one of the most important strategic issues in the current digital economy. Digital ecosystems are dynamic and generative. They evolve as new firms join and as heterogeneous systems are integrated into other systems. These features digital ecosystems determine economic and technological success in the competition among…

  10. Digital imaging a practical approach

    CERN Document Server

    Koelling, Jill Marie

    2004-01-01

    Digital Imaging is the essential guide to understanding digitization and managing a digitizing project. Koelling covers everything from deciding if digitizing is for you to planning and management, choosing equipment, and managing databases. Not only does she guide you in mastering the technical details, she also helps you find the fun in working with images.

  11. Escaping the Digital Dark Age.

    Science.gov (United States)

    Brand, Stewart

    1999-01-01

    Discusses the loss of stored knowledge due to the continuous obsolescence of digital formats and platforms. Topics include digital storage versus digital preservation; the use of metadata and efforts to create standards for it; information on the Internet; and the need for long-term planning to solve digital degradation. (LRW)

  12. Digital Interactive TV Network Architecture

    Institute of Scientific and Technical Information of China (English)

    Vincent; Dureau

    2001-01-01

    Introduction The infrastructure of digital TV is evolving very rapidly.TheTV infrastructure is quickly migrating from analog to digital TV.Even though digital transmission really launched only 10 yearsago.there are already more than 50 M digital receivers worldwide.

  13. The Web and Digital Humanities

    DEFF Research Database (Denmark)

    Brügger, Niels; Finnemann, Niels Ole

    2013-01-01

    and archived Web materials. It is argued that both of these characteristics differ from the concepts of digital materials developed within the frameworks of digital humanities and that the growing variety of different kinds of digital materials and processes calls for a reinterpretation of the computer......, stressing the variability of the functional architecture of digital media....

  14. The Coevolution of Digital Ecosystems

    Science.gov (United States)

    SungYong, Um

    2016-01-01

    Digital ecosystems are one of the most important strategic issues in the current digital economy. Digital ecosystems are dynamic and generative. They evolve as new firms join and as heterogeneous systems are integrated into other systems. These features digital ecosystems determine economic and technological success in the competition among…

  15. Fabelagtig digital isvinter

    DEFF Research Database (Denmark)

    Mygind, Sarah

    2015-01-01

    Hybrid: Merete Pryds Helles litterære app sætter helt nye standarder for digital litteratur til børn. Hos ”Wuwu & Co.” kan man hverken tie eller sidde stille.......Hybrid: Merete Pryds Helles litterære app sætter helt nye standarder for digital litteratur til børn. Hos ”Wuwu & Co.” kan man hverken tie eller sidde stille....

  16. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18...

  17. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9...

  18. Digital Heritage Experiences

    DEFF Research Database (Denmark)

    Munar, Ana Maria; Ooi, Can-Seng

    The evolution of the Web and the expansion of social media are transforming our heritage experiences. Social media offer an innovative element to personal travel reflections by providing digital global platforms on which tourists can create and publish their travel stories. Social media transform...... the traditional creative processes, distribution mechanisms and consumption patterns of these experiences. This study provides insight on how personal heritage moments are constructed, digitalized and shared. The methodological perspective adopted draws on a constructivist epistemology (Markham 2004...

  19. Prensa digital en 2006

    OpenAIRE

    2007-01-01

    Radiography about the situation of digital press in Spain in the beginning of 2006, including the next points: number of digital media, multimedia evolution, media without printed counterparts, participation services, search systems, free versus payment, and distribution with rss. The article includes a discussion in the IweTel list with the participation of Lluís Codina, Jorge Serrano Cobos, Àngels Jiménez and Rosana López Carreño.

  20. Boundaries in digital planes

    Directory of Open Access Journals (Sweden)

    Efim Khalimsky

    1990-01-01

    Full Text Available The importance of topological connectedness properties in processing digital pictures is well known. A natural way to begin a theory for this is to give a definition of connectedness for subsets of a digital plane which allows one to prove a Jordan curve theorem. The generally accepted approach to this has been a non-topological Jordan curve theorem which requires two different definitions, 4-connectedness, and 8-connectedness, one for the curve and the other for its complement.

  1. Digital scholarship, tenure & barometers

    OpenAIRE

    Weller, Martin

    2012-01-01

    Martin Weller highlights the essential responsibility on the side of the university in institutionalising recognition and reward for academics’ digital activities. Furthermore, he argues a university’s response on digital practice can serve as a barometer for their own overall innovation and success. This article originally appeared on Martin Weller’s personal blog, The Ed Techie and is reposted under a Creative Commons License.

  2. Fabelagtig digital isvinter

    DEFF Research Database (Denmark)

    Mygind, Sarah

    2015-01-01

    Hybrid: Merete Pryds Helles litterære app sætter helt nye standarder for digital litteratur til børn. Hos ”Wuwu & Co.” kan man hverken tie eller sidde stille.......Hybrid: Merete Pryds Helles litterære app sætter helt nye standarder for digital litteratur til børn. Hos ”Wuwu & Co.” kan man hverken tie eller sidde stille....

  3. Traditional to Digital Books

    Institute of Scientific and Technical Information of China (English)

    JING XIAOLEI

    2010-01-01

    @@ A book fair wouldn't be a book fair without books.And while the number of book fairs in China has increased in recent years,the Guangzhou Book Fair has been helping to redefine the very nature of books by promoting digital works and reading technology.This year,the fair again set up an exclusive digital reading experience exhibition hall to showcase the host province's latest achievements in the field.

  4. Digital Identity Management Systems

    OpenAIRE

    Kuhar, Marko

    2010-01-01

    The goal of this thesis is a review of existing systems and technologies for managing digital identities. After the selection of the two most promising systems there will be a detailed comparison for a typical environment. In the first part of my thesis, the theory for understanding issues of identity management is introduced. Furthermore, the difference between identity and digital identity is explained and identity management itself is interpreted. An example of identity management solut...

  5. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18...

  6. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9...

  7. Advanced digital optical communications

    CERN Document Server

    Binh, Le Nguyen

    2015-01-01

    This book provides a fundamental understanding of digital communication applications in optical communication technologies. Emphasizing operation principles versus mathematical analysis, the Second Edition includes new coverage of superchannel optical transmission systems, metropolitan and long-haul optical systems and networks, and Nyquist pulse shaping and high spectral efficiency of optical transmission systems, as well as new homework problems and examples. Featuring theoretical foundations as well as practical case studies, the text focuses on enhancements to digital technologies that are

  8. Digitalization of daycare institutions

    DEFF Research Database (Denmark)

    Chimirri, Niklas Alexander

    The digitalization of Danish daycare institutions is not only affecting the ways staff is documenting and reporting on its pedagogical work. It also appears to be redefining what pedagogical work itself is about, given the drastic increase in deployment of digital (mobile) media devices in the in......The digitalization of Danish daycare institutions is not only affecting the ways staff is documenting and reporting on its pedagogical work. It also appears to be redefining what pedagogical work itself is about, given the drastic increase in deployment of digital (mobile) media devices...... in the intergenerational interaction with as well as the intragenerational interaction among daycare children. To some extent, digital media usage, foremost of tablet computers, has seen a discursive and material normalization across a number Danish daycare institutions before at all clarifying how it could be rendered...... meaningful for the respective pedagogical practice. Against this background, the presentation will in particular explore what this digitalization process may entail for the aim of promoting reciprocal intergenerational communication and practice. It draws on recent work in childhood geography as well...

  9. Comparison Of Digital Radiographic Units

    Science.gov (United States)

    Wang, Yen

    1986-06-01

    A total PACS will be inevitable for radiology practice within several years. To achieve a total PACS for radiology, a satisfactory digital radiographic unit is required, because approximately 65% of digital data for PACS comes from digital radiographs. There are several possibilities for producing digital radiographs, and 3 - 4 companies have been marketing digital radiographic devices. Some data regarding the digital radiographic units on the market are compared. It will aid in assessing the current status and availability of this aspect of development, as well as providing a summary of further development of digital radiographic technology.

  10. Splenosis involving the gastric fundus, a rare cause of massive upper gastrointestinal bleeding: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Reinglas J

    2016-09-01

    Full Text Available Jason Reinglas,1 Kirstin Perdrizet,1 Stephen E Ryan,2 Rakesh V Patel1 1Department of Medicine, 2Department of Diagnostic Imaging, University of Ottawa, Ottawa Hospital, Ottawa, ON, Canada Abstract: Splenosis, the autotransplantation of splenic tissue following splenic trauma, is uncommonly clinically significant. Splenosis is typically diagnosed incidentally on imaging or at laparotomy and has been mistakenly attributed to various malignancies and pathological conditions. On the rare occasion when splenosis plays a causative role in a pathological condition, a diagnostic challenge may ensue that can lead to a delay in both diagnosis and treatment. The following case report describes a patient presenting with a massive upper gastrointestinal bleed resulting from arterial enlargement within the gastric fundus secondary to perigastric splenosis. The cause of the bleeding was initially elusive and this case highlights the importance of a thorough clinical history when faced with a diagnostic challenge. Treatment options, including the successful use of transarterial embolization in this case, are also presented. Keywords: therapeutic, endoscopy, UGIB, intervention

  11. Correlation Between the Findings of Optical Coherent Retinal Tomography (OCT), Stereo Biomicroscopic Images from Fundus of an Eye and Values from Visual Acuity of Diabetic Macular Edema

    Science.gov (United States)

    Nisic, Faruk; Turkovic, Samir; Mavija, Milka; Jovanovic, Nina; Alimanovic, Emina Halilovic-

    2014-01-01

    Introduction: Diabetic maculopathy is the major cause of reduced visual acuity in patients with non-proliferative diabetic retinopathy and occurs on average in 29% of patients who have diabetes for 20 or more years. Aim: The aim of this study is to re examine the correlation between the findings of optical coherence retinal tomography, stereo bio-microscopic images from fundus of an eye and values from visual acuity of diabetic macular edema. In addition, the aim is to show the importance of various ophthalmic tests for establishing diagnosis in time. Material and methods: The research sample consisted of 90 subjects-patients from Cabinet for photographic documentation, fluorescein angiography and laser photocoagulation in Department of Ophthalmology at the University Clinical Centre in Sarajevo. The study was a one-year long, prospective, clinical study. Results: Research has shown a positive correlation between the various tests that are applied for the diagnosis of diabetic macular edema. Accurate and early diagnosis is of great importance for the treatment in time of this disease by applying laser photocoagulation, intravitreal injections of Anti-VEGF drugs or surgical treatment by Pars Plana Vitrectomy. PMID:25395723

  12. SMARTPHONE-BASED DILATED FUNDUS PHOTOGRAPHY AND NEAR VISUAL ACUITY TESTING AS INEXPENSIVE SCREENING TOOLS TO DETECT REFERRAL WARRANTED DIABETIC EYE DISEASE.

    Science.gov (United States)

    Toy, Brian C; Myung, David J; He, Lingmin; Pan, Carolyn K; Chang, Robert T; Polkinhorne, Alison; Merrell, Douglas; Foster, Doug; Blumenkranz, Mark S

    2016-05-01

    To compare clinical assessment of diabetic eye disease by standard dilated examination with data gathered using a smartphone-based store-and-forward teleophthalmology platform. 100 eyes of 50 adult patients with diabetes from a health care safety-net ophthalmology clinic. All patients underwent comprehensive ophthalmic examination. Concurrently, a smartphone was used to estimate near visual acuity and capture anterior and dilated posterior segment photographs, which underwent masked, standardized review. Quantitative comparison of clinic and smartphone-based data using descriptive, kappa, Bland-Altman, and receiver operating characteristic analyses was performed. Smartphone visual acuity was successfully measured in all eyes. Anterior and posterior segment photography was of sufficient quality to grade in 96 and 98 eyes, respectively. There was good correlation between clinical Snellen and smartphone visual acuity measurements (rho = 0.91). Smartphone-acquired fundus photographs demonstrated 91% sensitivity and 99% specificity to detect moderate nonproliferative and worse diabetic retinopathy, with good agreement between clinic and photograph grades (kappa = 0.91 ± 0.1, P smartphone-based telemedicine system that demonstrated sensitivity and specificity to detect referral-warranted diabetic eye disease as a proof-of-concept. Additional studies are warranted to evaluate this approach to expanding screening for diabetic retinopathy.

  13. A hybrid segmentation approach for geographic atrophy in fundus auto-fluorescence images for diagnosis of age-related macular degeneration.

    Science.gov (United States)

    Lee, Noah; Laine, Andrew F; Smith, R Theodore

    2007-01-01

    Fundus auto-fluorescence (FAF) images with hypo-fluorescence indicate geographic atrophy (GA) of the retinal pigment epithelium (RPE) in age-related macular degeneration (AMD). Manual quantification of GA is time consuming and prone to inter- and intra-observer variability. Automatic quantification is important for determining disease progression and facilitating clinical diagnosis of AMD. In this paper we describe a hybrid segmentation method for GA quantification by identifying hypo-fluorescent GA regions from other interfering retinal vessel structures. First, we employ background illumination correction exploiting a non-linear adaptive smoothing operator. Then, we use the level set framework to perform segmentation of hypo-fluorescent areas. Finally, we present an energy function combining morphological scale-space analysis with a geometric model-based approach to perform segmentation refinement of false positive hypo- fluorescent areas due to interfering retinal structures. The clinically apparent areas of hypo-fluorescence were drawn by an expert grader and compared on a pixel by pixel basis to our segmentation results. The mean sensitivity and specificity of the ROC analysis were 0.89 and 0.98%.

  14. A confocal study of mechanism of 5-hydroxytryptaminoinduced intracellular calcium dynamics in cultured ratstomach fundus smooth muscle cells with a new Ca2+indicator STDIn-AM

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xiaoling; (张小玲); YAN; Hongtao; (阎宏涛)

    2002-01-01

    A new fluorescent Ca2+ indicator STDIn-AM for detecting i transients in cultured smooth muscle cells is presented. By making a comparison, the difference between STDIn and fluo-3 is discussed in detail. Using the new Ca2+ indicator, the mechanism of 5-hydroxytryptamino (5-HT) induced intracellular calcium dynamics in stomach fundus smooth muscle cells (SFSMC) of rats is investigated. It is shown that in contrast with fluo-3, STDIn is uniformly distributed in the cytosolic compartment but excluded from the nucleus, when it is transfected into cells. This feature makes it a real cytosol Ca2+ indicator and can reflect changes of cytosol more accurately than that of fluo-3. In addition, STDIn responds to the i transients more sensitive and faster than fluo-3. The results also show that, the L-type Ca2+ channel inhibitor Mn9202 and the PLC inhibitor Compound 48/80 can significantly inhibit the i elevation induced by 5-HT, while the PKC inhibitor D-Sphingosine can enhance the effect of 5-HT. The results suggest that 5-HT acts by the way of 5-HT2 receptors on SFSMC, then through 5-HT2 receptors coupled IP3/Ca2+ and GC/PKC double signal transduction pathways to make Ca2+ release from intracellular Ca2+ stores and Ca2+ influx possibly through L-type calcium channels.

  15. A veterinary digital anatomical database.

    OpenAIRE

    Snell, J.R.; Green, R; Stott, G; Van Baerle, S.

    1991-01-01

    This paper describes the Veterinary Digital Anatomical Database Project. The purpose of the project is to investigate the construction and use of digitally stored anatomical models. We will be discussing the overall project goals and the results to date. Digital anatomical models are 3 dimensional, solid model representations of normal anatomy. The digital representations are electronically stored and can be manipulated and displayed on a computer graphics workstation. A digital database of a...

  16. The Accuracy and Reliability of Crowdsource Annotations of Digital Retinal Images

    Science.gov (United States)

    Mitry, Danny; Zutis, Kris; Dhillon, Baljean; Peto, Tunde; Hayat, Shabina; Khaw, Kay-Tee; Morgan, James E.; Moncur, Wendy; Trucco, Emanuele; Foster, Paul J.

    2016-01-01

    Purpose Crowdsourcing is based on outsourcing computationally intensive tasks to numerous individuals in the online community who have no formal training. Our aim was to develop a novel online tool designed to facilitate large-scale annotation of digital retinal images, and to assess the accuracy of crowdsource grading using this tool, comparing it to expert classification. Methods We used 100 retinal fundus photograph images with predetermined disease criteria selected by two experts from a large cohort study. The Amazon Mechanical Turk Web platform was used to drive traffic to our site so anonymous workers could perform a classification and annotation task of the fundus photographs in our dataset after a short training exercise. Three groups were assessed: masters only, nonmasters only and nonmasters with compulsory training. We calculated the sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic (ROC) plots for all classifications compared to expert grading, and used the Dice coefficient and consensus threshold to assess annotation accuracy. Results In total, we received 5389 annotations for 84 images (excluding 16 training images) in 2 weeks. A specificity and sensitivity of 71% (95% confidence interval [CI], 69%–74%) and 87% (95% CI, 86%–88%) was achieved for all classifications. The AUC in this study for all classifications combined was 0.93 (95% CI, 0.91–0.96). For image annotation, a maximal Dice coefficient (∼0.6) was achieved with a consensus threshold of 0.25. Conclusions This study supports the hypothesis that annotation of abnormalities in retinal images by ophthalmologically naive individuals is comparable to expert annotation. The highest AUC and agreement with expert annotation was achieved in the nonmasters with compulsory training group. Translational Relevance The use of crowdsourcing as a technique for retinal image analysis may be comparable to expert graders and has the potential to deliver

  17. From Digital Divides to Digital Inequality -- The Emerging Digital Inequality in the Norwegian Unitarian School

    Science.gov (United States)

    Krumsvik, Rune J.

    2008-01-01

    This position paper highlights existing and emerging, prospective digital divides in Norwegian schools and asks whether we are now moving from traditional digital divides to digital inequality in our digitized society and schools. Despite very good technology density in Norwegian society and schools in general, there is the reason to pay attention…

  18. Digital forestry research in China

    Institute of Scientific and Technical Information of China (English)

    TANG; Shouzheng; TANG; Lina; Guofan; Shao; DAI; Limin

    2006-01-01

    Digital Forestry as a concept was developed after the Digital Earth program. The Chinese scientists were not only among the pioneers who first proposed the concept of Digital Forestry, but also contributed a lot to the development of Digital Forestry. Digital Forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital Forestry. Under this situation, the experience of Digital Forestry development in China is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital Forestry Construction Scheme. The Project of Digital Forestry Practicability approved by the State Forestry Administration is a major instance in developing Digital Forestry standard and key techniques. By introducing a case study of Digital Forestry, this paper reviews the concept of Digital Forestry, the way turning traditional forestry into Digital Forestry, and the future development of Digital Forestry.

  19. Literature Review on Artificial Neural Network Classifier Based on Fundus Image%基于眼底图像的人工神经网络分类器研究现状与进展

    Institute of Scientific and Technical Information of China (English)

    姜玉苹; 吴辉群; 余杰; 袁媛; 黄佳聪; 王磊; 陈亚兰; 施李丽; 蒋葵

    2015-01-01

    Objective: To summarize the artificial neural network classifier based on fundus image, which is fundamental to fundus image based computer aided diagnosis. Methods: In our study, literature search and review was utilized, and the artificial neural network studies on fundus images were obtained and which feature extraction technology were extracted and analyzed. Results: A total of 27 relevant studies were collected and eventually 17 of them were selected for information extraction. Of these studies, the content, feature extraction and neural network classification type and method, the number of artificial neural network (ANN) input layer, the number of hidden layer neurons, output, as well as classification were summarized. For different studies, the extracted features were different. Besides, the main ANN method for fundus images was back propagation ANN (BP-ANN). Conclusion: The ANN can provide certain help for retinopathy aided analysis on fundus images.%目的:总结基于眼底图像的人工神经网络分类器研究现状与进展,为基于眼底图像的疾病计算机辅助诊断提供基础.方法:本研究采用文献检索和综述的方法,对国内外关于眼底图像的人工神经网络(Artificial Neural Network, ANN)研究进行整理,主要对已发表的文献中ANN技术以及相关眼底图像的特征提取技术进行整理和分析.结果:本次研究检索到符合要求的研究共计27篇,最终纳入17篇研究进行资料提取.提取的指标为分类内容、特征提取、神经网络类型/方法、ANN输入层层数、隐藏层神经元数量、输出、分类指标等.针对不同样本的研究,提取的特征有所区别.目前研究眼底图像的主要ANN方法是后反馈神经网络(BP-ANN).结论:基于眼底图像的ANN能够为视网膜病变的辅助分析提供一定帮助.

  20. Digital Actuator Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst

    2014-09-01

    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator