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Sample records for fundus albipunctatus asociado

  1. Fundus albipunctatus: review of the literature and report of a novel RDH5 gene mutation affecting the invariant tyrosine (p.Tyr175Phe).

    PubMed

    Skorczyk-Werner, Anna; Pawłowski, Przemysław; Michalczuk, Marta; Warowicka, Alicja; Wawrocka, Anna; Wicher, Katarzyna; Bakunowicz-Łazarczyk, Alina; Krawczyński, Maciej R

    2015-08-01

    Fundus albipunctatus (FA) is a rare, congenital form of night blindness with rod system impairment, characterised by the presence of numerous small, white-yellow retinal lesions. FA belongs to a heterogenous group of so-called flecked retina syndromes. This disorder shows autosomal recessive inheritance and is caused mostly by mutations in the RDH5 gene. This gene encodes the enzyme that is a part of the visual cycle, the 11-cis retinol dehydrogenase. This study is a brief review of the literature on FA and a report of the first molecular evidence for RDH5 gene mutation in a Polish patient with this rare disorder. We present a novel pathogenic RDH5 gene mutation in a 16-year-old female patient with symptoms of night blindness. The patient underwent ophthalmological examinations, including colour vision testing, fundus photography, automated visual field testing, full-field electroretinography (ERG) and spectral optical coherent tomography (SOCT). The patient showed typical FA ERG records, the visual field was constricted and fundus examination revealed numerous characteristic, small, white-yellowish retinal lesions. DNA sequencing of the RDH5 gene coding sequence (exons 2-5) enabled the detection of the homozygous missense substitution c.524A > T (p.Tyr175Phe) in exon 3. This is the first report of RDH5 gene mutation that affects the invariant tyrosine, one of the most conserved amino acid residues in short-chain alcohol dehydrogenases/reductases (SDRs), crucial for these enzymes' activity. The location of this substitution, together with its predicted influence on the protein function, indicate that the p.Tyr175Phe mutation is the cause of FA in our patient. PMID:25820994

  2. Novel fundus camera design

    NASA Astrophysics Data System (ADS)

    Dehoog, Edward A.

    A fundus camera a complex optical system that makes use of the principle of reflex free indirect ophthalmoscopy to image the retina. Despite being in existence as early as 1900's, little has changed in the design of a fundus camera and there is minimal information about the design principles utilized. Parameters and specifications involved in the design of fundus camera are determined and their affect on system performance are discussed. Fundus cameras incorporating different design methods are modeled and a performance evaluation based on design parameters is used to determine the effectiveness of each design strategy. By determining the design principles involved in the fundus camera, new cameras can be designed to include specific imaging modalities such as optical coherence tomography, imaging spectroscopy and imaging polarimetry to gather additional information about properties and structure of the retina. Design principles utilized to incorporate such modalities into fundus camera systems are discussed. Design, implementation and testing of a snapshot polarimeter fundus camera are demonstrated.

  3. Portable dynamic fundus instrument

    NASA Technical Reports Server (NTRS)

    Taylor, Gerald R. (Inventor); Meehan, Richard T. (Inventor); Hunter, Norwood R. (Inventor); Caputo, Michael P. (Inventor); Gibson, C. Robert (Inventor)

    1992-01-01

    A portable diagnostic image analysis instrument is disclosed for retinal funduscopy in which an eye fundus image is optically processed by a lens system to a charge coupled device (CCD) which produces recordable and viewable output data and is simultaneously viewable on an electronic view finder. The fundus image is processed to develop a representation of the vessel or vessels from the output data.

  4. The fundus slit lamp.

    PubMed

    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. Digital infrared fundus reflectance.

    PubMed

    Packer, S; Schneider, K; Lin, H Z; Feldman, M

    1980-06-01

    An infrared sensor was inserted at the film plane of a fundus camera. The signal was visualized on an oscilloscope. In this manner we measured infrared reflectance from the surface of the fundus. The purpose was to characterize choroidal malignant melanomas more reliably than is done with infrared color translation photography. Control lesions were choroidal nevi, metastatic tumors, and disciform macular degenerations. Correlations were made with radioactive phosphorus (32P) uptake, fluorescein angiography, and histopathologic findings. Several cases are presented, one in which this new method of infrared detection was the first diagnostic test to detect the spread of a choroidal melanoma. The simplicity of this technique and its increased accuracy justify the needed further refinements. PMID:7413142

  6. Fundus Camera Guided Photoacoustic Ophthalmoscopy

    PubMed Central

    Liu, Tan; Li, Hao; Song, Wei; Jiao, Shuliang; Zhang, Hao F.

    2014-01-01

    Purpose To demonstrate the feasibility of fundus camera guided photoacoustic ophthalmoscopy (PAOM) system and its multimodal imaging capabilities. Methods We integrated PAOM and a fundus camera consisting of a white-light illuminator and a high-sensitivity, high-speed CCD. The fundus camera captures both retinal anatomy and PAOM illumination at the same time to provide a real-time feedback when we position the PAOM illuminating light. We applied the integrated system to image rat eyes in vivo and used full-spectrum, visible (VIS), and near infrared (NIR) illuminations in fundus photography. Results Both albino and pigmented rat eyes were imaged in vivo. During alignment, different trajectories of PAOM laser scanning were successfully visualized by the fundus camera, which reduced the PAOM alignment time from several minutes to 30 s. In albino eyes, in addition to retinal vessels, main choroidal vessels were observed using VIS-illumination, which is similar to PAOM images. In pigmented eyes, the radial striations of retinal nerve fiber layer were visualized by fundus photography using full-spectrum illumination; meanwhile, PAOM imaged both retinal vessels and the retinal pigmented epithelium melanin distribution. Conclusions The results demonstrated that PAOM can be well-integrated with fundus camera without affecting its functionality. The fundus camera guidance is faster and easier comparing with our previous work. The integrated system also set the stage for the next-step verification between oximetry methods based on PAOM and fundus photography. PMID:24131226

  7. Hyperspectral fundus imager

    NASA Astrophysics Data System (ADS)

    Truitt, Paul W.; Soliz, Peter; Meigs, Andrew D.; Otten, Leonard John, III

    2000-11-01

    A Fourier Transform hyperspectral imager was integrated onto a standard clinical fundus camera, a Zeiss FF3, for the purposes of spectrally characterizing normal anatomical and pathological features in the human ocular fundus. To develop this instrument an existing FDA approved retinal camera was selected to avoid the difficulties of obtaining new FDA approval. Because of this, several unusual design constraints were imposed on the optical configuration. Techniques to calibrate the sensor and to define where the hyperspectral pushbroom stripe was located on the retina were developed, including the manufacturing of an artificial eye with calibration features suitable for a spectral imager. In this implementation the Fourier transform hyperspectral imager can collect over a hundred 86 cm-1 spectrally resolved bands with 12 micro meter/pixel spatial resolution within the 1050 nm to 450 nm band. This equates to 2 nm to 8 nm spectral resolution depending on the wavelength. For retinal observations the band of interest tends to lie between 475 nm and 790 nm. The instrument has been in use over the last year successfully collecting hyperspectral images of the optic disc, retinal vessels, choroidal vessels, retinal backgrounds, and macula diabetic macular edema, and lesions of age-related macular degeneration.

  8. [Fundus Autofluorescence Imaging].

    PubMed

    Schmitz-Valckenberg, S

    2015-09-01

    Fundus autofluorescence (FAF) imaging allows for non-invasive mapping of changes at the level of the retinal pigment epithelium/photoreceptor complex and of alterations of macular pigment distribution. This imaging method is based on the visualisation of intrinsic fluorophores and may be easily and rapidly used in routine patient care. Main applications include degenerative disorders of the outer retina such as age-related macular degeneration, hereditary and acquired retinal diseases. FAF imaging is particularly helpful for differential diagnosis, detection and extent of involved retinal areas, structural-functional correlations and monitoring of changes over time. Recent developments include - in addition to the original application of short wavelength light for excitation ("blue" FAF imaging) - the use of other wavelength ranges ("green" or "near-infrared" FAF imaging), widefield imaging for visualisation of peripheral retinal areas and quantitative FAF imaging. PMID:26280647

  9. Ocular Fundus Photography as an Educational Tool.

    PubMed

    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. PMID:26444395

  10. Unconventional techniques of fundus imaging: A review.

    PubMed

    Shanmugam, Mahesh P; Mishra, Divyansh Kailash Chandra; Rajesh, R; Madhukumar, R

    2015-07-01

    The methods of fundus examination include direct and indirect ophthalmoscopy and imaging with a fundus camera are an essential part of ophthalmic practice. The usage of unconventional equipment such as a hand-held video camera, smartphone, and a nasal endoscope allows one to image the fundus with advantages and some disadvantages. The advantages of these instruments are the cost-effectiveness, ultra portability and ability to obtain images in a remote setting and share the same electronically. These instruments, however, are unlikely to replace the fundus camera but then would always be an additional arsenal in an ophthalmologist's armamentarium. PMID:26458475

  11. Unconventional techniques of fundus imaging: A review

    PubMed Central

    Shanmugam, Mahesh P; Mishra, Divyansh Kailash Chandra; Rajesh, R; Madhukumar, R

    2015-01-01

    The methods of fundus examination include direct and indirect ophthalmoscopy and imaging with a fundus camera are an essential part of ophthalmic practice. The usage of unconventional equipment such as a hand-held video camera, smartphone, and a nasal endoscope allows one to image the fundus with advantages and some disadvantages. The advantages of these instruments are the cost-effectiveness, ultra portability and ability to obtain images in a remote setting and share the same electronically. These instruments, however, are unlikely to replace the fundus camera but then would always be an additional arsenal in an ophthalmologist's armamentarium. PMID:26458475

  12. Coaxial fundus camera for opthalmology

    NASA Astrophysics Data System (ADS)

    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.

  13. Dark-without-pressure fundus lesions.

    PubMed Central

    Nagpal, K C; Goldberg, M F; Asdourian, G; Goldbaum, M; Huamonte, F

    1975-01-01

    Seven black patients had dark brown homogeneous geographical areas of the fundus. Six cases were associated with sickle cell haemoglobinopathies and one was associated with systemic hypertension. These flat lesions were uniform in colour and occurred in the posterior pole or in the midperiphery. They appeared to be transient and often disappeared leaving no residue. The cause is unknown. By analogy with white-without-pressure fundus lesions, we have called these areas dark-without-pressure. Images PMID:1203232

  14. [Enhancement and assessment of the fundus image].

    PubMed

    Chen, Mengmeng; Xiong, Xingliang; Li, Guang; Zhang, Tingting

    2014-10-01

    A new enhancement method is proposed based on the characteristics of fundus images in this paper. Firstly, top-hat transform is utilized to weaken the background. Secondly, contrast limited adaptive histogram equalization (CLAHE) is performed to improve the uneven illumination. Finally, two-dimensional matched filters are designed to further enhance the contrast between blood vessels and background. The algorithm was tested in DIARETDB0 databases and showed good applicability for both normal and pathological fundus images. A new no-reference image quality assessment method was used to evaluate the enhancement methods objectively. The results demonstrated that the proposed method could effectively weaken the background, increase contrast, enhance details in the fundus images and improve the image quality greatly. PMID:25764739

  15. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  16. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  17. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  18. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  19. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  20. Robust vessel segmentation in fundus images.

    PubMed

    Budai, A; Bock, R; Maier, A; Hornegger, J; Michelson, G

    2013-01-01

    One of the most common modalities to examine the human eye is the eye-fundus photograph. The evaluation of fundus photographs is carried out by medical experts during time-consuming visual inspection. Our aim is to accelerate this process using computer aided diagnosis. As a first step, it is necessary to segment structures in the images for tissue differentiation. As the eye is the only organ, where the vasculature can be imaged in an in vivo and noninterventional way without using expensive scanners, the vessel tree is one of the most interesting and important structures to analyze. The quality and resolution of fundus images are rapidly increasing. Thus, segmentation methods need to be adapted to the new challenges of high resolutions. In this paper, we present a method to reduce calculation time, achieve high accuracy, and increase sensitivity compared to the original Frangi method. This method contains approaches to avoid potential problems like specular reflexes of thick vessels. The proposed method is evaluated using the STARE and DRIVE databases and we propose a new high resolution fundus database to compare it to the state-of-the-art algorithms. The results show an average accuracy above 94% and low computational needs. This outperforms state-of-the-art methods. PMID:24416040

  1. Fundus autofluorescence applications in retinal imaging.

    PubMed

    Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

    2015-05-01

    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. PMID:26139802

  2. Fundus autofluorescence applications in retinal imaging

    PubMed Central

    Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

    2015-01-01

    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. PMID:26139802

  3. Improved scanning laser fundus imaging using polarimetry

    NASA Astrophysics Data System (ADS)

    Bueno, Juan M.; Hunter, Jennifer J.; Cookson, Christopher J.; Kisilak, Marsha L.; Campbell, Melanie C. W.

    2007-05-01

    We present a polarimetric technique to improve fundus images that notably simplifies and extends a previous procedure [Opt. Lett.27, 830 (2002)]. A generator of varying polarization states was incorporated into the illumination path of a confocal scanning laser ophthalmoscope. A series of four images, corresponding to independent incoming polarization states, were recorded. From these images, the spatially resolved elements of the top row of the Mueller matrix were computed. From these elements, images with the highest and lowest quality (according to different image quality metrics) were constructed, some of which provided improved visualization of fundus structures of clinical importance (vessels and optic nerve head). The metric values were better for these constructed images than for the initially recorded images and better than averaged images. Entropy is the metric that is most sensitive to differences in the image quality. Improved visualization of features could aid in the detection, localization, and tracking of ocular disease and may be applicable in other biomedical imaging.

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

    PubMed Central

    Shanmugam, Mahesh P; Mishra, Divyansh KC; Madhukumar, R; Ramanjulu, Rajesh; Reddy, Srinivasulu Y; Rodrigues, Gladys

    2014-01-01

    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. PMID:25370404

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

    PubMed

    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. PMID:24163061

  6. [Ocular fundus lesions in systemic lupus erythematosus model mice].

    PubMed

    Nakamura, A; Yokoyama, T; Kodera, S; Zhang, D; Hirose, S

    1998-01-01

    To evaluate spontaneous development of the ocular fundus abnormalities associated with collagen disease, we investigated the ocular fundus lesions in systemic lupus erythematosus (SLE) models. (NZW x BXSB) F1 mice were employed as SLE models with antiphospholipid syndrome. The abnormal findings in the ocular fundus were recorded with a fundus camera for small animals (KOWA Co., Ltd.), and the chorioretinal lesions were studied histopathologically. As in the systemic symptoms of SLE, the incidence of ocular fundus abnormalities in these (NZW x BXSB) F1 mice was significantly higher in males than in females, suggesting the influence of the Yaa (Y chromosome-linked autoimmune acceleration) gene. Lesions in the fundus appeared in the form of white spots, which increased in number along with the course of the disease. The lesion developed into retinal detachment in some animals. Dilatation of veins and narrowing of arteries were marked. These lesions were very similar to multifocal posterior pigment epitheliopathy (MPPE) in humans in that white spots appear first and then develop into exudative retinal detachment caused by retinal pigment epithelial disorder. Histopathological findings included 1. structural destruction of the photoreceptor cell layer, 2. degeneration and loss of the retinal pigment epithelium, and 3. narrowing and occlusion of the choriocapillaris associated with thrombus formation, cellular infiltration into the surrounding tissues, and wall thickening of the choroidal arterioles. The study of these SLE mouse may contribute to the elucidation of abnormalities in the fundus associated with collagen diseases, including the relationship between thrombus formation and antiphospholipid syndrome. PMID:9489364

  7. [The application of industrial endoscope to observation of the ocular-fundus in small laboratory animals].

    PubMed

    Kiyosawa, I; Aruga, N; Kawakubo, M; Naito, J; Saito, T R; Takahashi, K W

    1992-01-01

    Observation and recording methods of the ocular-fundus in small laboratory animals were studied using the industrial endoscope and VTR systems, respectively. The ocular-fundus was observed widely, brightly and clearly in the usual animal facility. In addition, the ocular-fundus was recorded easily and it was possible to examine the ocular-fundus recorded by the VTR systems. PMID:1740168

  8. Glare-free optical system for fundus visualization

    NASA Astrophysics Data System (ADS)

    Salakhutdinov, Viktor K.; Smetanin, Yuriy G.; Doroshenko, Jasser; Sivachenko, Eugene A.

    2014-05-01

    The paper describes results of development of fundus-camera with non-glare optical scheme. The scheme is based on multiple lenses with a light gathering power (D/F <= 1) substantially less than one. Illumination of fundus can be provided through eye's pupil less than 3 mm. And much attention was directed to method of calculation of the no-glare optical scheme. The key idea is that geometry of optic elements of the system provides that glare in the form of ghost reflection from optical surface of one element focuses on a small-size absorbing screen located on another optical surface. Shows the possibility of implementation and the experimental results. During experiments with B/W camera we got Full HD color image of fundus having the eye's pupil diameter of 1.5 mm and illumination of fundus tissue in accordance with sanitary rules.

  9. Human Visual System-Based Fundus Image Quality Assessment of Portable Fundus Camera Photographs.

    PubMed

    Wang, Shaoze; Jin, Kai; Lu, Haitong; Cheng, Chuming; Ye, Juan; Qian, Dahong

    2016-04-01

    Telemedicine and the medical "big data" era in ophthalmology highlight the use of non-mydriatic ocular fundus photography, which has given rise to indispensable applications of portable fundus cameras. However, in the case of portable fundus photography, non-mydriatic image quality is more vulnerable to distortions, such as uneven illumination, color distortion, blur, and low contrast. Such distortions are called generic quality distortions. This paper proposes an algorithm capable of selecting images of fair generic quality that would be especially useful to assist inexperienced individuals in collecting meaningful and interpretable data with consistency. The algorithm is based on three characteristics of the human visual system--multi-channel sensation, just noticeable blur, and the contrast sensitivity function to detect illumination and color distortion, blur, and low contrast distortion, respectively. A total of 536 retinal images, 280 from proprietary databases and 256 from public databases, were graded independently by one senior and two junior ophthalmologists, such that three partial measures of quality and generic overall quality were classified into two categories. Binary classification was implemented by the support vector machine and the decision tree, and receiver operating characteristic (ROC) curves were obtained and plotted to analyze the performance of the proposed algorithm. The experimental results revealed that the generic overall quality classification achieved a sensitivity of 87.45% at a specificity of 91.66%, with an area under the ROC curve of 0.9452, indicating the value of applying the algorithm, which is based on the human vision system, to assess the image quality of non-mydriatic photography, especially for low-cost ophthalmological telemedicine applications. PMID:26672033

  10. Spectral characterization of an ophthalmic fundus camera

    NASA Astrophysics Data System (ADS)

    Miller, Clayton T.; Bassi, Carl J.; Brodsky, Dale; Holmes, Timothy

    2010-02-01

    A fundus camera is an optical system designed to illuminate and image the retina while minimizing stray light and backreflections. Modifying such a device requires characterization of the optical path in order to meet the new design goals and avoid introducing problems. This work describes the characterization of one system, the Topcon TRC-50F, necessary for converting this camera from film photography to spectral imaging with a CCD. This conversion consists of replacing the camera's original xenon flash tube with a monochromatic light source and the film back with a CCD. A critical preliminary step of this modification is determining the spectral throughput of the system, from source to sensor, and ensuring there are sufficient photons at the sensor for imaging. This was done for our system by first measuring the transmission efficiencies of the camera's illumination and imaging optical paths with a spectrophotometer. Combining these results with existing knowledge of the eye's reflectance, a relative sensitivity profile is developed for the system. Image measurements from a volunteer were then made using a few narrowband sources of known power and a calibrated CCD. With these data, a relationship between photoelectrons/pixel collected at the CCD and narrowband illumination source power is developed.

  11. Robust approach to ocular fundus image analysis

    NASA Astrophysics Data System (ADS)

    Tascini, Guido; Passerini, Giorgio; Puliti, Paolo; Zingaretti, Primo

    1993-07-01

    The analysis of morphological and structural modifications of retinal blood vessels plays an important role both to establish the presence of some systemic diseases as hypertension and diabetes and to study their course. The paper describes a robust set of techniques developed to quantitatively evaluate morphometric aspects of the ocular fundus vascular and micro vascular network. They are defined: (1) the concept of 'Local Direction of a vessel' (LD); (2) a special form of edge detection, named Signed Edge Detection (SED), which uses LD to choose the convolution kernel in the edge detection process and is able to distinguish between the left or the right vessel edge; (3) an iterative tracking (IT) method. The developed techniques use intensively both LD and SED in: (a) the automatic detection of number, position and size of blood vessels departing from the optical papilla; (b) the tracking of body and edges of the vessels; (c) the recognition of vessel branches and crossings; (d) the extraction of a set of features as blood vessel length and average diameter, arteries and arterioles tortuosity, crossing position and angle between two vessels. The algorithms, implemented in C language, have an execution time depending on the complexity of the currently processed vascular network.

  12. Fundus image registration for vestibularis research

    NASA Astrophysics Data System (ADS)

    Ithapu, Vamsi K.; Fritsche, Armin; Oppelt, Ariane; Westhofen, Martin; Deserno, Thomas M.

    2010-03-01

    In research on vestibular nerve disorders, fundus images of both left and right eyes are acquired systematically to precisely assess the rotation of the eye ball that is induced by the rotation of entire head. The measurement is still carried out manually. Although various methods have been proposed for medical image registration, robust detection of rotation especially in images with varied quality in terms of illumination, aberrations, blur and noise still is challenging. This paper evaluates registration algorithms operating on different levels of semantics: (i) data-based using Fourier transform and log polar maps; (ii) point-based using scaled image feature transform (SIFT); (iii) edge-based using Canny edge maps; (iv) object-based using matched filters for vessel detection; (v) scene-based detecting papilla and macula automatically and (vi) manually by two independent medical experts. For evaluation, a database of 22 patients is used, where each of left and right eye images is captured in upright head position and in lateral tilt of +/-200. For 66 pairs of images (132 in total), the results are compared with ground truth, and the performance measures are tabulated. Best correctness of 89.3% were obtained using the pixel-based method and allowing 2.5° deviation from the manual measures. However, the evaluation shows that for applications in computer-aided diagnosis involving a large set of images with varied quality, like in vestibularis research, registration methods based on a single level of semantics are not sufficiently robust. A multi-level semantics approach will improve the results since failure occur on different images.

  13. Iterative Vessel Segmentation of Fundus Images.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Parhi, Keshab K

    2015-07-01

    This paper presents a novel unsupervised iterative blood vessel segmentation algorithm using fundus images. First, a vessel enhanced image is generated by tophat reconstruction of the negative green plane image. An initial estimate of the segmented vasculature is extracted by global thresholding the vessel enhanced image. Next, new vessel pixels are identified iteratively by adaptive thresholding of the residual image generated by masking out the existing segmented vessel estimate from the vessel enhanced image. The new vessel pixels are, then, region grown into the existing vessel, thereby resulting in an iterative enhancement of the segmented vessel structure. As the iterations progress, the number of false edge pixels identified as new vessel pixels increases compared to the number of actual vessel pixels. A key contribution of this paper is a novel stopping criterion that terminates the iterative process leading to higher vessel segmentation accuracy. This iterative algorithm is robust to the rate of new vessel pixel addition since it achieves 93.2-95.35% vessel segmentation accuracy with 0.9577-0.9638 area under ROC curve (AUC) on abnormal retinal images from the STARE dataset. The proposed algorithm is computationally efficient and consistent in vessel segmentation performance for retinal images with variations due to pathology, uneven illumination, pigmentation, and fields of view since it achieves a vessel segmentation accuracy of about 95% in an average time of 2.45, 3.95, and 8 s on images from three public datasets DRIVE, STARE, and CHASE_DB1, respectively. Additionally, the proposed algorithm has more than 90% segmentation accuracy for segmenting peripapillary blood vessels in the images from the DRIVE and CHASE_DB1 datasets. PMID:25700436

  14. Automated lesion detectors in retinal fundus images.

    PubMed

    Figueiredo, I N; Kumar, S; Oliveira, C M; Ramos, J D; Engquist, B

    2015-11-01

    Diabetic retinopathy (DR) is a sight-threatening condition occurring in persons with diabetes, which causes progressive damage to the retina. The early detection and diagnosis of DR is vital for saving the vision of diabetic persons. The early signs of DR which appear on the surface of the retina are the dark lesions such as microaneurysms (MAs) and hemorrhages (HEMs), and bright lesions (BLs) such as exudates. In this paper, we propose a novel automated system for the detection and diagnosis of these retinal lesions by processing retinal fundus images. We devise appropriate binary classifiers for these three different types of lesions. Some novel contextual/numerical features are derived, for each lesion type, depending on its inherent properties. This is performed by analysing several wavelet bands (resulting from the isotropic undecimated wavelet transform decomposition of the retinal image green channel) and by using an appropriate combination of Hessian multiscale analysis, variational segmentation and cartoon+texture decomposition. The proposed methodology has been validated on several medical datasets, with a total of 45,770 images, using standard performance measures such as sensitivity and specificity. The individual performance, per frame, of the MA detector is 93% sensitivity and 89% specificity, of the HEM detector is 86% sensitivity and 90% specificity, and of the BL detector is 90% sensitivity and 97% specificity. Regarding the collective performance of these binary detectors, as an automated screening system for DR (meaning that a patient is considered to have DR if it is a positive patient for at least one of the detectors) it achieves an average 95-100% of sensitivity and 70% of specificity at a per patient basis. Furthermore, evaluation conducted on publicly available datasets, for comparison with other existing techniques, shows the promising potential of the proposed detectors. PMID:26378502

  15. The Reflexes of the Fundus Oculi

    PubMed Central

    Ballantyne, A. J.

    1940-01-01

    The fundus reflexes reveal, in a manner not yet completely understood, the texture and contour of the reflecting surfaces and the condition of the underlying tissues. In this way they may play an important part in the biomicroscopy of the eye. The physiological reflexes are seen at their best in the eyes of young subjects, in well-pigmented eyes, with undilated pupils and with emmetropic refraction. Their absence during the first two decades, or their presence after the forties, their occurrence in one eye only, their appearance, disappearance or change of character should suggest the possibility of some pathological state. The investigation and interpretation of the reflexes are notably assisted by comparing the appearances seen with long and short wave lights such as those of the sodium and mercury vapour lamps, in addition to the usual ophthalmoscopic lights. Most of the surface reflexes disappear in the light of the sodium lamp, sometimes revealing important changes in the deeper layers of the retina and choroid. The physiological reflexes, chiefly formed on the surface of the internal limiting membrane, take the forms of the familiar watered silk or patchy reflexes, the peri-macular halo, the fan reflex in the macular depression and the reflex from the foveal pit. The watered silk or patchy reflexes often show a delicate striation which follows the pattern of the nerve-fibre layer, or there may be a granular or criss-cross texture. Reflexes which entirely lack these indications of “texture” should be considered as possibly pathological. This applies to the “beaten metal” reflexes and to those formed on the so-called hyaloid membrane. The occurrence of physiological reflexes in linear form is doubtful, and the only admittedly physiological punctate reflexes are the so-called Gunn's dots. Surface reflexes which are broken up into small points or flakes are pathological, and are most frequently seen in the central area of the fundus in cases of pigmentary

  16. Image analysis of ocular fundus for retinopathy characterization

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Textureless Macula Swelling Detection with Multiple Retinal Fundus Images

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Tobin Jr, Kenneth William; Grisan, Enrico; Favaro, Paolo; Ruggeri, Alfredo; Chaum, Edward

    2010-01-01

    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 relatively low cost, these cameras can be employed by operators with limited training for telemedicine or Point-of-Care applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyse the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image which are useful in Point-of-Care automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalises the image; second, all available views are registered using non-morphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naiveheight- map of the macula. Results are presented on three sets of synthetic images and two sets of real world images. These preliminary tests show the ability to infer a minimum swelling of 300 microns and to correlate the reconstruction with the swollen location.

  19. Fundus image change analysis: geometric and radiometric normalization

    NASA Astrophysics Data System (ADS)

    Shin, David S.; Kaiser, Richard S.; Lee, Michael S.; Berger, Jeffrey W.

    1999-06-01

    Image change analysis will potentiate fundus feature quantitation in natural history and intervention studies for major blinding diseases such as age-related macular degeneration and diabetic retinopathy. Geometric and radiometric normalization of fundus images acquired at two points in time are required for accurate change detection, but existing methods are unsatisfactory for change analysis. We have developed and explored algorithms for correction of image misalignment (geometric) and inter- and intra-image brightness variation (radiometric) in order to facilitate highly accurate change detection. Thirty-five millimeter color fundus photographs were digitized at 500 to 1000 dpi. Custom-developed registration algorithms correcting for translation only; translation and rotation; translation, rotation, and scale; and polynomial based image-warping algorithms allowed for exploration of registration accuracy required for change detection. Registration accuracy beyond that offered by rigid body transformation is required for accurate change detection. Radiometric correction required shade-correction and normalization of inter-image statistical parameters. Precise geometric and radiometric normalization allows for highly accurate change detection. To our knowledge, these results are the first demonstration of the combination of geometric and radiometric normalization offering sufficient accuracy to allow for accurate fundus image change detection potentiating longitudinal study of retinal disease.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Referral system for hard exudates in eye fundus.

    PubMed

    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. PMID:26231313

  2. Diabetic Rethinopathy Screening by Bright Lesions Extraction from Fundus Images

    NASA Astrophysics Data System (ADS)

    Hanđsková, Veronika; Pavlovičova, Jarmila; Oravec, Miloš; Blaško, Radoslav

    2013-09-01

    Retinal images are nowadays widely used to diagnose many diseases, for example diabetic retinopathy. In our work, we propose the algorithm for the screening application, which identifies the patients with such severe diabetic complication as diabetic retinopathy is, in early phase. In the application we use the patient's fundus photography without any additional examination by an ophtalmologist. After this screening identification, other examination methods should be considered and the patient's follow-up by a doctor is necessary. Our application is composed of three principal modules including fundus image preprocessing, feature extraction and feature classification. Image preprocessing module has the role of luminance normalization, contrast enhancement and optical disk masking. Feature extraction module includes two stages: bright lesions candidates localization and candidates feature extraction. We selected 16 statistical and structural features. For feature classification, we use multilayer perceptron (MLP) with one hidden layer. We classify images into two classes. Feature classification efficiency is about 93 percent.

  3. Absolute blood velocity measured with a modified fundus camera

    NASA Astrophysics Data System (ADS)

    Duncan, Donald D.; Lemaillet, Paul; Ibrahim, Mohamed; Nguyen, Quan Dong; Hiller, Matthias; Ramella-Roman, Jessica

    2010-09-01

    We present a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides absolute velocity and flow direction along the vessel centerline or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated velocity.

  4. [Optical coherence tomography and fundus autofluorescence in Best macular dystrophy].

    PubMed

    Chebil, A; Charfi, H; Largueche, L; El Matri, L

    2016-06-01

    Best vitelliform macular dystrophy is the second most frequent hereditary maculopathy, with bilateral involvement and juvenile onset. It is clinically characterized by bilateral deposits of lipofuscin-like autofluorescent material in the subretinal space, with a typical phenotypic manifestation taking the form of a vitelliform macular lesion evolving gradually into more advanced stages. The purpose of our study was to describe fundus autofluorescence patterns and OCT findings in three patients (6 eyes) with several stages of Best vitelliform macular dystrophy. Optical coherence tomography (OCT) has become the first imaging technique to order when confronted with a hereditary maculopathy suggesting Best disease. Fundus autofluorescence combined with OCT allow for better diagnosis and management, which are necessary for any genetic analysis. PMID:27206620

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

    SciTech Connect

    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).

  6. Multispectral imaging of the ocular fundus using LED illumination

    NASA Astrophysics Data System (ADS)

    Everdell, N. L.; Styles, I. B.; Claridge, E.; Hebden, J. C.; Calcagni, A. S.

    2009-07-01

    We present preliminary data from an imaging system based on LED illumination for obtaining sequential multispectral optical images of the human ocular fundus. The system is capable of acquiring images at speeds of up to 20fps and we have demonstrated that the system is fast enough to allow images to be acquired with minimal inter-frame movement. Further improvements have been identified that will improve both imaging speed and image quality. The long-term goal is to use the system in conjunction with novel image analysis algorithms to extract chromophore concentrations from images of the ocular fundus, with a particular emphasis on age-related macular degeneration. The system has also found utility in fluorescence microscopy.

  7. High-Procession Eye Tracking Using Fundus Images

    NASA Technical Reports Server (NTRS)

    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.

  8. Validation of tablet-based evaluation of color fundus images

    PubMed Central

    Christopher, Mark; Moga, Daniela C.; Russell, Stephen R.; Folk, James C.; Scheetz, Todd; Abràmoff, Michael D.

    2012-01-01

    Purpose To compare diabetic retinopathy (DR) referral recommendations made by viewing fundus images using a tablet computer to recommendations made using a standard desktop display. Methods A tablet computer (iPad) and a desktop PC with a high-definition color display were compared. For each platform, two retinal specialists independently rated 1200 color fundus images from patients at risk for DR using an annotation program, Truthseeker. The specialists determined whether each image had referable DR, and also how urgently each patient should be referred for medical examination. Graders viewed and rated the randomly presented images independently and were masked to their ratings on the alternative platform. Tablet- and desktop display-based referral ratings were compared using cross-platform, intra-observer kappa as the primary outcome measure. Additionally, inter-observer kappa, sensitivity, specificity, and area under ROC (AUC) were determined. Results A high level of cross-platform, intra-observer agreement was found for the DR referral ratings between the platforms (κ=0.778), and for the two graders, (κ=0.812). Inter-observer agreement was similar for the two platforms (κ=0.544 and κ=0.625 for tablet and desktop, respectively). The tablet-based ratings achieved a sensitivity of 0.848, a specificity of 0.987, and an AUC of 0.950 compared to desktop display-based ratings. Conclusions In this pilot study, tablet-based rating of color fundus images for subjects at risk for DR was consistent with desktop display-based rating. These results indicate that tablet computers can be reliably used for clinical evaluation of fundus images for DR. PMID:22495326

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Multimodal fundus imaging in Best vitelliform macular dystrophy

    PubMed Central

    Ferrara, Daniela C.; Tsang, Stephen; Calucci, Daniela; Jorge, Rodrigo; Freund, K. Bailey

    2010-01-01

    Background Best vitelliform macular dystrophy (BVMD) is a rare autosomal dominant retinal disease of highly variable phenotypic expression. Interpretations of disease mechanisms based on histopathology, electrophysiology, genetic analysis, and retinal imaging are somewhat discordant in fundamental issues such as the location and extension of primary retinal changes. Herein we describe the morphological macular features in patients with BVMD undergoing simultaneous multimodal fundus imaging and compare to those of normal age-matched subjects. Methods Comparative study including seven patients with BVMD (14 eyes) and seven age-matched healthy subjects (14 eyes). All participants were submitted to complete ophthalmological examination, fundus photography, and standardized multimodal fundus imaging protocol including Fourier-domain optical coherence tomography (Fd-OCT) combined with near-infrared reflectance and blue-light fundus autofluorescence (FAF). Results In two eyes in the “subclinical” stage, Fd-OCT revealed thickening of the middle highly reflective layer (HRL) localized between the photoreceptors’ inner/outer segments junction (inner-HRL) and RPE/Bruch’s membrane reflective complex (outer-HRL) throughout the macula. In one eye in the “vitelliform” stage, a homogeneous hyper-reflective material on Fd-OCT was observed between the middle-HRL and outer-HRL; this material presented increased fluorescence on FAF. The outer nuclear layer (ONL) was thinned in the central macula and subretinal fluid was not identified in these earlier disease stages. In patients of “pseudohypopyon” (two eyes), “vitelliruptive” (eight eyes) and “atrophic” (one eye) stages, Fd-OCT revealed a variety of changes in the middle- and inner-HRLs and thinning of ONL. These changes were found to be associated with the level of visual acuity observed. Thickening of the middle-HRL was observed beyond the limits of the clinically evident macular lesion in all eyes

  11. Effect of small head tilt on ocular fundus image: Consideration of proper head positioning for ocular fundus scanning.

    PubMed

    Park, Shin Hae; Kang, Nam Yeo; Kim, Jihyun; Baek, Jiwon; Hong, Seung Woo

    2016-08-01

    Head tilt and resultant ocular cyclotorsion can influence the results of ophthalmologic examinations. Thus, proper head positioning during fundus scanning has been emphasized. However, there is no perfect method to control the head tilt and little is known about the effect of small head tilts. In this study, we investigated the effect of minimal head tilt on the ocular cyclotorsion which we cannot easily detect.Forty-seven participants without ophthalmologic or vestibular abnormalities were recruited as normal subjects. Their faces were positioned at the desired head tilt using a customized adjustable head tilter and facial and fundus photographs of both the left and right eyes were taken in the upright neutral position; as well as at rightward and leftward head tilts of 2°, 4°, and 6°. The actual head tilt was determined using the facial photographs by measuring the slope of a line that intersected the corneal reflexes of both eyes. Rotational changes in the fundus images were recorded and the correlation of these changes with the degree of head tilt was determined.The degree of head tilt was significantly correlated with rotational changes in the fundus images from both the right and left eyes (P < 0.001; right eye: R = 0.897, left eye: R = 0.899). The mean relative compensations for head tilt, mediated by the ocular counterrolling reflex, were 0.376 ± 0.255 in the right eye (range: -0.02 to 1.0), and 0.350 ± 0.263 in the left eye (range: -0.03 to 1.0), and exhibited a significant negative correlation with head tilt (P < 0.05). The mean relative compensation of the right eye did not differ significantly from that of the left eye (P = 0.380), but the value did vary widely among individuals and within individuals.Even very small head tilt was partially and variably compensated for, and caused significant rotation in the fundus image. We concluded that proper head positioning does not guarantee the minimal ocular cyclotorsion change

  12. Effect of small head tilt on ocular fundus image: Consideration of proper head positioning for ocular fundus scanning

    PubMed Central

    Park, Shin Hae; Kang, Nam Yeo; Kim, Jihyun; Baek, Jiwon; Hong, Seung Woo

    2016-01-01

    Abstract Head tilt and resultant ocular cyclotorsion can influence the results of ophthalmologic examinations. Thus, proper head positioning during fundus scanning has been emphasized. However, there is no perfect method to control the head tilt and little is known about the effect of small head tilts. In this study, we investigated the effect of minimal head tilt on the ocular cyclotorsion which we cannot easily detect. Forty-seven participants without ophthalmologic or vestibular abnormalities were recruited as normal subjects. Their faces were positioned at the desired head tilt using a customized adjustable head tilter and facial and fundus photographs of both the left and right eyes were taken in the upright neutral position; as well as at rightward and leftward head tilts of 2°, 4°, and 6°. The actual head tilt was determined using the facial photographs by measuring the slope of a line that intersected the corneal reflexes of both eyes. Rotational changes in the fundus images were recorded and the correlation of these changes with the degree of head tilt was determined. The degree of head tilt was significantly correlated with rotational changes in the fundus images from both the right and left eyes (P < 0.001; right eye: R2 = 0.897, left eye: R2 = 0.899). The mean relative compensations for head tilt, mediated by the ocular counterrolling reflex, were 0.376 ± 0.255 in the right eye (range: −0.02 to 1.0), and 0.350 ± 0.263 in the left eye (range: −0.03 to 1.0), and exhibited a significant negative correlation with head tilt (P < 0.05). The mean relative compensation of the right eye did not differ significantly from that of the left eye (P = 0.380), but the value did vary widely among individuals and within individuals. Even very small head tilt was partially and variably compensated for, and caused significant rotation in the fundus image. We concluded that proper head positioning does not guarantee the minimal ocular

  13. Cataract screening by minimally trained remote observer with non-mydriatic digital fundus camera

    NASA Astrophysics Data System (ADS)

    Choi, Ann; Hjelmstad, David; Taibl, Jessica N.; Sayegh, Samir I.

    2013-03-01

    We propose a method that allows an inexperienced observer, through the examination of the digital fundus image of a retina on a computer screen, to simply determine the presence of a cataract and the necessity to refer the patient for further evaluation. To do so, fundus photos obtained with a non-mydriatic camera were presented to an inexperienced observer that was briefly instructed on fundus imaging, nature of cataracts and their probable effect on the image of the retina and the use of a computer program presenting fundus image pairs. Preliminary results of pair testing indicate the method is very effective.

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

    NASA Astrophysics Data System (ADS)

    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

  15. Retinal fundus imaging in mouse models of retinal diseases.

    PubMed

    Alex, Anne F; Heiduschka, Peter; Eter, Nicole

    2013-01-01

    The development of in vivo retinal fundus imaging in mice has opened a new research horizon, not only in ophthalmic research. The ability to monitor the dynamics of vascular and cellular changes in pathological conditions, such as neovascularization or degeneration, longitudinally without the need to sacrifice the mouse, permits longer observation periods in the same animal. With the application of the high-resolution confocal scanning laser ophthalmoscopy in experimental mouse models, access to a large spectrum of imaging modalities in vivo is provided. PMID:23150359

  16. Fundus changes in mesangiocapillary glomerulonephritis type II: vitreous fluorophotometry.

    PubMed Central

    Raines, M F; Duvall-Young, J; Short, C D

    1989-01-01

    We have described a complex abnormality of retinal pigment epithelium, Bruch's membrane, and choriocapillaris in mesangiocapillary glomerulonephritis (MCGN) type II. Patients with MCGN type II were examined by vitreous fluorophotometry which reveals that there is a breakdown of the blood retinal barrier (BRB) in those patients with the typical fundus lesions. The function of this barrier was calculated as a penetration ratio and was statistically greater in these patients when compared with a group of (a) normal persons, (b) patients with drusen, and (c) patients with other forms of glomerulonephritis. Images PMID:2605145

  17. Fundus Autofluorescence Imaging in an Ocular Screening Program

    PubMed Central

    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. PMID:23316224

  18. Angiogram, fundus, and oxygen saturation optic nerve head image fusion

    NASA Astrophysics Data System (ADS)

    Cao, Hua; Khoobehi, Bahram

    2009-02-01

    A novel multi-modality optic nerve head image fusion approach has been successfully designed. The new approach has been applied on three ophthalmologic modalities: angiogram, fundus, and oxygen saturation retinal optic nerve head images. It has achieved an excellent result by giving the visualization of fundus or oxygen saturation images with a complete angiogram overlay. During this study, two contributions have been made in terms of novelty, efficiency, and accuracy. The first contribution is the automated control point detection algorithm for multi-sensor images. The new method employs retina vasculature and bifurcation features by identifying the initial good-guess of control points using the Adaptive Exploratory Algorithm. The second contribution is the heuristic optimization fusion algorithm. In order to maximize the objective function (Mutual-Pixel-Count), the iteration algorithm adjusts the initial guess of the control points at the sub-pixel level. A refinement of the parameter set is obtained at the end of each loop, and finally an optimal fused image is generated at the end of the iteration. It is the first time that Mutual-Pixel-Count concept has been introduced into biomedical image fusion area. By locking the images in one place, the fused image allows ophthalmologists to match the same eye over time and get a sense of disease progress and pinpoint surgical tools. The new algorithm can be easily expanded to human or animals' 3D eye, brain, or body image registration and fusion.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Haddock, Luis J.; Kim, David Y.

    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. PMID:24171108

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

    PubMed

    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. PMID:26444394

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

    PubMed Central

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

    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. PMID:27174333

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Rapid Grading of Fundus Photographs for Diabetic Retinopathy Using Crowdsourcing

    PubMed Central

    Villanti, Andrea C; Pearson, Jennifer L; Kirchner, Thomas R; Gupta, Omesh P; Shah, Chirag P

    2014-01-01

    Background Screening for diabetic retinopathy is both effective and cost-effective, but rates of screening compliance remain suboptimal. As screening improves, new methods to deal with screening data may help reduce the human resource needs. Crowdsourcing has been used in many contexts to harness distributed human intelligence for the completion of small tasks including image categorization. Objective Our goal was to develop and validate a novel method for fundus photograph grading. Methods An interface for fundus photo classification was developed for the Amazon Mechanical Turk crowdsourcing platform. We posted 19 expert-graded images for grading by Turkers, with 10 repetitions per photo for an initial proof-of-concept (Phase I). Turkers were paid US $0.10 per image. In Phase II, one prototypical image from each of the four grading categories received 500 unique Turker interpretations. Fifty draws of 1-50 Turkers were then used to estimate the variance in accuracy derived from randomly drawn samples of increasing crowd size to determine the minimum number of Turkers needed to produce valid results. In Phase III, the interface was modified to attempt to improve Turker grading. Results Across 230 grading instances in the normal versus abnormal arm of Phase I, 187 images (81.3%) were correctly classified by Turkers. Average time to grade each image was 25 seconds, including time to review training images. With the addition of grading categories, time to grade each image increased and percentage of images graded correctly decreased. In Phase II, area under the curve (AUC) of the receiver-operator characteristic (ROC) indicated that sensitivity and specificity were maximized after 7 graders for ratings of normal versus abnormal (AUC=0.98) but was significantly reduced (AUC=0.63) when Turkers were asked to specify the level of severity. With improvements to the interface in Phase III, correctly classified images by the mean Turker grade in four-category grading

  5. Statistical Characterization and Segmentation of Drusen in Fundus Images

    SciTech Connect

    Santos-Villalobos, Hector J; Karnowski, Thomas Paul; Aykac, Deniz; Giancardo, Luca; Li, Yaquin; Nichols, Trent L; Tobin Jr, Kenneth William; Chaum, Edward

    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.

  6. Abnormalities of fundus autofluorescence in pigmented paravenous chorioretinal atrophy.

    PubMed

    Hashimoto, Yuki; Kase, Satoru; Saito, Wataru; Ishida, Susumu

    2012-01-01

    The aim of this study is to investigate fundus autofluorescence (FAF) as well as fluorescein angiography (FA), indocyanine green angiography (IA), and optical coherence tomography (OCT) in a patient with pigmented paravenous chorioretinal atrophy (PPCRA). A funduscopic examination revealed chorioretinal atrophy along the paravenous area in both eyes. A marked bone spicule pigment clumping together with the atrophy was noted left eye. FA and IA showed a window defect and hypofluorescence, respectively, which exclusively corresponds to the atrophic area along the retinal vein area and the optic disc both eyes. FAF revealed geographic hypofluorescence along the paravenous and supranasal retinal areas. Hyperfluorescence was noted, which comparatively surrounded the hypofluorescence in the peripheral paravenous distribution. Hypofluorescence detected by FAF corresponded to the areas of retinal thinning and atrophy detected by OCT and FA. FAF is a useful examination in PPCRA, which can noninvasively demonstrate the distribution of deficit and dysfunction of retinal pigment epithelium. PMID:23264840

  7. Validating retinal fundus image analysis algorithms: issues and a proposal.

    PubMed

    Trucco, Emanuele; Ruggeri, Alfredo; Karnowski, Thomas; Giancardo, Luca; Chaum, Edward; Hubschman, Jean Pierre; Al-Diri, Bashir; Cheung, Carol Y; Wong, Damon; Abràmoff, Michael; Lim, Gilbert; Kumar, Dinesh; Burlina, Philippe; Bressler, Neil M; Jelinek, Herbert F; Meriaudeau, Fabrice; Quellec, Gwénolé; Macgillivray, Tom; Dhillon, Bal

    2013-05-01

    This paper concerns the validation of automatic retinal image analysis (ARIA) algorithms. For reasons of space and consistency, we concentrate on the validation of algorithms processing color fundus camera images, currently the largest section of the ARIA literature. We sketch the context (imaging instruments and target tasks) of ARIA validation, summarizing the main image analysis and validation techniques. We then present a list of recommendations focusing on the creation of large repositories of test data created by international consortia, easily accessible via moderated Web sites, including multicenter annotations by multiple experts, specific to clinical tasks, and capable of running submitted software automatically on the data stored, with clear and widely agreed-on performance criteria, to provide a fair comparison. PMID:23794433

  8. Pattern Recognition Of Blood Vessel Networks In Ocular Fundus Images

    NASA Astrophysics Data System (ADS)

    Akita, K.; Kuga, H.

    1982-11-01

    We propose a computer method of recognizing blood vessel networks in color ocular fundus images which are used in the mass diagnosis of adult diseases such as hypertension and diabetes. A line detection algorithm is applied to extract the blood vessels, and the skeleton patterns of them are made to analyze and describe their structures. The recognition of line segments of arteries and/or veins in the vessel networks consists of three stages. First, a few segments which satisfy a certain constraint are picked up and discriminated as arteries or veins. This is the initial labeling. Then the remaining unknown ones are labeled by utilizing the physical level knowledge. We propose two schemes for this stage : a deterministic labeling and a probabilistic relaxation labeling. Finally the label of each line segment is checked so as to minimize the total number of labeling contradictions. Some experimental results are also presented.

  9. Next generation high resolution adaptive optics fundus imager

    NASA Astrophysics Data System (ADS)

    Fournier, P.; Erry, G. R. G.; Otten, L. J.; Larichev, A.; Irochnikov, N.

    2005-12-01

    The spatial resolution of retinal images is limited by the presence of static and time-varying aberrations present within the eye. An updated High Resolution Adaptive Optics Fundus Imager (HRAOFI) has been built based on the development from the first prototype unit. This entirely new unit was designed and fabricated to increase opto-mechanical integration and ease-of-use through a new user interface. Improved camera systems for the Shack-Hartmann sensor and for the scene image were implemented to enhance the image quality and the frequency of the Adaptive Optics (AO) control loop. An optimized illumination system that uses specific wavelength bands was applied to increase the specificity of the images. Sample images of clinical trials of retinas, taken with and without the system, are shown. Data on the performance of this system will be presented, demonstrating the ability to calculate near diffraction-limited images.

  10. Multiwavelength adaptive optical fundus camera and continuous retinal imaging

    NASA Astrophysics Data System (ADS)

    Yang, Han-sheng; Li, Min; Dai, Yun; Zhang, Yu-dong

    2009-08-01

    We have constructed a new version of retinal imaging system with chromatic aberration concerned and the correlated optical design presented in this article is based on the adaptive optics fundus camera modality. In our system, three typical wavelengths of 550nm, 650nm and 480nm were selected. Longitude chromatic aberration (LCA) was traded off to a minimum using ZEMAX program. The whole setup was actually evaluated on human subjects and retinal imaging was performed at continuous frame rates up to 20 Hz. Raw videos at parafovea locations were collected, and cone mosaics as well as retinal vasculature were clearly observed in one single clip. In addition, comparisons under different illumination conditions were also made to confirm our design. Image contrast and the Strehl ratio were effectively increased after dynamic correction of high order aberrations. This system is expected to bring new applications in functional imaging of human retina.

  11. Validating Retinal Fundus Image Analysis Algorithms: Issues and a Proposal

    PubMed Central

    Trucco, Emanuele; Ruggeri, Alfredo; Karnowski, Thomas; Giancardo, Luca; Chaum, Edward; Hubschman, Jean Pierre; al-Diri, Bashir; Cheung, Carol Y.; Wong, Damon; Abràmoff, Michael; Lim, Gilbert; Kumar, Dinesh; Burlina, Philippe; Bressler, Neil M.; Jelinek, Herbert F.; Meriaudeau, Fabrice; Quellec, Gwénolé; MacGillivray, Tom; Dhillon, Bal

    2013-01-01

    This paper concerns the validation of automatic retinal image analysis (ARIA) algorithms. For reasons of space and consistency, we concentrate on the validation of algorithms processing color fundus camera images, currently the largest section of the ARIA literature. We sketch the context (imaging instruments and target tasks) of ARIA validation, summarizing the main image analysis and validation techniques. We then present a list of recommendations focusing on the creation of large repositories of test data created by international consortia, easily accessible via moderated Web sites, including multicenter annotations by multiple experts, specific to clinical tasks, and capable of running submitted software automatically on the data stored, with clear and widely agreed-on performance criteria, to provide a fair comparison. PMID:23794433

  12. Automatic arteriovenous crossing phenomenon detection on retinal fundus images

    NASA Astrophysics Data System (ADS)

    Hatanaka, Yuji; Muramatsu, Chisako; Hara, Takeshi; Fujita, Hiroshi

    2011-03-01

    Arteriolosclerosis is one cause of acquired blindness. Retinal fundus image examination is useful for early detection of arteriolosclerosis. In order to diagnose the presence of arteriolosclerosis, the physicians find the silver-wire arteries, the copper-wire arteries and arteriovenous crossing phenomenon on retinal fundus images. The focus of this study was to develop the automated detection method of the arteriovenous crossing phenomenon on the retinal images. The blood vessel regions were detected by using a double ring filter, and the crossing sections of artery and vein were detected by using a ring filter. The center of that ring was an interest point, and that point was determined as a crossing section when there were over four blood vessel segments on that ring. And two blood vessels gone through on the ring were classified into artery and vein by using the pixel values on red and blue component image. Finally, V2-to-V1 ratio was measured for recognition of abnormalities. V1 was the venous diameter far from the blood vessel crossing section, and V2 was the venous diameter near from the blood vessel crossing section. The crossing section with V2-to-V1 ratio over 0.8 was experimentally determined as abnormality. Twenty four images, including 27 abnormalities and 54 normal crossing sections, were used for preliminary evaluation of the proposed method. The proposed method was detected 73% of crossing sections when the 2.8 sections per image were mis-detected. And, 59% of abnormalities were detected by measurement of V1-to-V2 ratio when the 1.7 sections per image were mis-detected.

  13. The Portable Dynamic Fundus Instrument: Uses in telemedicine and research

    NASA Technical Reports Server (NTRS)

    Hunter, Norwood; Caputo, Michael; Billica, Roger; Taylor, Gerald; Gibson, C. Robert; Manuel, F. Keith; Mader, Thomas; Meehan, Richard

    1994-01-01

    For years ophthalmic photographs have been used to track the progression of many ocular diseases such as macular degeneration and glaucoma as well as the ocular manifestations of diabetes, hypertension, and hypoxia. In 1987 a project was initiated at the Johnson Space Center (JSC) to develop a means of monitoring retinal vascular caliber and intracranial pressure during space flight. To conduct telemedicine during space flight operations, retinal images would require real-time transmissions from space. Film-based images would not be useful during in-flight operations. Video technology is beneficial in flight because the images may be acquired, recorded, and transmitted to the ground for rapid computer digital image processing and analysis. The computer analysis techniques developed for this project detected vessel caliber changes as small as 3 percent. In the field of telemedicine, the Portable Dynamic Fundus Instrument demonstrates the concept and utility of a small, self-contained video funduscope. It was used to record retinal images during the Gulf War and to transmit retinal images from the Space Shuttle Columbia during STS-50. There are plans to utilize this device to provide a mobile ophthalmic screening service in rural Texas. In the fall of 1993 a medical team in Boulder, Colorado, will transmit real-time images of the retina during remote consultation and diagnosis. The research applications of this device include the capability of operating in remote locations or small, confined test areas. There has been interest shown utilizing retinal imaging during high-G centrifuge tests, high-altitude chamber tests, and aircraft flight tests. A new design plan has been developed to incorporate the video instrumentation into face-mounted goggle. This design would eliminate head restraint devices, thus allowing full maneuverability to the subjects. Further development of software programs will broaden the application of the Portable Dynamic Fundus Instrument in

  14. Relations between contractile responses and. beta. -adrenoceptors in gastric fundus of diabetic rats

    SciTech Connect

    Sakai, Yasushi; Inazu, Masato; Aihara, Kazuo; Inoue, Kazuaki; Homma, Ikuo )

    1991-01-01

    Contractile responses to norepinephrine (NE), and the population of {beta}-adrenoceptors, were determined in gastric fundus smooth muscle from rats with diabetes induced by streptozotocin(STZ), and age-matched controls. Relaxation and/or contraction of fundus strips of controls and diabetics were induced by 10{sup {minus}5}M NE. Responses to NE were mainly relaxation in gastric fundus isolated from controls, and contraction in fundus isolated from diabetics. Contraction was blocked by 10{sup {minus}8}M prazosin and relaxation was blocked by 10{sup {minus}6}M propranolol. Relaxation by isoproterenol of contraction induced by 10{sup {minus}6}M acetylcholine was significantly less in fundus from diabetics than in that from controls. The number of {beta}-adrenoceptors, measured with ({sup 125}I)iodocyanopindorol as a ligand, was significantly less in gastic fundus membrane isolated from diabetics than in that from controls, but affinity was no different. The level of plasma catecholamine was higher in diabetics than in controls. Results suggest that depression of gastric fundus relaxation and increase of contraction by NE in diabetics could be due to fewer {beta}-adrenoceptor binding sites caused by down-regulation by higher catecholamine level in diabetic rats.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Time course and topographic distribution of ocular fundus pulsation measured by low-coherence tissue interferometry.

    PubMed

    Dragostinoff, Nikolaus; Werkmeister, René M; Klaizer, József; Gröschl, Martin; Schmetterer, Leopold

    2013-12-01

    Low-coherence tissue interferometry is a technique for the depth-resolved measurement of ocular fundus pulsations. Whereas fundus pulsation amplitudes at preselected axial positions can readily be assessed by this method, coupling of the interferometer with a pulse oximeter additionally allows for the reconstruction of the time course of ocular fundus pulsation with respect to the cardiac cycle of the subject. For this purpose, the interferogram resulting from the superposition of waves reflected at the cornea and the ocular fundus is recorded synchronously with the plethysmogram. A new method for evaluating the time course of synthetic interferograms in combination with plethysmograms based on averaging several pulse periods has been developed. This technique allows for the analysis of amplitudes, time courses, and phase differences of fundus pulsations at preselected axial and transversal positions and for creating fundus pulsation movies. Measurements are performed in three healthy emmetropic subjects at angles from 0 deg to 18 deg to the axis of vision. Considerably different time courses, amplitudes, and phases with respect to the cardiac cycle are found at different angles. Data on ocular fundus pulsation obtained with this technique can--among other applications--be used to verify and to improve biomechanical models of the eye. PMID:24091698

  17. OCT angiography in the management of choroidal neovascular membrane secondary to Sorsby fundus dystrophy.

    PubMed

    Mohla, Aditi; Khan, Kamron; Kasilian, Melissa; Michaelides, Michel

    2016-01-01

    We describe the management of a woman aged 52 years with molecularly confirmed Sorsby fundus dystrophy, who presented with acute visual deterioration in her right eye. Fundus examination identified a right macular lesion suggestive of a choroidal neovascular membrane (CNVM). Optical coherence tomography angiography (OCTA) confirmed the presence of a CNVM. She was treated with 2 monthly intravitreal injections of bevacizumab, associated with OCTA evidence of regression of the CNVM and improvement in her visual acuity. OCTA is a novel, non-invasive method of imaging the retinal vasculature. Images are acquired rapidly, with no associated side effects, offering advantages over the current gold standard technique-fundus fluorescein angiography. PMID:27587748

  18. Non-mydriatic ocular fundus photography and telemedicine: past, present, and future

    PubMed Central

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

    2013-01-01

    Non-mydriatic ocular fundus photography is a promising alternative to direct ophthalmoscopy, particularly when combined with telemedicine. This review discusses these technologies from a longitudinal perspective: past, present, and future. The focus is directed to the role that non-mydriatic fundus photography and telemedicine have played in medical research and patient care, with emphasis on the major advances to date. Also discussed are the challenges to their widespread application and their substantial promise for revitalizing the importance of the ocular fundus examination in patient care, providing improved access to ophthalmic consultative services, and facilitating clinical and epidemiologic research. PMID:24244059

  19. Automatic generation of a retinal sensitivity map using infra-red fundus television images.

    PubMed

    Kawai, H; Tamura, S

    1989-01-01

    We have already developed an eye movement analyzing system using an infra-red television fundus camera. Although the quality of the fundus TV images is not good, the system can measure eye movement with an accuracy order of 0.1 degree. We try to apply this system to compensating for eye movements in producing a retinal sensitivity map. A target with variable brightness is presented to various positions on the retina of a subject through a CRT assembled in the infra-red TV fundus camera. The subject is supposed to respond if he can perceive the target. The TV image of the eye fundus, together with the overlaid target and response sign, is recorded on a U-matic (3/4 in) VTR. The image of the video tape is then analyzed by a computer. We have obtained retinal sensitivity maps which show good agreement with the results obtained using the Goldmann perimeter. PMID:2486764

  20. Advances in Image Processing Techniques for Drusens Detection and Quantification in Fundus Images

    NASA Astrophysics Data System (ADS)

    Mora, André; Vieira, Pedro; Fonseca, José

    Age-Related Macular Degeneration (ARMD) is considered the leading cause of irreversible blindness in developed countries. One of its risk factors is the presence of drusens, which are retina abnormalities appearing as yellowish spots in fundus images.

  1. Imaging autofluorescence temporal signatures of the human ocular fundus in vivo

    NASA Astrophysics Data System (ADS)

    Papour, Asael; Taylor, Zachary; Stafsudd, Oscar; Tsui, Irena; Grundfest, Warren

    2015-11-01

    We demonstrate real-time in vivo fundus imaging capabilities of our fluorescence lifetime imaging technology for the first time. This implementation of lifetime imaging uses light emitting diodes to capture full-field images capable of showing direct tissue contrast without executing curve fitting or lifetime calculations. Preliminary results of fundus images are presented, investigating autofluorescence imaging potential of various retina biomarkers for early detection of macular diseases.

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

    PubMed

    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. PMID:25974230

  3. Multimodal Retinal Vessel Segmentation from Spectral-Domain Optical Coherence Tomography and Fundus Photography

    PubMed Central

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

    2014-01-01

    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

  4. A Novel Image Recuperation Approach for Diagnosing and Ranking Retinopathy Disease Level Using Diabetic Fundus Image

    PubMed Central

    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. PMID:25974230

  5. The Role of Fundus Autofluorescence in Late-Onset Retinitis Pigmentosa (LORP) Diagnosis

    PubMed Central

    Lee, Tamara J.; Hwang, John C.; Chen, Royce W. S.; Lima, Luiz H.; Wang, Nan-Kai; Tosi, Joaquin; Freund, K. Bailey; Yannuzzi, Lawrence A.; Tsang, Stephen H.

    2015-01-01

    Purpose To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. Methods Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. Results All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. Conclusion Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis. PMID:23899229

  6. Quantitative Fundus Autofluorescence for the Evaluation of Retinal Diseases.

    PubMed

    Armenti, Stephen T; Greenberg, Jonathan P; Smith, R Theodore

    2016-01-01

    The retinal pigment epithelium (RPE) is juxtaposed to the overlying sensory retina, and supports the function of the visual system. Among the tasks performed by the RPE are phagocytosis and processing of outer photoreceptor segments through lysosome-derived organelles. These degradation products, stored and referred to as lipofuscin granules, are composed partially of bisretinoids, which have broad fluorescence absorption and emission spectra that can be detected clinically as fundus autofluorescence with confocal scanning laser ophthalmoscopy (cSLO). Lipofuscin accumulation is associated with increasing age, but is also found in various patterns in both acquired and inherited degenerative diseases of the retina. Thus, studying its pattern of accumulation and correlating such patterns with changes in the overlying sensory retina are essential to understanding the pathophysiology and progression of retinal disease. Here, we describe a technique employed by our lab and others that uses cSLO in order to quantify the level of RPE lipofuscin in both healthy and diseased eyes. PMID:27023389

  7. Adaptive optics fundus camera using a liquid crystal phase modulator

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tatsuo; Nakazawa, Naoki; Bessho, Kenichiro; Kitaguchi, Yoshiyuki; Maeda, Naoyuki; Fujikado, Takashi; Mihashi, Toshifumi

    2008-05-01

    We have developed an adaptive optics (AO) fundus camera to obtain high resolution retinal images of eyes. We use a liquid crystal phase modulator to compensate the aberrations of the eye for better resolution and better contrast in the images. The liquid crystal phase modulator has a wider dynamic range to compensate aberrations than most mechanical deformable mirrors and its linear phase generation makes it easy to follow eye movements. The wavefront aberration was measured in real time with a sampling rate of 10 Hz and the closed loop system was operated at around 2 Hz. We developed software tools to align consecutively obtained images. From our experiments with three eyes, the aberrations of normal eyes were reduced to less than 0.1 μm (RMS) in less than three seconds by the liquid crystal phase modulator. We confirmed that this method was adequate for measuring eyes with large aberrations including keratoconic eyes. Finally, using the liquid crystal phase modulator, high resolution images of retinas could be obtained.

  8. Automatic detection of red lesions in digital color fundus photographs.

    PubMed

    Niemeijer, Meindert; van Ginneken, Bram; Staal, Joes; Suttorp-Schulten, Maria S A; Abràmoff, Michael D

    2005-05-01

    The robust detection of red lesions in digital color fundus photographs is a critical step in the development of automated screening systems for diabetic retinopathy. In this paper, a novel red lesion detection method is presented based on a hybrid approach, combining prior works by Spencer et al. (1996) and Frame et al. (1998) with two important new contributions. The first contribution is a new red lesion candidate detection system based on pixel classification. Using this technique, vasculature and red lesions are separated from the background of the image. After removal of the connected vasculature the remaining objects are considered possible red lesions. Second, an extensive number of new features are added to those proposed by Spencer-Frame. The detected candidate objects are classified using all features and a k-nearest neighbor classifier. An extensive evaluation was performed on a test set composed of images representative of those normally found in a screening set. When determining whether an image contains red lesions the system achieves a sensitivity of 100% at a specificity of 87%. The method is compared with several different automatic systems and is shown to outperform them all. Performance is close to that of a human expert examining the images for the presence of red lesions. PMID:15889546

  9. Automated retinal vessel type classification in color fundus images

    NASA Astrophysics Data System (ADS)

    Yu, H.; Barriga, S.; Agurto, C.; Nemeth, S.; Bauman, W.; Soliz, P.

    2013-02-01

    Automated retinal vessel type classification is an essential first step toward machine-based quantitative measurement of various vessel topological parameters and identifying vessel abnormalities and alternations in cardiovascular disease risk analysis. This paper presents a new and accurate automatic artery and vein classification method developed for arteriolar-to-venular width ratio (AVR) and artery and vein tortuosity measurements in regions of interest (ROI) of 1.5 and 2.5 optic disc diameters from the disc center, respectively. This method includes illumination normalization, automatic optic disc detection and retinal vessel segmentation, feature extraction, and a partial least squares (PLS) classification. Normalized multi-color information, color variation, and multi-scale morphological features are extracted on each vessel segment. We trained the algorithm on a set of 51 color fundus images using manually marked arteries and veins. We tested the proposed method in a previously unseen test data set consisting of 42 images. We obtained an area under the ROC curve (AUC) of 93.7% in the ROI of AVR measurement and 91.5% of AUC in the ROI of tortuosity measurement. The proposed AV classification method has the potential to assist automatic cardiovascular disease early detection and risk analysis.

  10. Multispectral fundus imaging for early detection of diabetic retinopathy

    NASA Astrophysics Data System (ADS)

    Beach, James M.; Tiedeman, James S.; Hopkins, Mark F.; Sabharwal, Yashvinder S.

    1999-04-01

    Functional imaging of the retina and associated structures may provide information for early assessment of risks of developing retinopathy in diabetic patients. Here we show results of retinal oximetry performed using multi-spectral reflectance imaging techniques to assess hemoglobin (Hb) oxygen saturation (OS) in blood vessels of the inner retina and oxygen utilization at the optic nerve in diabetic patients without retinopathy and early disease during experimental hyperglycemia. Retinal images were obtained through a fundus camera and simultaneously recorded at up to four wavelengths using image-splitting modules coupled to a digital camera. Changes in OS in large retinal vessels, in average OS in disk tissue, and in the reduced state of cytochrome oxidase (CO) at the disk were determined from changes in reflectance associated with the oxidation/reduction states of Hb and CO. Step to high sugar lowered venous oxygen saturation to a degree dependent on disease duration. Moderate increase in sugar produced higher levels of reduced CO in both the disk and surrounding tissue without a detectable change in average tissue OS. Results suggest that regulation of retinal blood supply and oxygen consumption are altered by hyperglycemia and that such functional changes are present before clinical signs of retinopathy.

  11. Robust Multiscale Stereo Matching from Fundus Images with Radiometric Differences

    PubMed Central

    Tang, Li; Garvin, Mona K.; Lee, Kyungmoo; Alward, Wallace L.M.; Kwon, Young H.; Abràmoff, Michael D.

    2013-01-01

    A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation. PMID:21464502

  12. Fundus oculi pigmentation studies simulating the fs-LASIK process Fundus oculi pigmentation studies simulating the fs-LASIK process

    NASA Astrophysics Data System (ADS)

    Sander, M.; Minet, O.; Zabarylo, U.; Müller, M.; Tetz, M. R.

    2012-06-01

    The femtosecond-laser in situ keratomileusis (fs-LASIK) technique has successfully entered the refractive surgery market to correct ametropia by cutting transparent corneal tissue with ultra-short laser pulses based on photodisruption. The laser pulses in the near infrared range (NIR) generate a laser-induced breakdown (LIOB) in the cornea. By propagating through the eye, a certain amount of the pulse is deposited in the cornea and the remaining energy interacts with the strong absorbing tissue behind. Due to the absorption by the retinal pigment epithelium and the transfer of the thermal energy to surrounding tissue, the transmitted energy can induce damage to the retina. The aim of this project was to find out the threshold influences concerning the tissue and the correlation between the results of the macroscopical appraisal and the fundus oculi pigmentation by simulating the fs-LASIK procedure with two various laser systems in the continuous wave (CW) and fs-regime. Therefore ex-vivo determinations were carried out macroscopically and histopathologically on porcine tissue.

  13. Nonmydriatic ocular fundus photography among headache patients in an emergency department

    PubMed Central

    Thulasi, Praneetha; Fraser, Clare L.; Biousse, Valérie; Wright, David W.; Newman, Nancy J.

    2013-01-01

    Objectives: Determine the frequency of and the predictive factors for abnormal ocular fundus findings among emergency department (ED) headache patients. Methods: Cross-sectional study of prospectively enrolled adult patients presenting to our ED with a chief complaint of headache. Ocular fundus photographs were obtained using a nonmydriatic fundus camera that does not require pupillary dilation. Demographic and neuroimaging information was collected. Photographs were reviewed independently by 2 neuroophthalmologists for findings relevant to acute care. The results were analyzed using univariate statistics and logistic regression modeling. Results: We included 497 patients (median age: 40 years, 73% women), among whom 42 (8.5%, 95% confidence interval: 6%–11%) had ocular fundus abnormalities. Of these 42 patients, 12 had disc edema, 9 had optic nerve pallor, 6 had grade III/IV hypertensive retinopathy, and 15 had isolated retinal hemorrhages. Body mass index ≥35 kg/m2 (odds ratio [OR]: 2.3, p = 0.02), younger age (OR: 0.7 per 10-year increase, p = 0.02), and higher mean arterial blood pressure (OR: 1.3 per 10-mm Hg increase, p = 0.003) were predictive of abnormal retinal photography. Patients with an abnormal fundus had a higher percentage of hospital admission (21% vs 10%, p = 0.04). Among the 34 patients with abnormal ocular fundi who had brain imaging, 14 (41%) had normal imaging. Conclusions: Ocular fundus abnormalities were found in 8.5% of patients with headache presenting to our ED. Predictors of abnormal funduscopic findings included higher body mass index, younger age, and higher blood pressure. Our study confirms the importance of funduscopic examination in patients with headache, particularly in the ED, and reaffirms the utility of nonmydriatic fundus photography in this setting. PMID:23284060

  14. Automatic detection of age-related macular degeneration pathologies in retinal fundus images.

    PubMed

    Güven, Ayşegül

    2013-04-01

    Advanced techniques in image processing and analysis are being extensively studied to assist clinical diagnoses. Digital colour retinal fundus images are widely utilised to investigate various eye diseases. In this paper, we describe the detection of optic disc (OD), macula and age-related macular degeneration (ARMD) pathologies of the macular regions in colour fundus images. ARMD causes the loss of central vision in older adults. If the disease is detected early and treated promptly, much of the vision loss can be prevented. Eighty colour retinal fundus images were tested using our proposed algorithm. The Hough transform was employed for OD determination. A fundus coordinate system was established based on the macula location. An ARMD pathology detection methodology using a subtraction process after contrast-limited adaptive histogram equalisation operations was proposed. The accuracies of the automated segmentations of the OD, macula and ARMD pathologies obtained were 100%, 100% and 95.49%, respectively. These results show that our algorithm is a useful tool for detecting ARMD in retinal fundus images. The application of our method may reduce the time needed by ophthalmologists to diagnose ARMD pathology while providing dependable detection precision. Integration of our technique into traditional software could be used in clinical implementations as an aid in disease diagnosis and as a tool for quantitative evaluation of treatment effectiveness. PMID:22372623

  15. Subretinal Fibrosis in Stargardt's Disease with Fundus Flavimaculatus and ABCA4 Gene Mutation

    PubMed Central

    Rossi, Settimio; Testa, Francesco; Attanasio, Marcella; Orrico, Ada; de Benedictis, Antonella; Corte, Michele Della; Simonelli, Francesca

    2012-01-01

    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. PMID:23341817

  16. Diagnosing and Ranking Retinopathy Disease Level Using Diabetic Fundus Image Recuperation Approach

    PubMed Central

    Somasundaram, K.; Alli Rajendran, P.

    2015-01-01

    Retinal fundus images are widely used in diagnosing different types of eye diseases. The existing methods such as Feature Based Macular Edema Detection (FMED) and Optimally Adjusted Morphological Operator (OAMO) effectively detected the presence of exudation in fundus images and identified the true positive ratio of exudates detection, respectively. These mechanically detected exudates did not include more detailed feature selection technique to the system for detection of diabetic retinopathy. To categorize the exudates, Diabetic Fundus Image Recuperation (DFIR) method based on sliding window approach is developed in this work to select the features of optic cup in digital retinal fundus images. The DFIR feature selection uses collection of sliding windows with varying range to obtain the features based on the histogram value using Group Sparsity Nonoverlapping Function. Using support vector model in the second phase, the DFIR method based on Spiral Basis Function effectively ranks the diabetic retinopathy disease level. The ranking of disease level on each candidate set provides a much promising result for developing practically automated and assisted diabetic retinopathy diagnosis system. Experimental work on digital fundus images using the DFIR method performs research on the factors such as sensitivity, ranking efficiency, and feature selection time. PMID:25945362

  17. Automated multimodality concurrent classification for segmenting vessels in 3D spectral OCT and color fundus images

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    Segmenting vessels in spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging in the region near and inside the neural canal opening (NCO). Furthermore, accurately segmenting them in color fundus photographs also presents a challenge near the projected NCO. However, both modalities also provide complementary information to help indicate vessels, such as a better NCO contrast from the NCO-aimed OCT projection image and a better vessel contrast inside the NCO from fundus photographs. We thus present a novel multimodal automated classification approach for simultaneously segmenting vessels in SD-OCT volumes and fundus photographs, with a particular focus on better segmenting vessels near and inside the NCO by using a combination of their complementary features. In particular, in each SD-OCT volume, the algorithm pre-segments the NCO using a graph-theoretic approach and then applies oriented Gabor wavelets with oriented NCO-based templates to generate OCT image features. After fundus-to-OCT registration, the fundus image features are computed using Gaussian filter banks and combined with OCT image features. A k-NN classifier is trained on 5 and tested on 10 randomly chosen independent image pairs of SD-OCT volumes and fundus images from 15 subjects with glaucoma. Using ROC analysis, we demonstrate an improvement over two closest previous works performed in single modal SD-OCT volumes with an area under the curve (AUC) of 0.87 (0.81 for our and 0.72 for Niemeijer's single modal approach) in the region around the NCO and 0.90 outside the NCO (0.84 for our and 0.81 for Niemeijer's single modal approach).

  18. The Characteristics of Peripapillary Retinal Perfusion by Optical Coherence Tomography Angiography in Tessellated Fundus Eyes

    PubMed Central

    Kong, Xiangmei; Zhu, Li; Sun, Xinghuai

    2016-01-01

    Purpose To evaluate the peripapillary and perifoveal retinal perfusions of young healthy eyes with a tessellated fundus using optical coherence tomography (OCT) angiography. Methods Thirty-five Chinese subjects with a tessellated fundus and 35 subjects without a tessellated fundus from a population-based cross-sectional study in Shanghai were included. All participants underwent OCT angiography. The flow index and vessel density were examined in the peripapillary and perifoveal retinal areas, and their relationships with other ocular parameters were analyzed. Results In the peripapillary area, the eyes with a tessellated fundus had a lower retinal nerve fiber layer (RNFL) flow index (0.055 ± 0.009 vs. 0.061 ± 0.007, P = 0.006), RNFL vessel density (61.8 ± 7.3 vs. 65.9 ± 5.2, P = 0.010), retinal flow index (0.086 ± 0.010 vs. 0.092 ± 0.008, P = 0.012), and retinal vessel density (83.7 ± 5.0 vs. 86.4 ± 3.7, P = 0.018) than the control eyes, and the difference remained significant even after adjustments were made for gender and RNFL thickness. No difference was found in the perifoveal area. Multivariable linear regression analysis showed that the retinal flow index and vessel density in the peripapillary area were significantly correlated with the tessellated fundus diagnosis (flow index: β = -0.006, P = 0.005; vessel density: β = -2.597, P = 0.006), gender (flow index: β = 0.005, P = 0.019; vessel density: β = 3.129, P = 0.002) and RNFL thickness (flow index: β = 0.000, P = 0.002; vessel density: β = 0.190, P = 0.002). The RNFL flow index and vessel density were significantly associated with the tessellated fundus diagnosis (flow index: β = -0.005, P = 0.005; vessel density: β = -3.572, P = 0.008) and the thickness of RNFL (flow index: β = 0.001, P < 0.001; vessel density: β = 0.421, P < 0.001). Conclusions Eyes with tessellated fundus with a relative decreased peripapillary retinal perfusion compared with eyes without a tessellated fundus were

  19. Comparison of Drusen Area Detected by Spectral Domain Optical Coherence Tomography and Color Fundus Imaging

    PubMed Central

    Yehoshua, Zohar; Gregori, Giovanni; Sadda, SriniVas R.; Penha, Fernando M.; Goldhardt, Raquel; Nittala, Muneeswar G.; Konduru, Ranjith K.; Feuer, William J.; Gupta, Pooja; Li, Ying; Rosenfeld, Philip J.

    2013-01-01

    Purpose. To compare the measurements of drusen area from manual segmentation of color fundus photographs with those generated by an automated algorithm designed to detect elevations of the retinal pigment epithelium (RPE) on spectral domain optical coherence tomography (SD-OCT) images. Methods. Fifty eyes with drusen secondary to nonexudative age-related macular degeneration were enrolled. All eyes were imaged with a high-definition OCT instrument using a 200 × 200 A-scan raster pattern covering a 6 mm × 6 mm area centered on the fovea. Digital color fundus images were taken on the same day. Drusen were traced manually on the fundus photos by graders at the Doheny Image Reading Center, whereas quantitative OCT measurements of drusen were obtained by using a fully automated algorithm. The color fundus images were registered to the OCT data set and measurements within corresponding 3- and 5-mm circles centered at the fovea were compared. Results. The mean areas (±SD [range]) for the 3-mm circles were SD-OCT = 1.57 (±1.08 [0.03–4.44]); 3-mm color fundus = 1.92 (±1.08 [0.20–3.95]); 5-mm SD-OCT = 2.12 (±1.55 [0.03–5.40]); and 5-mm color fundus = 3.38 (±1.90 [0.39–7.49]). The mean differences between color images and the SD-OCT (color − SD-OCT) were 0.36 (±0.93) (P = 0.008) for the 3-mm circle and 1.26 (±1.38) (P < 0.001) for the 5-mm circle measurements. Intraclass correlation coefficients of agreements for 3- and 5-mm measurements were 0.599 and 0.540, respectively. Conclusions. There was only fair agreement between drusen area measurements obtained from SD-OCT images and color fundus photos. Drusen area measurements on color fundus images were larger than those with SD-OCT scans. This difference can be attributed to the fact that the OCT algorithm defines drusen in terms of RPE deformations above a certain threshold, and will not include small, flat drusen and subretinal drusenoid deposits. The two approaches provide complementary information about

  20. Comparing the utility of the non-mydriatic fundus camera to the direct ophthalmoscope for medical education.

    PubMed

    Chen, Ming; Swinney, Christian; Chen, Mindy; Bal, Minder; Nakatsuka, Austin

    2015-03-01

    Visualization of the fundus is an important component of any ophthalmologic exam. Students are taught to visualize the fundus using a direct handheld ophthalmoscope. However, this device has many limitations, which may be a detriment to medical education and patient care. The invention of the non-mydriatic automatic fundus camera could significantly improve medical education. Our study examined the ability of a group of 5 medical students to visualize pathology and form a diagnosis with a traditional handheld ophthalmoscope and an automatic fundus camera. With the direct ophthalmoscope, none of the students were able to visualize the macula, a crucial aspect of the ophthalmologic exam. With the automatic fundus camera, all students were able to visualize the fundus. The latter modality also increased the proportion of students that was able to correctly diagnose the patients with diabetic retinopathy, 100% vs 40%. On average, students were also more confident in their ability to visualize basic retinal anatomy with the automatic fundus camera, 9.6/10 vs 6.4/10. Thus, incorporating the non-mydriatic automatic fundus camera into medical education, alongside the handheld ophthalmoscope, has the potential to improve both learning outcomes and patient care. PMID:25821651

  1. Comparing the Utility of the Non-Mydriatic Fundus Camera to the Direct Ophthalmoscope for Medical Education

    PubMed Central

    Chen, Ming; Chen, Mindy; Bal, Minder; Nakatsuka, Austin

    2015-01-01

    Visualization of the fundus is an important component of any ophthalmologic exam. Students are taught to visualize the fundus using a direct handheld ophthalmoscope. However, this device has many limitations, which may be a detriment to medical education and patient care. The invention of the non-mydriatic automatic fundus camera could significantly improve medical education. Our study examined the ability of a group of 5 medical students to visualize pathology and form a diagnosis with a traditional handheld ophthalmoscope and an automatic fundus camera. With the direct ophthalmoscope, none of the students were able to visualize the macula, a crucial aspect of the ophthalmologic exam. With the automatic fundus camera, all students were able to visualize the fundus. The latter modality also increased the proportion of students that was able to correctly diagnose the patients with diabetic retinopathy, 100% vs 40%. On average, students were also more confident in their ability to visualize basic retinal anatomy with the automatic fundus camera, 9.6/10 vs 6.4/10. Thus, incorporating the non-mydriatic automatic fundus camera into medical education, alongside the handheld ophthalmoscope, has the potential to improve both learning outcomes and patient care. PMID:25821651

  2. 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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:27260483

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

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Tobin Jr, Kenneth William; Chaum, Edward

    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.

  5. Bone Remodeling in Choroidal Osteoma Monitored by Fundus Photography and Spectral-Domain Optical Coherence Tomography

    PubMed Central

    Kamalden, Tengku Ain; Lingam, Gopal; Sundar, Gangadhara

    2014-01-01

    Choroidal osteoma is a benign ossifying tumor of the choroid, consisting of mature bone tissue. It has been described to enlarge and evolve at varying rates over time. Here, we report and quantify the progression of a unilateral choroidal osteoma in a 7-year-old boy by fundus photography, and document tumor remodeling by spectral domain optical coherence tomography images. PMID:27175357

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

    PubMed

    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. PMID:26444393

  7. Evaluation of optic disc size in patients with optic nerve head drusen using fundus photography

    PubMed Central

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

    2012-01-01

    Purpose To evaluate if fundus photography is useful to study the size of the optic disc in patients with optic nerve head drusen (ONHD). Methods Cross-sectional study. Fifty-five patients with ONHD confirmed by B-scan echography and 52 patients’ normal controls were studied. Fundus photography was done in all the cases with a telecentric optical system FF450 IR plus from Zeiss with 20° magnification and Visupac measuring system. We measured total optic disc area, vertical and horizontal diameter. Results Patients with ONHD had smaller optic disc area 2.6 ± 0.55 mm2 (mean ± SD), horizontal diameter (1.68 ± 0.18 mm) and vertical diameter (1.94 ± 0.28 mm) than normal controls (2.93 ± 0.43 mm2, 1.86 ± 0.14 mm and 1.98 ± 0.17 mm, respectively). Significant differences were found in area (p = 0.002) and horizontal diameter (p < 0.001). Conclusions Patients with optic nerve head drusen had smaller optic disc size than normal controls, under digital fundus photography. Fundus photography could be helpful to differentiate optic nerve drusen from other ocular conditions.

  8. Differential gene expression in the murine gastric fundus lacking interstitial cells of Cajal

    PubMed Central

    Daigo, Yataro; Takayama, Ichiro; Ponder, Bruce AJ; Caldas, Carlos; Ward, Sean M; Sanders, Kenton M; Fujino, Masayuki A

    2003-01-01

    Background The muscle layers of murine gastric fundus have no interstitial cells of Cajal at the level of the myenteric plexus and only possess intramuscular interstitial cells and this tissue does not generate electric slow waves. The absence of intramuscular interstitial cells in W/WV mutants provides a unique opportunity to study the molecular changes that are associated with the loss of these intercalating cells. Method The gene expression profile of the gastric fundus of wild type and W/WV mice was assayed by murine microarray analysis displaying a total of 8734 elements. Queried genes from the microarray analysis were confirmed by semi-quantitative reverse transcription-polymerase chain reaction. Results Twenty-one genes were differentially expressed in wild type and W/WV mice. Eleven transcripts had 2.0–2.5 fold higher mRNA expression in W/WV gastric fundus when compared to wild type tissues. Ten transcripts had 2.1–3.9 fold lower expression in W/WV mutants in comparison with wild type animals. None of these genes have ever been implicated in any bowel motility function. Conclusions These data provides evidence that several important genes have significantly changed in the murine fundus of W/WV mutants that lack intramuscular interstitial cells of Cajal and have reduced enteric motor neurotransmission. PMID:12795813

  9. Role of Telokin in Regulating Murine Gastric Fundus Smooth Muscle Tension

    PubMed Central

    An, Changlong; Bhetwal, Bhupal P.; Sanders, Kenton M.; Somlyo, Avril V.; Perrino, Brian A.

    2015-01-01

    Telokin phosphorylation by cyclic GMP-dependent protein kinase facilitates smooth muscle relaxation. In this study we examined the relaxation of gastric fundus smooth muscles from basal tone, or pre-contracted with KCl or carbachol (CCh), and the phosphorylation of telokin S13, myosin light chain (MLC) S19, MYPT1 T853, T696, and CPI-17 T38 in response to 8-Bromo-cGMP, the NO donor sodium nitroprusside (SNP), or nitrergic neurotransmission. We compared MLC phosphorylation and the contraction and relaxation responses of gastric fundus smooth muscles from telokin-/- mice and their wild-type littermates to KCl or CCh, and 8-Bromo-cGMP, SNP, or nitrergic neurotransmission, respectively. We compared the relaxation responses and telokin phosphorylation of gastric fundus smooth muscles from wild-type mice and W/WV mice which lack ICC-IM, to 8-Bromo-cGMP, SNP, or nitrergic neurotransmission. We found that telokin S13 is basally phosphorylated and that 8-Bromo-cGMP and SNP increased basal telokin phosphorylation. In muscles pre-contracted with KCl or CCh, 8-Bromo-cGMP and SNP had no effect on CPI-17 or MYPT1 phosphorylation, but increased telokin phosphorylation and reduced MLC phosphorylation. In telokin-/- gastric fundus smooth muscles, basal tone and constitutive MLC S19 phosphorylation were increased. Pre-contracted telokin-/- gastric fundus smooth muscles have increased contractile responses to KCl, CCh, or cholinergic neurotransmission and reduced relaxation to 8-Bromo-cGMP, SNP, and nitrergic neurotransmission. However, basal telokin phosphorylation was not increased when muscles were stimulated with lower concentrations of SNP or when the muscles were stimulated by nitrergic neurotransmission. SNP, but not nitrergic neurotransmission, increased telokin Ser13 phosphorylation in both wild-type and W/WV gastric fundus smooth muscles. Our findings indicate that telokin may play a role in attenuating constitutive MLC phosphorylation and provide an additional mechanism to

  10. Inverse image alignment method for image mosaicing and video stabilization in fundus indocyanine green angiography under confocal scanning laser ophthalmoscope.

    PubMed

    Zhou, Yongjin; Xue, Hui; Wan, Mingxi

    2003-01-01

    An efficient image registration algorithm, the Inverse Compositional image alignment method based on minimization of Sum of Squared Differences of images, is applied in fundus blood vessel angiography under confocal scanning laser ophthalmoscope, to build image mosaics which have larger field of view without loss of resolution to assist diagnosis. Furthermore, based on similar technique, the angiography video stabilization algorithm is implemented for fundus documenting. The actual underlying models of motion between images and corresponding convergence criteria are also discussed. The experiment results in fundus images demonstrate the effectiveness of the registration scheme. PMID:14575786

  11. Bio-medical imaging: Localization of main structures in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Basit, A.; Egerton, S. J.

    2013-12-01

    Retinal fundus images have three main structures, the optic disk, fovea and blood vessels. By examining fundus images, an ophthalmologist can diagnose various clinical disorders of the eye and the body, typically indicated by changes in the diameter, area, branching angles and tortuosity of the three ma in retinal structures. Knowledge of the optic disk position is an important diagnostic index fo r many diseases related to the retina. In this paper, localization of optic disc is discussed. Optic disk detection is based on morphological operationsand smoothing filters. Blood vessels are extracted using the green component of a colour retinal image with the help of a median filter. Maximum intensity values are validated with blood vessels to localize the optic disk location. The proposed method has shown significant improvements in results.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Optical contrast enhancement of high-resolution ocular fundus imaging in vivo using polarimetry

    NASA Astrophysics Data System (ADS)

    Yang, Hansheng; Rao, Xuejun; Zhang, Yudong

    2007-11-01

    The adaptive optics (AO) retina imaging was performed with contrast enhancement by characterizing polarization parameters of the living retina. A removable pair of polarization state generating unit near the optical source and analysis unit near the CCD camera was incorporated into the basic 37-channle deformable mirror AO microscopic ophthalmoscope. Double-pass imaging polarimetry of the human eye was carried out, then incomplete Mueller matrix was calculated and analyzed to optimize the retina imaging condition using polarized light, which caused the subretinal structures with different polarization properties to emerge from the scattering light background, so the contrast of the image can be substantially enhanced. This method is demonstrated briefly and its validity was tested in the laboratory. The high-resolution images of ocular fundus are compared with 8-frame-averaging images we obtained prior to this method. The experiment results now show improved visualization of fundus structures to some extent without greatly sacrificing image resolution.

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

    PubMed

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

    2015-10-01

    Abstract. 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. PMID:26502233

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

    PubMed Central

    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. PMID:25187693

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

    PubMed

    Li, Kun-Hsien; Chen, San-Ni; Hwang, Jiunn-Feng; Lin, Chun-Ju

    2012-01-01

    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. PMID:23202400

  17. Simultaneous hand-held contact color fundus and SD-OCT imaging for pediatric retinal diseases (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ruggeri, Marco; Hernandez, Victor; De Freitas, Carolina; Relhan, Nidhi; Silgado, Juan; Manns, Fabrice; Parel, Jean-Marie

    2016-03-01

    Hand-held wide-field contact color fundus photography is currently the standard method to acquire diagnostic images of children during examination under anesthesia and in the neonatal intensive care unit. The recent development of portable non-contact hand-held OCT retinal imaging systems has proved that OCT is of tremendous help to complement fundus photography in the management of pediatric patients. Currently, there is no commercial or research system that combines color wide-field digital fundus and OCT imaging in a contact-fashion. The contact of the probe with the cornea has the advantages of reducing motion experienced by the photographer during the imaging and providing fundus and OCT images with wider field of view that includes the periphery of the retina. In this study we produce proof of concept for a contact-type hand-held unit for simultaneous color fundus and OCT live view of the retina of pediatric patients. The front piece of the hand-held unit consists of a contact ophthalmoscopy lens integrating a circular light guide that was recovered from a digital fundus camera for pediatric imaging. The custom-made rear piece consists of the optics to: 1) fold the visible aerial image of the fundus generated by the ophthalmoscopy lens on a miniaturized level board digital color camera; 2) conjugate the eye pupil to the galvanometric scanning mirrors of an OCT delivery system. Wide-field color fundus and OCT images were simultaneously obtained in an eye model and sequentially obtained on the eye of a conscious 25 year-old human subject with healthy retina.

  18. Design, simulation and experimental analysis of an anti-stray-light illumination system of fundus camera

    NASA Astrophysics Data System (ADS)

    Ma, Chen; Cheng, Dewen; Xu, Chen; Wang, Yongtian

    2014-11-01

    Fundus camera is a complex optical system for retinal photography, involving illumination and imaging of the retina. Stray light is one of the most significant problems of fundus camera because the retina is so minimally reflective that back reflections from the cornea and any other optical surface are likely to be significantly greater than the light reflected from the retina. To provide maximum illumination to the retina while eliminating back reflections, a novel design of illumination system used in portable fundus camera is proposed. Internal illumination, in which eyepiece is shared by both the illumination system and the imaging system but the condenser and the objective are separated by a beam splitter, is adopted for its high efficiency. To eliminate the strong stray light caused by corneal center and make full use of light energy, the annular stop in conventional illumination systems is replaced by a fiber-coupled, ring-shaped light source that forms an annular beam. Parameters including size and divergence angle of the light source are specially designed. To weaken the stray light, a polarized light source is used, and an analyzer plate is placed after beam splitter in the imaging system. Simulation results show that the illumination uniformity at the fundus exceeds 90%, and the stray light is within 1%. Finally, a proof-of-concept prototype is developed and retinal photos of an ophthalmophantom are captured. The experimental results show that ghost images and stray light have been greatly reduced to a level that professional diagnostic will not be interfered with.

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

    PubMed

    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. PMID:26574297

  20. A new procedure for fundus photography and fluorescein angiography in small laboratory animal eyes.

    PubMed

    DiLoreto, D; Grover, D A; del Cerro, C; del Cerro, M

    1994-02-01

    Increasing interest in retinal research demands continuous improvement of experimental techniques and interpretation. Thus, the purpose of our research was to devise a new method for funduscopic photography and fluorescein angiography in the normal or diseased retina of the small laboratory animal that would produce results comparable in optical quality and field coverage to those obtained in human clinical practice. To enhance the view of the small eye, a 2.2 Volk Panretinal lens was held in apposition to the lens of a clinical fundus camera, the Topcon TRC 50FT, by means of a custom made metal sleeve. Albino mice, albino rats, and pigmented rats were photographed. Fluorescein angiography was performed on pigmented rats. Fluorescein was administered intravenously via the jugular vein at a dose of 5 mg/kg. Various speeds of film and flash settings were used depending on the light source and the pigmentation of the animal. Attachment of the 2.2 Panretinal lens to the clinical fundus camera allowed for more clearly defined fundus photographs of the small laboratory animal, as well as an enlarged field of observation over conventional techniques. Consequently, angiography fields and stages documented in the small laboratory animal approximated those obtained in human clinical practice. This technique facilitates the visualization of small fundi and it allows for a fuller documentation of experimental retinal models. PMID:8194363

  1. Optic disc detection in color fundus images using ant colony optimization.

    PubMed

    Pereira, Carla; Gonçalves, Luís; Ferreira, Manuel

    2013-03-01

    Diabetic retinopathy has been revealed as the most common cause of blindness among people of working age in developed countries. However, loss of vision could be prevented by an early detection of the disease and, therefore, by a regular screening program to detect retinopathy. Due to its characteristics, the digital color fundus photographs have been the easiest way to analyze the eye fundus. An important prerequisite for automation is the segmentation of the main anatomical features in the image, particularly the optic disc. Currently, there are many works reported in the literature with the purpose of detecting and segmenting this anatomical structure. Though, none of them performs as needed, especially when dealing with images presenting pathologies and a great variability. Ant colony optimization (ACO) is an optimization algorithm inspired by the foraging behavior of some ant species that has been applied in image processing with different purposes. In this paper, this algorithm preceded by anisotropic diffusion is used for optic disc detection in color fundus images. Experimental results demonstrate the good performance of the proposed approach as the optic disc was detected in most of all the images used, even in the images with great variability. PMID:23160896

  2. Detection of exudates in fundus imagery using a constant false-alarm rate (CFAR) detector

    NASA Astrophysics Data System (ADS)

    Khanna, Manish; Kapoor, Elina

    2014-05-01

    Diabetic retinopathy is the leading cause of blindness in adults in the United States. The presence of exudates in fundus imagery is the early sign of diabetic retinopathy so detection of these lesions is essential in preventing further ocular damage. In this paper we present a novel technique to automatically detect exudates in fundus imagery that is robust against spatial and temporal variations of background noise. The detection threshold is adjusted dynamically, based on the local noise statics around the pixel under test in order to maintain a pre-determined, constant false alarm rate (CFAR). The CFAR detector is often used to detect bright targets in radar imagery where the background clutter can vary considerably from scene to scene and with angle to the scene. Similarly, the CFAR detector addresses the challenge of detecting exudate lesions in RGB and multispectral fundus imagery where the background clutter often exhibits variations in brightness and texture. These variations present a challenge to common, global thresholding detection algorithms and other methods. Performance of the CFAR algorithm is tested against a publicly available, annotated, diabetic retinopathy database and preliminary testing suggests that performance of the CFAR detector proves to be superior to techniques such as Otsu thresholding.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:26964319

  5. Two-photon excited fluorescence microscopy application for ex vivo investigation of ocular fundus samples

    NASA Astrophysics Data System (ADS)

    Peters, Sven; Hammer, Martin; Schweitzer, Dietrich

    2011-07-01

    Two-photon excited fluorescence (TPEF) imaging of ocular tissue has recently become a promising tool in ophthalmology for diagnostic and research purposes. The feasibility and the advantages of TPEF imaging, namely deeper tissue penetration and improved high-resolution imaging of microstructures, have been demonstrated lately using human ocular samples. The autofluorescence properties of endogenous fluorophores in ocular fundus tissue are well known from spectrophotometric analysis. But fluorophores, especially when it comes to fluorescence lifetime, typically display a dependence of their fluorescence properties on local environmental parameters. Hence, a more detailed investigation of ocular fundus autofluorescence ideally in vivo is of utmost interest. The aim of this study is to determine space-resolved the stationary and time-resolved fluorescence properties of endogenous fluorophores in ex vivo porcine ocular fundus samples by means of two-photon excited fluorescence spectrum and lifetime imaging microscopy (FSIM/FLIM). By our first results, we characterized the autofluorescence of individual anatomical structures of porcine retina samples excited at 760 nm. The fluorescence properties of almost all investigated retinal layers are relatively homogenous. But as previously unknown, ganglion cell bodies show a significantly shorter fluorescence lifetime compared to the adjacent mueller cells. Since all retinal layers exhibit bi-exponential autofluorescence decays, we were able to achieve a more precise characterization of fluorescence properties of endogenous fluorophores compared to a present in vivo FLIM approach by confocal scanning laser ophthalmoscope (cSLO).

  6. Analysis of Fundus Photography and Fluorescein Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy and Optic Neuritis

    PubMed Central

    Kim, Min Kyung

    2016-01-01

    Purpose We evaluated fundus and fluorescein angiography (FAG) findings and characteristics that can help distinguish nonarteritic anterior ischemic optic neuropathy (NAION) from optic neuritis (ON). Methods Twenty-three NAION patients and 17 ON with disc swelling patients were enrolled in this study. We performed fundus photography and FAG. The disc-swelling pattern, hyperemia grade, presence of splinter hemorrhages, cotton-wool spots, artery/vein ratio and degree of focal telangiectasia were investigated. The FAG findings for each patient were compared with respect to the following features: the pattern of disc leakage in the early phase, arteriovenous (artery/vein) transit time (second), and the presence and pattern of the filling delay. Results Cotton-wool spots, focal telangiectasia, and venous congestion were more common in the affected eyes of NAION patients. Upon FAG, 76.5% of the patients in the ON group exhibited normal choroidal circulation. However, 56.5% of patients in the NAION group demonstrated abnormal filling defects, such as peripapillary, generalized, or watershed zone filling delays. Conclusions Fundus findings, including cotton-wool spots, focal telangiectasia, and venous congestion in the affected eye, may be clues that can be used to diagnose NAION. In addition, choroidal insufficiencies on FAG could be also helpful in differentiating NAION from ON. PMID:27478356

  7. Development of a screening tool for staging of diabetic retinopathy in fundus images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Bency, Mayur Joseph; Rangayyan, Rangaraj M.; Bansal, Reema; Gupta, Amod

    2015-03-01

    Diabetic retinopathy is a condition of the eye of diabetic patients where the retina is damaged because of long-term diabetes. The condition deteriorates towards irreversible blindness in extreme cases of diabetic retinopathy. Hence, early detection of diabetic retinopathy is important to prevent blindness. Regular screening of fundus images of diabetic patients could be helpful in preventing blindness caused by diabetic retinopathy. In this paper, we propose techniques for staging of diabetic retinopathy in fundus images using several shape and texture features computed from detected microaneurysms, exudates, and hemorrhages. The classification accuracy is reported in terms of the area (Az) under the receiver operating characteristic curve using 200 fundus images from the MESSIDOR database. The value of Az for classifying normal images versus mild, moderate, and severe nonproliferative diabetic retinopathy (NPDR) is 0:9106. The value of Az for classification of mild NPDR versus moderate and severe NPDR is 0:8372. The Az value for classification of moderate NPDR and severe NPDR is 0:9750.

  8. Multimodal segmentation of optic disc and cup from stereo fundus and SD-OCT images

    NASA Astrophysics Data System (ADS)

    Miri, Mohammad Saleh; Lee, Kyungmoo; Niemeijer, Meindert; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

    2013-03-01

    Glaucoma is one of the major causes of blindness worldwide. One important structural parameter for the diagnosis and management of glaucoma is the cup-to-disc ratio (CDR), which tends to become larger as glaucoma progresses. While approaches exist for segmenting the optic disc and cup within fundus photographs, and more recently, within spectral-domain optical coherence tomography (SD-OCT) volumes, no approaches have been reported for the simultaneous segmentation of these structures within both modalities combined. In this work, a multimodal pixel-classification approach for the segmentation of the optic disc and cup within fundus photographs and SD-OCT volumes is presented. In particular, after segmentation of other important structures (such as the retinal layers and retinal blood vessels) and fundus-to-SD-OCT image registration, features are extracted from both modalities and a k-nearest-neighbor classification approach is used to classify each pixel as cup, rim, or background. The approach is evaluated on 70 multimodal image pairs from 35 subjects in a leave-10%-out fashion (by subject). A significant improvement in classification accuracy is obtained using the multimodal approach over that obtained from the corresponding unimodal approach (97.8% versus 95.2%; p < 0:05; paired t-test).

  9. Fundus image fusion in EYEPLAN software: An evaluation of a novel technique for ocular melanoma radiation treatment planning

    SciTech Connect

    Daftari, Inder K.; Mishra, Kavita K.; O'Brien, Joan M.; and others

    2010-10-15

    Purpose: The purpose of this study is to evaluate a novel approach for treatment planning using digital fundus image fusion in EYEPLAN for proton beam radiation therapy (PBRT) planning for ocular melanoma. The authors used a prototype version of EYEPLAN software, which allows for digital registration of high-resolution fundus photographs. The authors examined the improvement in tumor localization by replanning with the addition of fundus photo superimposition in patients with macular area tumors. Methods: The new version of EYEPLAN (v3.05) software allows for the registration of fundus photographs as a background image. This is then used in conjunction with clinical examination, tantalum marker clips, surgeon's mapping, and ultrasound to draw the tumor contour accurately. In order to determine if the fundus image superimposition helps in tumor delineation and treatment planning, the authors identified 79 patients with choroidal melanoma in the macular location that were treated with PBRT. All patients were treated to a dose of 56 GyE in four fractions. The authors reviewed and replanned all 79 macular melanoma cases with superimposition of pretreatment and post-treatment fundus imaging in the new EYEPLAN software. For patients with no local failure, the authors analyzed whether fundus photograph fusion accurately depicted and confirmed tumor volumes as outlined in the original treatment plan. For patients with local failure, the authors determined whether the addition of the fundus photograph might have benefited in terms of more accurate tumor volume delineation. Results: The mean follow-up of patients was 33.6{+-}23 months. Tumor growth was seen in six eyes of the 79 macular lesions. All six patients were marginal failures or tumor miss in the region of dose fall-off, including one patient with both in-field recurrence as well as marginal. Among the six recurrences, three were managed by enucleation and one underwent retreatment with proton therapy. Three

  10. Color Fundus Photography versus Fluorescein Angiography in Identification of the Macular Center and Zone in Retinopathy of Prematurity

    PubMed Central

    Patel, Samir N.; Klufas, Michael A.; Ryan, Michael C.; Jonas, Karyn E.; Ostmo, Susan; Martinez-Castellanos, Maria Ana; Berrocal, Audina M.; Chiang, Michael F.; Chan, R.V. Paul

    2016-01-01

    Purpose To examine the utility of fluorescein angiography (FA) in identification of the macular center and the diagnosis of zone in patients with retinopathy of prematurity (ROP). Design Validity and reliability analysis of diagnostic tools Methods 32 sets (16 color fundus photographs; 16 color fundus photographs paired with the corresponding FA) of wide-angle retinal images obtained from 16 eyes of eight infants with ROP were compiled on a secure web site. 9 ROP experts (3 pediatric ophthalmologists; 6 vitreoretinal surgeons) participated in the study. For each image set, experts identified the macular center and provided a diagnosis of zone. Main Outcome Measures (1) Sensitivity and specificity of zone diagnosis (2) “Computer facilitated diagnosis of zone,” based on precise measurement of the macular center, optic disc center, and peripheral ROP. Results Computer facilitated diagnosis of zone agreed with the expert’s diagnosis of zone in 28/45 (62%) cases using color fundus photographs and in 31/45 (69%) cases using FA. Mean (95% CI) sensitivity for detection of zone I by experts as compared to a consensus reference standard diagnosis when interpreting the color fundus images alone versus interpreting the color fundus photographs and FA was 47% (35.3% – 59.3%) and 61.1% (48.9% – 72.4%), respectively, (t(9) ≥ (2.063), p = 0.073). Conclusions There is a marginally significant difference in zone diagnosis when using color fundus photographs compared to using color fundus photographs and the corresponding fluorescein angiograms. There is inconsistency between traditional zone diagnosis (based on ophthalmoscopic exam and image review) compared to a computer-facilitated diagnosis of zone. PMID:25637180

  11. Myosin light chain phosphatase activation is involved in the hydrogen sulfide-induced relaxation in mouse gastric fundus.

    PubMed

    Dhaese, Ingeborg; Lefebvre, Romain A

    2009-03-15

    The relaxant effect of hydrogen sulfide (H(2)S) in the vascular tree is well established but its influence and mechanism of action in gastrointestinal smooth muscle was hardly investigated. The influence of H(2)S on contractility in mouse gastric fundus was therefore examined. Sodium hydrogen sulfide (NaHS; H(2)S donor) was administered to prostaglandin F(2alpha) (PGF(2alpha))-contracted circular muscle strips of mouse gastric fundus, before and after incubation with interfering drugs. NaHS caused a concentration-dependent relaxation of the pre-contracted mouse gastric fundus strips. The K(+) channels blockers glibenclamide, apamin, charybdotoxin, 4-aminopyridin and barium chloride had no influence on the NaHS-induced relaxation. The relaxation by NaHS was also not influenced by L-NAME, ODQ and SQ 22536, inhibitors of the cGMP and cAMP pathway, by nerve blockers capsazepine, omega-conotoxin and tetrodotoxin or by several channel and receptor blockers (ouabain, nifedipine, 2-aminoethyl diphenylborinate, ryanodine and thapsigargin). The myosin light chain phosphatase (MLCP) inhibitor calyculin-A reduced the NaHS-induced relaxation, but the Rho-kinase inhibitor Y-27632 had no influence. We show that NaHS is able to relax PGF(2alpha)-contracted mouse gastric fundus strips. The results suggest that in the mouse gastric fundus, H(2)S causes relaxation at least partially via activation of MLCP. PMID:19374871

  12. Automated diagnosis of Age-related Macular Degeneration using greyscale features from digital fundus images.

    PubMed

    Mookiah, Muthu Rama Krishnan; Acharya, U Rajendra; Koh, Joel E W; Chandran, Vinod; Chua, Chua Kuang; Tan, Jen Hong; Lim, Choo Min; Ng, E Y K; Noronha, Kevin; Tong, Louis; Laude, Augustinus

    2014-10-01

    Age-related Macular Degeneration (AMD) is one of the major causes of vision loss and blindness in ageing population. Currently, there is no cure for AMD, however early detection and subsequent treatment may prevent the severe vision loss or slow the progression of the disease. AMD can be classified into two types: dry and wet AMDs. The people with macular degeneration are mostly affected by dry AMD. Early symptoms of AMD are formation of drusen and yellow pigmentation. These lesions are identified by manual inspection of fundus images by the ophthalmologists. It is a time consuming, tiresome process, and hence an automated diagnosis of AMD screening tool can aid clinicians in their diagnosis significantly. This study proposes an automated dry AMD detection system using various entropies (Shannon, Kapur, Renyi and Yager), Higher Order Spectra (HOS) bispectra features, Fractional Dimension (FD), and Gabor wavelet features extracted from greyscale fundus images. The features are ranked using t-test, Kullback-Lieber Divergence (KLD), Chernoff Bound and Bhattacharyya Distance (CBBD), Receiver Operating Characteristics (ROC) curve-based and Wilcoxon ranking methods in order to select optimum features and classified into normal and AMD classes using Naive Bayes (NB), k-Nearest Neighbour (k-NN), Probabilistic Neural Network (PNN), Decision Tree (DT) and Support Vector Machine (SVM) classifiers. The performance of the proposed system is evaluated using private (Kasturba Medical Hospital, Manipal, India), Automated Retinal Image Analysis (ARIA) and STructured Analysis of the Retina (STARE) datasets. The proposed system yielded the highest average classification accuracies of 90.19%, 95.07% and 95% with 42, 54 and 38 optimal ranked features using SVM classifier for private, ARIA and STARE datasets respectively. This automated AMD detection system can be used for mass fundus image screening and aid clinicians by making better use of their expertise on selected images that

  13. Evaluation of time-resolved autofluorescence images of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Schweitzer, Dietrich; Hammer, Martin; Schweitzer, Frank; Schenke, Stefan; Gaillard, Elizabeth R.

    2003-10-01

    Changes in the metabolism can be assumed as a first sign of several ocular diseases. If such metabolic alterations are detectable, diseases might be treatable, before morphological alterations are manifest. The redox pairs of co-enzymes fluoresce after excitation and change their fluorescence properties depending on the oxidative state of cellular metabolism. Metabolic by-products and connective tissue exhibit also auto-fluorescence. The detection and discrimination of endogenous fluorophores at the fundus by selected excitation or evaluation of emission spectra is not possible with a high spatial resolution. The lifetime of electrons in the excited stage is also substance specific and is not influenced by the absorption spectra of non-fluorescent substances at the fundus. For that reason, a Laser Scanning Ophthalmoscope was developed for the 2-dimensional measurement of time - resolved auto-fluorescence at the living human eye-ground. In first studies, different changes in auto-fluorescence were found after respiration of oxygen between fundus sites. Between young and older persons as well as patients suffering from age-related macular degeneration different lifetime-ranges were detected from the same anatomical region. For comparison, lifetime measurements were performed on single substances. In a first step of interpretation, the frequency distribution of each lifetime in a region of interest can be compared between in vivo and in vitro measurements. Presenting the results in Tau 1-Tau 2 diagrams, specific clusters can be found in both types of measurement, covering each other partially and allowing interpretation of measurements from the living human eye.

  14. Quantitative Fundus Autofluorescence and Optical Coherence Tomography in Best Vitelliform Macular Dystrophy

    PubMed Central

    Duncker, Tobias; Greenberg, Jonathan P.; Ramachandran, Rithambara; Hood, Donald C.; Smith, R. Theodore; Hirose, Tatsuo; Woods, Russell L.; Tsang, Stephen H.; Delori, François C.; Sparrow, Janet R.

    2014-01-01

    Purpose. Quantitative fundus autofluorescence (qAF), spectral domain optical coherence tomography (SD-OCT) segmentation, and multimodal imaging were performed to elucidate the pathogenesis of Best vitelliform macular dystrophy (BVMD) and to identify abnormalities in lesion versus nonlesion fundus areas. Methods. Sixteen patients with a clinical diagnosis of BVMD were studied. Autofluorescence images (30°, 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The grey levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density, to yield qAF. Horizontal SD-OCT scans were obtained and retinal layers manually segmented. Additionally, color and near-infrared reflectance (NIR-R) images were registered to AF images. All patients were screened for mutations in BEST1. In three additional BVMD patients, in vivo spectrofluorometric measurements were obtained within the vitelliform lesion. Results. Mean nonlesion qAF was within normal limits for age. Maximum qAF within the lesion was markedly increased compared with controls. By SD-OCT segmentation, outer segment equivalent thickness was increased and outer nuclear layer thickness decreased in the lesion. Changes were also present in a transition zone beyond the lesion border. In subclinical patients, no abnormalities in retinal layer thickness were identified. Fluorescence spectra recorded from the vitelliform lesion were consistent with those of retinal pigment epithelial cell lipofuscin. Conclusions. Based on qAF, mutations in BEST1 do not cause increased lipofuscin levels in nonlesion fundus areas. PMID:24526438

  15. Nitrergic and purinergic interplay in inhibitory transmission in rat gastric fundus.

    PubMed

    Vetri, T; Bonvissuto, F; Marino, A; Postorino, A

    2007-07-01

    1 This study was undertaken to analyse the involvement of ATP in non-adrenergic non- cholinergic (NANC) relaxation and possible interplay between nitrergic and purinergic systems in rat gastric fundus. 2 Experiments were performed in vitro on strips of longitudinal muscle from rat gastric fundus, recording the mechanical activity as changes in isometric force. In addition, NO release induced by different experimental conditions was assayed. 3 Under NANC conditions in serotonin-precontracted strips, electrical field stimulation (EFS) elicited a tetrodotoxin (TTX)-sensitive relaxation accompanied by nitric oxide (NO) release. This effect was antagonized by pretreatment with the NO synthase antagonist Nomega-nitro-L-arginine (L-NA) or by desensitization of purinergic receptors. Purinergic desensitization was also able to further antagonize the residual EFS-induced relaxation remaining after L-NA treatment. Exogenously applied NO [delivered as sodium nitroprusside (SNP)] or ATP (and related purines) induced concentration-dependent, TTX-insensitive relaxant responses. ATP also induced the release of NO. A reduction in the responses to ATP was observed in the presence of L-NA. In contrast, SNP-induced relaxation remained unchanged after desensitization of purinergic receptors. Finally, apamin, a blocker of the small conductance Ca2+ -dependent K+ channels, reduced the amplitude of the muscular relaxation evoked by either EFS, ATP or SNP. 4 In conclusion, this study provides evidence that in rat gastric fundus, ATP is one of the inhibitory transmitters released from NANC intramural neurones acting directly on the muscle, through receptors coupled to apamin-sensitive Ca2+ -dependent K+ channels and, indirectly, through the stimulation of NO production. PMID:17584445

  16. Detection of retinal capillary nonperfusion in fundus fluorescein angiogram of diabetic retinopathy

    PubMed Central

    Rasta, Seyed Hossein; Nikfarjam, Shima; Javadzadeh, Alireza

    2015-01-01

    Introduction: Retinal capillary nonperfusion (CNP) is one of the retinal vascular diseases in diabetic retinopathy (DR) patients. As there is no comprehensive detection technique to recognize CNP areas, we proposed a different method for computing detection of ischemic retina, non-perfused (NP) regions, in fundus fluorescein angiogram (FFA) images. Methods: Whilst major vessels appear as ridges, non-perfused areas are usually observed as ponds that are surrounded by healthy capillaries in FFA images. A new technique using homomorphic filtering to correct light illumination and detect the ponds surrounded in healthy capillaries on FFA images was designed and applied on DR fundus images. These images were acquired from the diabetic patients who had referred to the Nikookari hospital and were diagnosed for diabetic retinopathy during one year. Our strategy was screening the whole image with a fixed window size, which is small enough to enclose areas with identified topographic characteristics. To discard false nominees, we also performed a thresholding operation on the screen and marked images. To validate its performance we applied our detection algorithm on 41 FFA diabetic retinopathy fundus images in which the CNP areas were manually delineated by three clinical experts. Results: Lesions were found as smooth regions with very high uniformity, low entropy, and small intensity variations in FFA images. The results of automated detection method were compared with manually marked CNP areas so achieved sensitivity of 81%, specificity of 78%, and accuracy of 91%.The result was present as a Receiver operating character (ROC) curve, which has an area under the curve (AUC) of 0.796 with 95% confidence intervals. Conclusion: This technique introduced a new automated detection algorithm to recognize non-perfusion lesions on FFA. This has potential to assist detecting and managing of ischemic retina and may be incorporated into automated grading diabetic retinopathy structures

  17. ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)--a pilot study.

    PubMed

    Vickers, Laura A; Freedman, Sharon F; Wallace, David K; Prakalapakorn, S Grace

    2015-12-01

    The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDA-approved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool's ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy. PMID:26691046

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

    SciTech Connect

    Giancardo, Luca; Chaum, Edward; Karnowski, Thomas Paul; Meriaudeau, Fabrice; Tobin Jr, Kenneth William; Abramoff, M.D.

    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.

  19. Deep neural network and random forest hybrid architecture for learning to detect retinal vessels in fundus images.

    PubMed

    Maji, Debapriya; Santara, Anirban; Ghosh, Sambuddha; Sheet, Debdoot; Mitra, Pabitra

    2015-08-01

    Vision impairment due to pathological damage of the retina can largely be prevented through periodic screening using fundus color imaging. However the challenge with large-scale screening is the inability to exhaustively detect fine blood vessels crucial to disease diagnosis. In this work we present a computational imaging framework using deep and ensemble learning based hybrid architecture for reliable detection of blood vessels in fundus color images. A deep neural network (DNN) is used for unsupervised learning of vesselness dictionaries using sparse trained denoising auto-encoders (DAE), followed by supervised learning of the DNN response using a random forest for detecting vessels in color fundus images. In experimental evaluation with the DRIVE database, we achieve the objective of vessel detection with max. avg. accuracy of 0.9327 and area under ROC curve of 0.9195. PMID:26736930

  20. Radial fundus autofluorescence in the periphery in patients with X-linked retinitis pigmentosa

    PubMed Central

    Ogino, Ken; Oishi, Maho; Oishi, Akio; Morooka, Satoshi; Sugahara, Masako; Gotoh, Norimoto; Kurimoto, Masafumi; Yoshimura, Nagahisa

    2015-01-01

    Purpose To describe the peripheral autofluorescence images and clinical features of patients with retinal dystrophy who showed radial fundus autofluorescence (FAF) at the posterior pole. Methods The authors retrospectively reviewed pooled wide-field FAF images of 711 patients with retinal dystrophy and 56 family members. Results Eleven eyes of seven women exhibited radial FAF at the posterior pole. Wide-field FAF showed extension of the radial pattern to the periphery in all eyes except one. One woman showed radial hyper-FAF only in the periphery, not at the posterior pole. These eight individuals were X-linked retinitis pigmentosa patients or carriers. The tapetal-like reflex was not observed in their color fundus photographs. The peripheral visual field showed wedge-shaped restriction in some individuals. Conclusion Wide-field FAF imaging can depict radial FAF not only at the posterior pole but also in the periphery in X-linked retinitis pigmentosa carriers. The authors therefore agree with previous reports that radial FAF may be a hallmark of X-linked retinitis pigmentosa. PMID:26316687

  1. Pilot Study on Visual Function and Fundus Autofluorescence Assessment in Diabetic Patients

    PubMed Central

    Calvo-Maroto, Ana M.; Esteve-Taboada, José J.; Pérez-Cambrodí, Rafael J.; Madrid-Costa, David; Cerviño, Alejandro

    2016-01-01

    Purpose. Evaluate optimized fundus autofluorescence (FAF) imaging in early stages of diabetic retinopathy (DR) and relate findings with conventional colour fundus imaging and visual function in diabetic patients and control subjects. Materials and Methods. FAF and colour images were obtained using the CR-2 Plus digital nonmydriatic retinal camera in seven diabetic patients and thirteen control subjects. Visual-Functioning Questionnaire-25 (VFQ-25) and Diabetes Self-Management Questionnaire (DSMQ) were used to assess the quality of life and diabetes self-care. Contrast sensitivity function (CSF) was evaluated with the Vistech 6500 chart. Results. FAF and optimized-FAF imaging showed more retinal alterations related to DR than colour imaging. In diabetic patients, compatible signs with microaneurysms, capillary dilations, and haemorrhages were less numerous in colour imaging than optimized-FAF and FAF imaging in areas analysed. Control subjects at risk of developing DM showed more retinal pigment epithelium defects than those without risk in all retinal areas. Significant differences were not found in VFQ-25 and CSF between diabetic patients and control subjects. Conclusions. FAF and optimized-FAF imaging showed significant alterations related to DR not observed in colour imaging. FAF and optimized-FAF images could be a useful complementary tool for detecting early alterations associated with the development and progression of DR. PMID:26977312

  2. Automatic multiresolution age-related macular degeneration detection from fundus images

    NASA Astrophysics Data System (ADS)

    Garnier, Mickaël.; Hurtut, Thomas; Ben Tahar, Houssem; Cheriet, Farida

    2014-03-01

    Age-related Macular Degeneration (AMD) is a leading cause of legal blindness. As the disease progress, visual loss occurs rapidly, therefore early diagnosis is required for timely treatment. Automatic, fast and robust screening of this widespread disease should allow an early detection. Most of the automatic diagnosis methods in the literature are based on a complex segmentation of the drusen, targeting a specific symptom of the disease. In this paper, we present a preliminary study for AMD detection from color fundus photographs using a multiresolution texture analysis. We analyze the texture at several scales by using a wavelet decomposition in order to identify all the relevant texture patterns. Textural information is captured using both the sign and magnitude components of the completed model of Local Binary Patterns. An image is finally described with the textural pattern distributions of the wavelet coefficient images obtained at each level of decomposition. We use a Linear Discriminant Analysis for feature dimension reduction, to avoid the curse of dimensionality problem, and image classification. Experiments were conducted on a dataset containing 45 images (23 healthy and 22 diseased) of variable quality and captured by different cameras. Our method achieved a recognition rate of 93:3%, with a specificity of 95:5% and a sensitivity of 91:3%. This approach shows promising results at low costs that in agreement with medical experts as well as robustness to both image quality and fundus camera model.

  3. Fundus Autofluorescence and Optical Coherence Tomography of Congenital Grouped Albinotic Spots

    PubMed Central

    Kim, David Y.; Hwang, John C.; Moore, Anthony T.; Bird, Alan C.; Tsang, Stephen H.

    2010-01-01

    Purpose To describe fundus autofluorescence (FAF) and optical coherence tomography (OCT) in a series of patients with congenital grouped albinotic spots (CGAS). Methods Three eyes of three patients with CGAS were evaluated with FAF and OCT imaging to evaluate the nature of the albinotic spots. Results In all three eyes with CGAS, FAF imaging revealed autofluorescent spots corresponding to the albinotic spots seen on stereo biomicroscopy. One eye also had additional spots detected on FAF imaging that were not visible on stereo biomicroscopy or color fundus photographs. FAF imaging of the spots demonstrated decreased general autofluorescence as well as decreased peripheral autofluorescence surrounding central areas of retained or increased autofluorescence. OCT revealed a disruption in signal from the hyper-reflective layer corresponding to the photoreceptor inner and outer segment junction as well as increased signal backscattering from the choroid in the area of the spots. Fluorescein angiography (FA) demonstrated early and stable hyperfluorescence of the spots without leakage. Conclusion In this case series, FAF demonstrated decreased autofluorescence of the spots consistent with focal RPE atrophy or abnormal material blocking normal autofluorescence as well as areas of increased autofluorescence suggesting RPE dysfunction. OCT and FA findings suggest photoreceptor and RPE layer abnormalities. FAF and OCT are useful noninvasive diagnostic adjuncts that can aid in the diagnosis of GCAS, help determine extent of disease, and contribute to our understanding of its pathophysiology. PMID:20539258

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

    SciTech Connect

    Giancardo, Luca; Karnowski, Thomas Paul; Chaum, Edward; Meriaudeau, Fabrice; Tobin Jr, Kenneth William; Li, Yaquin

    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.

  5. Automatic Screening and Grading of Age-Related Macular Degeneration from Texture Analysis of Fundus Images.

    PubMed

    Phan, Thanh Vân; Seoud, Lama; Chakor, Hadi; Cheriet, Farida

    2016-01-01

    Age-related macular degeneration (AMD) is a disease which causes visual deficiency and irreversible blindness to the elderly. In this paper, an automatic classification method for AMD is proposed to perform robust and reproducible assessments in a telemedicine context. First, a study was carried out to highlight the most relevant features for AMD characterization based on texture, color, and visual context in fundus images. A support vector machine and a random forest were used to classify images according to the different AMD stages following the AREDS protocol and to evaluate the features' relevance. Experiments were conducted on a database of 279 fundus images coming from a telemedicine platform. The results demonstrate that local binary patterns in multiresolution are the most relevant for AMD classification, regardless of the classifier used. Depending on the classification task, our method achieves promising performances with areas under the ROC curve between 0.739 and 0.874 for screening and between 0.469 and 0.685 for grading. Moreover, the proposed automatic AMD classification system is robust with respect to image quality. PMID:27190636

  6. Pilot Study on Visual Function and Fundus Autofluorescence Assessment in Diabetic Patients.

    PubMed

    Calvo-Maroto, Ana M; Esteve-Taboada, José J; Pérez-Cambrodí, Rafael J; Madrid-Costa, David; Cerviño, Alejandro

    2016-01-01

    Purpose. Evaluate optimized fundus autofluorescence (FAF) imaging in early stages of diabetic retinopathy (DR) and relate findings with conventional colour fundus imaging and visual function in diabetic patients and control subjects. Materials and Methods. FAF and colour images were obtained using the CR-2 Plus digital nonmydriatic retinal camera in seven diabetic patients and thirteen control subjects. Visual-Functioning Questionnaire-25 (VFQ-25) and Diabetes Self-Management Questionnaire (DSMQ) were used to assess the quality of life and diabetes self-care. Contrast sensitivity function (CSF) was evaluated with the Vistech 6500 chart. Results. FAF and optimized-FAF imaging showed more retinal alterations related to DR than colour imaging. In diabetic patients, compatible signs with microaneurysms, capillary dilations, and haemorrhages were less numerous in colour imaging than optimized-FAF and FAF imaging in areas analysed. Control subjects at risk of developing DM showed more retinal pigment epithelium defects than those without risk in all retinal areas. Significant differences were not found in VFQ-25 and CSF between diabetic patients and control subjects. Conclusions. FAF and optimized-FAF imaging showed significant alterations related to DR not observed in colour imaging. FAF and optimized-FAF images could be a useful complementary tool for detecting early alterations associated with the development and progression of DR. PMID:26977312

  7. Depth-resolved measurement of ocular fundus pulsations by low-coherence tissue interferometry

    NASA Astrophysics Data System (ADS)

    Dragostinoff, Nikolaus; Werkmeister, René M.; Gröschl, Martin; Schmetterer, Leopold

    2009-09-01

    A device that allows for the measurement of ocular fundus pulsations at preselected axial positions of a subject's eye is presented. Unlike previously presented systems, which only allow for observation of the strongest reflecting retinal layer, our system enables the measurement of fundus pulsations at a preselected ocular layer. For this purpose the sample is illuminated by light of low temporal coherence. The layer is then selected by positioning one mirror of a Michelson interferometer according to the depth of the layer. The device contains a length measurement system based on partial coherence interferometry and a line scan charge-coupled device camera for recording and online inspection of the fringe system. In-vivo measurements in healthy humans are performed as proof of principle. The algorithms used for enhancing the recorded images are briefly introduced. The contrast of the observed interference pattern is evaluated for different positions of the measurement mirror and at various distances from the front surface of the cornea. The applications of such a system may be wide, including assessment of eye elongation during myopia development and blood-flow-related changes in intraocular volume.

  8. Accurate and reliable segmentation of the optic disc in digital fundus images

    PubMed Central

    Giachetti, Andrea; Ballerini, Lucia; Trucco, Emanuele

    2014-01-01

    Abstract. We describe a complete pipeline for the detection and accurate automatic segmentation of the optic disc in digital fundus images. This procedure provides separation of vascular information and accurate inpainting of vessel-removed images, symmetry-based optic disc localization, and fitting of incrementally complex contour models at increasing resolutions using information related to inpainted images and vessel masks. Validation experiments, performed on a large dataset of images of healthy and pathological eyes, annotated by experts and partially graded with a quality label, demonstrate the good performances of the proposed approach. The method is able to detect the optic disc and trace its contours better than the other systems presented in the literature and tested on the same data. The average error in the obtained contour masks is reasonably close to the interoperator errors and suitable for practical applications. The optic disc segmentation pipeline is currently integrated in a complete software suite for the semiautomatic quantification of retinal vessel properties from fundus camera images (VAMPIRE). PMID:26158034

  9. Accurate and reliable segmentation of the optic disc in digital fundus images.

    PubMed

    Giachetti, Andrea; Ballerini, Lucia; Trucco, Emanuele

    2014-07-01

    We describe a complete pipeline for the detection and accurate automatic segmentation of the optic disc in digital fundus images. This procedure provides separation of vascular information and accurate inpainting of vessel-removed images, symmetry-based optic disc localization, and fitting of incrementally complex contour models at increasing resolutions using information related to inpainted images and vessel masks. Validation experiments, performed on a large dataset of images of healthy and pathological eyes, annotated by experts and partially graded with a quality label, demonstrate the good performances of the proposed approach. The method is able to detect the optic disc and trace its contours better than the other systems presented in the literature and tested on the same data. The average error in the obtained contour masks is reasonably close to the interoperator errors and suitable for practical applications. The optic disc segmentation pipeline is currently integrated in a complete software suite for the semiautomatic quantification of retinal vessel properties from fundus camera images (VAMPIRE). PMID:26158034

  10. Blood Vessel Segmentation of Fundus Images by Major Vessel Extraction and Subimage Classification.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Parhi, Keshab K

    2015-05-01

    This paper presents a novel three-stage blood vessel segmentation algorithm using fundus photographs. In the first stage, the green plane of a fundus image is preprocessed to extract a binary image after high-pass filtering, and another binary image from the morphologically reconstructed enhanced image for the vessel regions. Next, the regions common to both the binary images are extracted as the major vessels. In the second stage, all remaining pixels in the two binary images are classified using a Gaussian mixture model (GMM) classifier using a set of eight features that are extracted based on pixel neighborhood and first and second-order gradient images. In the third postprocessing stage, the major portions of the blood vessels are combined with the classified vessel pixels. The proposed algorithm is less dependent on training data, requires less segmentation time and achieves consistent vessel segmentation accuracy on normal images as well as images with pathology when compared to existing supervised segmentation methods. The proposed algorithm achieves a vessel segmentation accuracy of 95.2%, 95.15%, and 95.3% in an average of 3.1, 6.7, and 11.7 s on three public datasets DRIVE, STARE, and CHASE_DB1, respectively. PMID:25014980

  11. Automatic Screening and Grading of Age-Related Macular Degeneration from Texture Analysis of Fundus Images

    PubMed Central

    Phan, Thanh Vân; Seoud, Lama; Chakor, Hadi; Cheriet, Farida

    2016-01-01

    Age-related macular degeneration (AMD) is a disease which causes visual deficiency and irreversible blindness to the elderly. In this paper, an automatic classification method for AMD is proposed to perform robust and reproducible assessments in a telemedicine context. First, a study was carried out to highlight the most relevant features for AMD characterization based on texture, color, and visual context in fundus images. A support vector machine and a random forest were used to classify images according to the different AMD stages following the AREDS protocol and to evaluate the features' relevance. Experiments were conducted on a database of 279 fundus images coming from a telemedicine platform. The results demonstrate that local binary patterns in multiresolution are the most relevant for AMD classification, regardless of the classifier used. Depending on the classification task, our method achieves promising performances with areas under the ROC curve between 0.739 and 0.874 for screening and between 0.469 and 0.685 for grading. Moreover, the proposed automatic AMD classification system is robust with respect to image quality. PMID:27190636

  12. Optoelectrophysiological stimulation of the human eye using fundus-controlled silent substitution technique

    NASA Astrophysics Data System (ADS)

    Klee, Sascha; Link, Dietmar; Bessler, Patrick; Haueisen, Jens

    2011-01-01

    We design, characterize, and apply a novel optoelectrophysiological setup for a fundus-controlled silent substitution technique that accounts for interindividual variability in retina morphology and simultaneously monitors the stimulation site under investigation. We connect a digital color liquid crystal on silicon projector, an electron-multiplying imager, and a light-emitting diode to a fundus camera. The temporal and spatial characterization reveal a maximal contrast loss of 7% for the highest stimulation frequency (30 Hz) and maximum cutoff spatial frequencies of ~120 cycles/deg. Two silent substitution flash sequences are applied to modulate selective activity in the short-wavelength-sensitive cone (S-cone) and combined long- and middle-wavelength-sensitive cone (LM-cone) pathways. Simultaneously, the visual evoked potentials are recorded. The data are compared to the grand average responses from a previous study that employed standard computer-screen presentation and showed very good latency matches. All the volunteers in the present examination exhibit differences between the S-cone and LM-cone evoked potentials (parameters mean values: peak-to-peak amplitude, N1 latency, and P1 latency for S-cone/LM-cone responses: 8 μV/15 μV, 113 ms/89 ms, 170 ms/143 ms). We demonstrate that the developed optoelectrophysiological setup simultaneously provides imaging, functional stimulation, and electrophysiological investigation of the retina.

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

    PubMed Central

    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

  14. Trans-palpebral illumination: an approach for wide-angle fundus photography without the need for pupil dilation.

    PubMed

    Toslak, Devrim; Thapa, Damber; Chen, Yanjun; Erol, Muhammet Kazim; Paul Chan, R V; Yao, Xincheng

    2016-06-15

    It is technically difficult to construct wide-angle fundus imaging devices due to the complexity of conventional transpupillary illumination and imaging mechanisms. We report here a new method, i.e., trans-palpebral illumination, for wide-angle fundus photography without the need for pupil dilation. By constructing a smartphone-based prototype imaging device, we demonstrated a 152° view in a single-shot image. The unique combination of low-cost smartphone design and automatic illumination optimization promises an affordable solution to conduct telemedicine assessment of eye diseases, which will improve access to eye care for patients in rural and underserved areas. PMID:27304264

  15. Trans-palpebral illumination: an approach for wide-angle fundus photography without the need for pupil dilation

    PubMed Central

    Toslak, Devrim; Thapa, Damber; Chen, Yanjun; Erol, Muhammet Kazim; Paul Chan, R. V.; Yao, Xincheng

    2016-01-01

    It is technically difficult to construct wide-angle fundus imaging devices due to the complexity of conventional transpupillary illumination and imaging mechanisms. We report here a new method, i.e., trans-palpebral illumination, for wide-angle fundus photography without the need for pupil dilation. By constructing a smartphone-based prototype imaging device, we demonstrated a 152° view in a single-shot image. The unique combination of low-cost smartphone design and automatic illumination optimization promises an affordable solution to conduct telemedicine assessment of eye diseases, which will improve access to eye care for patients in rural and underserved areas. PMID:27304264

  16. KV7 channels regulate muscle tone and nonadrenergic noncholinergic relaxation of the rat gastric fundus.

    PubMed

    Ipavec, V; Martire, M; Barrese, V; Taglialatela, M; Currò, D

    2011-10-01

    Voltage-dependent type 7 K+ (KV7) channels play important physiological roles in neurons and muscle cells. The aims of the present study were to investigate the motor effects of KV7 channel modulators in the rat gastric fundus and the expression of KV7 channels in this tissue. Muscle tone and electrical field stimulation (EFS)-evoked relaxations of precontracted longitudinal muscle strips of the rat gastric fundus were investigated under nonadrenergic noncholinergic conditions by organ bath studies. Gene expression was studied by real-time PCR and tissue localization of channels was investigated by immunohistochemistry. The KV7 channel blocker XE-991 induced concentration-dependent contractions, with mean pD2 and Emax of 5.4 and 48% of the maximal U46619-induced contraction, respectively. The KV7 channel activators retigabine and flupirtine concentration-dependently relaxed U46619-precontracted strips, with pD2s of 4.7 and 4.4 and Emax of 93% and 91% of the maximal relaxation induced by papaverine, respectively. XE-991 concentration-dependently inhibited retigabine-induced relaxation with a pIC50 of 6.2. XE-991 and DMP-543, another KV7 channel blocker, increased by 13-25% or reduced by 11-21% the relaxations evoked by low- or high-frequency EFS, respectively. XE-991 also reduced the relaxation induced by vasoactive intestinal polypeptide (VIP) by 33% of controls. Transcripts encoded by all KV7 genes were detected in the fundus, with 7.4 and 7.5 showing the highest expression levels. KV7.4 and 7.5 channels were visualized by confocal immunofluorescence in both circular and longitudinal muscle layers. In conclusion, in the rat proximal stomach, KV7 channels appear to contribute to the resting muscle tone and to VIP- and high-frequency EFS-induced relaxation. KV7 channel activators could be useful relaxant agents of the gastric smooth muscle. PMID:21740972

  17. Fundus optic disc localization and segmentation method based on phase congruency.

    PubMed

    Geng, Lei; Shao, Yi-Ting; Xiao, Zhi-Tao; Zhang, Fang; Wu, Jun; Li, Min; Shan, Chun-Yan

    2014-01-01

    It has been demonstrated that shape, area and depth of the optic disc are relevant indices of diabetic retinopathy. In this paper, we present a new fundus optic disc localization and segmentation method based on phase congruency (PC). Firstly, in order to highlight the optic disc, channel images with the highest contrast between optic disc and background are selected in LAB, YUV, YIQ and HSV spaces respectively. Secondly, with the use of PC, features of four selected channel images can be extracted. Multiplication operation is then used to enhance PC detection results. Thirdly, window scanning and gray accumulating are utilized to locate the optic disc. Finally, iterative OTSU automatic threshold segmentation and Hough transform are performed on location images, before the final optic disc segmentation result can be obtained. The experimental results showed that the proposed method can effectively and accurately perform optic disc location and segmentation. PMID:25227031

  18. An efficient algorithm for measurement of retinal vessel diameter from fundus images based on directional filtering

    NASA Astrophysics Data System (ADS)

    Wang, Xuchu; Niu, Yanmin

    2011-02-01

    Automatic measurement of vessels from fundus images is a crucial step for assessing vessel anomalies in ophthalmological community, where the change in retinal vessel diameters is believed to be indicative of the risk level of diabetic retinopathy. In this paper, a new retinal vessel diameter measurement method by combining vessel orientation estimation and filter response is proposed. Its interesting characteristics include: (1) different from the methods that only fit the vessel profiles, the proposed method extracts more stable and accurate vessel diameter by casting this problem as a maximal response problem of a variation of Gabor filter; (2) the proposed method can directly and efficiently estimate the vessel's orientation, which is usually captured by time-consuming multi-orientation fitting techniques in many existing methods. Experimental results shows that the proposed method both retains the computational simplicity and achieves stable and accurate estimation results.

  19. Optic Disc and Cup Segmentation from Color Fundus Photograph Using Graph Cut with Priors

    PubMed Central

    Zheng, Yuanjie; Stambolian, Dwight; O’Brien, Joan; Gee, James C.

    2014-01-01

    For automatic segmentation of optic disc and cup from color fundus photograph, we describe a fairly general energy function that can naturally fit into a global optimization framework with graph cut. Distinguished from most previous work, our energy function includes priors on the shape & location of disc & cup, the rim thickness and the geometric interaction of “disc contains cup”. These priors together with the effective optimization of graph cut enable our algorithm to generate reliable and robust solutions. Our approach is able to outperform several state-of-the-art segmentation methods, as shown by a set of experimental comparisons with manual delineations and a series of results of correlations with the assessments of a merchant-provided software from Optical Coherence Tomography (OCT) regarding several cup and disc parameters. PMID:24579126

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

    PubMed

    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. PMID:27231583

  1. 3D Reconstruction of the Retinal Arterial Tree Using Subject-Specific Fundus Images

    NASA Astrophysics Data System (ADS)

    Liu, D.; Wood, N. B.; Xu, X. Y.; Witt, N.; Hughes, A. D.; Samcg, Thom

    Systemic diseases, such as hypertension and diabetes, are associated with changes in the retinal microvasculature. Although a number of studies have been performed on the quantitative assessment of the geometrical patterns of the retinal vasculature, previous work has been confined to 2 dimensional (2D) analyses. In this paper, we present an approach to obtain a 3D reconstruction of the retinal arteries from a pair of 2D retinal images acquired in vivo. A simple essential matrix based self-calibration approach was employed for the "fundus camera-eye" system. Vessel segmentation was performed using a semi-automatic approach and correspondence between points from different images was calculated. The results of 3D reconstruction show the centreline of retinal vessels and their 3D curvature clearly. Three-dimensional reconstruction of the retinal vessels is feasible and may be useful in future studies of the retinal vasculature in disease.

  2. Improved diagnostics by automated matching and enhancement in fluorescein angiography of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Noordmans, Herke Jan; van den Biesen, Pieter; de Roode, Rowland; Verdaasdonk, Rudolf

    2008-02-01

    An interactive image matching program has been developed to help ophthalmologists in perceiving subtle differences between sequential images obtained during fluorescein angiography. In a pilot experiment, it appeared that the image matching program could effectively correct camera alignment errors. By offering simple tools like image overlay, blinking and image subtraction, differences between angiograms can be greatly enhanced and interpreted. It appeared that newly formed, leaking blood vessels could be detected at an earlier stage of the disease process using these tools. Treatment can be initiated right away, thereby preventing the patient from having additional visual loss. The matching program seems to improve the quality of fundus diagnostics but needs to be validated in future studies.

  3. Variability in grading diabetic retinopathy from stereo fundus photographs: comparison of physician and lay readers.

    PubMed Central

    Milton, R. C.; Ganley, J. P.; Lynk, R. H.

    1977-01-01

    Two physicians and two lay readers were trained according to a detailed protocol in the grading of 17 lesions found in diabetic retinopathy by evaluation of stereo fundus photographs according to a modified Airlie House classification. Intraobserver and interobserver variability of these readers was assessed by two methods: weighted kappa, and frequency of agreement within one grade. In general, physician readers were found to be less variable on replicate readings than were lay leaders, and had slightly better agreement with each other than with the lay readers. The physiological significance of the direction and magnitude of the difference between physician and lay reader variability for individual lesions was often uncertain. Assessment of contribution to disagreement by individual readers was possible and permits future training directed at reducing disagreement to acceptable values. PMID:851521

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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.

    2016-01-01

    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. PMID:27231583

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Obtaining optic disc center and pixel region by automatic thresholding methods on morphologically processed fundus images.

    PubMed

    Marin, Diego; Gegundez-Arias, Manuel E; Suero, Angel; Bravo, Jose M

    2015-02-01

    Development of automatic retinal disease diagnosis systems based on retinal image computer analysis can provide remarkably quicker screening programs for early detection. Such systems are mainly focused on the detection of the earliest ophthalmic signs of illness and require previous identification of fundal landmark features such as optic disc (OD), fovea or blood vessels. A methodology for accurate center-position location and OD retinal region segmentation on digital fundus images is presented in this paper. The methodology performs a set of iterative opening-closing morphological operations on the original retinography intensity channel to produce a bright region-enhanced image. Taking blood vessel confluence at the OD into account, a 2-step automatic thresholding procedure is then applied to obtain a reduced region of interest, where the center and the OD pixel region are finally obtained by performing the circular Hough transform on a set of OD boundary candidates generated through the application of the Prewitt edge detector. The methodology was evaluated on 1200 and 1748 fundus images from the publicly available MESSIDOR and MESSIDOR-2 databases, acquired from diabetic patients and thus being clinical cases of interest within the framework of automated diagnosis of retinal diseases associated to diabetes mellitus. This methodology proved highly accurate in OD-center location: average Euclidean distance between the methodology-provided and actual OD-center position was 6.08, 9.22 and 9.72 pixels for retinas of 910, 1380 and 1455 pixels in size, respectively. On the other hand, OD segmentation evaluation was performed in terms of Jaccard and Dice coefficients, as well as the mean average distance between estimated and actual OD boundaries. Comparison with the results reported by other reviewed OD segmentation methodologies shows our proposal renders better overall performance. Its effectiveness and robustness make this proposed automated OD location and

  8. Quantitative Fundus Autofluorescence and Optical Coherence Tomography in ABCA4 Carriers

    PubMed Central

    Duncker, Tobias; Stein, Gregory E.; Lee, Winston; Tsang, Stephen H.; Zernant, Jana; Bearelly, Srilaxmi; Hood, Donald C.; Greenstein, Vivienne C.; Delori, François C.; Allikmets, Rando; Sparrow, Janet R.

    2015-01-01

    Purpose To assess whether carriers of ABCA4 mutations have increased RPE lipofuscin levels based on quantitative fundus autofluorescence (qAF) and whether spectral-domain optical coherence tomography (SD-OCT) reveals structural abnormalities in this cohort. Methods Seventy-five individuals who are heterozygous for ABCA4 mutations (mean age, 47.3 years; range, 9–82 years) were recruited as family members of affected patients from 46 unrelated families. For comparison, 57 affected family members with biallelic ABCA4 mutations (mean age, 23.4 years; range, 6–67 years) and two noncarrier siblings were also enrolled. Autofluorescence images (30°, 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Horizontal SD-OCT scans through the fovea were obtained and the thicknesses of the outer retinal layers were measured. Results In 60 of 65 carriers of ABCA4 mutations (age range, 9–60), qAF levels were within normal limits (95% confidence level) observed for healthy noncarrier subjects, while qAF levels of affected family members were significantly increased. Perifoveal fleck-like abnormalities were observed in fundus AF images in four carriers, and corresponding changes were detected in the outer retinal layers in SD-OCT scans. Thicknesses of the outer retinal layers were within the normal range. Conclusions With few exceptions, individuals heterozygous for ABCA4 mutations and between the ages of 9 and 60 years do not present with elevated qAF. In a small number of carriers, perifoveal fleck-like changes were visible. PMID:26551331

  9. Automatic classification of pathological myopia in retinal fundus images using PAMELA

    NASA Astrophysics Data System (ADS)

    Liu, Jiang; Wong, Damon W. K.; Tan, Ngan Meng; Zhang, Zhuo; Lu, Shijian; Lim, Joo Hwee; Li, Huiqi; Saw, Seang Mei; Tong, Louis; Wong, Tien Yin

    2010-03-01

    Pathological myopia is the seventh leading cause of blindness. We introduce a framework based on PAMELA (PAthological Myopia dEtection through peripapilLary Atrophy) for the detection of pathological myopia from fundus images. The framework consists of a pre-processing stage which extracts a region of interest centered on the optic disc. Subsequently, three analysis modules focus on detecting specific visual indicators. The optic disc tilt ratio module gives a measure of the axial elongation of the eye through inference from the deformation of the optic disc. In the texturebased ROI assessment module, contextual knowledge is used to demarcate the ROI into four distinct, clinically-relevant zones in which information from an entropy transform of the ROI is analyzed and metrics generated. In particular, the preferential appearance of peripapillary atrophy (PPA) in the temporal zone compared to the nasal zone is utilized by calculating ratios of the metrics. The PPA detection module obtains an outer boundary through a level-set method, and subtracts this region against the optic disc boundary. Temporal and nasal zones are obtained from the remnants to generate associated hue and color values. The outputs of the three modules are used as in a SVM model to determine the presence of pathological myopia in a retinal fundus image. Using images from the Singapore Eye Research Institute, the proposed framework reported an optimized accuracy of 90% and a sensitivity and specificity of 0.85 and 0.95 respectively, indicating promise for the use of the proposed system as a screening tool for pathological myopia.

  10. Application of 3-Dimensional Printing Technology to Construct an Eye Model for Fundus Viewing Study

    PubMed Central

    Li, Xinhua; Gao, Zhishan; Yuan, Dongqing; Liu, Qinghuai

    2014-01-01

    Objective To construct a life-sized eye model using the three-dimensional (3D) printing technology for fundus viewing study of the viewing system. Methods 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. Results 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. Conclusions 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

  11. Localised calcium release events in cells from the muscle of guinea-pig gastric fundus

    PubMed Central

    Parsons, S P; Bolton, T B

    2004-01-01

    After enzymatic dispersion of the muscle of the guinea-pig gastric fundus, single elongated cells were observed which differed from archetypal smooth muscle cells due to their knurled, tuberose or otherwise irregular surface morphology. These, but not archetypal smooth muscle cells, consistently displayed spontaneous localized (i.e. non-propagating) intracellular calcium ([Ca2+]i) release events. Such calcium events were novel in their magnitude and kinetic profiles. They included short transient events, plateau events and events which coalesced spatially or temporally (compound events). Quantitative analysis of the events with an automatic detection programme showed that their spatio-temporal characteristics (full width and full duration at half-maximum amplitude) were approximately exponentially distributed. Their amplitude distribution suggested the presence of two release modes. Carbachol application caused an initial cell-wide calcium transient followed by an increase in localized calcium release events. Pharmacological analysis suggested that localized calcium release was largely dependent on external calcium entry acting on both inositol trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) to release stored calcium. Nominally calcium-free external solution immediately and reversibly abolished all localized calcium release without blocking the initial transient calcium release response to carbachol. This was inhibited by 2-APB (100 μm), ryanodine (10 or 50 μm) or U-73122 (1 μm). 2-APB (100 μm), xestospongin C (XeC, 10 μm) or U-73122 (1 μm) blocked both spontaneous localized calcium release and localized release stimulated by 10 μm carbachol. Ryanodine (50 μm) also inhibited spontaneous release, but enhanced localized release in response to carbachol. This study represents the first characterization of localized calcium release events in cells from the gastric fundus. PMID:14608011

  12. Nonmydriatic Fundus Photography for Teleophthalmology Diabetic Retinopathy Screening in Rural and Urban Clinics

    PubMed Central

    Chin, Eric K.; Ventura, Bruna V.; See, Kai-Yin; Seibles, Joann

    2014-01-01

    Abstract Purpose: To evaluate the relative diagnostic value of nonmydriatic fundus photography (nFP) among patients screened for diabetic retinopathy in remote rural medical clinics and an urban academic medical center for nonadherence to recommended annual dilated eye examination. Subjects and Methods: A retrospective cross-sectional study was performed among diabetic patients seen in primary outpatient clinics between 2006 and 2011 who were screened for diabetic retinopathy with nFP for history of nonadherence to recommended annual dilated eye examination. A single nonstereoscopic, 45°, 10-megapixel digital image of the disc and macula of both eyes was obtained locally and transmitted electronically to a retinal specialist for remote review. The results from remote rural Native American Indian reservations were compared with those from an urban academic family practice clinic. The proportion of subjects diagnosed with diabetic retinopathy and the quality of fundus images were compared. Results: Among 872 patients (1,744 eyes) screened from rural sites and 517 subjects (1,034 eyes) screened from an urban site, images were of good quality for evaluation in 82.4% and 85.7% of subjects, respectively. Diabetic retinopathy was noted in 12.6% of rural subjects and 29.6% of urban subjects (p<0.001). Conclusions: nFP can be a useful tool in both rural and urban settings to screen for diabetic retinopathy in patients who are nonadherent to the recommended dilated annual eye exam. In our study population, a surprisingly higher percentage of diabetic subjects screened from the urban clinic had retinopathy compared with subjects screened in rural clinics. PMID:24219153

  13. Detection of necrosis of the gastric fundus after blunt abdominal trauma by PET-CT.

    PubMed

    Hofer, A; Kratochwill, H; Pentsch, A; Gabriel, M

    2015-02-01

    Positron emission tomography with [(18)F]-fluorodeoxyglucose provides functional and anatomic information by visualising the uptake of radiolabelled glucose in tumour and inflammatory cells. We report delayed diagnosis of necrosis of the gastric fundus after blunt abdominal trauma in a 73-year-old man. After a car accident with head-on collision, the patient was stabilised in our emergency room. His femur was treated by internal fixation, his ellbow was stabilised by a fixateur externe. During surgery his status deteriorated. The patient was in need of high dosage of inotrops during the following days. He had a biventricular pacemaker implanted because of ischemic myocardiopathy, and he suffered from renal insufficiency. Over the next days, his haemodynamics improved. A central venous line had to be removed because of ensuing septic fever. The patient complained of upper abdominal pain and nausea. A sonography and computer tomography without contrast medium were performed with negative result. Because of contamination of the central venous line with Staphylococcus epidermidis the pacemaker was evaluated for infection by transoesophageal echocardiography, again without any findings. Because of ongoing fever and positive inflammatory markers a positron emission tomography was indicated, as a contrast examination and a magnetic resonance examination were not feasible because of the renal insufficiency and the pacemaker, respectively. Prophylactic removal of the pacemaker would have been a substantial risk for the patient due to his underlying myocardiopathy. Positron emission tomography showed an increased tracer uptake in the gastric fundus, which turned out to be necrotic by endoscopy. A laparoscopic resection followed, and drainage of an abscess, which had evolved subsequently between stomach and spleen stopped the inflammatory process. This case report demonstrates that positron emission tomography may be an alternative to computer tomography with contrast medium

  14. Ridge-based retinal image registration algorithm involving OCT fundus images

    NASA Astrophysics Data System (ADS)

    Li, Ying; Gregori, Giovanni; Knighton, Robert W.; Lujan, Brandon J.; Rosenfeld, Philip J.; Lam, Byron L.

    2011-03-01

    This paper proposes an algorithm for retinal image registration involving OCT fundus images (OFIs). The first application of the algorithm is to register OFIs with color fundus photographs; such registration between multimodal retinal images can help correlate features across imaging modalities, which is important for both clinical and research purposes. The second application is to perform the montage of several OFIs, which allows us to construct 3D OCT images over a large field of view out of separate OCT datasets. We use blood vessel ridges as registration features. The brute force search and an Iterative Closest Point (ICP) algorithm are employed for image pair registration. Global alignment to minimize the distance between matching pixel pairs is used to obtain the montage of OFIs. Quality of OFIs is the big limitation factor of the registration algorithm. In the first experiment, the effect of manual OFI enhancement on registration was evaluated for the affine model on 11 image pairs from diseased eyes. The average root mean square error (RMSE) decreases from 58 μm to 40 μm. This indicates that the registration algorithm is robust to manual enhancement. In the second experiment for the montage of OFIs, the algorithm was tested on 6 sets from healthy eyes and 6 sets from diseased eyes, each set having 8 partially overlapping SD-OCT images. Visual evaluation showed that the montage performance was acceptable for normal cases, and not good for abnormal cases due to low visibility of blood vessels. The average RMSE for a typical montage case from a healthy eye is 2.3 pixels (69 μm).

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

    PubMed

    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. PMID:23516954

  16. Myorelaxant activity of 2-t-butyl-4-methoxyphenol (BHA) in guinea pig gastric fundus.

    PubMed

    Fusi, F; Valoti, M; Petkov, G V; Boev, K K; Sgaragli, G P

    1998-10-30

    This study investigates the mechanism whereby the antioxidant 2-t-butyl-4-methoxyphenol (BHA) relaxes guinea pig gastric fundus smooth muscle. In circular smooth muscle strips, 10 microM cyclopiazonic acid, a specific inhibitor of sarcoplasmic reticulum Ca2+-ATPase, induced a prolonged rise in tension which depended on the presence of extracellular Ca2+. BHA (pIC50 = 5.83), sodium nitroprusside (6.85), isoproterenol (7.69) and nifedipine (8.02), but not 2,6-di-t-butyl-4-methoxyphenol (DTBHA) (up to 30 microM), relaxed muscle strips contracted with cyclopiazonic acid. Methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyri dine-5-carboxylate (Bay K 8644) (1 microM) antagonised the nifedipine- but not the BHA-induced relaxation. Nifedipine and isoproterenol (10 microM) caused a decrease in spontaneous tone, but did not counteract the subsequent rise in tension elicited by 10 microM cyclopiazonic acid. Conversely, 100 microM BHA and 100 microM sodium nitroprusside not only significantly reduced spontaneous tone but also markedly impaired the response of the muscles to cyclopiazonic acid. DTBHA failed to show either effect. When added to preparations completely relaxed by 100 microM BHA, 10 mM tetraethylammonium still elicited nifedipine-sensitive tonic and phasic contractions in the presence or absence of 10 microM cyclopiazonic acid. BHA and DTBHA inhibited, in a concentration-dependent manner, the Ca2+-promoted contraction of strips depolarised by 10 mM tetraethylammonium. The BHA antagonism showed a non-competitive profile while that of DTBHA was competitive. In muscle strips at rest, 10 microM BHA caused a significant increase in tissue cAMP concentration, leaving cGMP unmodified. To conclude, the myorelaxant action of BHA on gastric fundus smooth muscle appears to be mediated partly by an increase in cAMP levels and partly by inhibition of Ca2+ influx from the extracellular space. PMID:9845271

  17. Dissociation between electrical and mechanical responses to nitrergic stimulation in the canine gastric fundus.

    PubMed

    Bayguinov, O; Sanders, K M

    1998-06-01

    1. We examined the relationships between membrane potential, intracellular [Ca2+] ([Ca2+]i), and tension in muscles of the canine gastric fundus in response to nitrergic stimulation by NO donors and electrical field stimulation (EFS) of intrinsic enteric inhibitory neurons when adrenergic and cholinergic responses were blocked. 2. NO donors reduced [Ca2+]i and tension in a concentration-dependent manner. A close relationship was noted between these parameters. 3. In terms of the [Ca2+] vs. force relationship, relaxation responses to EFS differed from responses to NO donors. EFS resulted in smaller decreases in [Ca2+]i to produce a given relaxation compared with responses to NO donors. Thus, muscles stimulated with EFS were less sensitive to [Ca2+]i than muscles stimulated with exogenous NO. 4. When membrane potential, [Ca2+]i and tension were monitored simultaneously in the same muscles, a temporal dissociation was noted between the electrical responses and changes in [Ca2+]i and tension. Brief electrical responses were associated with more sustained changes in [Ca2+]i and tension. 5. Further dissociation between electrical and mechanical effects was noted. Changes in [Ca2+]i and tension caused by sodium nitroprusside and EFS were blocked by arginine analogues and by oxyhaemoglobin, but electrical responses were unaffected. 1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase, also blocked the effects of nitrergic stimulation on [Ca2+]i and tension, without affecting hyperpolarization. Thus, in the presence of continued hyperpolarization, the reductions in [Ca2+]i and tension caused by nitrergic stimulation were blocked. 6. Block of hyperpolarization in response to nitrergic stimulation with tetrapentylammonium chloride (TPEA) had relatively little effect on the [Ca2+]i and tension responses. Thus, hyperpolarization is not required for nitrergic effects on [Ca2+]i and tension. 7. In summary, reduction in [Ca2+]i and tension

  18. Quantitative Fundus Autofluorescence in Best Vitelliform Macular Dystrophy: RPE Lipofuscin is not Increased in Non-Lesion Areas of Retina.

    PubMed

    Sparrow, Janet R; Duncker, Tobias; Woods, Russell; Delori, François C

    2016-01-01

    Since the lipofuscin of retinal pigment epithelial (RPE) cells has been implicated in the pathogenesis of Best vitelliform macular dystrophy, we quantified fundus autofluorescence (quantitative fundus autofluorescence, qAF) as an indirect measure of RPE lipofuscin levels. Mean non-lesion qAF was found to be within normal limits for age. By spectral domain optical coherence tomography (SD-OCT) vitelliform lesions presented as fluid-filled subretinal detachments containing reflective material. We discuss photoreceptor outer segment debris as the source of the intense fluorescence of these lesions and loss of anion channel functioning as an explanation for the bullous photoreceptor-RPE detachment. Unexplained is the propensity of the disease for central retina. PMID:26427423

  19. Spectral-Domain Optical Coherence Tomography, Wide-Field Photography, and Fundus Autofluorescence Correlation of Posterior Ophthalmomyiasis Interna.

    PubMed

    Paulus, Yannis M; Butler, Nicholas J

    2016-07-01

    Posterior ophthalmomyiasis interna is a rare, potentially devastating infestation of the posterior segment by fly larvae. The authors report the first demonstration of spectral-domain optical coherence tomography (SD-OCT) (Spectralis; Heidelberg Engineering, Heidelberg, Germany), wide-field angiography (Optos, Dunfermline, Scotland) and photography, and fundus autofluorescence with temporal progression during a period of 6 months. A 12-year-old white female presented with acute, painless vision loss with hand motions visual acuity. No larva was visible, so she was treated with oral ivermectin. Visual acuity improved to 20/80. OCT demonstrated hyporeflective spaces of the outer retina and retinal pigment epithelium, which resolved during 1-month period with improved ellipsoid layer by 6 months. Fundus autofluorescence demonstrated linear hypoautofluorescent tracks. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:682-685.]. PMID:27434903

  20. Early detection of glaucoma using fully automated disparity analysis of the optic nerve head (ONH) from stereo fundus images

    NASA Astrophysics Data System (ADS)

    Sharma, Archie; Corona, Enrique; Mitra, Sunanda; Nutter, Brian S.

    2006-03-01

    Early detection of structural damage to the optic nerve head (ONH) is critical in diagnosis of glaucoma, because such glaucomatous damage precedes clinically identifiable visual loss. Early detection of glaucoma can prevent progression of the disease and consequent loss of vision. Traditional early detection techniques involve observing changes in the ONH through an ophthalmoscope. Stereo fundus photography is also routinely used to detect subtle changes in the ONH. However, clinical evaluation of stereo fundus photographs suffers from inter- and intra-subject variability. Even the Heidelberg Retina Tomograph (HRT) has not been found to be sufficiently sensitive for early detection. A semi-automated algorithm for quantitative representation of the optic disc and cup contours by computing accumulated disparities in the disc and cup regions from stereo fundus image pairs has already been developed using advanced digital image analysis methodologies. A 3-D visualization of the disc and cup is achieved assuming camera geometry. High correlation among computer-generated and manually segmented cup to disc ratios in a longitudinal study involving 159 stereo fundus image pairs has already been demonstrated. However, clinical usefulness of the proposed technique can only be tested by a fully automated algorithm. In this paper, we present a fully automated algorithm for segmentation of optic cup and disc contours from corresponding stereo disparity information. Because this technique does not involve human intervention, it eliminates subjective variability encountered in currently used clinical methods and provides ophthalmologists with a cost-effective and quantitative method for detection of ONH structural damage for early detection of glaucoma.

  1. Interoperative fundus image and report sharing in compliance with integrating the healthcare enterprise conformance and web access to digital imaging and communication in medicine persistent object protocol

    PubMed Central

    Wu, Hui-Qun; Lv, Zheng-Min; Geng, Xing-Yun; Jiang, Kui; Tang, Le-Min; Zhou, Guo-Min; Dong, Jian-Cheng

    2013-01-01

    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. PMID:24392341

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

    PubMed Central

    Roser, Pia; Kalscheuer, Hannes; Groener, Jan B.; Lehnhoff, Daniel; Klein, Roman; Auffarth, Gerd U.; Nawroth, Peter P.; Schuett, Florian; Rudofsky, Gottfried

    2016-01-01

    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. PMID:26904690

  3. Effects on amine oxidase of substances which antagonize 5-hydroxytryptamine more than tryptamine on the rat fundus strip

    PubMed Central

    Barlow, R. B.

    1961-01-01

    Certain substances, 2-bromolysergic acid diethylamide, dimethyltryptamine (3-(2-dimethylaminoethyl)indole), 2-methyldimethyltryptamine (3-(2-dimethylaminoethyl)-2-methylindole), and 5-benzyloxydimethyltryptamine (5-benzyloxy-3-(2-dimethylaminoethyl)indole), antagonize the effects of 5-hydroxytryptamine on the rat fundus strip more than those of tryptamine. These substances have been tested for their ability to inhibit the oxidation of tryptamine and 5-hydroxytryptamine by suspensions of guinea-pig liver and rat fundus. 2-Bromolysergic acid diethylamide has virtually no inhibitory activity and it is doubtful if the others produce any significant inhibition of amine oxidase in the concentrations which antagonize the effects of 5-hydroxytryptamine more than those of tryptamine. It seems that the differential character of the blocking action of these compounds should be ascribed either to interference with the transport of tryptamine (but not 5-hydroxytryptamine) through the cell wall, coupled with the block of a receptor common to both tryptamine and 5-hydroxytryptamine, or to the existence of separate tryptamine and 5-hydroxytryptamine receptors. The amine oxidases of the guinea-pig liver and rat fundus appear to be a mixture of at least two types of enzyme, one of which has a higher affinity for 5-hydroxytryptamine than the other and is more susceptible to inhibition by 2-methyldimethyltryptamine. PMID:13687054

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

    PubMed Central

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

    2016-01-01

    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. PMID:27231621

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

    PubMed

    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. PMID:27231621

  6. Vertical cup-to-disc ratio measurement for diagnosis of glaucoma on fundus images

    NASA Astrophysics Data System (ADS)

    Hatanaka, Yuji; Noudo, Atsushi; Muramatsu, Chisako; Sawada, Akira; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2010-03-01

    Glaucoma is a leading cause of permanent blindness. Retinal fundus image examination is useful for early detection of glaucoma. In order to evaluate the presence of glaucoma, the ophthalmologists determine the cup and disc areas and they diagnose glaucoma using a vertical cup-to-disc ratio. However, determination of the cup area is very difficult, thus we propose a method to measure the cup-to-disc ratio using a vertical profile on the optic disc. First, the blood vessels were erased from the image and then the edge of optic disc was then detected by use of a canny edge detection filter. Twenty profiles were then obtained around the center of the optic disc in the vertical direction on blue channel of the color image, and the profile was smoothed by averaging these profiles. After that, the edge of the cup area on the vertical profile was determined by thresholding technique. Lastly, the vertical cup-to-disc ratio was calculated. Using seventy nine images, including twenty five glaucoma images, the sensitivity of 80% and a specificity of 85% were achieved with this method. These results indicated that this method can be useful for the analysis of the optic disc in glaucoma examinations.

  7. [Calcium antagonism by papaverine in isolated rat gastric fundus strips in a model system].

    PubMed

    Simon, L; Sallai, J; Szontagh, M; Simon-Talpas, G; Müller, A

    1984-04-01

    Examining isolated strips of gastric fundus tissue of rats the authors observed that papaverin up to 7.8 X 10(-8) to 6.25 X 10(-7) mol/l increased the intensity of convulsions induced by constant amounts of barium chloride (9.5 X 10(-4); with further increase of the concentration the intensity of convulsions gradually sank under the initial value. An increased proneness to cramping was also observed when the calcium content of the Tyrode solution was reduced. In this case the proneness to cramping was highest between 1 and 1.3 mmol/l calcium content. When the calcium content was 1 mmol/l, papaverin increased the proneness to cramping only to a smaller degree, in agreement with the effect measured when the calcium content of the organ bath was reduced below 1 mmol/l. In model experiments, calcium antagonized the potential difference-increasing effect of papaverin at the ether/NaCl (0.1 mol/l) phase boundary. From this the authors infer an interaction (complex formation) between papaverin and calcium at the phase boundary, which is independent of the biological medium. Their findings and the papaverin -calcium antagonism first observed by Benigni [2] can be interpreted in this way. PMID:6739529

  8. Fundus Autofluorescence and Optical Coherence Tomography Findings in Choroidal Melanocytic Lesions

    PubMed Central

    Materin, Miguel A.; Raducu, Raluca; Bianciotto, Carlos; Shields, Carol L.

    2010-01-01

    Purpose: To establish the characteristics of secondary retinal and retinal pigment epithelial (RPE) changes associated with the presence of choroidal melanoma and choroidal nevus as documented by optical coherence tomography (OCT) and fundus autofluorescence (FAF). Materials and Methods: PubMed review of major English publications examining the correlation between clinical characteristics of choroidal melanoma and nevus with OCT and FAF findings. Results: The intrinsic properties of choroidal melanoma, as well as overlying RPE changes, drusen, and lipofuscin are best characterized by FAF, while OCT is more sensitive for the identification of subretinal and intraretinal fluid as well as atrophy, degeneration, and photoreceptor loss in the neurosensory retina. Conclusions: Secondary retinal changes associated with choroidal melanocytic lesions can be documented by OCT and FAF. OCT-evident changes are observed more often with choroidal melanoma than choroidal nevus. OCT is better suited to identify the overlying retinal detachment and edema, even before these findings are clinically apparent. FAF is most useful in documenting the presence of lipofuscin, a finding that represents one of the important criteria in differentiating small choroidal melanoma from benign choroidal nevus. PMID:20844674

  9. Fundus depolarization imaging with GDx VCC scanning laser polarimeter and depolarization characteristics of normal eyes

    NASA Astrophysics Data System (ADS)

    Zhou, Qienyuan; Leder, Henry A.; Lo, Barrick P.; Reed, Geradus C.; Knighton, Robert W.; Cousins, Scott W.

    2009-02-01

    GDx VCC is a confocal scanning laser polarimeter (SLP) developed to assess the retinal nerve fiber layer (RNFL) of the eye based on measurement of the phase retardation in the backscattered light from the fundus. In addition to the phase retardation measurement, a depolarization measurement is readily available from the same image series. We hypothesize that the depolarized light in the GDx signal consists of backscattering from the retinal pigment epithelium (RPE) and the RPE-Bruch's membrane junction, and further, that subRPE deposits contribute to the depolarized backscattered light in proportion to their thickness. Therefore, a quantitative macular depolarization map will provide information about both spatial distribution and heterogeneity of the RPE structure and deposit thickness. Ultimately we predict that depolarization mapping will significantly increase the positive predictive power to identify early dry AMD eyes. In this paper, depolarization measurements in normal eyes and age related changes are reported. Data collection was performed at the Duke University Eye Center. A commercial GDx VCC system was modified with a central fixation target and, instead of depolarized light intensity images, normalized depolarization images were derived and saved in the database. Macular depolarization was observed to increase with age in normal eyes at a rate of 0.27%/yr.

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

    NASA Astrophysics Data System (ADS)

    Giancardo, Luca; Mériaudeau, Fabrice; Karnowski, Thomas P.; Tobin, Kenneth W.; Li, Yaqin; Chaum, Edward

    2010-03-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. A Novel Device to Exploit the Smartphone Camera for Fundus Photography.

    PubMed

    Russo, Andrea; Morescalchi, Francesco; Costagliola, Ciro; Delcassi, Luisa; Semeraro, Francesco

    2015-01-01

    Purpose. To construct an inexpensive, convenient, and portable attachment for smartphones for the acquisition of still and live retinal images. Methods. A small optical device based on the principle of direct ophthalmoscopy was designed to be magnetically attached to a smartphone. Representative images of normal and pathological fundi were taken with the device. Results. A field-of-view up to ~20° was captured at a clinical resolution for each fundus image. The cross-polarization technique adopted in the optical design dramatically diminished corneal Purkinje reflections, making it possible to screen patients even through undilated pupils. Light emission proved to be well within safety limits. Conclusions. This optical attachment is a promising, inexpensive, and valuable alternative to the direct ophthalmoscope, potentially eliminating problems of poor exam skills and inexperienced observer bias. Its portability, together with the wireless connectivity of smartphones, presents a promising platform for screening and telemedicine in nonhospital settings. Translational Relevance. Smartphones have the potential to acquire retinal imaging for a portable ophthalmoscopy. PMID:26137320

  13. Diagnostic Accuracy of Nonmydriatic Fundus Photography for the Detection of Glaucoma in Diabetic Patients

    PubMed Central

    Muñoz-Negrete, Francisco J.; Contreras, Inés; Oblanca, Noelia; Pinazo-Durán, M. Dolores; Rebolleda, Gema

    2015-01-01

    Purpose. To determine the diagnostic accuracy for glaucoma of a set of criteria with nonmydriatic monoscopic fundus photography (NMFP) in diabetics. Methods. Diabetics recruited from a screening program for diabetic retinopathy and diabetic glaucoma patients recruited from our glaucoma unit were included. Any patient with evidence of diabetic retinopathy was excluded. Diabetic patients had to have no visual field defects to be included as controls. Glaucoma patients had to have a glaucomatous field defect in at least one eye to be included. One NMFP was taken per eye for all subjects. These photographs were evaluated by two masked glaucoma specialists for the presence of the following: bilateral cup to disc (C/D) ratio ≥0.6, notching or thinning of the neuroretinal rim, disc hemorrhages, and asymmetry in the C/D ratio between both eyes ≥0.2. This evaluation led to a dichotomous classification: if any of the above criteria was present, the patient was classified as glaucoma. If none were present, the patient was classified as normal. Results. 72 control subjects and 72 glaucoma patients were included. Evaluation of NMFP had a sensitivity of 79.17% and a specificity of 80.56% for specialist 1 and a sensitivity of 72.22% and a specificity of 88.88% for specialist 2 for the detection of glaucoma. The overall accuracy was 79.83% and 80.55%, respectively. Discussion. NMFP evaluation by a glaucoma specialist may be useful for the detection of glaucoma in diabetics. PMID:26557709

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

    NASA Astrophysics Data System (ADS)

    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. Depression by relaxin of neurally induced contractile responses in the mouse gastric fundus.

    PubMed

    Baccari, Maria Caterina; Nistri, Silvia; Quattrone, Silvia; Bigazzi, Mario; Bani Sacchi, Tatiana; Calamai, Franco; Bani, Daniele

    2004-01-01

    The peptide hormone relaxin, which attains high circulating levels during pregnancy, has been shown to depress small-bowel motility through a nitric oxide (NO)-mediated mechanism. In the present study we investigated whether relaxin also influences gastric contractile responses in mice. Female mice in proestrus or estrus were treated for 18 h with relaxin (1 microg s.c.) or vehicle (controls). Mechanical responses of gastric fundal strips were recorded via force-displacement transducers. Evaluation of the expression of nitric oxide synthase (NOS) isoforms was performed by immunohistochemistry and Western blot. In control mice, neurally induced contractile responses elicited by electrical field stimulation (EFS) were reduced in amplitude by addition of relaxin to the organ bath medium. In the presence of the NO synthesis inhibitor l-NNA, relaxin was ineffective. Direct smooth muscle contractile responses were not influenced by relaxin or l-NNA. In strips from relaxin-pretreated mice, the amplitude of neurally induced contractile responses was also reduced in respect to the controls, while that of direct smooth muscle contractions was not. Further addition of relaxin to the bath medium did not influence EFS-induced responses, whereas l-NNA did. An increased expression of NOS I and NOS III was observed in gastric tissues from relaxin-pretreated mice. In conclusion, the peptide hormone relaxin depresses cholinergic contractile responses in the mouse gastric fundus by up-regulating NO biosynthesis at the neural level. PMID:14522837

  16. Splat feature classification with application to retinal hemorrhage detection in fundus images.

    PubMed

    Tang, Li; Niemeijer, Meindert; Reinhardt, Joseph M; Garvin, Mona K; Abràmoff, Michael D

    2013-02-01

    A novel splat feature classification method is presented with application to retinal hemorrhage detection in fundus images. Reliable detection of retinal hemorrhages is important in the development of automated screening systems which can be translated into practice. Under our supervised approach, retinal color images are partitioned into nonoverlapping segments covering the entire image. Each segment, i.e., splat, contains pixels with similar color and spatial location. A set of features is extracted from each splat to describe its characteristics relative to its surroundings, employing responses from a variety of filter bank, interactions with neighboring splats, and shape and texture information. An optimal subset of splat features is selected by a filter approach followed by a wrapper approach. A classifier is trained with splat-based expert annotations and evaluated on the publicly available Messidor dataset. An area under the receiver operating characteristic curve of 0.96 is achieved at the splat level and 0.87 at the image level. While we are focused on retinal hemorrhage detection, our approach has potential to be applied to other object detection tasks. PMID:23193310

  17. High sensitive fundus autofluorescence imaging combined with speckle-free optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Stremplewski, Patrycjusz; Komar, Katarzyna; Szkulmowski, Maciej; Motoczyńska, Marta; Wojtkowski, Maciej

    2013-03-01

    Scattering and fluorescence images provide complementary information about the health condition of the human eye, so getting them in a single measurement, using a single device may significantly improve a quality of diagnosis as it has been already demonstrated in Spectralis (Heidelberg Eng.) OCT instrument. There is still challenge to improve quality of fundus autofluorescence (FAF) images. The biggest obstacle in obtaining in vivo images of sufficient quality is very low fluorescence signal. For eye safety reasons, and because of patient comfort, using highpower fluorescence excitation is not an adequate solution to the low signal problem. In this contribution we show a new detection method in the retinal autofluorescence imaging, which may improve the sensitivity. We used a fast modulated (up to 500 MHz) diode laser of wavelength 473 nm and detected fluorescence in the spectral range 500-680 nm by photomultiplier and lock-in amplifier. Average power of the collimated blue beam on the cornea used for FAF measurements was set to 50 μW, 10 μW, and even 4.5 μW.

  18. Optic disc segmentation by balloon snake with texture from color fundus image.

    PubMed

    Sun, Jinyang; Luan, Fangjun; Wu, Hanhui

    2015-01-01

    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. PMID:25861249

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

    PubMed Central

    Sun, Jinyang; Luan, Fangjun; Wu, Hanhui

    2015-01-01

    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. PMID:25861249

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

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Garg, Seema; Tobin Jr, Kenneth William; Chaum, Edward

    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.

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

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Garg, Seema; Tobin Jr, Kenneth William; Chaum, Edward

    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.

  2. Spectral reflectance of the ocular fundus as a diagnostic marker for cerebral malaria

    NASA Astrophysics Data System (ADS)

    Liu, Xun; Rice, David A.; Khoobehi, Bahram

    2012-03-01

    The challenge of correctly identifying malaria infection continues to impede our efforts to control this disease. Recent studies report highly specific retinal changes in severe malaria patients; these retinal changes may represent a very useful diagnostic indicator for this disease. To further explore the ocular manifestations of malaria, we used hyperspectral imaging to study retinal changes caused by Plasmodium berghei ANKA parasitization in a mouse model. We collected the spectral reflectance of the ocular fundus from hyperspectral images of the mouse eye. The blood oxygen sensitive spectral region was normalized for variances in illumination, and used to calculate relative values that correspond to oxygenated hemoglobin levels. Oxygen hemoglobin levels are markedly lower in parasitized mice, indicating that hemoglobin digestion by P. berghei may be detected using spectral reflectance. Furthermore, the ocular reflectance of parasitized mice was abnormally elevated between 660nm and 750nm, suggesting fluorescence in this region. While the source of this fluorescence is not yet clear, its presence correlates strongly with P. Berghei parasitization, and may indicate the presence of hemozoin deposits in the retinal vasculature. The pathology of severe malaria still presents many questions for clinicians and scientists, and our understanding of cerebral malaria has been generally confined to clinical observation and postmortem examination. As the retina represents a portion of the central nervous system that can be easily examined noninvasively, our technique may provide the basis for an automated tool to detect and examine severe malaria via retinal changes.

  3. Intra-familial Similarity of Wide-Field Fundus Autofluorescence in Inherited Retinal Dystrophy.

    PubMed

    Furutani, Yuka; Ogino, Ken; Oishi, Akio; Gotoh, Norimoto; Makiyama, Yukiko; Oishi, Maho; Kurimoto, Masafumi; Yoshimura, Nagahisa

    2016-01-01

    To examine the similarity of wide-field fundus autofluorescence (FAF) imaging in inherited retinal dystrophy between siblings and between parents and their children. The subjects included 17 siblings (12 with retinitis pigmentosa and 5 with cone rod dystrophy) and 10 parent-child pairs (8 with retinitis pigmentosa and 2 with cone rod dystrophy). We quantified the similarity of wide-field FAF using image processing techniques of cropping, binarization, superimposition, and subtraction. The estimated similarity of the siblings was compared with that of the parent-child pairs and that of the age-matched unrelated patients. The similarity between siblings was significantly higher that of parent-child pairs or that of age-matched unrelated patients (P = 0.004 and P = 0.049, respectively). Wide-field FAF images were similar between siblings with inherited retinal dystrophy but different between parent-child pairs. This suggests that aging is a confounding factor in genotype-phenotype correlation studies. PMID:26427425

  4. Wide-Field Fundus Autofluorescence for Retinitis Pigmentosa and Cone/Cone-Rod Dystrophy.

    PubMed

    Oishi, Akio; Oishi, Maho; Ogino, Ken; Morooka, Satoshi; Yoshimura, Nagahisa

    2016-01-01

    Retinitis pigmentosa and cone/cone-rod dystrophy are inherited retinal diseases characterized by the progressive loss of rod and/or cone photoreceptors. To evaluate the status of rod/cone photoreceptors and visual function, visual acuity and visual field tests, electroretinogram, and optical coherence tomography are typically used. In addition to these examinations, fundus autofluorescence (FAF) has recently garnered attention. FAF visualizes the intrinsic fluorescent material in the retina, which is mainly lipofuscin contained within the retinal pigment epithelium. While conventional devices offer limited viewing angles in FAF, the recently developed Optos machine enables recording of wide-field FAF. With wide-field analysis, an association between abnormal FAF areas and visual function was demonstrated in retinitis pigmentosa and cone-rod dystrophy. In addition, the presence of "patchy" hypoautofluorescent areas was found to be correlated with symptom duration. Although physicians should be cautious when interpreting wide-field FAF results because the peripheral parts of the image are magnified significantly, this examination method provides previously unavailable information. PMID:26427426

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

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Tobin Jr, Kenneth William; Li, Yaquin; Chaum, Edward

    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.

  6. A Novel Device to Exploit the Smartphone Camera for Fundus Photography

    PubMed Central

    Morescalchi, Francesco; Semeraro, Francesco

    2015-01-01

    Purpose. To construct an inexpensive, convenient, and portable attachment for smartphones for the acquisition of still and live retinal images. Methods. A small optical device based on the principle of direct ophthalmoscopy was designed to be magnetically attached to a smartphone. Representative images of normal and pathological fundi were taken with the device. Results. A field-of-view up to ~20° was captured at a clinical resolution for each fundus image. The cross-polarization technique adopted in the optical design dramatically diminished corneal Purkinje reflections, making it possible to screen patients even through undilated pupils. Light emission proved to be well within safety limits. Conclusions. This optical attachment is a promising, inexpensive, and valuable alternative to the direct ophthalmoscope, potentially eliminating problems of poor exam skills and inexperienced observer bias. Its portability, together with the wireless connectivity of smartphones, presents a promising platform for screening and telemedicine in nonhospital settings. Translational Relevance. Smartphones have the potential to acquire retinal imaging for a portable ophthalmoscopy. PMID:26137320

  7. Retinal nerve fiber layer retardation measurements using a polarization-sensitive fundus camera

    NASA Astrophysics Data System (ADS)

    Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Shirakashi, Motohiro; Yaoeda, Kiyoshi; Abe, Haruki; Ohnuma, Kazuhiko

    2011-07-01

    To measure the retardation distribution of the optic retinal nerve fiber layer (RNFL) from a single image, we have developed a new polarization analysis system that is able to detect the Stokes vector using a fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a microphase plate array, and a circularly polarized light illumination unit. In this system, the Stokes vector expressing the whole state of polarization is detected, and the influence of the background scattering in the retina and of the retardation caused by the cornea are numerically eliminated. The measurement method is based on the hypothesis that the retardation process of the eye optics can be quantified by a numerical equation that consists of a retardation matrix of all the polarization components. We show the method and the measurement results for normal eyes. Our results indicate that the present method may provide a useful means for the evaluation of retardation distribution of the RNFL.

  8. Fundus topology visualization and registration with high resolution and in a wide range of angles

    NASA Astrophysics Data System (ADS)

    Tyurina, Mariya I.; Vorob'eva, Irina V.; Salakhutdinov, Viktor K.; Doroshenko, Djaser

    2006-08-01

    The problem of software and hardware implementation of methods for the visualization of fundus is considered. The parameters of the visualization must meet the medical requirements for the devices of early diagnostics of various diseases including insular diabetes, abnormalities in the permeability of the carotid artery, AIDS, etc. The requirements to the resolution and the field of registration are analyzed. It is demonstrated that the size of the registered image must be at least 2 times 10 3 x 2 times 10 3 TV lines (4 times 10 3 x 4 times 10 3 pixels). A device for measuring out-of-the-axis aberrations of the optical system of the eye (OEA) is described, which is based on the Hartmann-Shack sensor (HSS). The results of the investigation of OEA under various oblique angles and sizes of the patient's pupil are presented. It is shown that the visualization with acceptable quality within the field of the order requires 90° the size of the pupil at most 3 mm and the angular size of the registered fragment ofthe image at most 15° near the optical axis of the eye and 8° in the peripheral areas.

  9. Clinical research on intravitreal injection of bevacizumab in the treatment of macula lutea and retinal edema of ocular fundus disease.

    PubMed

    Yan, Ying; Wang, Tao; Cao, Jing; Wang, Meng; Li, Fenghua

    2015-07-01

    This paper aimed to explore clinically curative effect of intravitreal injection of bevacizumab in the treatment of macula lutea and retinal edema of ocular fundus disease. The number of 300 patients (390 eyes) with ocular fundus diseases including retinal vein occlusion (RVO), diabetic retinopathy (DR), age-related macular degeneration (ARMD), central serous chorioretinopathy (CSC), choridal new vessel (CNV) received and cured in the hospital from February 2010 to February 2014 were given intravitreal injection of bevacizumab (1.5mg) with once per month and a total of 2-3 times. Results of patients' vision and fluorescence fundus angiography (FFA), optical coherence tomography (OCT) before and after treatment were compared and curative effects were evaluated. Vision of 349 eyes (89.49%) improved obviously with the average of more than 2 lines, patient's intraocular pressure (IOP) was normal and all indexes were clearly better; vision of 26 eyes (6.67%) was stable before the treatment and without any changes after the treatment, the situation of fundus got better without increased IOP; vision of 15 eyes (3.85%) decreased to some extent, and the symptoms eased slightly after symptomatic treatment. In the 1st day after intravitreal injection, best-corrected visual acuity increased to 0.239±0.175, best-corrected visual acuity in 1 m was 0.315±0.182, in 3m continuously climbed to 0.350±0.270, and in 6 m was 0.362±0.282. Compared with vision before injection, t value was t=3.184, t=7.213, t=9.274 and t=9.970 (P=0.002, P=0.000, P=0.000 and P=0.000) respectively, and all P were less than 0.01. Furthermore, the difference was significant if a=0.01, which could confirm that 1m best corrected visual acuity of patients after intravitreal injection improved clearly in combination with before injection and 3m and 6 m visions enhanced constantly after injection. To sum up, intravitreal injection of bevacizumab in treating ocular fundus disease improves patient's vision

  10. Diagnostic accuracy and use of non-mydriatic ocular fundus photography by emergency department physicians: Phase II of the FOTO-ED study

    PubMed Central

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

    2013-01-01

    Objective During the first phase of the FOTO-ED Study, 13% (44/350;95%CI:9–17%) of patients had an ocular fundus finding, such as papilledema, relevant to their emergency department (ED) management found by non-mydriatic ocular fundus photography reviewed by neuro-opthalmologists. All of these findings were missed by ED physicians (EPs), who only examined 14% of enrolled patients by direct ophthalmoscopy. In the present study, we evaluated the sensitivity of non-mydriatic ocular fundus photography, an alternative to direct ophthalmoscopy, for relevant findings when photographs were made available for use by EPs during routine clinical care. Methods 354 patients presenting to our ED with headache, focal neurologic deficit, visual change, or diastolic blood pressure ≥120 mmHg had non-mydriatic fundus photography obtained (Kowa nonmyd-alpha-D). Photographs were placed on the electronic medical record for EPs review. Identification of relevant findings on photographs by EPs was compared to a reference standard of neuro-ophthalmologist review. Results EPs reviewed photographs of 239 patients (68%). 35 patients (10%;95%CI:7–13%) 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). EPs identified 16/35 relevant findings (sensitivity:46%;95%CI:29–63%), and also identified 289/319 normal findings (specificity:96%; 95%CI:87–94%). EPs reported that photographs were helpful for 125 patients (35%). Conclusions EPs used non-mydriatic fundus photographs more frequently than they perform direct ophthalmoscopy, and their detection of relevant abnormalities improved. Ocular fundus photography often assisted ED care even when normal. Non-mydriatic ocular fundus photography offers a promising alternative to direct ophthalmoscopy. PMID:23433654

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Computerised calculation scheme for ocular magnification with the Zeiss telecentric fundus camera.

    PubMed

    Langenbucher, Achim; Seitz, Berthold; Viestenz, Arne

    2003-09-01

    Littmann (1982) described a method to determine the magnification of the eye in order to relate the size of a retinal feature to its measured image size on a telecentric fundus camera film. This required information only about ametropia and corneal curvature. Several other methods have been reported since then which consider other biometric data to enhance the accuracy of this classical method. The purpose of this study is to describe a numerical calculation scheme to determine the magnification q of the eye in two cardinal meridians using paraxial raytracing. Our calculation scheme is based on ametropia, keratometry, as well as biometric data such as axial length, anterior chamber depth and thickness of the crystalline lens. It is described step-by-step in order (1) to determine the refractive powers of both surfaces of the crystalline lens, which are not directly measurable in vivo, (2) to derive the retinal image conjugate to a circular object using paraxial raytracing, (3) to fit an ellipse to the retinal image, (4) to determine the secondary principal points (Gaussian length) separately for both cardinal meridians and (5) to calculate the ocular magnification q. The power of the crystalline lens is estimated to compensate for the spherocylindrical refraction at the spectacle plane and the corneal refraction with an astigmatic component thus creating a sharp image focused at the retinal plane. The capabilities of this computing scheme are demonstrated with five clinical examples and are related to the respective values of the classical Littmann formula as well as to enhanced methods described by Bennett (1988), Bennett et al. (1994) and Garway-Heath et al. (1998). PMID:12950891

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

    PubMed

    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. PMID:26259029

  14. Automated microaneurysm detection method based on double ring filter in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Mizutani, Atsushi; Muramatsu, Chisako; Hatanaka, Yuji; Suemori, Shinsuke; Hara, Takeshi; Fujita, Hiroshi

    2009-02-01

    The presence of microaneurysms in the eye is one of the early signs of diabetic retinopathy, which is one of the leading causes of vision loss. We have been investigating a computerized method for the detection of microaneurysms on retinal fundus images, which were obtained from the Retinopathy Online Challenge (ROC) database. The ROC provides 50 training cases, in which "gold standard" locations of microaneurysms are provided, and 50 test cases without the gold standard locations. In this study, the computerized scheme was developed by using the training cases. Although the results for the test cases are also included, this paper mainly discusses the results for the training cases because the "gold standard" for the test cases is not known. After image preprocessing, candidate regions for microaneurysms were detected using a double-ring filter. Any potential false positives located in the regions corresponding to blood vessels were removed by automatic extraction of blood vessels from the images. Twelve image features were determined, and the candidate lesions were classified into microaneurysms or false positives using the rule-based method and an artificial neural network. The true positive fraction of the proposed method was 0.45 at 27 false positives per image. Forty-two percent of microaneurysms in the 50 training cases were considered invisible by the consensus of two co-investigators. When the method was evaluated for visible microaneurysms, the sensitivity for detecting microaneurysms was 65% at 27 false positives per image. Our computerized detection scheme could be improved for helping ophthalmologists in the early diagnosis of diabetic retinopathy.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    Akeo, Keiichiro; Kameya, Shuhei; Gocho, Kiyoko; Kubota, Daiki; Yamaki, Kunihiko; Takahashi, Hiroshi

    2015-01-01

    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. PMID:26356828

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

    PubMed Central

    Akeo, Keiichiro; Kameya, Shuhei; Gocho, Kiyoko; Kubota, Daiki; Yamaki, Kunihiko; Takahashi, Hiroshi

    2015-01-01

    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. PMID:26356828

  18. 3D papillary image capturing by the stereo fundus camera system for clinical diagnosis on retina and optic nerve

    NASA Astrophysics Data System (ADS)

    Motta, Danilo A.; Serillo, André; de Matos, Luciana; Yasuoka, Fatima M. M.; Bagnato, Vanderlei S.; Carvalho, Luis A. V.

    2014-03-01

    Glaucoma is the second main cause of the blindness in the world and there is a tendency to increase this number due to the lifetime expectation raise of the population. Glaucoma is related to the eye conditions, which leads the damage to the optic nerve. This nerve carries visual information from eye to brain, then, if it has damage, it compromises the visual quality of the patient. In the majority cases the damage of the optic nerve is irreversible and it happens due to increase of intraocular pressure. One of main challenge for the diagnosis is to find out this disease, because any symptoms are not present in the initial stage. When is detected, it is already in the advanced stage. Currently the evaluation of the optic disc is made by sophisticated fundus camera, which is inaccessible for the majority of Brazilian population. The purpose of this project is to develop a specific fundus camera without fluorescein angiography and red-free system to accomplish 3D image of optic disc region. The innovation is the new simplified design of a stereo-optical system, in order to make capable the 3D image capture and in the same time quantitative measurements of excavation and topography of optic nerve; something the traditional fundus cameras do not do. The dedicated hardware and software is developed for this ophthalmic instrument, in order to permit quick capture and print of high resolution 3D image and videos of optic disc region (20° field-of-view) in the mydriatic and nonmydriatic mode.

  19. An image-based software tool for screening retinal fundus images using vascular morphology and network transport analysis

    NASA Astrophysics Data System (ADS)

    Clark, Richard D.; Dickrell, Daniel J.; Meadows, David L.

    2014-03-01

    As the number of digital retinal fundus images taken each year grows at an increasing rate, there exists a similarly increasing need for automatic eye disease detection through image-based analysis. A new method has been developed for classifying standard color fundus photographs into both healthy and diseased categories. This classification was based on the calculated network fluid conductance, a function of the geometry and connectivity of the vascular segments. To evaluate the network resistance, the retinal vasculature was first manually separated from the background to ensure an accurate representation of the geometry and connectivity. The arterial and venous networks were then semi-automatically separated into two separate binary images. The connectivity of the arterial network was then determined through a series of morphological image operations. The network comprised of segments of vasculature and points of bifurcation, with each segment having a characteristic geometric and fluid properties. Based on the connectivity and fluid resistance of each vascular segment, an arterial network flow conductance was calculated, which described the ease with which blood can pass through a vascular system. In this work, 27 eyes (13 healthy and 14 diabetic) from patients roughly 65 years in age were evaluated using this methodology. Healthy arterial networks exhibited an average fluid conductance of 419 ± 89 μm3/mPa-s while the average network fluid conductance of the diabetic set was 165 ± 87 μm3/mPa-s (p < 0.001). The results of this new image-based software demonstrated an ability to automatically, quantitatively and efficiently screen diseased eyes from color fundus imagery.

  20. The Retinal Disease Screening Study: Prospective Comparison of Nonmydriatic Fundus Photography and Optical Coherence Tomography for Detection of Retinal Irregularities

    PubMed Central

    Ouyang, Yanling; Heussen, Florian M.; Keane, Pearse A.; Sadda, SriniVas R.; Walsh, Alexander C.

    2013-01-01

    Purpose. To compare the sensitivity of volume scanning with optical coherence tomography (OCT) to nonmydriatic color fundus photography (FP) for the detection of retinal irregularities in asymptomatic populations. Methods. Asymptomatic subjects without known ocular disease were recruited over a 6-month period. For each eye, two undilated 45° fundus images and four undilated volume OCT image sets covering the macula and optic nerve were obtained. Color images were evaluated for irregularities both inside and outside the area covered by OCT. OCT image sets were evaluated for internal limiting membrane irregularities, abnormal retinal thickness, hyper/hyporeflective features, and photoreceptor/retinal pigment epithelium (RPE) irregularities. Detection sensitivities were compared and false-negative cases were analyzed. Results. A total of 284 eyes (144 subjects) were included, with a mean age of 38.1 years (range 18–77). Among 253 eyes (135 subjects) with gradable images from both FP and OCTs, the detection sensitivities for OCT were higher (96.2% infield and 85.7% in full field) than for FP (19.9% infield and 43.8% in full field) for all irregularities evaluated in the study (including epiretinal irregularities, abnormal retinal thickness, intraretinal hyperreflective/hyporeflective features, and photoreceptor/RPE irregularities). Overall, the presence of definite irregularities on either fundus imaging or OCT by eye in this asymptomatic population was 42.6% (121/284), with 39.4% (112/284) of eyes having RPE irregularities such as drusen. Conclusions. For detection of a variety of retinal irregularities evaluated in the current study, volume OCT scanning was more sensitive than nonmydriatic retinal photography in our asymptomatic individuals. OCT detected clinically relevant disease features, such as subretinal fluid, that were missed by FP, and had a lower ungradable image rate. It is likely that OCT will be added to photography screening in the near future for

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

    PubMed Central

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

    2014-01-01

    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 Zeiss FF450+ fundus camera. Arterio-venous ratios (AVR), central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) were calculated on three separate occasions by one single observer semi-automatically using the software VesselMap (ImedosSystems, Jena, Germany). Following the automated grading, three examiners graded the AVR visually on three separate occasions in order to assess their agreement. Results Reproducibility of the semi-automatic parameters was excellent (ICCs: 0.97 (CRAE); 0.985 (CRVE) and 0.952 (AVR)). However, visual grading of AVR showed inter grader differences as well as discrepancies between subjectively derived and objectively calculated AVR (all p < 0.000001). Conclusion Grader education and experience leads to inter-grader differences but more importantly, subjective grading is not capable to pick up subtle differences across healthy individuals and does not represent true AVR when compared with an objective assessment method. Technology advancements mean we no longer rely on opthalmoscopic evaluation but can capture and store fundus images with retinal cameras, enabling us to measure vessel calibre more accurately compared to visual estimation; hence it should be integrated in optometric practise for improved accuracy and reliability of clinical assessments of retinal vessel calibres. PMID:26386537

  2. Can Novel Treatment of Age-Related Macular Degeneration Be Developed by Better Understanding of Sorsby’s Fundus Dystrophy

    PubMed Central

    Gourier, Hanae C. Y.; Chong, N. Victor

    2015-01-01

    Sorsby’s Fundus Dystrophy (SFD) is a rare autosomal dominant maculopathy that shares many clinical features with Age-Related Macular Degeneration (AMD). It is caused by a mutation in a single gene, TIMP-3, which accumulates in Bruch’s membrane (BM). BM thickening and TIMP-3 accumulation can also be found in AMD. From our understanding of the pathophysiology of SFD we hypothesize that BM thickening could be responsible for making the elastic layer vulnerable to invasion by choriocapillaris, thereby leading to choroidal neovascularization in some cases of AMD, whilst in others it could deprive the retinal pigment epithelium of its blood supply, thereby causing geographic atrophy. PMID:26239453

  3. An effective fovea detection and automatic assessment of diabetic maculopathy in color fundus images.

    PubMed

    Medhi, Jyoti Prakash; Dandapat, Samarendra

    2016-07-01

    Prolonged diabetes causes severe damage to the vision through leakage of blood and blood constituents over the retina. The effect of the leakage becomes more threatening when these abnormalities involve the macula. This condition is known as diabetic maculopathy and it leads to blindness, if not treated in time. Early detection and proper diagnosis can help in preventing this irreversible damage. To achieve this, the possible way is to perform retinal screening at regular intervals. But the ratio of ophthalmologists to patients is very small and the process of evaluation is time consuming. Here, the automatic methods for analyzing retinal/fundus images prove handy and help the ophthalmologists to screen at a faster rate. Motivated from this aspect, an automated method for detection and analysis of diabetic maculopathy is proposed in this work. The method is implemented in two stages. The first stage involves preprocessing required for preparing the image for further analysis. During this stage the input image is enhanced and the optic disc is masked to avoid false detection during bright lesion identification. The second stage is maculopathy detection and its analysis. Here, the retinal lesions including microaneurysms, hemorrhages and exudates are identified by processing the green and hue plane color images. The macula and the fovea locations are determined using intensity property of processed red plane image. Different circular regions are thereafter marked in the neighborhood of the macula. The presence of lesions in these regions is identified to confirm positive maculopathy. Later, the information is used for evaluating its severity. The principal advantage of the proposed algorithm is, utilization of the relation of blood vessels with optic disc and macula, which enhances the detection process. Proper usage of various color plane information sequentially enables the algorithm to perform better. The method is tested on various publicly available databases

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

    PubMed

    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

  5. Contour Photography Of The Ocular Fundus: Evaluation Of An Automated Image Processing Algorithm

    NASA Astrophysics Data System (ADS)

    Shapiro, Jerrold M.; Bush, Karen S.

    1986-07-01

    A new technique for making a three dimensional map of the optic nerve head is expected to have a major impact on the way in which glaucoma is diagnosed and treated. The new technique, contour photography, allows the health of the optic nerve head to be objectively evaluated every six months during the patient's routine office visit. In contour photography, a set of parallel lines of light are projected into the patient's eye and the back of the eye is photographed using a standard camera that is available in almost all ophthalmologist's offices. The three dimensional information is encoded in the positions of the photographed lines, and is decoded by treating each stripe as the intersection of a plane of light with the fundus. At present, a trained human observer identifies the edges of the stripes. In order to decrease the data extraction time, several automated edge detection algorithms were examined for their suitability in the analysis of contour photographs, and the best was extensively evaluated using Monte Carlo simulation. The accuracy and reproducibility of the edge position estimate in images with various amounts of film grain noise were measured for many values of the edge detector parameter and of the signal parameter, its modulation, m. When normalized by the amount of film grain noise, the relationship between reproducibility and l/m was found to be linear over the range of parameters likely to be encountered in contour photography. The accuracy was found to be independent of the amount of film grain noise, and linearly related to 1/m. By estimating m for each edge, the accuracy could be treated as a correctable systematic error of the edge detection process. A sample calculation which used parameter values that are likely to be found in contour photography showed that the automated edge detection process would be expected to produce a random variation in the measurement of the depth of the optic nerve head surface whose standard deviation is 0

  6. Application of A Mobile Platform-based System for the Management of Fundus Diease in Outpatient Settings.

    PubMed

    Dend, Xun; Li, Hong-Yan; Yin, Hong; Liang, Jian-Hong; Chen, Yi; Li, Xiao-Xin; Zhao, Ming-Wei

    2016-08-01

    Objective To evaluate the application of a mobile platform-based system in the management of fundus disease in outpatient settings. Methods In the outpatient departments of fundus disease,premature babies requiring eye examination under general anesthesia and adults requiring intraocular surgery were enrolled as the subjects. According to the existing clinical practices,we developed a system that met the requirements of clinical practices and optimized the clinical management. Based on the FileMaker database,the tablet computers were used as the mobile platform and the system could also be run in iPad and PC terminals.Results Since 2013,the system recorded 7500 cases of special examinations. Since July 2015,4100 cases of intravitreal drug injection were also recored in the system. Multiple-point and real-time reservation pattern increased the efficiency and opimize the clinical management. All the clinical data were digitalized. Conclusion The mobile platform-based system can increase the efficacy of examination and other clinical processes and standardize data collection;thus,it is feasible for the clinical practices in outpatient departments of ophthalmology. PMID:27594159

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

    PubMed

    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. PMID:25822397

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

    SciTech Connect

    Gerber, S.; Rozet, J.M.; Bonneau, D.; Souied, E.; Camuzat, A.; Munnich, A.; Kaplan, J.; Dufier, J.L.; Amalric, P.; Weissenbach, J.

    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.

  9. Validity of retinal oxygen saturation analysis: Hyperspectral imaging in visible wavelength with fundus camera and liquid crystal wavelength tunable filter

    NASA Astrophysics Data System (ADS)

    Hirohara, Yoko; Okawa, Yoshitaka; Mihashi, Toshifumi; Yamaguchi, Tatsuo; Nakazawa, Naoki; Tsuruga, Yasuko; Aoki, Hiroyuki; Maeda, Naoyuki; Uchida, Ichiro; Fujikado, Takashi

    2007-05-01

    The purpose of this paper was to investigate the feasibility of a newly developed hyperspectral fundus imaging camera with a liquid crystal tunable filter. The intensities of different wavelengths of light transmitted through an artery, vein, and the area surrounding these vessels and reflected out were measured, and the differential spectral absorptions were analyzed. Measurements were made from 16 normal eyes and from two artificial capillaries. The ratios of absorption (ROA) of arteries to veins from 500 to 580 nm (range 1) and from 600 to 720 nm (range 2) were calculated. For all eyes, the ROArange1 was larger than ROArange2. The ROA obtained from the artificial capillary filled with blood saturated with oxygen or nitrogen was similar to that of simulated data of oxy- and deoxyhemoglobin extinction rate. Most ROAs of human eyes were lower than those of the simulated data and the artificial capillaries. Oxygen saturation analysis by hyperspectral fundus imaging of retinal vessels were qualitatively in agreement with the in vitro analysis or simulated values. However, further improvements are necessary to evaluate the oxygen saturation quantitatively in the retinal blood vessels.

  10. A multi-scale tensor voting approach for small retinal vessel segmentation in high resolution fundus images.

    PubMed

    Christodoulidis, Argyrios; Hurtut, Thomas; Tahar, Houssem Ben; Cheriet, Farida

    2016-09-01

    Segmenting the retinal vessels from fundus images is a prerequisite for many CAD systems for the automatic detection of diabetic retinopathy lesions. So far, research efforts have concentrated mainly on the accurate localization of the large to medium diameter vessels. However, failure to detect the smallest vessels at the segmentation step can lead to false positive lesion detection counts in a subsequent lesion analysis stage. In this study, a new hybrid method for the segmentation of the smallest vessels is proposed. Line detection and perceptual organization techniques are combined in a multi-scale scheme. Small vessels are reconstructed from the perceptual-based approach via tracking and pixel painting. The segmentation was validated in a high resolution fundus image database including healthy and diabetic subjects using pixel-based as well as perceptual-based measures. The proposed method achieves 85.06% sensitivity rate, while the original multi-scale line detection method achieves 81.06% sensitivity rate for the corresponding images (p<0.05). The improvement in the sensitivity rate for the database is 6.47% when only the smallest vessels are considered (p<0.05). For the perceptual-based measure, the proposed method improves the detection of the vasculature by 7.8% against the original multi-scale line detection method (p<0.05). PMID:27341026

  11. [Diagnosis of tumor-like fundus changes by means of a combination of echography, infrared photography and fluorescein angiography (author's transl)].

    PubMed

    Freyler, H

    1975-10-01

    Using a combination of echography, infrared photography and fluorescein angiography in tumor simulating changes of the fundus an optimum combination of these diagnostic methods was achieved. The echography allows exact measurements of the prominence and in lesions exceeding 1.1 to 1.5 mm also a tissue differentiation. By infrared photography melanin could be differentiated from the bloodpigments and lipofuscin and the extension of pigmented tissues could be revealed. Fluoresceinangiography visualizes the vascular pattern and the permeability of the vessels of tumors or pseudotumors. Up to now 100 cases with tumorlike fundus lesions were subjected to this combined examination method and many of these cases preserved from enucleation. PMID:1206936

  12. Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics. [for blood vessel monitoring during space flight

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Harrison, G.; Turnbill, C.; Bailey, P. F.

    1979-01-01

    Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark-adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

  13. Detection of early metabolic alterations in the ocular fundus of diabetic patients by time-resolved autofluorescence of endogenous fluorophores

    NASA Astrophysics Data System (ADS)

    Schweitzer, D.; Klemm, M.; Quick, S.; Deutsch, L.; Jentsch, S.; Hammer, M.; Dawczynski, J.; Kloos, C. H.; Mueller, U. A.

    2011-07-01

    Measurements of time-resolved autofluorescence (FLIM) at the human ocular fundus of diabetic patients permit the detection of early pathologic alterations before signs of diabetic retinopathy are visible. The measurements were performed by the Jena Fluorescence Lifetime Laser Scanner Ophthalmoscope applying time-correlated single photon counting (TCSPC) in two spectral channels (K1: 490-560 nm, K2:560-700ps). The fluorescence was excited by 70 ps pulses (FWHM) at 448 nm. The decay of fluorescence intensity was triple-exponentially approximated. The frequency of amplitudes, lifetimes, and relative contributions was compared in fields of the same size and position in healthy subjects and in diabetic patients. The most sensitive parameter was the lifetime T2 in the short-wavelength channel, which corresponds to the neuronal retina. The changes in lifetime point to a loss of free NADH and an increased contribution of protein-bound NADH in the pre-stage of diabetic retinopathy.

  14. Influence of additional resection of the gastric fundus on excessive weight loss in laparoscopic very very long limb Roux-en-Y gastric bypass.

    PubMed

    Delko, T; Köstler, T; Peev, M; Oertli, D; Zingg, U

    2013-03-01

    Roux-en-Y gastric bypass (RYGB) is the gold standard in bariatric surgery. The effect of the procedure is based on restriction, malabsorption and changes in hormonal axis. Ghrelin is an important appetite hormone which is produced mainly in the gastric fundus. By adding a resection of the gastric fundus, we hypothesized that excessive weight loss will be more prominent and the satiety feelings less pronounced compared to standard RYGB. A total of 73 patients with standard very very long limb (VVLL) RYGB (group A) were compared with 44 patients with VVLL RYGB with resection of the fundus (group B). Outcome measures were excessive weight loss (EWL), body mass index (BMI), early postoperative morbidity, change of co-morbidities, and appetite reduction as assessed by an appetite questionnaire over a postoperative period of 24 months. Groups were comparable in basic preoperative descriptions. Additional fundus resection did not influence EWL (group A 66.1 % vs. group B 70.6 %, p = 0.383) or BMI (group A 29 kg/m(2) vs. group B 27 kg/m(2), p = 0.199). No significant difference in morbidity or change of co-morbidities occurred. The appetite and satiety questionnaire showed no difference between group A and group B, respectively. Adding a resection of the gastric fundus in RYGB did not alter the clinical results, i.e., increased excessive weight loss, decrease of appetite, or increase of satiety. The value of removing a part of the ghrelin-producing cells might be overestimated. PMID:23135881

  15. Preliminary study on differentiation between glaucomatous and non-glaucomatous eyes on stereo fundus images using cup gradient models

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Hatanaka, Yuji; Ishida, Kyoko; Sawada, Akira; Yamamoto, Tetsuya; Fujita, Hiroshi

    2014-03-01

    Glaucoma is one of the leading causes of blindness in Japan and the US. One of the indices for diagnosis of glaucoma is the cup-to-disc ratio (CDR). We have been developing a computerized method for measuring CDR on stereo fundus photographs. Although our previous study indicated that the method may be useful, cup determination was not always successful, especially for the normal eyes. In this study, we investigated a new method to quantify the likelihood of glaucomatous disc based on the similarity scores to the glaucoma and non-glaucoma models. Eighty-seven images, including 40 glaucomatous eyes, were used in this study. Only one eye from each patient was used. Using a stereo fundus camera, two images were captured from different angles, and the depth image was created by finding the local corresponding points. One of the characteristics of a glaucomatous disc can be not only that the cup is enlarged but it has an acute slope. On the other hand, a non-glaucomatous cup generally has a gentle slope. Therefore, our models were constructed by averaging the depth gradient images. In order to account for disc size, disc outline was automatically detected, and all images were registered by warping the disc outline to a circle with a predetermined diameter using thin plate splines. Similarity scores were determined by multiplying a test case with both models. At the sensitivity of 90.0%, the specificity was improved from 83.0% using the CDR to 97.9% by the model-based method. The proposed method may be useful for differentiation of glaucomatous eyes.

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

    PubMed

    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 %. PMID:27086033

  17. Fundus photography as a convenient tool to study microvascular responses to cardiovascular disease risk factors in epidemiological studies.

    PubMed

    De Boever, Patrick; Louwies, Tijs; Provost, Eline; Int Panis, Luc; Nawrot, Tim S

    2014-01-01

    The microcirculation consists of blood vessels with diameters less than 150 µm. It makes up a large part of the circulatory system and plays an important role in maintaining cardiovascular health. The retina is a tissue that lines the interior of the eye and it is the only tissue that allows for a non-invasive analysis of the microvasculature. Nowadays, high-quality fundus images can be acquired using digital cameras. Retinal images can be collected in 5 min or less, even without dilatation of the pupils. This unobtrusive and fast procedure for visualizing the microcirculation is attractive to apply in epidemiological studies and to monitor cardiovascular health from early age up to old age. Systemic diseases that affect the circulation can result in progressive morphological changes in the retinal vasculature. For example, changes in the vessel calibers of retinal arteries and veins have been associated with hypertension, atherosclerosis, and increased risk of stroke and myocardial infarction. The vessel widths are derived using image analysis software and the width of the six largest arteries and veins are summarized in the Central Retinal Arteriolar Equivalent (CRAE) and the Central Retinal Venular Equivalent (CRVE). The latter features have been shown useful to study the impact of modifiable lifestyle and environmental cardiovascular disease risk factors. The procedures to acquire fundus images and the analysis steps to obtain CRAE and CRVE are described. Coefficients of variation of repeated measures of CRAE and CRVE are less than 2% and within-rater reliability is very high. Using a panel study, the rapid response of the retinal vessel calibers to short-term changes in particulate air pollution, a known risk factor for cardiovascular mortality and morbidity, is reported. In conclusion, retinal imaging is proposed as a convenient and instrumental tool for epidemiological studies to study microvascular responses to cardiovascular disease risk factors. PMID

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2014-01-01

    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. PMID:25321400

  20. Perceived Image Quality Improvements from the Application of Image Deconvolution to Retinal Images from an Adaptive Optics Fundus Imager

    NASA Astrophysics Data System (ADS)

    Soliz, P.; Nemeth, S. C.; Erry, G. R. G.; Otten, L. J.; Yang, S. Y.

    Aim: The objective of this project was to apply an image restoration methodology based on wavefront measurements obtained with a Shack-Hartmann sensor and evaluating the restored image quality based on medical criteria.Methods: Implementing an adaptive optics (AO) technique, a fundus imager was used to achieve low-order correction to images of the retina. The high-order correction was provided by deconvolution. A Shack-Hartmann wavefront sensor measures aberrations. The wavefront measurement is the basis for activating a deformable mirror. Image restoration to remove remaining aberrations is achieved by direct deconvolution using the point spread function (PSF) or a blind deconvolution. The PSF is estimated using measured wavefront aberrations. Direct application of classical deconvolution methods such as inverse filtering, Wiener filtering or iterative blind deconvolution (IBD) to the AO retinal images obtained from the adaptive optical imaging system is not satisfactory because of the very large image size, dificulty in modeling the system noise, and inaccuracy in PSF estimation. Our approach combines direct and blind deconvolution to exploit available system information, avoid non-convergence, and time-consuming iterative processes. Results: The deconvolution was applied to human subject data and resulting restored images compared by a trained ophthalmic researcher. Qualitative analysis showed significant improvements. Neovascularization can be visualized with the adaptive optics device that cannot be resolved with the standard fundus camera. The individual nerve fiber bundles are easily resolved as are melanin structures in the choroid. Conclusion: This project demonstrated that computer-enhanced, adaptive optic images have greater detail of anatomical and pathological structures.

  1. Inherited Retinal Degenerative Disease Registry

    ClinicalTrials.gov

    2016-03-21

    Eye Diseases Hereditary; Retinal Disease; Achromatopsia; Bardet-Biedl Syndrome; Bassen-Kornzweig Syndrome; Batten Disease; Best Disease; Choroidal Dystrophy; Choroideremia; Cone Dystrophy; Cone-Rod Dystrophy; Congenital Stationary Night Blindness; Enhanced S-Cone Syndrome; Fundus Albipunctatus; Goldmann-Favre Syndrome; Gyrate Atrophy; Juvenile Macular Degeneration; Kearns-Sayre Syndrome; Leber Congenital Amaurosis; Refsum Syndrome; Retinitis Pigmentosa; Retinitis Punctata Albescens; Retinoschisis; Rod-Cone Dystrophy; Rod Dystrophy; Rod Monochromacy; Stargardt Disease; Usher Syndrome

  2. Fundus Autofluorescence in the Abca4−/− Mouse Model of Stargardt Disease—Correlation With Accumulation of A2E, Retinal Function, and Histology

    PubMed Central

    Charbel Issa, Peter; Barnard, Alun R.; Singh, Mandeep S.; Carter, Emma; Jiang, Zhichun; Radu, Roxana A.; Schraermeyer, Ulrich; MacLaren, Robert E.

    2013-01-01

    Purpose. To investigate fundus autofluorescence (AF) characteristics in the Abca4−/− mouse, an animal model for AMD and Stargardt disease, and to correlate findings with functional, structural, and biochemical assessments. Methods. Blue (488 nm) and near-infrared (790 nm) fundus AF images were quantitatively and qualitatively analyzed in pigmented Abca4−/− mice and wild type (WT) controls in vivo. Functional, structural, and biochemical assessments included electroretinography (ERG), light and electron microscopic analysis, and A2E quantification. All assessments were performed across age groups. Results. In Abca4−/− mice, lipofuscin-related 488 nm AF increased early in life with a ceiling effect after 6 months. This increase was first paralleled by an accumulation of typical lipofuscin granules in the retinal pigment epithelium (RPE). Later, lipofuscin and melanin granules decreased in number, whereas melanolipofuscin granules increased. This increase in melanolipofuscin granules paralleled an increase in melanin-related 790 nm AF. Old Abca4−/− mice revealed a flecked fundus AF pattern at both excitation wavelengths. The amount of A2E, a major lipofuscin component, increased 10- to 12-fold in 6- to 9-month-old Abca4−/− mice compared with controls, while 488 nm AF intensity only increased 2-fold. Despite pronounced lipofuscin accumulation in the RPE of Abca4−/− mice, ERG and histology showed a slow age-related thinning of the photoreceptor layer similar to WT controls up to 12 months. Conclusions. Fundus AF can be used to monitor lipofuscin accumulation and melanin-related changes in vivo in mouse models of retinal disease. High RPE lipofuscin may not adversely affect retinal structure or function over prolonged time intervals, and melanin-related changes (melanolipofuscin formation) may occur before the decline in retinal function. PMID:23761084

  3. Application of Optical Coherence Tomography and Contrast Sensitivity Test for Observing Fundus Changes of Patients With Pregnancy-Induced Hypertension Syndrome

    PubMed Central

    Wang, Zhixue; Zou, Yuanyuan; Li, Wenying; Wang, Xueyan; Zhang, Min; Wang, Wenying

    2015-01-01

    Abstract This study was aimed to investigate the fundus changes of patients with pregnancy-induced hypertension syndrome (PIHS) using optical coherence tomography (OCT) technology and contrast sensitivity (CS) tests. Ninety-eight patients with PIHS underwent routine eye examinations including vision correction, fundus examination, OCT, and CS tests. The CS test was performed at low, medium, and high frequency, respectively. Moreover, the difference in CS tests between 2 groups was analyzed by independent-samples T test. The Kruskal–Wallis rank sum test and linear regression model were used to detect the correlation of OCT with CS, respectively. Meanwhile Satterthwaite approximate T test was adopted for pairwise comparisons after nonparametric analysis of variance. The OCT test revealed that 56.76% of the examined eyes showed shallow retinal detachment in the macula lutea and around the optic disk. The differences in CS at each spatial frequency between the case and control group were statistically significant (P < 0.01). Besides, OCT manifestations were associated with CS at each spacial frequency including 1.5, 3, 6, 12, and 18 frequency (P < 0.01). And patients with abnormal manifestations of OCT showed lower CS at each spacial frequency than those without abnormal OCT manifestations. What's more the OCT manifestation 1 showed the greatest impact on CS at each spacial frequency. The results showed that abnormal OCT manifestations were correlated with CS in PIHS. OCT and CS tests might be valuable methods in observing fundus changes for PIHS patients. PMID:26554764

  4. Computer-aided diagnosis of proliferative diabetic retinopathy via modeling of the major temporal arcade in retinal fundus images.

    PubMed

    Oloumi, Faraz; Rangayyan, Rangaraj M; Ells, Anna L

    2013-12-01

    Monitoring the openness of the major temporal arcade (MTA) and how it changes over time could facilitate diagnosis and treatment of proliferative diabetic retinopathy (PDR). We present methods for user-guided semiautomated modeling and measurement of the openness of the MTA based on Gabor filters for the detection of retinal vessels, morphological image processing, and a form of the generalized Hough transform for the detection of parabolas. The methods, implemented via a graphical user interface, were tested with retinal fundus images of 11 normal individuals and 11 patients with PDR in the present pilot study on potential clinical application. A method of arcade angle measurement was used for comparative analysis. The results using the openness parameters of single- and dual-parabolic models as well as the arcade angle measurements indicate areas under the receiver operating characteristics of A z = 0.87, 0.82, and 0.80, respectively. The proposed methods are expected to facilitate quantitative analysis of the architecture of the MTA, as well as assist in detection and diagnosis of PDR. PMID:23579735

  5. Gastric fundus tension before and after division of the short gastric vessels in a cadaveric model of fundoplication.

    PubMed

    Szor, D J; Herbella, F A M; Bonini, A L; Moreno, D G; Del Grande, J C

    2009-01-01

    Short gastric vessels (SGV) division is a controversial topic in antireflux surgery. Some surgeons do not divide the SGV routinely to perform a fundoplication; however, excessive tension of the gastric fundus (GF) forces this procedure necessary in some cases. This study aims to evaluate in a cadaveric model of Nissen fundoplication: (i) the correlation of GF tension with anatomic parameters; and (ii) the effect of SGV division on GF tension. In total, 23 fresh cadavers (18 men, mean age 62 years) were studied. The abdominal esophagus was dissected, and the GF transposed to a limit of 3 cm to the right border of the esophagus. A dynamometer was attached to the GF and the tension recorded. Cadavers were grouped according to the presence or absence of tension. SGV were divided and GF tension measured again. The presence or absence of initial GF tension was correlated to: (i) number of SGV; (ii) length of the GF; (iii) distance between His angle and the first SGV; and (iv) size of the spleen. The mean GF pressure was 0.5 N +/- 1.0 (0-2.5) before SGV division and 0.1 N +/- 0.3 (0-1.5) after SGV division (P= 0.002). Initial tension was absent in 12 (52.2%) cases. GF tension did not correlate with any of the anatomic parameters. Our results show that: (i) GF tension does not correlate with anatomic parameters; and (ii) SGV division affects GF tension significantly. PMID:19222530

  6. Automatic detection of microaneurysms in diabetic retinopathy fundus images using the L*a*b color space.

    PubMed

    Navarro, Pedro J; Alonso, Diego; Stathis, Kostas

    2016-01-01

    We develop an automated image processing system for detecting microaneurysm (MA) in diabetic patients. Diabetic retinopathy is one of the main causes of preventable blindness in working age diabetic people with the presence of an MA being one of the first signs. We transform the eye fundus images to the L*a*b* color space in order to separately process the L* and a* channels, looking for MAs in each of them. We then fuse the results, and last send the MA candidates to a k-nearest neighbors classifier for final assessment. The performance of the method, measured against 50 images with an ophthalmologist's hand-drawn ground-truth, shows high sensitivity (100%) and accuracy (84%), and running times around 10 s. This kind of automatic image processing application is important in order to reduce the burden on the public health system associated with the diagnosis of diabetic retinopathy given the high number of potential patients that need periodic screening. PMID:26831588

  7. Significance of the disc damage likelihood scale objectively measured by a non-mydriatic fundus camera in preperimetric glaucoma

    PubMed Central

    Pahlitzsch, Milena; Torun, Necip; Erb, Carl; Bruenner, Jeanette; Maier, Anna Karina B; Gonnermann, Johannes; Bertelmann, Eckart; Klamann, Matthias K J

    2015-01-01

    Purpose To assess the correlation between the disc damage likelihood scale (DDLS) objectively measured by a non-mydriatic fundus camera, Heidelberg Retina Tomograph 3, and optic coherence tomography in preperimetric glaucoma. Methods One-hundred-twenty-five patients with preperimetric primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (n=30) were included (mean age 58.9±15.9 years). All three devices graded the optic disc topography: Diagnosis 1 was defined as “outside normal limits”, while Diagnosis 2 as “borderline or outside normal limits”. Results For Diagnosis 1, a significant correlation was shown between DDLS and Moorfields regression analysis (P=0.022), and for Diagnosis 2 with glaucoma probability score analysis (P=0.024), in POAG. In pseudoexfoliation glaucoma, DDLS did not correlate significantly with Heidelberg Retina Tomograph 3 and optic coherence tomography. Regarding the area under the curve the highest predictive power was demonstrated by the objective DDLS (0.513–0.824) compared to Burk (0.239–0.343) and Mikelberg (0.093–0.270) coefficients. Conclusions The DDLS showed a significant correlation to the Moorfields regression analysis in preperimetric POAG. The objective DDLS showed the highest predictive power and thus is an additive tool in diagnosing preperimetric glaucoma. PMID:26640365

  8. In vitro effects of bethanechol on smooth muscle preparations from abomasal fundus, corpus, and antrum of dairy cows.

    PubMed

    Buehler, M; Steiner, A; Meylan, M; Portier, C J; Mevissen, M

    2008-06-01

    Abomasal displacement has been associated with gastric hypomotility. The supply of prokinetic drugs available to address this problem is insufficient. The goal of the study was to investigate the effect of the muscarinic agonist bethanechol (BeCh) on contractility parameters of smooth muscle preparations from several regions of the bovine abomasum (fundus, corpus, and antrum). Cumulative concentration-response curves were constructed using BeCh in vitro with and without pre-incubation with antagonists targeted at M(2) and M(3) muscarinic acetylcholine receptor (mAChR) subtypes. In all preparations investigated, BeCh induced a significant and concentration-dependent increase in all contractility parameters investigated. The maximal attainable effect (V(max)) was more pronounced in circular specimens, and V(max) of antral specimens in circular orientation were significantly lower when compared to the other preparations. Both antagonists caused a rightward shift of the concentration-response curve, suggesting that the effect of BeCh is mediated at least partly by M(2) and M(3) AChRs. PMID:17632190

  9. Grading of Age-Related Macular Degeneration: Comparison between Color Fundus Photography, Fluorescein Angiography, and Spectral Domain Optical Coherence Tomography

    PubMed Central

    Mokwa, Nils F.; Keane, Pearse A.; Kirchhof, Bernd; Sadda, Srinivas R.

    2013-01-01

    Purpose. To compare color fundus photography (FP), fluorescein angiography (FA), and spectral domain optical coherence tomography (SDOCT) for the detection of age-related macular degeneration (AMD), choroidal neovascularisation (CNV), and CNV activity. Methods. FPs, FAs, and SDOCT volume scans from 120 eyes of 66 AMD and control patients were randomly collected. Control eyes were required to show no AMD, but other retinal pathology was allowed. The presence of drusen, pigmentary changes, CNV, and signs for CNV activity was independently analyzed for all imaging modalities. Results. AMD was diagnosed based on FP in 75 eyes. SDOCT and FA showed sensitivity (specificity) of 89% (76%) and 92% (82%), respectively. CNV was present on FA in 68 eyes. Sensitivity (specificity) was 78% (100%) for FP and 94% (98%) for SDOCT. CNV activity was detected by SDOCT or FA in 60 eyes with an agreement in 46 eyes. Sensitivity was 88% for SDOCT and 88% for FA. FP showed sensitivity of 38% and specificity of 98%. Conclusions. CNV lesions and activity may be missed by FP alone, but FP may help identifying drusen and pigmentary changes. SDOCT is highly sensitive for the detection of AMD, CNV, and CNV activity; however, it cannot fully replace FA. PMID:23762528

  10. [Ophthalmoscopic observations of ocular fundus in colony-born cynomolgus monkeys aged from 0 day to 90 days].

    PubMed

    Suzuki, M T; Narita, H; Tanaka, Y; Cho, F; Fukui, M

    1984-04-01

    Apparently healthy 242 colony-born cynomolgus monkeys (Macaca fascicularis) aged from 0 day to 90 days were examined for the findings of ocular fundus by using ophthalmoscope. One drop of mixed solution of 0.5% tropicamide and 0.5% phenylephrine hydrochloride was instilled into each eye of the monkey. Then, those monkeys were anesthetized with ketamine-HC1 at the dose level of 10mg/kg B. W. Regular and fluorescein photographs were taken with Kowa RC-II ophthalmoscope-camera by using daylight typed color film. Following findings were obtained in each age class: Retinal color was salmon pink with 0 to 3-days-old neonates, salmon pink and blue to green with 7 days to 14-days-old animals and blue to green with 60-days to 90-days-old monkeys. As regards optic disc, 0- to 14-days-old animals were observed to be light orange in color, and the infant aged more than 28-days showed orange color. Retinal arteries and veins were lightly reddish in color with every age class. Macular color was salmon pink in 0-day-old cases, slightly dark in 3-days-old neonates and very dark after 14-days of age. Lightly retinal reflex was noted in 0- and 7-days-old animals. The reflex was observable in 14-days-old animals without any case of exception. Retinal hemorrhages were recorded in 22 (67%) of 36 neonates born in natural condition and 10 (33%) of 30 neonates born by cesarean section. These findings will be useful as the criteria for ophthalmoscopic observations of the cynomolgus monkeys as laboratory use. PMID:6468512

  11. Manifestations of central retinal artery occlusion revealed by fundus fluorescein angiography are associated with the degree of visual loss

    PubMed Central

    GONG, HONGXIA; SONG, QIUYING; WANG, LANHUI

    2016-01-01

    The aim of this study was to investigate the association between central visual impairment and the characteristics of fundus fluorescein angiography (FFA) in patients with central retinal artery occlusion (CRAO). A total of 63 patients were diagnosed with CRAO by FFA. The visual dysfunction was classified into severe, mild and light degrees. Tropicamide was administered for mydriasis. FFA examination was performed using Heidelberg retinal tomography. The associations of age, gender and disease course with CRAO type were analyzed. Three types of manifestations were identified by FFA in 63 eyes, including poor perfusion (18 cases), exudation (22 cases) and mixed types (23 cases) of CRAO. No significant difference was found in age (F=0.171, P=0.844) and disease course (F=0.016, P=0.984) among the three types of CRAO. Similarly, no significant difference was found in gender among the three types of CRAO (χ2=0.176, P=0.916). The damage to vision caused by the exudation type of CRAO was not as severe as that caused by the poor perfusion and mixed types of CRAO. The distributions of damage severity caused by the poor perfusion and mixed types of CRAO were similar. In conclusion, the FFA observations for CRAO can be classified into three types of manifestations. The damage to vision in patients with CRAO is likely to be associated with poor perfusion in the retinal artery rather than exudation affecting the retina or optic disc. The patterns of clinical manifestations are not associated with age, gender or disease course. PMID:27313672

  12. Classification of abnormal fundus autofluorescence patterns in the junctional zone of geographic atrophy in patients with age related macular degeneration

    PubMed Central

    Bindewald, A; Schmitz-Valckenberg, S; Jorzik, J J; Dolar-Szczasny, J; Sieber, H; Keilhauer, C; Weinberger, A W A; Dithmar, S; Pauleikhoff, D; Mansmann, U; Wolf, S; Holz, F G

    2005-01-01

    Aim: To describe and classify patterns of abnormal fundus autofluorescence (FAF) in the junctional zone of geographic atrophy (GA) in patients with age related macular degeneration. Methods: Digital FAF images were recorded in 164 eyes of 107 patients using a confocal scanning laser ophthalmoscope (cSLO; excitation 488 nm, detection above 500 nm) as part of a prospective multicentre natural history study (FAM Study). FAF images were obtained in accordance with a standardised protocol for digital image acquisition and generation of mean images after automated alignment. Results: Image quality was sufficient for classification of FAF patterns in 149 eyes (90.9%) with lens opacities being the most common reason for insufficient image quality. Abnormal FAF outside GA in 149 eyes was classified into four patterns: focal (12.1%), banded (12.8%), patchy (2.0%), and diffuse (57.0%), whereby 12.1% had normal background FAF in the junctional zone. In 4% there was no predominant pattern. The diffuse pattern was subdivided into four groups including reticular (4.7%), branching (27.5%), fine granular (18.1%), and fine granular with peripheral punctate spots (6.7%). Conclusions: Different phenotypic patterns of abnormal FAF in the junctional zone of GA can be identified with cSLO FAF imaging. These distinct patterns may reflect heterogeneity at a cellular and molecular level in contrast with a non-specific ageing process. A refined phenotypic classification may be helpful to identify prognostic determinants for the spread of atrophy and visual loss, for identification of genetic risk factors as well as for the design of future interventional trials. PMID:15965170

  13. Expression of mutant and wild-type TIMP3 in primary gingival fibroblasts from Sorsby's fundus dystrophy patients.

    PubMed

    Arris, Christine E; Bevitt, Debra J; Mohamed, Jeseem; Li, Zheng; Langton, Kevin P; Barker, Michael D; Clarke, Michael P; McKie, Norman

    2003-05-20

    Gingival fibroblast cell lines were derived from Sorsby's fundus dystrophy (SFD) patients carrying the S181C TIMP3 and the E139X TIMP3 mutations. These cell lines were grown in culture to study expression of the wild-type and mutant tissue inhibitor of metalloproteinase 3 (TIMP3) alleles from a normal diploid cell type. Firstly, patient cells were found to co-express the wild-type and mutant TIMP3 alleles, S181C TIMP3 or E139X TIMP3, at the mRNA level using restriction fragment length polymorphism (RFLP) analysis. A SpeI RFLP for E139X TIMP3 is described. Low levels of endogenous TIMP3 protein expression were elevated using the natural polysaccharide calcium pentosan polysulfate (CaPPs) in combination with the cytokine IL-1alpha. Immunoblotting detected protein expression from both wild-type and mutant alleles, S181C TIMP3 or E139X TIMP3. S181C TIMP3 from these cells was found to dimerise and retain MMP2 inhibitory activity. To facilitate studies of the E139X TIMP3 protein, the allele was expressed using HighFive insect cells. In this cell type, the E139X TIMP3 was synthesised as a mixture of monomer and dimer. Both monomeric and dimeric E139X TIMP3 protein retained MMP2 inhibitory activity in gelatin zymography. Expression of mutant E139X or S181C TIMP3 protein from a normal diploid patient-derived fibroblast cell had no effect on either MMP2 or MMP9 expression or activation whilst transcribed from their normal promoter context. PMID:12757930

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

    PubMed Central

    Chiquet, Christophe; Godin-Ribuot, Diane; Amoos, Serge; Loeuillet, Corinne; Bernabei, Mario; Geiser, Martial

    2015-01-01

    Purpose 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). Methods 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). Results 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. Conclusion 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. PMID:26226150

  15. Application of Optical Coherence Tomography and Contrast Sensitivity Test for Observing Fundus Changes of Patients With Pregnancy-Induced Hypertension Syndrome.

    PubMed

    Wang, Zhixue; Zou, Yuanyuan; Li, Wenying; Wang, Xueyan; Zhang, Min; Wang, Wenying

    2015-11-01

    This study was aimed to investigate the fundus changes of patients with pregnancy-induced hypertension syndrome (PIHS) using optical coherence tomography (OCT) technology and contrast sensitivity (CS) tests.Ninety-eight patients with PIHS underwent routine eye examinations including vision correction, fundus examination, OCT, and CS tests. The CS test was performed at low, medium, and high frequency, respectively. Moreover, the difference in CS tests between 2 groups was analyzed by independent-samples T test. The Kruskal-Wallis rank sum test and linear regression model were used to detect the correlation of OCT with CS, respectively. Meanwhile Satterthwaite approximate T test was adopted for pairwise comparisons after nonparametric analysis of variance.The OCT test revealed that 56.76% of the examined eyes showed shallow retinal detachment in the macula lutea and around the optic disk. The differences in CS at each spatial frequency between the case and control group were statistically significant (P < 0.01). Besides, OCT manifestations were associated with CS at each spacial frequency including 1.5, 3, 6, 12, and 18 frequency (P < 0.01). And patients with abnormal manifestations of OCT showed lower CS at each spacial frequency than those without abnormal OCT manifestations. What's more the OCT manifestation 1 showed the greatest impact on CS at each spacial frequency.The results showed that abnormal OCT manifestations were correlated with CS in PIHS. OCT and CS tests might be valuable methods in observing fundus changes for PIHS patients. PMID:26554764

  16. Location of Tessellations in Ocular Fundus and Their Associations with Optic Disc Tilt, Optic Disc Area, and Axial Length in Young Healthy Eyes

    PubMed Central

    Terasaki, Hiroto; Yamashita, Takehiro; Yoshihara, Naoya; Kii, Yuya; Tanaka, Minoru; Nakao, Kumiko; Sakamoto, Taiji

    2016-01-01

    Tessellated fundus is found as common and early-phase characteristic of myopic eyes and their locations are varied among patients. However, the relationship between their locations and morphological parameters of the eyes is still unknown. The purpose is this study is to determine the locations of the tessellations in the ocular fundus of young healthy eyes, and to determine relationships between their locations and morphological parameters of the eyes. This is a prospective observational cross sectional study of 126 eyes of 126 healthy volunteers (mean age 26.0±4.1 years). The eyes were classified into eight groups based on the location of the tessellations; no tessellation, temporal, infra-temporal, inferior, nasal, peripapillary, whole retina, and unclassified tessellations. The degree of optic disc tilt was quantified using a sine curve fitting program on the optical coherence tomographic circle scan images. The correlations between each tessellation location and the axial length, area of the optic disc plus conus (AOC), and optic disc tilt were determined. Forty-four eyes were place in the no tessellation group, 12 eyes in the temporal, 21 eyes in the infra-temporal, 9 eyes in the inferior, 8 eyes in the nasal, 15 eyes in the peripapillary, 11 eyes in the whole, and 6 eyes in the unclassified groups. The differences in the axial lengths between the no tessellation group and the infra-temporal groups were significant. A significant difference was found in the AOC between the no tessellation and the inferior, infra-temporal, and peripapilalry groups. A significant difference was found in the optic disc tilt between the no tessellation and infra-temporal groups (P<0.05). The tessellations are located at specific sites in the fundus of young healthy eyes with the infra-temporal location most frequent. It was correlated with some parameters associated with myopia. PMID:27275584

  17. Location of Tessellations in Ocular Fundus and Their Associations with Optic Disc Tilt, Optic Disc Area, and Axial Length in Young Healthy Eyes.

    PubMed

    Terasaki, Hiroto; Yamashita, Takehiro; Yoshihara, Naoya; Kii, Yuya; Tanaka, Minoru; Nakao, Kumiko; Sakamoto, Taiji

    2016-01-01

    Tessellated fundus is found as common and early-phase characteristic of myopic eyes and their locations are varied among patients. However, the relationship between their locations and morphological parameters of the eyes is still unknown. The purpose is this study is to determine the locations of the tessellations in the ocular fundus of young healthy eyes, and to determine relationships between their locations and morphological parameters of the eyes. This is a prospective observational cross sectional study of 126 eyes of 126 healthy volunteers (mean age 26.0±4.1 years). The eyes were classified into eight groups based on the location of the tessellations; no tessellation, temporal, infra-temporal, inferior, nasal, peripapillary, whole retina, and unclassified tessellations. The degree of optic disc tilt was quantified using a sine curve fitting program on the optical coherence tomographic circle scan images. The correlations between each tessellation location and the axial length, area of the optic disc plus conus (AOC), and optic disc tilt were determined. Forty-four eyes were place in the no tessellation group, 12 eyes in the temporal, 21 eyes in the infra-temporal, 9 eyes in the inferior, 8 eyes in the nasal, 15 eyes in the peripapillary, 11 eyes in the whole, and 6 eyes in the unclassified groups. The differences in the axial lengths between the no tessellation group and the infra-temporal groups were significant. A significant difference was found in the AOC between the no tessellation and the inferior, infra-temporal, and peripapilalry groups. A significant difference was found in the optic disc tilt between the no tessellation and infra-temporal groups (P<0.05). The tessellations are located at specific sites in the fundus of young healthy eyes with the infra-temporal location most frequent. It was correlated with some parameters associated with myopia. PMID:27275584

  18. Quality of non-mydriatic digital fundus photography obtained by nurse practitioners in the emergency department: the FOTO-ED study

    PubMed Central

    Lamirel, Cédric; Bruce, Beau B.; Wright, David W.; Delaney, Kevin P.; Newman, Nancy J.; Biousse, Valérie

    2011-01-01

    Objective Non-mydriatic fundus photography by non-ophthalmic trained personnel has recently been shown to be a potential alternative to direct ophthalmoscopy in the emergency department (ED). We evaluated the reliability of a novel quality rating scale and applied this scale to non-mydriatic fundus photographs taken during routine ED patient encounters to determine factors associated with diminished photograph quality. Design Prospective, cross-sectional Participants 350 patients enrolled in the Fundus photography vs. Ophthalmoscopy Trials Outcomes in the Emergency Department (FOTO-ED) study were photographed by nurse practitioners after <30 minutes of training followed by supervision. Methods Photographs of both eyes were graded for quality on two occasions by two neuro-ophthalmologists. Four regions were independently evaluated for quality: optic disc, macula, superior and inferior vascular arcades. Quality as a function of the number of photographs taken was evaluated by Kaplan-Meier analysis. Mixed effects ordinal logistic regression was used to evaluate for predictors of image quality while accounting for the repeated measures design. Main Outcome Measure Overall photographic quality (1–5 scale, 5 best). Results We evaluated 1734 photographs. Inter- and intra-observer agreements between neuro-ophthalmologists were very good (weighted kappa:0.84–0.87). Quality of the optic disc area was better than those of other retinal areas (p<0.002). Kaplan-Meier analysis showed that if a high-quality photograph of an eye was not obtained by the third attempt it was unlikely that one would be obtained at all. A 10 second increase in the inter-photograph interval before a total of forty seconds increased the odds of a one unit higher quality rating by 1.81 times (95%CI: 1.68–1.98), and a ten year increase in age decreased the odds by 0.76 times (95%CI: 0.69–0.85). Black patients had 0.42 times (95%CI: 0.28–0.63) the odds of a one unit higher quality rating compared

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

    PubMed Central

    2010-01-01

    Background In malaria-endemic areas, reliably establishing parasitaemia for diagnosis of malaria can be difficult. A retinopathy with some features unique to severe malaria with a predictive value on prognosis, has been described. Detection of this retinopathy could be a useful diagnostic tool. This study was designed to determine the diagnostic usefulness of retinopathy on ophthalmoscopy in severe malaria syndromes: Cerebral malaria (CM) and non-cerebral severe malaria (non-CM), i.e. malaria with respiratory distress (RD) and malaria with severe anaemia (SA), in Ghanaian children. 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 with papilloedema(OR = 0.9, CI = 0.3 - 3.0, p = 0.9), macular whitening(OR = 1.6, CI = 0.5 - 4.8, p = 0.4), macular haemorrhage(OR = 0.28, CI = 0.03 - 2.7 p = 0.2), retinal haemorrhage(OR = 1.9, CI = 0.6 - 5.6, p = 0.3), vessel abnormality(OR = 1.9, CI = 0.6 - 6.1, p = 0.3) and cotton wool spots(OR not calculated, p = 0.08). Tortuous and engorged retinal veins, not previously described as a feature of CM, was the most common vascular abnormality(15/58 = 26%) and was detected even

  20. Crowdsourcing as a Novel Technique for Retinal Fundus Photography Classification: Analysis of Images in the EPIC Norfolk Cohort on Behalf of the UKBiobank Eye and Vision Consortium

    PubMed Central

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

    2013-01-01

    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 technique in

  1. Analysis of Fundus Fluorescein Angiogram Based on the Hessian Matrix of Directional Curvelet Sub-bands and Distance Regularized Level Set Evolution.

    PubMed

    Soltanipour, Asieh; Sadri, Saeed; Rabbani, Hossein; Akhlaghi, Mohammad Reza

    2015-01-01

    This paper presents a new procedure for automatic extraction of the blood vessels and optic disk (OD) in fundus fluorescein angiogram (FFA). In order to extract blood vessel centerlines, the algorithm of vessel extraction starts with the analysis of directional images resulting from sub-bands of fast discrete curvelet transform (FDCT) in the similar directions and different scales. For this purpose, each directional image is processed by using information of the first order derivative and eigenvalues obtained from the Hessian matrix. The final vessel segmentation is obtained using a simple region growing algorithm iteratively, which merges centerline images with the contents of images resulting from modified top-hat transform followed by bit plane slicing. After extracting blood vessels from FFA image, candidates regions for OD are enhanced by removing blood vessels from the FFA image, using multi-structure elements morphology, and modification of FDCT coefficients. Then, canny edge detector and Hough transform are applied to the reconstructed image to extract the boundary of candidate regions. At the next step, the information of the main arc of the retinal vessels surrounding the OD region is used to extract the actual location of the OD. Finally, the OD boundary is detected by applying distance regularized level set evolution. The proposed method was tested on the FFA images from angiography unit of Isfahan Feiz Hospital, containing 70 FFA images from different diabetic retinopathy stages. The experimental results show the accuracy more than 93% for vessel segmentation and more than 87% for OD boundary extraction. PMID:26284170

  2. Frequency, severity and risk indicators of retinopathy in patients with diabetes screened by fundus photographs: a study from primary health care

    PubMed Central

    Memon, Saleh; Ahsan, Shahid; Riaz, Qamar; Basit, Abdul; Ali Sheikh, Sikandar; Fawwad, Asher; Shera, A Samad

    2014-01-01

    Objective: To determine the frequency, severity and risk indicators of diabetic retinopathy (DR) in patients with diabetes attending a primary care diabetes centre. Methods: This observational study was conducted at Diabetic Association of Pakistan - a World Health Organization collaborating center in Karachi, from March 2009 to December 2011. Registered patients with diabetes were screened by two field fundus photographs. Retina specialists graded the signs of retinopathy according to diabetic retinopathy disease severity scale. Results: Of total registered diabetic patients (n=11,158), 10,768 (96.5 %) were screened for DR. Overall DR was found in 2661 (24.7%) patients. DR was found in decreasing order of frequency in patients with type 2 (n= 2555, 23.7%) followed by patients with type 1 diabetes (n=101, 0.93% ) and patients with gestational diabetes mellitus (GDM) (n=5, 0.46%). Among patients with DR, signs of non-sight threatening retinopathy was dominant. Females and patients of working age group predominantly had retinopathy. Type 1 patients >16 years and type 2 patients < 5 years of history of diabetes had sign of retinopathy in increased frequency. Conclusion: Every forth patient with diabetes in this large cohort had signs of diabetic retinopathy. Females and patients in working age group predominantly had retinopathy. Type 2 patients with short while type 1 patients with long history of diabetes most frequently had DR. Dissemination of the present study findings may help in increasing the awareness of this serious complication of diabetes. PMID:24772145

  3. Determination of cup-to-disc ratio of optical nerve head for diagnosis of glaucoma on stereo retinal fundus image pairs

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2009-02-01

    A large cup-to-disc (C/D) ratio, which is the ratio of the diameter of the depression (cup) to that of the optical nerve head (ONH, disc), can be one of the important signs for diagnosis of glaucoma. Eighty eyes, including 25 eyes with the signs of glaucoma, were imaged by a stereo retinal fundus camera. An ophthalmologist provided the outlines of cup and disc on a regular monitor and on the stereo display. The depth image of the ONH was created by determining the corresponding pixels in a pair of images based on the correlation coefficient in localized regions. The areas of the disc and cup were determined by use of the red component in one of the color images and by use of the depth image, respectively. The C/D ratio was determined based on the largest vertical lengths in the cup and disc areas, which was then compared with that by the ophthalmologist. The disc areas determined by the computerized method agreed relatively well with those determined by the ophthalmologist, whereas the agreement for the cup areas was somewhat lower. When C/D ratios were employed for distinction between the glaucomatous and non-glaucomatous eyes, the area under the receiver operating characteristic curve (AUC) was 0.83. The computerized analysis of ONH can be useful for diagnosis of glaucoma.

  4. Reduced Fluorescein Angiography and Fundus Photography Use in the Management of Neovascular Macular Degeneration and Macular Edema During the Past Decade

    PubMed Central

    Schneider, Eric W.; Mruthyunjaya, Prithvi; Talwar, Nidhi; Harris Nwanyanwu, Kristen; Nan, Bin; Stein, Joshua D.

    2014-01-01

    Purpose. We assessed recent trends in the use of diagnostic testing for neovascular age-related macular degeneration (NVAMD) and macular edema (ME). Methods. Claims data from a managed-care network were analyzed on patients with NVAMD (n = 22,954) or ME (n = 31,810) to assess the use of fluorescein angiography (FA), fundus photography (FP), and optical coherence tomography (OCT) from 2001 to 2009. Repeated-measures logistic regression was performed to compare patients' odds of undergoing these procedures in 2001, 2005, and 2009. In addition, the proportions of patients with an incident NVAMD or ME diagnosis in 2003 or 2008 who underwent FA, FP, and OCT were compared. Results. From 2001 to 2009, among patients with NVAMD, the odds of undergoing OCT increased 23-fold, whereas the odds of receiving FA and FP decreased by 68% and 79%, respectively. Similar trends were observed for ME. From 2003 to 2008, the proportion of patients undergoing OCT within 1 year of initial diagnosis increased by 315% for NVAMD and by 143% for ME; the proportion undergoing OCT without FA within 1 year increased by 463% for NVAMD and by 216% for ME. Conclusions. Use of OCT increased dramatically during the past decade, whereas use of FA and FP declined considerably, suggesting that OCT may be replacing more traditional diagnostic testing in patients with NVAMD or ME. Future studies should evaluate whether this increased reliance on OCT instead of FA and FP affects patient outcomes. PMID:24346174

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

    PubMed Central

    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

  6. Classification of choroiditis based on inflammatory lesion process rather than fundus appearance: enhanced comprehension through the ICGA concepts of the iceberg and jellyfish effects.

    PubMed

    Herbort, C P; Papadia, M; Mantovani, A

    2012-04-01

    Choroidal inflammatory diseases have been classically grouped under the term of white dot syndromes (WDS), a term only based on the appearance (white-yellow dots) of inflammatory fundus lesions. This purely descriptive and vague terminology, regrouping a pot-pourri of posterior inflammatory conditions, probably came into use because the precise exploration of the choroid was not possible, and also because many of the diseases were rare and not well understood. Since the availability of indocyanine green angiography (ICGA) that allows one to explore the choroidal compartment, it became possible to understand the lesion mechanism of choroiditides and to classify this group of diseases according to their pathophysiological behaviour. It was our aim to show here that the term WDS is applied to and encompasses inflammatory conditions that are characterized by completely different lesion mechanisms and should therefore be classified separately from each other. ICGA made it possible to differentiate two types of choroiditides, including on the one hand inflammatory diseases of the choroidal stroma and on the other hand inflammatory diseases of the choriocapillaris. Unfortunately, twenty years after its advent, ICGA is still not used routinely in uveitis centres and the traditional inappropriate but overall useless term of WDS is still used, maintaining the confusion about these diseases. The aim of this work was (i) to illustrate that meaningful exploration of choroidal inflammation, mostly occult and inaccessible to usual investigations, has to be performed using ICGA, (ii) to insist on the crucial importance of ICGA in the management of choroiditis and (iii) to enhance the comprehension of the ICGA-based classification of choroiditis, by using the demonstrative and striking analogue concepts of iceberg and jellyfish effects. PMID:22495994

  7. Conocimientos y autoeficacia asociados a la prevención del VIH y SIDA en mujeres chilenas

    PubMed Central

    Villegas Rodríguez, Natalia; Ferrer Lagunas, Lilian Marcela; Cianelli Acosta, Rosina; Miner, Sarah; Lara Campos, Loreto; Peragallo, Nilda

    2014-01-01

    Resumen Objetivo Evaluar la relación existente entre conocimientos y autoeficacia asociados al VIH/SIDA en mujeres chilenas en desventaja social. Metodología Estudio correlacional, que utiliza la medición basal del estudio “Testeando una intervención en VIH y SIDA en mujeres chilenas”, realizada entre 2006 y 2008, que tiene una muestra de 496 mujeres entre 18 y 49 años residentes en dos comunas de Santiago de Chile. Las participantes respondieron un cuestionario estructurado aplicado por entrevistadoras entrenadas. Este cuestionario incluyó preguntas sobre datos sociodemográficos, escala de conocimientos de conductas de riesgo y autoeficacia, entre otros. Resultados Edad promedio de 32.3±9.1 años, 72.2% vive con su pareja y 42.7% poseen educación media completa. La puntuación media de los conocimientos de la infección por el VIH fue de 8.9±2.5, mientras que para las tres escalas empleadas para medir autoeficacia fueron: “Normas de los pares” =9.8±3.6, “Intención de reducir conductas de riesgo” =12.2±3.6 y “Self Efficacy Form”=20.2±4.7. Los conocimientos tuvieron una correlación positiva débil con la “intención de reducir conductas de riesgo” (r=0.19; p<0.0001) y con la escala “Self Efficacy Form” (r=0.34; p<0.0001), pero no se relacionaron con las “normas de los pares en cuanto a relaciones sexuales seguras” (r=0.13; p=0.78). Conclusión Existe una débil correlación positiva entre el nivel de conocimientos sobre el VIH/SIDA y la autoeficacia en mujeres chilenas en desventaja social. PMID:25284914

  8. Cobertura de los sistemas de pensiones y factores asociados al acceso a una pensión de jubilación en México

    PubMed Central

    Murillo-López, Sandra; Venegas-Martínez, Francisco

    2016-01-01

    Resumen Objetivos: obtener estimaciones de indicadores de cobertura de las pensiones por jubilación o retiro para la población mexicana de 65 y más años, y evaluar el impacto que tienen los sistemas de pensiones en las transiciones al retiro de los adultos en edades medias y avanzadas en México. Para ello se utilizan datos microeconómicos provenientes de la Encuesta Nacional de Salud y Envejecimiento. Mediante análisis econométrico se identifican los factores sociodemográficos, económicos, laborales e institucionales que están asociados al acceso a una pensión de jubilación, o bien, a la dependencia de otras fuentes de ingresos. Se encontró que, en México, las transiciones al retiro del mercado de trabajo en las etapas avanzadas del ciclo de vida son limitadas debido a las características eminentemente contributivas de los esquemas de pensiones, los cuales favorecen a la población con trayectorias laborales formales y más estables asociadas a: características de género, oportunidades educativas y posibilidades de inserción en el mercado laboral. PMID:27524936

  9. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D) and the Heidelberg Scanning Laser Ophthalmoscope (HRT III).

    PubMed

    Mariacher, Siegfried; Hipp, Stephanie; Wirthky, Robert; Blumenstock, Gunnar; Bartz-Schmidt, Karl-Ulrich; Ziemssen, Focke; Schiefer, Ulrich; Voykov, Bogomil; Januschowski, Kai

    2016-01-01

    Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR). Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI) were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement) of -0.06 (-0.36 to 0.24). For the CDR < 0.5 group (n = 24) mean difference in vertical CDR was -0.14 (-0.34 to 0.06) and for the CDR ≥ 0.5 group (n = 16) 0.06 (-0.21 to 0.34). Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5. PMID:27313870

  10. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D) and the Heidelberg Scanning Laser Ophthalmoscope (HRT III)

    PubMed Central

    Mariacher, Siegfried; Wirthky, Robert; Blumenstock, Gunnar; Bartz-Schmidt, Karl-Ulrich; Ziemssen, Focke; Schiefer, Ulrich; Voykov, Bogomil; Januschowski, Kai

    2016-01-01

    Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR). Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI) were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement) of −0.06 (−0.36 to 0.24). For the CDR < 0.5 group (n = 24) mean difference in vertical CDR was −0.14 (−0.34 to 0.06) and for the CDR ≥ 0.5 group (n = 16) 0.06 (−0.21 to 0.34). Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5. PMID:27313870

  11. The kinetics of regeneration of rhodopsin under enzyme-limited availability of 11-cis retinoid.

    PubMed

    Lamb, Trevor D; Corless, Robert M; Pananos, A Demetri

    2015-05-01

    In order to describe the regeneration of rhodopsin and the recovery of visual sensitivity following exposure of the eye to intense bleaching illumination, two models have been proposed, in which there is either a "resistive" or an "enzymatic" limit to the supply of retinoid. A solution has previously been derived for the resistive model, and here we derive an analytical solution for the enzymatic model and we investigate the form of this solution as a function of parameter values. We demonstrate that this enzymatic model provides a good fit to human post-bleach recovery, for four cases: for rhodopsin regeneration in normal subjects; for psychophysical scotopic dark adaptation in normal subjects; for rhodopsin regeneration and scotopic dark adaptation in fundus albipunctatus patients; and for cone pigment regeneration in normal subjects. Finally, we present arguments favouring the enzymatic model as the cellular basis for normal human rod and cone pigment regeneration. PMID:25769401

  12. Algorithms evaluation for fundus images enhancement

    NASA Astrophysics Data System (ADS)

    Braem, V.; Marcos, M.; Bizai, G.; Drozdowicz, B.; Salvatelli, y. A.

    2011-12-01

    Color images of the retina inherently involve noise and illumination artifacts. In order to improve the diagnostic quality of the images, it is desirable to homogenize the non-uniform illumination and increase contrast while preserving color characteristics. The visual result of different pre-processing techniques can be very dissimilar and it is necessary to make an objective assessment of the techniques in order to select the most suitable. In this article the performance of eight algorithms to correct the non-uniform illumination, contrast modification and color preservation was evaluated. In order to choose the most suitable a general score was proposed. The results got good impression from experts, although some differences suggest that not necessarily the best statistical quality of image is the one of best diagnostic quality to the trained doctor eye. This means that the best pre-processing algorithm for an automatic classification may be different to the most suitable one for visual diagnosis. However, both should result in the same final diagnosis.

  13. Factores socio-económicos asociados a la percepción de situación socioeconómica entre adultos mayores de dos países latinoamericanos

    PubMed Central

    Brenes-Camacho, Gilbert

    2014-01-01

    El objetivo principal del artículo es estudiar la asociación entre la percepción subjetiva sobre la situación económica propia y una serie de medidas objetivas de bienestar socioeconómico –fuentes de ingresos, tenencia de vivienda, nivel educativo y transferencias familiares informales de dinero- entre adultos mayores de dos países Latinoamericanos: México y Costa Rica. Los datos se obtienen de las primeras rondas de dos encuestas sobre envejecimiento: CRELES para Costa Rica y ENASEM para México. La variable dependiente más importante se obtiene de las respuestas a las pregunta “¿Cómo califica su situación económica actual?” en Costa Rica y “¿Diría usted que su situación económica es…?” en México. Para ambas encuestas, las respuestas se codificaron en forma binaria; el código 0 representa las categorías Excelente, Muy buena y Buena, y el código 1 representa a las categorías Regular y Mala. Se encontró que el ingreso por jubilación es un importante determinante de la percepción de bienestar en ambos países. En Costa Rica, el ingreso del cónyuge y la tenencia de vivienda son importantes predictores de la percepción de bienestar, mientras que en México, los ingresos por transferencias están fuertemente asociados con dicha percepción. PMID:25360057

  14. Retinal artery-vein caliber grading using color fundus imaging.

    PubMed

    Bhuiyan, Alauddin; Kawasaki, Ryo; Lamoureux, Ecosse; Ramamohanarao, Kotagiri; Wong, Tien Yin

    2013-07-01

    Recent research suggests that retinal vessel caliber (or cross-sectional width) measured from retinal photographs is an important feature for predicting cardiovascular diseases (CVDs). One of the most utilized measures is to quantify retinal arteriolar and venular caliber as the Central Retinal Artery Equivalent (CRAE) and Central Retinal Vein Equivalent (CRVE). However, current computer tools utilize manual or semi-automatic grading methods to estimate CRAE and CRVE. These methods involve a significant amount of grader's time and can add a significant level of inaccuracy due to repetitive nature of grading and intragrader distances. An automatic and time efficient grading of the vessel caliber with highly repeatable measurement is essential, but is technically challenging due to a substantial variation of the retinal blood vessels' properties. In this paper, we propose a new technique to measure the retinal vessel caliber, which is an "edge-based" vessel tracking method. We measured CRAE and CRVE from each of the vessel types. We achieve very high accuracy (average 96.23%) for each of the cross-sectional width measurement compared to manually graded width. For overall vessel caliber measurement accuracy of CRAE and CRVE, we compared the results with an existing semi-automatic method which showed high correlation of 0.85 and 0.92, respectively. The intra-grader reproducibility of our method was high, with the correlation coefficient of 0.881 for CRAE and 0.875 for CRVE. PMID:23535181

  15. Implantation of refractive multifocal intraocular lens with a surface-embedded near section for cataract eyes complicated with a coexisting ocular pathology

    PubMed Central

    Ouchi, M; Kinoshita, S

    2015-01-01

    Purpose To evaluate the postoperative outcomes of cataract eyes complicated with coexisting ocular pathologies that underwent implantation of a refractive multifocal intraocular lens (MIOL) with a surface-embedded near section. Methods LENTIS MPlus (Oculentis GmbH) refractive MIOLs were implanted in 15 eyes with ocular pathologies other than cataract (ie, six high-myopia eyes with an axial length longer than 28 mm, two fundus albipunctatus eyes, two branch retinal-vein occlusion eyes, four glaucoma eyes (one with high myopia), and two keratoconus eyes). Uncorrected or corrected distance and near visual acuity (VA) (UDVA, UNVA, CDVA, and CNVA), contrast sensitivity, and defocus curve were measured at 1 day and 6 months postoperatively, and each patient completed a 6-month postoperative questionnaire regarding vision quality and eyeglass use. Results Thirteen eyes (87%) registered 0 or better in CDVA and 12 eyes (73%) registered better than 0 in CNVA. Contrast sensitivity in the eyes of all patients was comparable to that of normal healthy subjects. No patient required eyeglasses for distance vision, but three patients (20%) required them for near vision. No patient reported poor or very poor vision quality. Conclusion With careful case selection, sectorial refractive MIOL implantation is effective for treating cataract eyes complicated with ocular pathologies. PMID:25744442

  16. Computer-aided diabetic retinopathy detection using trace transforms on digital fundus images.

    PubMed

    Ganesan, Karthikeyan; Martis, Roshan Joy; Acharya, U Rajendra; Chua, Chua Kuang; Min, Lim Choo; Ng, E Y K; Laude, Augustinus

    2014-08-01

    Diabetic retinopathy (DR) is a leading cause of vision loss among diabetic patients in developed countries. Early detection of occurrence of DR can greatly help in effective treatment. Unfortunately, symptoms of DR do not show up till an advanced stage. To counter this, regular screening for DR is essential in diabetic patients. Due to lack of enough skilled medical professionals, this task can become tedious as the number of images to be screened becomes high with regular screening of diabetic patients. An automated DR screening system can help in early diagnosis without the need for a large number of medical professionals. To improve detection, several pattern recognition techniques are being developed. In our study, we used trace transforms to model a human visual system which would replicate the way a human observer views an image. To classify features extracted using this technique, we used support vector machine (SVM) with quadratic, polynomial, radial basis function kernels and probabilistic neural network (PNN). Genetic algorithm (GA) was used to fine tune classification parameters. We obtained an accuracy of 99.41 and 99.12% with PNN-GA and SVM quadratic kernels, respectively. PMID:24958614

  17. New algorithm for detecting smaller retinal blood vessels in fundus images

    NASA Astrophysics Data System (ADS)

    LeAnder, Robert; Bidari, Praveen I.; Mohammed, Tauseef A.; Das, Moumita; Umbaugh, Scott E.

    2010-03-01

    About 4.1 million Americans suffer from diabetic retinopathy. To help automatically diagnose various stages of the disease, a new blood-vessel-segmentation algorithm based on spatial high-pass filtering was developed to automatically segment blood vessels, including the smaller ones, with low noise. Methods: Image database: Forty, 584 x 565-pixel images were collected from the DRIVE image database. Preprocessing: Green-band extraction was used to obtain better contrast, which facilitated better visualization of retinal blood vessels. A spatial highpass filter of mask-size 11 was applied. A histogram stretch was performed to enhance contrast. A median filter was applied to mitigate noise. At this point, the gray-scale image was converted to a binary image using a binary thresholding operation. Then, a NOT operation was performed by gray-level value inversion between 0 and 255. Postprocessing: The resulting image was AND-ed with its corresponding ring mask to remove the outer-ring (lens-edge) artifact. At this point, the above algorithm steps had extracted most of the major and minor vessels, with some intersections and bifurcations missing. Vessel segments were reintegrated using the Hough transform. Results: After applying the Hough transform, both the average peak SNR and the RMS error improved by 10%. Pratt's Figure of Merit (PFM) was decreased by 6%. Those averages were better than [1] by 10-30%. Conclusions: The new algorithm successfully preserved the details of smaller blood vessels and should prove successful as a segmentation step for automatically identifying diseases that affect retinal blood vessels.

  18. Fundus image mosaicking for information augmentation in computer-assisted slit-lamp imaging.

    PubMed

    Richa, Rogério; Linhares, Rodrigo; Comunello, Eros; von Wangenheim, Aldo; Schnitzler, Jean-Yves; Wassmer, Benjamin; Guillemot, Claire; Thuret, Gilles; Gain, Philippe; Hager, Gregory; Taylor, Russell

    2014-06-01

    Laser photocoagulation is currently the standard treatment for sight-threatening diseases worldwide, namely diabetic retinopathy and retinal vein occlusions. The slit lamp biomicroscope is the most commonly used device for this procedure, specially for the treatment of the eye periphery. However, only a small portion of the retina can be visualized through the biomicroscope, complicating the task of localizing and identifying surgical targets, increasing treatment duration and patient discomfort. In order to assist surgeons, we propose a method for creating intraoperative retina maps for view expansion using a slit-lamp device. Based on the mosaicking method described by Richa et al, 2012, the proposed method is a combination of direct and feature-based methods, suitable for the textured nature of the human retina. In this paper, we describe three major enhancements to the original formulation. The first is a visual tracking method using local illumination compensation to cope with the challenging visualization conditions. The second is an efficient pixel selection scheme for increased computational efficiency. The third is an entropy-based mosaic update method to dynamically improve the retina map during exploration. To evaluate the performance of the proposed method, we conducted several experiments on human subjects with a computer-assisted slit-lamp prototype. We also demonstrate the practical value of the system for photo documentation, diagnosis and intraoperative navigation. PMID:24718569

  19. Assessment of non-mydriatic fundus photography in detection of diabetic retinopathy.

    PubMed Central

    Williams, R; Nussey, S; Humphry, R; Thompson, G

    1986-01-01

    Non-mydriatic retinal photography with later interpretation of the photographs was assessed as a screening method for the detection of diabetic retinopathy; when compared with an ophthalmologist's clinical assessment in a random group of 62 diabetic patients it was accurate (false negative 6.8%, false positive 2%) and sensitive (sensitivity 96%, specificity 98%). The assessment of further management required based on analysis of the photographs was 96.5% in agreement with the further management suggested by the ophthalmologist after direct clinical assessment of the patient. If this technique were used to screen patients in a typical diabetic clinic the predicted positive accuracy rate would be 84% and the predicted negative accuracy rate 99.5%. Images p1141-a PMID:3094807

  20. Longitudinal graph-based segmentation of macular OCT using fundus alignment

    NASA Astrophysics Data System (ADS)

    Lang, Andrew; Carass, Aaron; Al-Louzi, Omar; Bhargava, Pavan; Ying, Howard S.; Calabresi, Peter A.; Prince, Jerry L.

    2015-03-01

    Segmentation of retinal layers in optical coherence tomography (OCT) has become an important diagnostic tool for a variety of ocular and neurological diseases. Currently all OCT segmentation algorithms analyze data independently, ignoring previous scans, which can lead to spurious measurements due to algorithm variability and failure to identify subtle changes in retinal layers. In this paper, we present a graph-based segmentation framework to provide consistent longitudinal segmentation results. Regularization over time is accomplished by adding weighted edges between corresponding voxels at each visit. We align the scans to a common subject space before connecting the graphs by registering the data using both the retinal vasculature and retinal thickness generated from a low resolution segmentation. This initial segmentation also allows the higher dimensional temporal problem to be solved more efficiently by reducing the graph size. Validation is performed on longitudinal data from 24 subjects, where we explore the variability between our longitudinal graph method and a cross-sectional graph approach. Our results demonstrate that the longitudinal component improves segmentation consistency, particularly in areas where the boundaries are difficult to visualize due to poor scan quality.

  1. The Rate of Vitamin A Dimerization in Lipofuscinogenesis, Fundus Autofluorescence, Retinal Senescence and Degeneration.

    PubMed

    Washington, Ilyas; Saad, Leonide

    2016-01-01

    One of the earliest events preceding several forms of retinal degeneration is the formation and accumulation of vitamin A dimers in the retinal pigment epithelium (RPE) and underlying Bruch's membrane (BM). Such degenerations include Stargardt disease, Best disease, forms of retinitis pigmentosa, and age-related macular degeneration (AMD). Since their discovery in the 1990's, dimers of vitamin A, have been postulated as chemical triggers driving retinal senescence and degeneration. There is evidence to suggest that the rate at which vitamin A dimerizes and the eye's response to the dimerization products may dictate the retina's lifespan. Here, we present outstanding questions, finding the answers to which may help to elucidate the role of vitamin A dimerization in retinal degeneration. PMID:26427431

  2. Improved automated optic cup segmentation based on detection of blood vessel bends in retinal fundus images.

    PubMed

    Hatanaka, Yuji; Nagahata, Yuuki; Muramatsu, Chisako; Okumura, Susumu; Ogohara, Kazunori; Sawada, Akira; Ishida, Kyoko; Yamamoto, Tetsuya; Fujita, Hiroshi

    2014-01-01

    Glaucoma is a leading cause of permanent blindness. Retinal imaging is useful for early detection of glaucoma. In order to evaluate the presence of glaucoma, ophthalmologists may determine the cup and disc areas and diagnose glaucoma using a vertical optic cup-to-disc (C/D) ratio and a rim-to-disc (R/D) ratio. Previously we proposed a method to determine cup edge by analyzing a vertical profile of pixel values, but this method provided a cup edge smaller than that of an ophthalmologist. This paper describes an improved method using the locations of the blood vessel bends. The blood vessels were detected by a concentration feature determined from the density gradient. The blood vessel bends were detected by tracking the blood vessels from the disc edge to the primary cup edge, which was determined by our previous method. Lastly, the vertical C/D ratio and the R/D ratio were calculated. Using forty-four images, including 32 glaucoma images, the AUCs of both the vertical C/D ratio and R/D ratio by this proposed method were 0.966 and 0.936, respectively. PMID:25569913

  3. Application of vascular bundle displacement in the optic disc for glaucoma detection using fundus images.

    PubMed

    Fuente-Arriaga, José Abel de la; Felipe-Riverón, Edgardo M; Garduño-Calderón, Eduardo

    2014-04-01

    This paper presents a methodology for glaucoma detection based on measuring displacements of blood vessels within the optic disc (vascular bundle) in human retinal images. The method consists of segmenting the region of the vascular bundle in an optic disc to set a reference point in the temporal side of the cup, determining the position of the centroids of the superior, inferior, and nasal vascular bundle segmented zones located within the segmented region, and calculating the displacement from normal position using the chessboard distance metric. The method was successful in 62 images out of 67, achieving 93.02% sensitivity, 91.66% specificity, and 91.34% global accuracy in pre-diagnosis. PMID:24530536

  4. [Albinism and the Range of Fundus Hypopigmentation, Macular Hypoplasia, and Nystagmus].

    PubMed

    Preising, M N; Lorenz, B

    2016-03-01

    From the ophthalmological view, albinism is a disorder of reduced pigmentation of the retinal and irdial pigment epithelium and the iris and choroid stroma. The reduced pigmentation is accompanied by morphological changes in the retina and the optic nerve. The functional relationship of these morphological changes is not yet well understood. This review summarises the genetic causes of reduced pigment synthesis and impaired pigment distribution, and discusses the variability of expression of albinism symptoms, in the light of other disorders affecting retinal development. PMID:27011028

  5. Photoreceptor counting and montaging of en-face retinal images from an adaptive optics fundus camera

    NASA Astrophysics Data System (ADS)

    Xue, Bai; Choi, Stacey S.; Doble, Nathan; Werner, John S.

    2007-05-01

    A fast and efficient method for quantifying photoreceptor density in images obtained with an en-face flood-illuminated adaptive optics (AO) imaging system is described. To improve accuracy of cone counting, en-face images are analyzed over extended areas. This is achieved with two separate semiautomated algorithms: (1) a montaging algorithm that joins retinal images with overlapping common features without edge effects and (2) a cone density measurement algorithm that counts the individual cones in the montaged image. The accuracy of the cone density measurement algorithm is high, with >97% agreement for a simulated retinal image (of known density, with low contrast) and for AO images from normal eyes when compared with previously reported histological data. Our algorithms do not require spatial regularity in cone packing and are, therefore, useful for counting cones in diseased retinas, as demonstrated for eyes with Stargardt's macular dystrophy and retinitis pigmentosa.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Computer-assisted grading of diabetic macular edema on retinal color fundus images.

    PubMed

    Sundaresan, Vaanathi; Ram, Keerthi; Joshi, Niranjan; Sivaprakasam, Mohanasankar; Gandhi, Rashmin

    2015-08-01

    Diabetic macular edema (DME) is one of the vision-impairing manifestations of Diabetic Retinopathy (DR). Early detection and treatment of DME can prevent permanent vision loss in people suffering from DR. However, the clinical detection through biomicroscopy is time-consuming. In this paper, a computer-assisted grading method has been proposed to determine the DME severity based on the spatial distribution of exudative lesions around macula. The region around macula is classified into zonal levels and severity of the DME is graded based on the presence of exudative lesions in each zone. The proposed method has been evaluated on diverse public and local databases, and produced the sensitivity of 89.54% for 9.1 false positive per image (FPPI) for exudate detection and 98.8% accuracy for DME grading. PMID:26737253

  8. [Effect of fundus image devices for early diagnosis of primary open angle glaucoma].

    PubMed

    Pan, Ying-zi

    2009-10-01

    Evaluation of the optic disc and retinal nerve fiber layer measurements (RNFL) with stereophotography is the current "gold standard" for the diagnosis of early primary open angle glaucoma (POAG), but it is still subjective and is dependent too much upon an experienced observer. Substantial variability exists in the interpretation of optic disc change over time. There are consistent evidences that image analysis devices such as optical coherence tomography (OCT) and Heidelberg retina tomograph (HRT-II) can detect early to moderate glaucoma as well as expert assessment of stereoscopic optic disc and RNFL photographs. Optic disc and RNFL defect can be quantitatively measured by these devices. But the sensitivity and specificity of the measurements obtained with these devices are not good enough for the early diagnosis of POAG at this time due to several reasons, such as individual variety of the structure parameters in normal subjects, lack of powerful normative database, lack of diagnostic parameters which are good enough both in sensitivity and specificity for detecting early glaucoma damage. However, information obtained from these image analysis devices might be helpful in early POAG diagnosis if clinicians can understand the advantages and limitations of these instruments. PMID:20137444

  9. Fundus changes in mesangiocapillary glomerulonephritis type II: clinical and fluorescein angiographic findings.

    PubMed Central

    Duvall-Young, J; Short, C D; Raines, M F; Gokal, R; Lawler, W

    1989-01-01

    Previously we have demonstrated a deposit in Bruch's membrane in a single case of mesangiocapillary glomerulonephritis type II. We studied a group of patients with this disease and described extensive clinical and fluorescein angiographic abnormalities, which were in marked contrast to the findings in a group of patients with other forms of glomerulonephritis. This finding contributes to our understanding of the pathophysiology of the complex of the retinal pigment epithelium, Bruch's membrane, and choriocapillaris. Images PMID:2605144

  10. Imaging the eye fundus with real-time en-face spectral domain optical coherence tomography.

    PubMed

    Bradu, Adrian; Podoleanu, Adrian Gh

    2014-04-01

    Real-time display of processed en-face spectral domain optical coherence tomography (SD-OCT) images is important for diagnosis. However, due to many steps of data processing requirements, such as Fast Fourier transformation (FFT), data re-sampling, spectral shaping, apodization, zero padding, followed by software cut of the 3D volume acquired to produce an en-face slice, conventional high-speed SD-OCT cannot render an en-face OCT image in real time. Recently we demonstrated a Master/Slave (MS)-OCT method that is highly parallelizable, as it provides reflectivity values of points at depth within an A-scan in parallel. This allows direct production of en-face images. In addition, the MS-OCT method does not require data linearization, which further simplifies the processing. The computation in our previous paper was however time consuming. In this paper we present an optimized algorithm that can be used to provide en-face MS-OCT images much quicker. Using such an algorithm we demonstrate around 10 times faster production of sets of en-face OCT images than previously obtained as well as simultaneous real-time display of up to 4 en-face OCT images of 200 × 200 pixels(2) from the fovea and the optic nerve of a volunteer. We also demonstrate 3D and B-scan OCT images obtained from sets of MS-OCT C-scans, i.e. with no FFT and no intermediate step of generation of A-scans. PMID:24761303

  11. High-Resolution Imaging of Parafoveal Cones in Different Stages of Diabetic Retinopathy Using Adaptive Optics Fundus Camera

    PubMed Central

    Soliman, Mohamed Kamel; Hassan, Muhammad; Hanout, Mostafa; Graf, Frank; High, Robin; Do, Diana V.; Nguyen, Quan Dong; Sepah, Yasir J.

    2016-01-01

    Purpose To assess cone density as a marker of early signs of retinopathy in patients with type II diabetes mellitus. Methods An adaptive optics (AO) retinal camera (rtx1™; Imagine Eyes, Orsay, France) was used to acquire images of parafoveal cones from patients with type II diabetes mellitus with or without retinopathy and from healthy controls with no known systemic or ocular disease. Cone mosaic was captured at 0° and 2°eccentricities along the horizontal and vertical meridians. The density of the parafoveal cones was calculated within 100×100-μm squares located at 500-μm from the foveal center along the orthogonal meridians. Manual corrections of the automated counting were then performed by 2 masked graders. Cone density measurements were evaluated with ANOVA that consisted of one between-subjects factor, stage of retinopathy and the within-subject factors. The ANOVA model included a complex covariance structure to account for correlations between the levels of the within-subject factors. Results Ten healthy participants (20 eyes) and 25 patients (29 eyes) with type II diabetes mellitus were recruited in the study. The mean (± standard deviation [SD]) age of the healthy participants (Control group), patients with diabetes without retinopathy (No DR group), and patients with diabetic retinopathy (DR group) was 55 ± 8, 53 ± 8, and 52 ± 9 years, respectively. The cone density was significantly lower in the moderate nonproliferative diabetic retinopathy (NPDR) and severe NPDR/proliferative DR groups compared to the Control, No DR, and mild NPDR groups (P < 0.05). No correlation was found between cone density and the level of hemoglobin A1c (HbA1c) or the duration of diabetes. Conclusions The extent of photoreceptor loss on AO imaging may correlate positively with severity of DR in patients with type II diabetes mellitus. Photoreceptor loss may be more pronounced among patients with advanced stages of DR due to higher risk of macular edema and its sequelae. PMID:27057752

  12. Adaptive optics in ophthalmology: current techniques and new methods of increasing field-of-view of fundus cameras

    NASA Astrophysics Data System (ADS)

    Dubinin, Alexander; Cherezova, Tatyana; Kudryashov, Alexis; Starikov, Fedor

    2007-06-01

    In this paper we investigate anisoplanatism effect in human eye. We measured off-axis aberrations of eyes of several subjects and also performed measurements of corneal and internal optics aberrations. Using the results of the experiments we estimated anisoplanatism effect in human eye and developed human eye models reproducing on-axis and off-axis eye aberrations and their distribution between optical elements of the eye.

  13. The influence of human eye aberrations on the resolution and field of view of fundus-cameras

    NASA Astrophysics Data System (ADS)

    Dubinin, Alexander; Cherezova, Tatyana; Belyakov, Alexey; Kudryashov, Alexis

    2007-05-01

    In this paper we estimate isoplanatic patch size of human eye using experimental results of human eye aberrations measurements. For examined subjects it was found to be in the range 1.1° to 2.5°. The size of isoplanatic patch for Gulistrand-Navarro model was calculated, it was found to be close to values obtained experimentally. We also measured contribution of corneal surface and internal optics into total aberrations of the eye. We modified Gullstrand-Navarro eye model to reproduce on-axis and off-axis performance of the eyes of each measured subject. The distribution of aberrations between optical elements of the eye was taken into account when modeling. We also investigated isoplanatic patch size widening methods such as average phase correction using 2 beacons and immersion method based on compensation of external corneal surface refraction with immersion liquid. Immersion method was found to be the most appropriate for isoplanatic patch widening as it allows us to increase isoplanatic patch size almost twice without loss of image quality at the center of the image.

  14. Transition from film to digital fundus photography in the Longitudinal Studies of the Ocular Complications of AIDS (LSOCA)

    PubMed Central

    Gangaputra, Sapna; Pak, Jeong Won; Peng, Qian; Hubbard, Larry D.; Thayer, Dennis; Krason, Zbigniew; Joyce, Jeff; Danis, Ronald P.

    2014-01-01

    Purpose To describe the transition to digital imaging and assess any impact on ocular disease classification. Methods Film and digital images, acquired by certified photographers, were evaluated independently according to standard procedures for the following: image quality, presence of cytomegalovirus (CMV) retinitis lesions, their extent, and proximity from disc and macula. Inter-grader agreement within the digital medium was also assessed. Results Among the fifteen eyes with CMV retinitis, the mean difference between film and digital images for linear distance of lesion edge to disc was 0.02 disc diameters (DD), for distance to center of macula was −0.04 DD and area covered by CMV retinitis was 0.95 disc area (DA). There was no statistically significant difference in distance and area measurements between media. Inter grader agreement in measurements of digital images was excellent for distance and area estimated. Conclusion Our results suggest that digital grading of CMV retinitis in LSOCA is comparable to that from film with respect to disease classification, measurements, and reproducibility. These findings provide support for continuity of grading data, despite the necessary transition in imaging media. PMID:21857393

  15. Fundamentos para Asociados en Desarrollo Infantil quienes trabajan con Ninos Pequenos (Essentials for Child Development Associates Working with Young Children).

    ERIC Educational Resources Information Center

    Phillips, Carol Brunson, Ed.

    A study guide for the Child Development Associate (CDA) Professional Preparation Program, this Spanish-language guidebook contains essential information on the basics of good professional practice for early childhood educators. It includes self-study activities, checklists, and resources for additional information. Unit 1 provides an overview of…

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Real-time calibration-free C-scan images of the eye fundus using Master Slave swept source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bradu, Adrian; Kapinchev, Konstantin; Barnes, Fred; Garway-Heath, David F.; Rajendram, Ranjan; Keane, Pearce; Podoleanu, Adrian G.

    2015-03-01

    Recently, we introduced a novel Optical Coherence Tomography (OCT) method, termed as Master Slave OCT (MS-OCT), specialized for delivering en-face images. This method uses principles of spectral domain interfereometry in two stages. MS-OCT operates like a time domain OCT, selecting only signals from a chosen depth only while scanning the laser beam across the eye. Time domain OCT allows real time production of an en-face image, although relatively slowly. As a major advance, the Master Slave method allows collection of signals from any number of depths, as required by the user. The tremendous advantage in terms of parallel provision of data from numerous depths could not be fully employed by using multi core processors only. The data processing required to generate images at multiple depths simultaneously is not achievable with commodity multicore processors only. We compare here the major improvement in processing and display, brought about by using graphic cards. We demonstrate images obtained with a swept source at 100 kHz (which determines an acquisition time [Ta] for a frame of 200×200 pixels2 of Ta =1.6 s). By the end of the acquired frame being scanned, using our computing capacity, 4 simultaneous en-face images could be created in T = 0.8 s. We demonstrate that by using graphic cards, 32 en-face images can be displayed in Td 0.3 s. Other faster swept source engines can be used with no difference in terms of Td. With 32 images (or more), volumes can be created for 3D display, using en-face images, as opposed to the current technology where volumes are created using cross section OCT images.

  18. The Diagnostic Accuracy of Optical Coherence Tomography Angiography for Neovascular Age-Related Macular Degeneration: A Comparison with Fundus Fluorescein Angiography.

    PubMed

    Gong, Jingwen; Yu, Suqin; Gong, Yuanyuan; Wang, Fenghua; Sun, Xiaodong

    2016-01-01

    Purpose. To describe the morphological characteristics and efficacy of OCTA in detecting CNV in nAMD. We retrospectively reviewed 53 patients (86 eyes) with suspected CNV secondary to wet AMD. All the patients underwent a multimodal assessment for CNV. Two independent readers calculated the sensitivity and specificity of OCTA in detecting CNV compared with FA. A qualitative analysis of OCTA was also performed to describe the morphological appearance of CNV. Among 86 eyes of 53 patients, 52 eyes were diagnosed as having CNV based on the FA imaging analysis. According to FA, CNV was classified as classic in 28 eyes, predominantly classic in 6 eyes, minimally classic in 9 eyes, and occult in 9 eyes. In 56 eyes, CNV was visualized on OCTA and corresponding OCT B-scans. In total, 46.4% (26/56) had well-circumscribed vessels, and 53.6% (30/56) showed poorly circumscribed vessels. There were 11 false positives and 7 false negatives using OCTA. The specificity of OCTA for the detection of CNV was 67.6%, with sensitivity of 86.5%. OCTA may help in the noninvasive diagnosis of CNV and may provide a method for monitoring the evolution of CNV. PMID:27110394

  19. A method to assist in the diagnosis of early diabetic retinopathy: Image processing applied to detection of microaneurysms in fundus images.

    PubMed

    Rosas-Romero, Roberto; Martínez-Carballido, Jorge; Hernández-Capistrán, Jonathan; Uribe-Valencia, Laura J

    2015-09-01

    Diabetes increases the risk of developing any deterioration in the blood vessels that supply the retina, an ailment known as Diabetic Retinopathy (DR). Since this disease is asymptomatic, it can only be diagnosed by an ophthalmologist. However, the growth of the number of ophthalmologists is lower than the growth of the population with diabetes so that preventive and early diagnosis is difficult due to the lack of opportunity in terms of time and cost. Preliminary, affordable and accessible ophthalmological diagnosis will give the opportunity to perform routine preventive examinations, indicating the need to consult an ophthalmologist during a stage of non proliferation. During this stage, there is a lesion on the retina known as microaneurysm (MA), which is one of the first clinically observable lesions that indicate the disease. In recent years, different image processing algorithms, which allow the detection of the DR, have been developed; however, the issue is still open since acceptable levels of sensitivity and specificity have not yet been reached, preventing its use as a pre-diagnostic tool. Consequently, this work proposes a new approach for MA detection based on (1) reduction of non-uniform illumination; (2) normalization of image grayscale content to improve dependence of images from different contexts; (3) application of the bottom-hat transform to leave reddish regions intact while suppressing bright objects; (4) binarization of the image of interest with the result that objects corresponding to MAs, blood vessels, and other reddish objects (Regions of Interest-ROIs) are completely separated from the background; (5) application of the hit-or-miss Transformation on the binary image to remove blood vessels from the ROIs; (6) two features are extracted from a candidate to distinguish real MAs from FPs, where one feature discriminates round shaped candidates (MAs) from elongated shaped ones (vessels) through application of Principal Component Analysis (PCA); (7) the second feature is a count of the number of times that the radon transform of the candidate ROI, evaluated at the set of discrete angle values {0°, 1°, 2°, …, 180°}, is characterized by a valley between two peaks. The proposed approach is tested on the public databases DiaretDB1 and Retinopathy Online Challenge (ROC) competition. The proposed MA detection method achieves sensitivity, specificity and precision of 92.32%, 93.87% and 95.93% for the diaretDB1 database and 88.06%, 97.47% and 92.19% for the ROC database. Theory, results, challenges and performance related to the proposed MA detecting method are presented. PMID:26245720

  20. The Diagnostic Accuracy of Optical Coherence Tomography Angiography for Neovascular Age-Related Macular Degeneration: A Comparison with Fundus Fluorescein Angiography

    PubMed Central

    Yu, Suqin; Wang, Fenghua

    2016-01-01

    Purpose. To describe the morphological characteristics and efficacy of OCTA in detecting CNV in nAMD. We retrospectively reviewed 53 patients (86 eyes) with suspected CNV secondary to wet AMD. All the patients underwent a multimodal assessment for CNV. Two independent readers calculated the sensitivity and specificity of OCTA in detecting CNV compared with FA. A qualitative analysis of OCTA was also performed to describe the morphological appearance of CNV. Among 86 eyes of 53 patients, 52 eyes were diagnosed as having CNV based on the FA imaging analysis. According to FA, CNV was classified as classic in 28 eyes, predominantly classic in 6 eyes, minimally classic in 9 eyes, and occult in 9 eyes. In 56 eyes, CNV was visualized on OCTA and corresponding OCT B-scans. In total, 46.4% (26/56) had well-circumscribed vessels, and 53.6% (30/56) showed poorly circumscribed vessels. There were 11 false positives and 7 false negatives using OCTA. The specificity of OCTA for the detection of CNV was 67.6%, with sensitivity of 86.5%. OCTA may help in the noninvasive diagnosis of CNV and may provide a method for monitoring the evolution of CNV. PMID:27110394

  1. The Application of Wavelet-Domain Hidden Markov Tree Model in Diabetic Retinal Image Denoising

    PubMed Central

    Cui, Dong; Liu, Minmin; Hu, Lei; Liu, Keju; Guo, Yongxin; Jiao, Qing

    2015-01-01

    The wavelet-domain Hidden Markov Tree Model can properly describe the dependence and correlation of fundus angiographic images’ wavelet coefficients among scales. Based on the construction of the fundus angiographic images Hidden Markov Tree Models and Gaussian Mixture Models, this paper applied expectation-maximum algorithm to estimate the wavelet coefficients of original fundus angiographic images and the Bayesian estimation to achieve the goal of fundus angiographic images denoising. As is shown in the experimental result, compared with the other algorithms as mean filter and median filter, this method effectively improved the peak signal to noise ratio of fundus angiographic images after denoising and preserved the details of vascular edge in fundus angiographic images. PMID:26628926

  2. Nonmydriatic retinal photography in the evaluation of acute neurologic conditions

    PubMed Central

    Bidot, Samuel; Bruce, Beau B.; Newman, Nancy J.; Biousse, Valérie

    2013-01-01

    Summary Ocular fundus examination is a fundamental component of the neurologic examination. Finding papilledema in headache patients or retinal arterial emboli in stroke patients can be extremely useful. Although examination of the ocular fundus with a direct ophthalmoscope is an important skill for all neurologists, it is rarely and unreliably performed. Nonmydriatic ocular fundus photography, which allows direct visualization of high-quality photographs of the ocular fundus, has been recently proposed for screening neurologic patients in urgent care settings such as emergency departments. This new technology has many potential applications in neurology, including e-transmission of images for remote interpretation. PMID:24353924

  3. Intensified charge-coupled-device-based eyetracker and image stabilizer.

    PubMed

    Milbocker, M T; Feke, G T

    1992-07-01

    An electro-optical eyetracker measures eye movement to stabilize a laser beam on the fundus in one dimension. Motion is detected by laser illumination of a fundus feature. The illuminated area is imaged on an intensified linear CCD. Electronics determine the intensity centroid of this image. Centroid motion on the CCD corresponds to eye movement in one dimension. Galvanometer-controlled mirrors reposition (at a 1-kHz rate) the illuminating beam on the fundus. The same mirrors reposition the centroid at the CCD center. Additional beams are also stabilized on the fundus. For typical fixational eye movement amplitudes and frequencies the beams follow the fundus feature within +/-10 microm. PMID:20725345

  4. The demise of direct ophthalmoscopy

    PubMed Central

    Mackay, Devin D.; Garza, Philip S.; Bruce, Beau B.; Newman, Nancy J.; Biousse, Valérie

    2015-01-01

    Summary Ocular funduscopy appears to be a dying art. Physicians and medical students alike lack confidence in the use of an ophthalmoscope. As a result, few clinicians perform ophthalmoscopy, and many who do are unable to reliably detect abnormalities of the ocular fundus. Approaches to remediation in undergraduate medical education have included simulators, longitudinal skill reinforcement, Web-based teaching, and other techniques. Preservation of the ophthalmoscopic art has been hindered by technical difficulty, waning enthusiasm for ophthalmoscopy, and even discouragement from preceptors in medical education. Ocular fundus photography may serve a role in medical education to help improve student confidence in interpretation of ocular fundus findings and improve awareness of the importance of examination of the ocular fundus. Because neurology clerkships and clinical practices remain an important forum for honing ocular funduscopy skills, the neurologist should be familiar with novel alternative techniques that facilitate examination of the ocular fundus. PMID:26137422

  5. Comparison Among Methods of Retinopathy Assessment (CAMRA) Study

    PubMed Central

    Ryan, Martha E.; Rajalakshmi, Ramachandran; Prathiba, Vijayaraghavan; Anjana, Ranjit Mohan; Ranjani, Harish; Narayan, K.M. Venkat; Olsen, Timothy W.; Mohan, Viswanathan; Ward, Laura A.; Lynn, Michael J.; Hendrick, Andrew M.

    2015-01-01

    Purpose We compared smartphone fundus photography, nonmydriatic fundus photography, and 7-field mydriatic fundus photography for their abilities to detect and grade diabetic retinopathy (DR). Design This was a prospective, comparative study of 3 photography modalities. Participants Diabetic patients (n = 300) were recruited at the ophthalmology clinic of a tertiary diabetes care center in Chennai, India. Methods Patients underwent photography by all 3 modalities, and photographs were evaluated by 2 retina specialists. Main Outcome Measures The sensitivity and specificity in the detection of DR for both smartphone and nonmydriatic photography were determined by comparison with the standard method, 7-field mydriatic fundus photography. Results The sensitivity and specificity of smartphone fundus photography, compared with 7-field mydriatic fundus photography, for the detection of any DR were 50% (95% confidence interval [CI], 43–56) and 94% (95% CI, 92–97), respectively, and of nonmydriatic fundus photography were 81% (95% CI, 75–86) and 94% (95% CI, 92–96%), respectively. The sensitivity and specificity of smartphone fundus photography for the detection of vision-threatening DR were 59% (95% CI, 46–72) and 100% (95% CI, 99–100), respectively, and of nonmydriatic fundus photography were 54% (95% CI, 40–67) and 99% (95% CI, 98–100), respectively. Conclusions Smartphone and nonmydriatic fundus photography are each able to detect DR and sight-threatening disease. However, the nonmydriatic camera is more sensitive at detecting DR than the smartphone. At this time, the benefits of the smartphone (connectivity, portability, and reduced cost) are not offset by the lack of sufficient sensitivity for detection of DR in most clinical circumstances. PMID:26189190

  6. Double-mirror peripheral vitrectomy lens.

    PubMed

    Ohji, M; Tano, Y

    1995-11-01

    Many surgeons use prism lenses to see the periphery of the fundus during vitrectomy; however, chromatic aberrations in higher-power prismatic lenses cause blurring of the peripheral image. For better visualization of the periphery of the fundus, we developed a new contact lens, the double-mirror peripheral vitrectomy lens. The new lens is a quartz cylinder with two mirrors, and it provides a crisp, clear, upright image of much more of the peripheral fundus than is visible through conventional prism lenses. The new lens also provides a wider area of view than conventional prism lenses. PMID:7487611

  7. [Combination of measurement of retinal vascular caliber, adaptive optics and fluorescent angiography in early diagnosis and monitoring of diabetic and hypertensive retinopathy].

    PubMed

    Stepushina, O A; Bol'shunov, A V

    2011-01-01

    15 patients with diabetic and hypertensive retinopathy are examined. Retinal vascular caliber was measured using adaptive multifocal fundus camera (AMFC), fundus camera "Topcon" TRS-NW200 and FAG. Combination of retinal vascular caliber measurement and fundus foto using AMFC in patients with ametropia and astigmatismus showed apparently lower arteriolovenular coefficient (A VC) compared with that estimated using FAG imaging. Retinal vascular caliber measurement using adaptive optics is a highly sensitive method of visualization and monitoring of early signs of diabetic and hypertensive retinopathy. PMID:21721269

  8. A new species of bright-eyed treefrog (Mantellidae) from Madagascar, with comments on call evolution and patterns of syntopy in the Boophis ankaratra complex.

    PubMed

    Hutter, Carl R; Lambert, Shea M; Cobb, Kerry A; Andriampenomanana, Zo Faniry; Vences, Miguel

    2015-01-01

    We describe a new species of Boophis treefrog from Ranomafana National Park in the southern central east of Madagascar. This region has remarkably high anuran diversity, and along with neighbouring sites, hosts more than 35 Boophis species. Boophis boppa sp. nov. is part of the B. ankaratra sub-clade (herein named the B. ankaratra complex), previously identified within the monophyletic B. albipunctatus species group. It occurs sympatrically with two other species of the complex (B. ankaratra and B. schuboeae). Morphological differentiation of species within the B. ankaratra clade remains elusive, but species are well characterized by distinct advertisement calls, with B. boppa having the longest note duration and inter-note intervals when compared to closely related species. Furthermore, it has moderate differentiation in mitochondrial DNA, with pairwise distances of 1.9-3.7% to all other species in sequences of the mitochondrial 16S rRNA marker. Additional evidence is given by the lack of haplotype sharing with related species for the nuclear exon DNAH-3. All examples of syntopic occurrence in this complex involve species with strongly different advertisement calls, while allopatric species have more similar calls. Such a pattern might result from adaptive call co-evolution but could also be the result of non-adaptive processes. Thorough clarification of the systematics of the B. ankaratra sub-clade is required, and we outline future directions for both bioacoustic and genetic research. PMID:26624456

  9. 21 CFR 886.1380 - Diagnostic condensing lens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... that produces an inverted or reversed direct magnified image of the eye) intended to focus reflected light from the fundus of the eye. (b) Classification. Class I (general controls). The device is...

  10. 21 CFR 886.1380 - Diagnostic condensing lens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... that produces an inverted or reversed direct magnified image of the eye) intended to focus reflected light from the fundus of the eye. (b) Classification. Class I (general controls). The device is...

  11. Multimodal Ultrawide-Field Imaging Features in Waardenburg Syndrome.

    PubMed

    Choudhry, Netan; Rao, Rajesh C

    2015-06-01

    A 45-year-old woman was referred for bilateral irregular fundus pigmentation. Dilated fundus examination revealed irregular hypopigmentation posterior to the equator in both eyes, confirmed by fundus autofluorescence. A thickened choroid was seen on enhanced-depth imaging spectral-domain optical coherence tomography (EDI SD-OCT). Systemic evaluation revealed sensorineural deafness, telecanthus, and a white forelock. Further investigation revealed a first-degree relative with Waardenburg syndrome. Waardenburg syndrome is characterized by a group of features including telecanthus, a broad nasal root, synophrys of the eyebrows, piedbaldism, heterochromia irides, and deafness. Choroidal hypopigmentation is a unique feature that can be visualized with ultrawide-field fundus autofluorescence. The choroid may also be thickened and its thickness measured with EDI SD-OCT. PMID:26114849

  12. Ophthalmoscopy

    MedlinePlus

    ... of the eye (fundus), which includes the retina , optic disc, choroid , and blood vessels. How the Test ... Normal Results The retina, blood vessels, and the optic disc appear normal. What Abnormal Results Mean Abnormal ...

  13. Overcoming the resolution limit in retinal imaging using the scattering properties of the sclera (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Carpentras, Dino; Laforest, Timothé; Psaltis, Demetri; Moser, Christophe

    2016-03-01

    In-vivo imaging of the eye's fundus is widely used to study eye's health. State of the art Adaptive Optics devices can resolve features up to a lateral resolution of 1.5 um. This resolution is still above what is needed to observe sub-cellular structures such as cone cells (1-1.25 um diameter). This limit in resolution is due to the small numerical aperture of the eye when the pupil is fully dilated (max 0.24). In our work, we overcome this limit using a non-standard illumination scheme. A laser beam is shined on the lateral choroid layer, whose scattered light is illuminating the eye's fundus. Thanks to a Spatial Light Modulator the scattered light from the choroid layer can be manipulated to produce a scanning focus spot on the fundus. The intensity of the reflected light from the fundus is collected from the pupil and used for reconstructing the image.

  14. Scanning technique for tracking small eye-movements

    NASA Technical Reports Server (NTRS)

    Kelly, D. H.; Crane, H. D.

    1972-01-01

    Scanning technique images spot of blue light on fundus, measures variations in reflectance of spot and compares reflectance pattern with a stored reference pattern. Method then converts the difference from stored pattern into infrared eye motion.

  15. LASER BIOLOGY AND MEDICINE: A laser-spectroscopy system for fluorescent diagnostics and photodynamic therapy of diseases of eye retina and choroid

    NASA Astrophysics Data System (ADS)

    Meerovich, G. A.; Shevchik, S. A.; Loshchenov, M. V.; Budzinskaya, M. V.; Ermakova, N. A.; Kharnas, S. S.

    2002-11-01

    A laser-spectroscopy system for the fluorescent diagnostics and photodynamic therapy of pathologic eye-fundus changes combined with the use of the Photosens compound is developed. The system is tested on experimental animals (mice and rabbits).

  16. Endogenous bacterial endophthalmitis masquerading as an intraocular tumor

    PubMed Central

    Salvetti, Anna Paola; Pellegrini, Marco; Bottoni, Ferdinando; Staurenghi, Giovanni

    2015-01-01

    A 40-year-old female patient referred for a possible intraocular tumor was found to have an endogenous bacterial endophthalmitis in her right eye. Fundus examination revealed an amelanotic dome shaped choroidal mass and an exudative retinal detachment. Enhanced Depth Imaging-Optical Coherence Tomography (EDI-OCT), fundus autofluorescence (FAF) and ultrasounds were suggestive of a possible choroidal melanoma. A multimodal imaging approach and a thorough anamnesis were instrumental in establishing the correct diagnosis. PMID:26949365

  17. Differential Diagnosis of Retinal Vasculitis

    PubMed Central

    Abu El-Asrar, Ahmed M.; Herbort, Carl P.; Tabbara, Khalid F.

    2009-01-01

    Retinal vaculitis is a sight-threatening inflammatory eye condition that involves the retinal vessels. Detection of retinal vasculitis is made clinically, and confirmed with the help of fundus fluorescein angiography. Active vascular disease is characterized by exudates around retinal vessels resulting in white sheathing or cuffing of the affected vessels. In this review, a practical approach to the diagnosis of retinal vasculitis is discussed based on ophthalmoscopic and fundus fluorescein angiographic findings. PMID:20404987

  18. Understanding and Facing Discipline-Related Challenges in the English as a Foreign Language Classroom at Public Schools (Comprensión y tratamiento de los retos asociados a la disciplina en el aula de lengua extranjera en escuelas públicas)

    ERIC Educational Resources Information Center

    Quintero Corzo, Josefina; Ramírez Contreras, Odilia

    2011-01-01

    Complying with school regulations and teachers' instructions is a basic principle of an excellent class; both novice and experienced teachers face challenging situations when getting into real classrooms, especially those related to classroom management. There are various reasons that explain discipline problems in public schools, as well as…

  19. Para Candidatos en Programas de Centros de Cuidado y Educacion Infantil con Bebes y "Toddlers": Asociado en Desarrollo Infantil Sistema de Evaluacion y Normas de Competencia CDA (Infant/Toddler Caregivers in Center-Based Programs: The Child Development Associate Assessment System and Competency Standards).

    ERIC Educational Resources Information Center

    Council for Early Childhood Professional Recognition, Washington, DC.

    This Spanish-language booklet outlines the requirements of the Child Development Associate (CDA) credential for caregivers working in center-based infant and toddler day care programs. Part 1 provides an overview of the CDA credentialing system and the various options, settings, standards, and stages of the CDA assessment system. Part 2 explains…

  20. Para Candidatos en Programas de Centros de Cuidado y Educacion Infantil con Ninos de Edad Pre-escolar: Asociado en Desarrollo Infantil Sistema de Evaluacion y Normas de Competencia CDA (Preschool Caregivers in Center-Based Programs: The Child Development Associate Assessment System and Competency Standards).

    ERIC Educational Resources Information Center

    Council for Early Childhood Professional Recognition, Washington, DC.

    This Spanish-language booklet outlines the requirements of the Child Development Associate (CDA) credential for preschool teachers or caregivers who work in center-based preschool day care programs. Part 1 provides an overview of the CDA credentialing system and the various options, settings, standards, and stages of the CDA assessment system.…

  1. Juegos - Cuentos - Cantos - Y - Rimas. Programa Piloto de Entrenamiento Para El Asociado Bilinque y Bicultural En El Desarrollo del Nino: Guia XII [Games - Stories - Songs -And - Rhymes. Pilot Program for the Training of Bilingual and Bicultural Teachers for the Cognitive Development of the Child: Guide XII].

    ERIC Educational Resources Information Center

    de Celis, Margarita

    This Child Development Associate (CDA) training module, the twelfth in a series of 16, is designed for preschool teachers and paraprofessional trainees and contains (in four separate sections) games, stories, songs and rhymes in Spanish that can be used in a bilingual, multicultural classroom setting. The module, written in Spanish, offers…

  2. Artesanias Mexico - Americanas. Programa Piloto de Entrenamiento Para El Asociado Bilingue y Bicultural En El Desarrollo del Nino: Guia XIII [Arts and Crafts of Mexico and the Americas. Pilot Program for the Training of Bilingual and Bicultural Teachers for the Cognitive Development of the Child: Guide XIII].

    ERIC Educational Resources Information Center

    de Celis, Margarita

    This Child Development Associate (CDA) training module, the thirteenth in a series of 16, provides creative experiences with arts and crafts for young children. Designed for preschool teachers and paraprofessional trainees, the Spanish text offers a variety of craft activities. A list of materials necessary, step-by-step directions and…

  3. Multispectral retinal image analysis: a novel non-invasive tool for retinal imaging

    PubMed Central

    Calcagni, A; Gibson, J M; Styles, I B; Claridge, E; Orihuela-Espina, F

    2011-01-01

    Purpose To develop a non-invasive method for quantification of blood and pigment distributions across the posterior pole of the fundus from multispectral images using a computer-generated reflectance model of the fundus. Methods A computer model was developed to simulate light interaction with the fundus at different wavelengths. The distribution of macular pigment (MP) and retinal haemoglobins in the fundus was obtained by comparing the model predictions with multispectral image data at each pixel. Fundus images were acquired from 16 healthy subjects from various ethnic backgrounds and parametric maps showing the distribution of MP and of retinal haemoglobins throughout the posterior pole were computed. Results The relative distributions of MP and retinal haemoglobins in the subjects were successfully derived from multispectral images acquired at wavelengths 507, 525, 552, 585, 596, and 611 nm, providing certain conditions were met and eye movement between exposures was minimal. Recovery of other fundus pigments was not feasible and further development of the imaging technique and refinement of the software are necessary to understand the full potential of multispectral retinal image analysis. Conclusion The distributions of MP and retinal haemoglobins obtained in this preliminary investigation are in good agreement with published data on normal subjects. The ongoing development of the imaging system should allow for absolute parameter values to be computed. A further study will investigate subjects with known pathologies to determine the effectiveness of the method as a screening and diagnostic tool. PMID:21904394

  4. Early and sustained treatment modifies the phenotype of birdshot retinochoroiditis.

    PubMed

    Knecht, Pascal B; Papadia, Marina; Herbort, Carl P

    2014-06-01

    In this single-centre retrospective case review, we investigate the long-term follow-up of birdshot retinochoroiditis (BRC) patients, analysing the impact of early, vigorous, and prolonged treatment on the evolution of indocyanine green angiography (ICGA) signs and fundus appearance. Treatment delay was calculated for each BRC patient, and patients were classified into two groups--treatment delay of <10 months (early-treatment group) and treatment delay of >10 months (delayed-treatment group). Fundus photographs and ICGA frames from the initial visit and from the last follow-up visit were assessed. Fundus photographs were evaluated for the presence of at least three circumpapillary, typical, rice-shaped birdshot lesions in one eye, inferior or nasal to the optic disc. ICGA pictures were evaluated for the presence of lesions (hypofluorescent dark dots, fuzziness). Differences were compared between the two groups and between the first visit and the last follow-up visit. In the early-treatment group, 5/6 patients had no characteristic BRC fundus lesions, but 7/7 patients in the delayed-treatment group displayed typical lesions. At last follow-up, 5/6 early-treatment patients showed no fundus lesions, and 6/7 delayed-treatment patients retained their fundus lesions. At presentation, all 13 patients exhibited lesions on ICGA. At last follow-up, ICGA lesions had completely disappeared in 4/6 early-treatment patients and 3/7 delayed-treatment patients. Thus, early and sufficiently dosed inflammation-suppressive treatment can prevent the appearance of typical BRC fundus lesions. It is therefore crucial to perform ICGA to detect otherwise occult stromal choroiditis in suspected BRC cases and to initiate adequate therapy immediately. PMID:24081916

  5. La distribución multimodal de cúmulos globulares en la galaxia NGC 1399

    NASA Astrophysics Data System (ADS)

    Forte, J. C.; Ostrov, P. G.

    Se presenta una discusión de las características del diagrama de dos colores para un muestreo de 400 cúmulos globulares asociados con NGC 1399. Los resultados indican la presencia de, por lo menos, tres familias de cúmulos. La naturaleza de una cuarta componente, muy azul, no es clara aunque podría tratarse de cúmulos ``sueltos" asociados con el sistema de Fornax.

  6. Application of different imaging modalities for diagnosis of Diabetic Macular Edema: A review.

    PubMed

    Mookiah, Muthu Rama Krishnan; Acharya, U Rajendra; Fujita, Hamido; Tan, Jen Hong; Chua, Chua Kuang; Bhandary, Sulatha V; Laude, Augustinus; Tong, Louis

    2015-11-01

    Diabetic Macular Edema (DME) is caused by accumulation of extracellular fluid from hyperpermeable capillaries within the macula. DME is one of the leading causes of blindness among Diabetes Mellitus (DM) patients. Early detection followed by laser photocoagulation can save the visual loss. This review discusses various imaging modalities viz. biomicroscopy, Fluorescein Angiography (FA), Optical Coherence Tomography (OCT) and colour fundus photographs used for diagnosis of DME. Various automated DME grading systems using retinal fundus images, associated retinal image processing techniques for fovea, exudate detection and segmentation are presented. We have also compared various imaging modalities and automated screening methods used for DME grading. The reviewed literature indicates that FA and OCT identify DME related changes accurately. FA is an invasive method, which uses fluorescein dye, and OCT is an expensive imaging method compared to fundus photographs. Moreover, using fundus images DME can be identified and automated. DME grading algorithms can be implemented for telescreening. Hence, fundus imaging based DME grading is more suitable and affordable method compared to biomicroscopy, FA, and OCT modalities. PMID:26453760

  7. Improvement of a snapshot spectroscopic retinal multi-aperture imaging camera

    NASA Astrophysics Data System (ADS)

    Lemaillet, Paul; Lompado, Art; Ramella-Roman, Jessica C.

    2009-02-01

    Measurement of oxygen saturation has proved to give important information about the eye health and the onset of eye pathologies such as Diabetic Retinopathy. Recently, we have presented a multi-aperture system enabling snapshot acquisition of human fundus images at six different wavelengths. In our setup a commercial fundus ophthalmoscope was interfaced with the multi-aperture system to acquire spectroscopic sensitive images of the retina vessel, thus enabling assessment of the oxygen saturation in the retina. Snapshot spectroscopic acquisition is meant to minimize the effects of eye movements. Higher measurement accuracy can be achieved by increasing the number of wavelengths at which the fundus images are taken. In this study we present an improvement of our setup by introducing an other multi-aperture camera that enables us to take snapshot images of the fundus at nine different wavelengths. Careful consideration is taken to improve image transfer by measuring the optical properties of the fundus camera used in the setup and modeling the optical train in Zemax.

  8. The effect of uterine motion and uterine margins on target and normal tissue doses in intensity modulated radiation therapy of cervical cancer

    NASA Astrophysics Data System (ADS)

    Gordon, J. J.; Weiss, E.; Abayomi, O. K.; Siebers, J. V.; Dogan, N.

    2011-05-01

    In intensity modulated radiation therapy (IMRT) of cervical cancer, uterine motion can be larger than cervix motion, requiring a larger clinical target volume to planning target volume (CTV-to-PTV) margin around the uterine fundus. This work simulates different motion models and margins to estimate the dosimetric consequences. A virtual study used image sets from ten patients. Plans were created with uniform margins of 1 cm (PTVA) and 2.4 cm (PTVC), and a margin tapering from 2.4 cm at the fundus to 1 cm at the cervix (PTVB). Three inter-fraction motion models (MM) were simulated. In MM1, all structures moved with normally distributed rigid body translations. In MM2, CTV motion was progressively magnified as one moved superiorly from the cervix to the fundus. In MM3, both CTV and normal tissue motion were magnified as in MM2, modeling the scenario where normal tissues move into the void left by the mobile uterus. Plans were evaluated using static and percentile DVHs. For a conventional margin (PTVA), quasi-realistic uterine motion (MM3) reduces fundus dose by about 5 Gy and increases normal tissue volumes receiving 30-50 Gy by ~5%. A tapered CTV-to-PTV margin can restore fundus and CTV doses, but will increase normal tissue volumes receiving 30-50 Gy by a further ~5%.

  9. Precise modelling of the eye for proton therapy of intra-ocular tumours

    NASA Astrophysics Data System (ADS)

    Dobler, Barbara; Bendl, Rolf

    2002-02-01

    A new method is described that allows precise modelling of organs at risk and target volume for radiation therapy of intra-ocular tumours. The aim is to optimize the dose distribution and thus to reduce normal tissue complication probability. A geometrical 3D model based on elliptic shapes was developed that can be used for multimodal model-based segmentation of 3D patient data. The tumour volume cannot be clearly identified in CT and MR data, whereas the tumour outline can be discriminated very precisely in fundus photographs. Therefore, a multimodal 2D fundus diagram was developed, which allows us to correlate and display simultaneously information extracted from the eye model, 3D data and the fundus photograph. Thus, the connection of fundus diagram and 3D data is well-defined and the 3D volume can be calculated directly from the tumour outline drawn onto the fundus photograph and the tumour height measured by ultrasound. The method allows the calculation of a precise 3D eye model of the patient, including the different structures of the eye as well as the tumour volume. The method was developed as part of the new 3D treatment planning system OCTOPUS for proton therapy of ocular tumours within a national research project together with the Hahn-Meitner-Institut Berlin.

  10. Retinal pigment epithelial detachments and tears, and progressive retinal degeneration in light chain deposition disease

    PubMed Central

    Spielberg, Leigh H; Heckenlively, John R; Leys, Anita M

    2013-01-01

    Background/purpose Light-chain deposition disease (LCDD) is a rare condition characterised by deposition of monoclonal immunoglobulin light chains (LCs) in tissues, resulting in varying degrees of organ dysfunction. This study reports the characteristic clinical ocular findings seen in advanced LCDD upon development of ocular fundus changes. This is the first report to describe this entity in vivo in a series of patients. Methods A case series of ocular fundus changes in three patients with kidney biopsy-proven LCDD. All patients underwent best corrected visual acuity (BCVA) exam, perimetry, colour fundus photography and fluorescein angiography; two patients underwent indocyanine green angiography, optical coherence tomography, ultrasound and electroretinography; and one patient underwent fundus autofluorescence. Results Three patients, 53–60 years old at initial presentation, were studied. All three presented with night blindness, poor dark adaptation, metamorphopsia and visual loss. Examination revealed serous and serohaemorrhagic detachments, multiple retinal pigment epithelial (RPE) tears, diffuse RPE degeneration and progressive fibrotic changes. Neither choroidal neovascularisation nor other vascular abnormalities were present. Final best corrected visual acuity (BCVA) ranged from 20/40 to 20/300. Conclusions Progressive LC deposition in the fundus seems to damage RPE pump function with flow disturbance between choroid and retina. This pathogenesis can explain the evolution to RPE detachments and subsequent rips and progressive retinal malfunction. PMID:23385633

  11. Diversity of the strongly rheophilous tadpoles of Malagasy tree frogs, genus Boophis (Anura, Mantellidae), and identification of new candidate species via larval DNA sequence and morphology

    PubMed Central

    Randrianiaina, Roger Daniel; Strauß, Axel; Glos, Julian; Vences, Miguel

    2012-01-01

    Abstract This study provides detailed morphological descriptions of previously unknown tadpoles of the treefrog genus Boophis Tschudi and analyses of habitat preferences of several of these tadpoles in Ranomafana National Park. A total of twenty-two tadpoles determined via DNA barcoding are characterized morphologically herein, fourteen of them for the first time. Twelve of these tadpoles belong to taxonomically undescribed candidate species which in several cases are so far only known from their larval stages. Our data show that the larvae of some of these candidate species occur syntopically yet maintaining a clearly correlated genetic and morphological identity, suggesting that they indeed are true biological and evolutionary species. Tadpoles considered to belong to the “adherent” ecomorphological guild inhabit fast-running waters and their oral disc is commonly to continuously attached to the rocky substrate, supposedly to keep their position in the water current. Some of these species are characterized by the presence of a dorsal gap of papillae and the absence of an upper jaw sheath. This guild includes the tadpoles of the Boophis albipuncatus group (Boophis ankaratra, Boophis schuboeae, Boophis albipunctatus, Boophis sibilans, Boophis luciae), and of the Boophis mandraka group (Boophis sambirano and six candidate species related to this species and to Boophis mandraka). Tadpoles considered belonging to the “suctorial” guild inhabit fast-running waters where they use frequently their oral disc to attach to the substrate. They have an enlarged oral disc without any dorsal gap, including two nominal species (Boophis marojezensis, Boophis vittatus), and five candidate species related to Boophis marojezensis. An ecological analysis of the tadpoles of Boophis luciae, Boophis schuboeae and Boophis marojezensis [Ca51 JQ518198] from Ranomafana National Park did not provide evidence for a clear preference of these tadpoles to the fast flowing microhabitat

  12. Diversity of the strongly rheophilous tadpoles of Malagasy tree frogs, genus Boophis (Anura, Mantellidae), and identification of new candidate species via larval DNA sequence and morphology.

    PubMed

    Randrianiaina, Roger Daniel; Strauß, Axel; Glos, Julian; Vences, Miguel

    2012-01-01

    This study provides detailed morphological descriptions of previously unknown tadpoles of the treefrog genus Boophis Tschudi and analyses of habitat preferences of several of these tadpoles in Ranomafana National Park. A total of twenty-two tadpoles determined via DNA barcoding are characterized morphologically herein, fourteen of them for the first time. Twelve of these tadpoles belong to taxonomically undescribed candidate species which in several cases are so far only known from their larval stages. Our data show that the larvae of some of these candidate species occur syntopically yet maintaining a clearly correlated genetic and morphological identity, suggesting that they indeed are true biological and evolutionary species. Tadpoles considered to belong to the "adherent" ecomorphological guild inhabit fast-running waters and their oral disc is commonly to continuously attached to the rocky substrate, supposedly to keep their position in the water current. Some of these species are characterized by the presence of a dorsal gap of papillae and the absence of an upper jaw sheath. This guild includes the tadpoles of the Boophis albipuncatus group (Boophis ankaratra, Boophis schuboeae, Boophis albipunctatus, Boophis sibilans, Boophis luciae), and of the Boophis mandraka group (Boophis sambirano and six candidate species related to this species and to Boophis mandraka). Tadpoles considered belonging to the "suctorial" guild inhabit fast-running waters where they use frequently their oral disc to attach to the substrate. They have an enlarged oral disc without any dorsal gap, including two nominal species (Boophis marojezensis, Boophis vittatus), and five candidate species related to Boophis marojezensis. An ecological analysis of the tadpoles of Boophis luciae, Boophis schuboeae and Boophis marojezensis [Ca51 JQ518198] from Ranomafana National Park did not provide evidence for a clear preference of these tadpoles to the fast flowing microhabitat sections of the

  13. Purtscher-Like Retinopathy Associated with Anorexia Nervosa.

    PubMed

    Karasu, Bugra; Gunay, Betul Onal; Erdogan, Gurkan; Kardes, Esra; Gunay, Murat

    2016-01-01

    A 21-year-old girl presented with acute painless vision loss in her right eye. There was no remarkable ocular history and she had a history of anorexia nervosa. At presentation best-corrected visual acuities were counting fingers from 2 meters and 20/20, in the right and left eyes, respectively. Slit lamp examination result was normal. Fundus examination revealed multiple cotton wool spots and intraretinal hemorrhages surrounding the optic disc and macula in the right eye. Fluorescein angiography showed capillary filling defect and leakage from optic disc in the late phase of the angiogram. One week later best-corrected visual acuities remained the same in both eyes with similar fundus appearance. One month after initial presentation visual acuity was 20/20 in both eyes with no abnormality in fundus appearance. PMID:27069703

  14. High-resolution retinal imaging through open-loop adaptive optics

    NASA Astrophysics Data System (ADS)

    Li, Chao; Xia, Mingliang; Li, Dayu; Mu, Quanquan; Xuan, Li

    2010-07-01

    Using the liquid crystal spatial light modulator (LC-SLM) as the wavefront corrector, an open-loop adaptive optics (AO) system for fundus imaging in vivo is constructed. Compared with the LC-SLM closed-loop AO system, the light energy efficiency is increased by a factor of 2, which is helpful for the safety of fundus illumination in vivo. In our experiment, the subjective accommodation method is used to precorrect the defocus aberration, and three subjects with different myopia 0, -3, and -5 D are tested. Although the residual wavefront error after correction cannot to detected, the fundus images adequately demonstrate that the imaging system reaches the resolution of a single photoreceptor cell through the open-loop correction. Without dilating and cyclopleging the eye, the continuous imaging for 8 s is recorded for one of the subjects.

  15. Automatic Detection of the Optic Disc of the Retina: A Fast Method.

    PubMed

    Jamshidi, M; Rabbani, H; Amini, Z; Kafieh, R; Ommani, A; Lakshminarayanan, V

    2016-01-01

    Localizing the optic disc (OD) in retinal fundus images is of critical importance and many techniques have been developed for OD detection. In this paper, we present the results obtained from two fast methods, correlation and least square, to approximate the location of optic cup. These methods are simple and are not complex, while most of the OD detection algorithms are. The methods were tested on two groups of data (a total of 100 color fundus images) and were 98% successful in the detection of the optic cup. An algorithm using the vessel mask of fundus images is proposed to be run after correlation to ensure that the localization of OD in all images is successful. It was tested on 40 of the test images and had a 100% rate of success. PMID:27014613

  16. A Probabilistic Framework for Content-Based Diagnosis of Retinal Disease

    SciTech Connect

    Tobin Jr, Kenneth William; Abdelrahman, Mohamed A; Chaum, Edward; Muthusamy Govindasamy, Vijaya Priya; Karnowski, Thomas Paul

    2007-01-01

    Diabetic retinopathy is the leading cause of blindness in the working age population around the world. Computer assisted analysis has the potential to assist in the early detection of diabetes by regular screening of large populations. The widespread availability of digital fundus cameras today is resulting in the accumulation of large image archives of diagnosed patient data that captures historical knowledge of retinal pathology. Through this research we are developing a content-based image retrieval method to verify our hypothesis that retinal pathology can be identified and quantified from visually similar retinal images in an image archive. We will present diagnostic results for specificity and sensitivity on a population of 395 fundus images representing the normal fundus and 14 stratified disease states.

  17. Grating visual evoked cortical potentials in the evaluation of laser bioeffects: instrumentation

    SciTech Connect

    Randolph, D.I.; Lund, D.J.; Van Sice, C.W.; Esgandarian, G.E.

    1982-12-01

    A system was designed to permit simultaneous viewing of the ocular fundus of the rhesus monkey (Macaca mulatta), the accurate placement of laser radiation on the retina, and the stimulation of the site to produce a grating visual evoked cortical potential (VECP). A fundus camera was modified to incorporate a grating whose image was projected onto the retina at specific locations. The evoked potential could thus be obtained for any rate of alternation before, during, and after the exposure of the fovea to any one of many laser sources. An example is shown of the use of this system to monitor the grating VECP before and after exposure of the animal's fundus to a 900 nm gallium arsenide laser source for 60 sec. In this case, changes were observed in the variability of the latency of components of the VECP when compared to the prelaser exposure potentials.

  18. Purtscher-Like Retinopathy Associated with Anorexia Nervosa

    PubMed Central

    Karasu, Bugra; Gunay, Betul Onal; Erdogan, Gurkan; Kardes, Esra; Gunay, Murat

    2016-01-01

    A 21-year-old girl presented with acute painless vision loss in her right eye. There was no remarkable ocular history and she had a history of anorexia nervosa. At presentation best-corrected visual acuities were counting fingers from 2 meters and 20/20, in the right and left eyes, respectively. Slit lamp examination result was normal. Fundus examination revealed multiple cotton wool spots and intraretinal hemorrhages surrounding the optic disc and macula in the right eye. Fluorescein angiography showed capillary filling defect and leakage from optic disc in the late phase of the angiogram. One week later best-corrected visual acuities remained the same in both eyes with similar fundus appearance. One month after initial presentation visual acuity was 20/20 in both eyes with no abnormality in fundus appearance. PMID:27069703

  19. Automatic assessment of macular edema from color retinal images.

    PubMed

    Deepak, K Sai; Sivaswamy, Jayanthi

    2012-03-01

    Diabetic macular edema (DME) is an advanced symptom of diabetic retinopathy and can lead to irreversible vision loss. In this paper, a two-stage methodology for the detection and classification of DME severity from color fundus images is proposed. DME detection is carried out via a supervised learning approach using the normal fundus images. A feature extraction technique is introduced to capture the global characteristics of the fundus images and discriminate the normal from DME images. Disease severity is assessed using a rotational asymmetry metric by examining the symmetry of macular region. The performance of the proposed methodology and features are evaluated against several publicly available datasets. The detection performance has a sensitivity of 100% with specificity between 74% and 90%. Cases needing immediate referral are detected with a sensitivity of 100% and specificity of 97%. The severity classification accuracy is 81% for the moderate case and 100% for severe cases. These results establish the effectiveness of the proposed solution. PMID:22167598

  20. Automatic Detection of the Optic Disc of the Retina: A Fast Method

    PubMed Central

    Jamshidi, M.; Rabbani, H.; Amini, Z.; Kafieh, R.; Ommani, A.; Lakshminarayanan, V.

    2016-01-01

    Localizing the optic disc (OD) in retinal fundus images is of critical importance and many techniques have been developed for OD detection. In this paper, we present the results obtained from two fast methods, correlation and least square, to approximate the location of optic cup. These methods are simple and are not complex, while most of the OD detection algorithms are. The methods were tested on two groups of data (a total of 100 color fundus images) and were 98% successful in the detection of the optic cup. An algorithm using the vessel mask of fundus images is proposed to be run after correlation to ensure that the localization of OD in all images is successful. It was tested on 40 of the test images and had a 100% rate of success. PMID:27014613

  1. Looking into the Eye with a Smartphone

    NASA Astrophysics Data System (ADS)

    Colicchia, Giuseppe; Wiesner, Hartmut

    2015-02-01

    Thanks to their sensors and the large number of apps available, smartphones can be used as a useful tool to carry out new laboratory experiments in physics.1-3 Such devices, very popular among young people, may be a successful approach to improve students' interest in the subject, particularly in a medical context. In addition to their small camera, smartphones usually have an integrated LED light source that is in line with the visual axis of the camera sensor. Using a smartphone, it is hence possible to take photos or videos of the fundus (retina) inside the eye through the pupil. We will explain the optical principles underlying the methods for observing the fundus of the eye (ophthalmoscopy) and describe how students can perform "fundus" photography on eye models using a smartphone.

  2. Stimulation of prostanoid IP and EP(2) receptors dilates retinal arterioles and increases retinal and choroidal blood flow in rats.

    PubMed

    Mori, Asami; Saito, Maki; Sakamoto, Kenji; Narita, Masami; Nakahara, Tsutomu; Ishii, Kunio

    2007-09-10

    We examined the effects of vasodilatory prostaglandins (prostacyclin and prostaglandin E(2)) and selective agonists for prostanoid EP(2) and EP(4) receptor on the diameters of retinal blood vessels and fundus (retinal/choroidal) blood flow in rats. Male Wistar rats (8- to 10-week-old) were treated with tetrodotoxin (50 microg/kg, i.v.) to eliminate any nerve activity and prevent movement of the eye and infused with a mixture solution of norepinephrine and epinephrine (1:9) to maintain adequate systemic circulation under artificial ventilation. Fundus images were captured with a digital camera that was equipped with the special objective lens for small animals, and the diameters of retinal arterioles and venules were measured on a personal computer. Fundus blood flow was estimated using a laser Doppler flowmetry. Intravenous infusions of prostacyclin and prostaglandin E(2) dilated retinal blood vessels, increased fundus blood flow and decreased systemic blood pressure in a dose-dependent manner. The effects of vasodilatory prostaglandins on retinal arterioles were greater than those on retinal venules. Similarly, a prostanoid EP(2) receptor agonist (ONO-AE1-259-01) dilated retinal blood vessels, and increased fundus blood flow and decreased systemic blood pressure. However, a prostanoid EP(4) receptor agonist (ONO-AE1-329) failed to increase fundus blood flow, despite its comparable depressor response with those to vasodilatory prostaglandins and the prostanoid EP(2) receptor agonist. The responses to forskolin, an activator of adenylyl cyclase, were very similar to those to prostacyclin and the prostanoid EP(2) receptor agonist. These results suggest that prostacyclin and prostaglandin E(2) act as vasodilators in retinal and choroidal circulation, and prostanoid IP and EP(2) receptors play an important role in the regulation of ocular hemodynamics in rats. PMID:17628525

  3. Age-dependent accumulation of lipofuscin in perivascular and subretinal microglia in experimental mice.

    PubMed

    Xu, Heping; Chen, Mei; Manivannan, Ayyakkannu; Lois, Noemi; Forrester, John V

    2008-01-01

    Fundus autofluorescence (AF) imaging by confocal scanning laser ophthalmoscopy has been widely used by ophthalmologists in the diagnosis/monitoring of various retinal disorders. It is believed that fundus AF is derived from lipofuscin in retinal pigment epithelial (RPE) cells; however, direct clinicopathological correlation has not been possible in humans. We examined fundus AF by confocal scanning laser ophthalmoscopy and confocal microscopy in normal C57BL/6 mice of different ages. Increasingly strong AF signals were observed with age in the neuroretina and subretinal/RPE layer by confocal scanning laser ophthalmoscopy. Unlike fundus AF detected in normal human subjects, mouse fundus AF appeared as discrete foci distributed throughout the retina. Most of the AF signals in the neuroretina were distributed around retinal vessels. Confocal microscopy of retinal and choroid/RPE flat mounts demonstrated that most of the AF signals were derived from Iba-1+ perivascular and subretinal microglia. An age-dependent accumulation of Iba-1+ microglia at the subretinal space was observed. Lipofuscin granules were detected in large numbers in subretinal microglia by electron microscopy. The number of AF+ microglia and the amount of AF granules/cell increased with age. AF granules/lipofuscin were also observed in RPE cells in mice older than 12 months, but the number of AF+ RPE cells was very low (1.48 mm(-2) and 5.02 mm(-2) for 12 and 24 months, respectively) compared to the number of AF+ microglial cells (20.63 mm(-2) and 76.36 mm(-2) for 6 and 24 months, respectively). The fluorescence emission fingerprints of AF granules in subretinal microglia were the same as those in RPE cells. Our observation suggests that perivascular and subretinal microglia are the main cells producing lipofuscin in normal aged mouse retina and are responsible for in vivo fundus AF. Microglia may play an important role in retinal aging and age-related retinal diseases. PMID:17988243

  4. Use of the argon aiming beam in visual function testing.

    PubMed

    Kelley, J S

    1978-12-01

    The aiming beam of the argon laser photocoagulator can be a useful tool in visual function testing. Applied with the slit lamp delivery system and fundus contact lens, it clearly documents the size of the blind spot surrounding the optic nerve head and the normal area of nonfunctional retina in the periphery. The size of pathologic field defects can be recorded on fundus photographs or retinal drawings by an observer. Safety precautions must be taken to protect all patients from excessive laser energy. PMID:736394

  5. Thermal macular injury from a 154 mW green laser pointer.

    PubMed

    Lim, Maria E; Suelzer, Joseph; Moorthy, Ramana S; Vemuri, Gautam

    2014-12-01

    We report a case of accidental thermal injury due to improper use of a laser pointer obtained outside of the United States. A 13-year-old received a laser pointer as a gift and looked at a reflection of the beam. The patient underwent full ophthalmologic examination with fundus photography, spectral domain optical coherence tomography, and fluorescein angiography. Visual acuity in the left eye was 20/100 at presentation. Fundus examination and ancillary tests were consistent with thermal macular injury. The laser pointer was analyzed and found to be a green diode laser with average power output of 154 mW. PMID:25448152

  6. Monte Carlo simulation of retinal light absorption by infants.

    PubMed

    Guo, Ya; Tan, Jinglu

    2015-02-01

    Retinal damage can occur in normal ambient lighting conditions. Infants are particularly vulnerable to retinal damage, and thousands of preterm infants sustain vision damage each year. The size of the ocular fundus affects retinal light absorption, but there is a lack of understanding of this effect for infants. In this work, retinal light absorption is simulated for different ocular fundus sizes, wavelengths, and pigment concentrations by using the Monte Carlo method. The results indicate that the neural retina light absorption per volume for infants can be two or more times that for adults. PMID:26366599

  7. Left paramedian abomasopexy in cattle.

    PubMed

    Lee, Inhyung; Yamagishi, Norio; Oboshi, Kenji; Yamada, Haruo

    2002-03-01

    Aims of surgery of left displacement of the abomasum (LDA) are to return the abomasum to its original position and create a permanent attachment in the position to prevent recurrence. Left paramedian abomasopexy was performed on six Holstein cows with LDA because normal position of the fundus of the abomasum is located in the left of the midline and the displacement initially only involves the fundus of the abomasum. All cows were recovered without recurrence of LDA. It is considered that the left paramedian abomasopexy could be a major alternative as a surgical treatment of LDA. PMID:14614273

  8. Wavelength scanning digital interference holography for high-resolution ophthalmic imaging

    NASA Astrophysics Data System (ADS)

    Potcoava, Mariana C.; Kim, M. K.; Kay, Christine N.

    2009-02-01

    An improved digital interference holography (DIH) technique suitable for fundus images is proposed. This technique incorporates a dispersion compensation algorithm to compensate for the unknown axial length of the eye. Using this instrument we acquired successfully tomographic fundus images in human eye with narrow axial resolution less than 5μm. The optic nerve head together with the surrounding retinal vasculature were constructed. We were able to quantify a depth of 84μm between the retinal fiber and the retinal pigmented epithelium layers. DIH provides high resolution 3D information which could potentially aid in guiding glaucoma diagnosis and treatment.

  9. Pitfalls in colour photography of choroidal tumours

    PubMed Central

    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

  10. Contemporary retinal imaging techniques in diabetic retinopathy: a review.

    PubMed

    Cole, Emily Dawn; Novais, Eduardo Amorim; Louzada, Ricardo Noguera; Waheed, Nadia K

    2016-05-01

    Over the last decade, there has been an expansion of imaging modalities available to clinicians to diagnose and monitor the treatment and progression of diabetic retinopathy. Recently, advances in image technologies related to OCT and OCT angiography have enabled improved visualization and understanding of this disease. In this review, we will describe the use of imaging techniques such as colour fundus photography, fundus autofluorescence, fluorescein angiography, infrared reflectance imaging, OCT, OCT-Angiography and techniques in adaptive optics and hyperspectral imaging in the diagnosis and management of diabetic retinopathy. PMID:26841250

  11. Birdshot chorioretinopathy in a male patient with facioscapulohumeral muscular dystrophy.

    PubMed

    Papavasileiou, Evangelia; Lobo, Ann-Marie

    2015-01-01

    We report a case of birdshot chorioretinopathy (BSCR) in a patient with facioscapulohumeral muscular dystrophy (FSHD). A 40-year-old male with history of facioscapulohumeral muscular dystrophy with significant facial diplegia and lagophthalmos presents for an evaluation of bilateral choroiditis with vasculitis and optic disc edema. Clinical examination included fundus and autofluorescence photographs, fluorescein angiography, and optical coherence tomography. To our knowledge, this patient represents the first reported case of birdshot chorioretinopathy with facioscapulohumeral muscular dystrophy. Patients with FSHD can present with ocular findings and should be screened with dilated fundus examinations for retinal vascular changes and posterior uveitis. PMID:25861398

  12. Exudative retinal detachment following strabismus surgery in Sturge-Weber syndrome.

    PubMed

    Kim, Yu Cheol; Lee, Se Yeop; Kim, Kwang Soo

    2015-06-01

    A 15-year-old boy with Sturge-Weber syndrome underwent strabismus surgery (oculus sinister [OS]) for the treatment of exotropia. The patient's visual acuity (OS) decreased to hand motion 10 days after the surgery. One month after the surgery, the patient's visual acuity decreased to light perception, and a fundus examination showed total exudative retinal detachment (OS). PMID:26265655

  13. Regional differences in neostigmine-induced contraction and relaxation of stomach from diabetic guinea pig

    PubMed Central

    Cellini, Joseph; DiNovo, Karyn; Harlow, Jessica; LePard, Kathy

    2010-01-01

    Delayed gastric emptying and autonomic neuropathy have been documented in patients with diabetes mellitus. Some medications used to treat delayed gastric emptying enhance release of acetylcholine from autonomic neurons to strengthen gastric contractions. Autonomic coordination among gastric regions may be altered in diabetes resulting in poor outcomes in response to prokinetic drugs. Fundus, antrum, and pylorus from STZ or control guinea pigs were treated with neostigmine to mimic release of acetylcholine from autonomic neurons by prokinetic agents. In diabetic animals, neostigmine-induced contractions were weaker in fundus and pylorus but similar in antrum. The muscarinic receptor antagonist 4-DAMP or the nicotinic receptor antagonist hexamethonium reduced neostigmine-induced contractions. Activation of presynaptic muscarinic receptors on nitrergic neurons was impaired in fundus and antrum from diabetic animals. Nerve-stimulated contractions and relaxations, number of nNOS myenteric neurons, and tissue choline content were reduced in fundus from diabetic animals. Despite reduced number of myenteric neurons, tissue choline content was increased in antrum from diabetic animals. Since cholinergic motility of each gastric region was affected differently by diabetes, prokinetic drugs that nondiscriminately enhance acetylcholine release from autonomic neurons may not effectively normalize delayed gastric emptying in patients with diabetes and more selective medications may be warranted. PMID:21075692

  14. 21 CFR 886.1250 - Euthyscope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... inspect the interior of the eye) that projects a bright light encompassing an arc of about 30 degrees onto the fundus of the eye. The center of the light bundle is blocked by a black disk covering the fovea... disease of the eye). (b) Classification. Class I for the battery powered device. The battery...

  15. The neglect of Purkinje's technique of ophthalmoscopy prior to Helmholtz's invention of the ophthalmoscope.

    PubMed

    Reese, P D

    1986-11-01

    A technique for examining the fundus of the eye was devised by Jan Evangelista Purkinje a generation before Helmholtz invented the ophthalmoscope. Yet, Purkinje's technique of ophthalmoscopy went virtually unnoticed by his contemporaries. This neglect of Purkinje's discovery has never been fully explained and warrants re-examination. PMID:3543788

  16. Black as night.

    PubMed

    Kleinberg, Teri T; Uretsky, Scott; Flanders, Adam E; Bilyk, Jurij R; Murchison, Ann P

    2015-01-01

    A 30-year-old man presented with painless total visual loss in the right eye. Fundus exam and imaging was consistent with total internal carotid artery occlusion and hemispheric stroke. The presentation and management options of retinal vascular occlusive disease in association with asymptomatic stroke are discussed. PMID:25311430

  17. Automated detection of microaneurysms using robust blob descriptors

    NASA Astrophysics Data System (ADS)

    Adal, K.; Ali, S.; Sidibé, D.; Karnowski, T.; Chaum, E.; Mériaudeau, F.

    2013-03-01

    Microaneurysms (MAs) are among the first signs of diabetic retinopathy (DR) that can be seen as round dark-red structures in digital color fundus photographs of retina. In recent years, automated computer-aided detection and diagnosis (CAD) of MAs has attracted many researchers due to its low-cost and versatile nature. In this paper, the MA detection problem is modeled as finding interest points from a given image and several interest point descriptors are introduced and integrated with machine learning techniques to detect MAs. The proposed approach starts by applying a novel fundus image contrast enhancement technique using Singular Value Decomposition (SVD) of fundus images. Then, Hessian-based candidate selection algorithm is applied to extract image regions which are more likely to be MAs. For each candidate region, robust low-level blob descriptors such as Speeded Up Robust Features (SURF) and Intensity Normalized Radon Transform are extracted to characterize candidate MA regions. The combined features are then classified using SVM which has been trained using ten manually annotated training images. The performance of the overall system is evaluated on Retinopathy Online Challenge (ROC) competition database. Preliminary results show the competitiveness of the proposed candidate selection techniques against state-of-the art methods as well as the promising future for the proposed descriptors to be used in the localization of MAs from fundus images.

  18. Photorefraction of the Eye

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Wiesner, Hartmut; Zollman, Dean

    2015-01-01

    Photorefraction is a method to easily estimate the refractive state of the eye. The principle of photorefraction involves projecting light into the eye during flash photography and then examining the paths of light that emerge from the pupil after scattering on the back portion of the interior of the eyeball (fundus). We will explain the optical…

  19. 21 CFR 886.1250 - Euthyscope.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... inspect the interior of the eye) that projects a bright light encompassing an arc of about 30 degrees onto the fundus of the eye. The center of the light bundle is blocked by a black disk covering the fovea... disease of the eye). (b) Classification. Class I for the battery powered device. The battery...

  20. 21 CFR 886.1250 - Euthyscope.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... inspect the interior of the eye) that projects a bright light encompassing an arc of about 30 degrees onto the fundus of the eye. The center of the light bundle is blocked by a black disk covering the fovea... disease of the eye). (b) Classification. Class I for the battery powered device. The battery...

  1. [The applications of informatics in ophthalmology].

    PubMed

    Cristina, V; Bărar, A; Gârceag, V; Brumaru, G; Ion, D

    1991-01-01

    The paper reports on the applications of information science in Romania in ophthalmology, and mainly in glaucoma, in the diagnosis of: degenerative affections of the fundus oculi, uveitis, strabismus, in functional exploration of the chromatic sense, ergo-ophthalmology, pupillary reflex and forms of the pupil, etc. The Romanian made computers Felix, Independent, Coral, Cobra, etc. were used. PMID:1811738

  2. Retinal Imaging: Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Goncharov, A. S.; Iroshnikov, N. G.; Larichev, Andrey V.

    This chapter describes several factors influencing the performance of ophthalmic diagnostic systems with adaptive optics compensation of human eye aberration. Particular attention is paid to speckle modulation, temporal behavior of aberrations, and anisoplanatic effects. The implementation of a fundus camera with adaptive optics is considered.

  3. Projections of scan patterns on human retina

    NASA Technical Reports Server (NTRS)

    Kelly, D. H.; Crane, H. D.

    1972-01-01

    Fundus camera tracks eye movements by using camera optics with the aid of an inverted system. Camera provides a flying-spot circular scanning light source in the normal film plane and a broadband photodetector in position normally occupied by light source.

  4. Clinicopathologic findings in Best vitelliform macular dystrophy

    PubMed Central

    Zhang, Qing; Small, Kent W.

    2012-01-01

    Purpose To correlate the clinical and histopathologic features of Best vitelliform macular dystrophy (BVMD). Methods Two eyes were obtained postmortem from a patient with BVMD. The patient’s clinical information was reviewed. Series sections of the globes were performed and sequentially stained with hematoxylin-eosin, periodic acid-Schiff or Masson trichrome. A section of the left macula was submitted for electron microscopic processing. Histopathologic findings were reconstructed in a scaled two-dimensional map and compared with fundus photography, fundus autofluorescence (FAF), fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) images. Results The macular lesion of the right eye was identified as a well-demarcated region with pigment, elevated submacular yellow material and subretinal fluid. This corresponded histopathologically to a well-circumscribed area of RPE hyperplasia, accumulation of lipofuscin in the RPE, deposition of granular material in the photoreceptors, macrophages and drusen. The left eye displayed a 1 disc diameter chorioretinal scar with surrounding shallow fluid and submacular pigment. This corresponded to RPE changes and a fibrocellular proliferation in the choriocapillaris. Conclusion Histopathologic mapping revealed retinal edema, RPE abnormalities, drusen and a chorioretinal scar in BVMD that correlated with the fundus, FFA, FAF and OCT findings. PMID:21136072

  5. Best's vitelliform macular dystrophy in 10- and 31-month-old siblings.

    PubMed

    Griffith, Joseph F; Hess, Ditte J; Berrocal, Audina M

    2014-01-01

    There are limited reports of Best's disease in children younger than 3 years. This is a case series of two family members aged 10 and 31 months with Best's disease. To the authors' knowledge, the 10-month-old male infant is the youngest patient with Best's disease documented by fundus photography. PMID:25314311

  6. 21 CFR 886.1380 - Diagnostic condensing lens.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Diagnostic condensing lens. 886.1380 Section 886.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... light from the fundus of the eye. (b) Classification. Class I (general controls). The device is...

  7. Failed transarterial embolization of subserosal uterine arteriovenous malformation

    PubMed Central

    Seo, Kyung Jin; Kim, Jin; Sohn, In Sook; Kwon, Han Sung; Park, Sang Woo

    2013-01-01

    Uterine arteriovenous malformation (AVM) is rare but potentially life-threatening from excessive vaginal bleeding. All uterine AVMs reported to date have been found in the endometrial or myometrial layers. Here we present a patient with a subserosal type AVM on the fundus of uterus, which spontaneously ruptured. PMID:24328024

  8. A case of Barber-Say syndrome in a male Japanese newborn

    PubMed Central

    Suga, Kenichi; Shono, Miki; Goji, Aya; Matsuura, Sato; Inoue, Miki; Kawahito, Masami; Kinoshita, Michiyo; Takeda, Misa; Mori, Kazuhiro

    2014-01-01

    Key Clinical Message We reported a case of Barber-Say syndrome (BSS) in a Japanese newborn. Distinctive features of BSS were found; macrostomia, gingival dysplasia, cup-shaped low-set ears, wrinkling redundant skin, and hypertrichosis. Fundus showed subretinal drusenoid deposits, a novel finding of BSS. Genetic analysis is underway using next-generation genome sequencing and microarray analysis. PMID:25614816

  9. Intrauterine bone contraceptive device: an accident of nature

    SciTech Connect

    Dajani, Y.F.; Khalaf, S.M.

    1985-01-01

    Ultrasonography and hysterosalpingography led to discovery of four bony plates retained in the uterine fundus after an abortion 33 months earlier and which had apparently led to secondary infertility in a 26-year-old woman. Removal of the bony plates was soon followed by a successful pregnancy.

  10. H2S, a novel gasotransmitter, involves in gastric accommodation.

    PubMed

    Xiao, Ailin; Wang, Hongjuan; Lu, Xin; Zhu, Jianchun; Huang, Di; Xu, Tonghui; Guo, Jianqiang; Liu, Chuanyong; Li, Jingxin

    2015-01-01

    H2S is produced mainly by two enzymes:cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), using L-cysteine (L-Cys) as the substrate. In this study, we investigated the role of H2S in gastric accommodation using CBS(+/-) mice, immunohistochemistry, immunoblot, methylene blue assay, intragastric pressure (IGP) recording and electrical field stimulation (EFS). Mouse gastric fundus expressed H2S-generating enzymes (CBS and CSE) and generated detectable amounts of H2S. The H2S donor, NaHS or L-Cys, caused a relaxation in either gastric fundus or body. The gastric compliance was significantly increased in the presence of L-Cys (1 mM). On the contrary, AOAA, an inhibitor for CBS, largely inhibited gastric compliance. Consistently, CBS(+/-) mice shows a lower gastric compliance. However, PAG, a CSE inhibitor, had no effect on gastric compliances. L-Cys enhances the non-adrenergic, non-cholinergic (NANC) relaxation of fundus strips, but AOAA reduces the magnitude of relaxations to EFS. Notably, the expression level of CBS but not CSE protein was elevated after feeding. Consistently, the production of H2S was also increased after feeding in mice gastric fundus. In addition, AOAA largely reduced food intake and body weight in mice. Furthermore, a metabolic aberration of H2S was found in patients with functional dyspepsia (FD). In conclusion, endogenous H2S, a novel gasotransmitter, involves in gastric accommodation. PMID:26531221

  11. Intrathoracic gastric perforation secondary to corrosive ingestion: a rare complication

    PubMed Central

    Varma Gunturi, Surya Ramachandra; Arora, Abhishek; Parmar, Abhijot

    2016-01-01

    This case report describes a rare and serious case of acid ingestion in a 50-year-old man who developed necrosis and perforation of gastric fundus and diaphragm with extension of air and fluid collection in the thorax. To the best of our knowledge, this complication has not been described so far in the literature. PMID:27190774

  12. Infrared imaging enhances retinal crystals in Bietti’s crystalline dystrophy

    PubMed Central

    Brar, Vikram S; Benson, William H

    2015-01-01

    Infrared imaging dramatically increased the number of crystalline deposits visualized compared with clinical examination, standard color fundus photography, and red free imaging in patients with Bietti’s crystalline dystrophy. We believe that this imaging modality significantly improves the sensitivity with which these lesions are detected, facilitating earlier diagnosis and may potentially serve as a prognostic indicator when examined over time. PMID:25931805

  13. A Case of Overlapping Choriocapillaritis Syndromes: Multimodal Imaging Appraisal

    PubMed Central

    Kuznetcova, Tatiana; Jeannin, Bruno; Herbort, Carl P

    2012-01-01

    Purpose: To present a patient with overlapping choriocapillaritis syndromes who first presented as a typical case of multiple evanescent white dot syndrome (MEWDS) and later with characteristic findings compatible with multifocal choroiditis (MFC). Case Report: A 40-year-old myopic woman presented with a paracentral scotoma OS. Fundus examination revealed pale discolored areas around the optic disc corresponding to faintly hyperfluorescent areas on fluorescein angiography (FA). On indocyanine green angiography (ICGA) there was extensive peripapillary hypofluorescence and confluent hypofluorescent dots superiorly. According to the clinical picture, a diagnosis of MEWDS was made. In 4 weeks, the visual field reverted to normal together with almost complete regression of hypofluorescence on ICGA. However, 4 months later fundus examination revealed some scars, a finding not typical for MEWDS. Besides, she developed another scotoma 12 months later accompanied by photopsia and the fundus illustrated more numerous scars than one year earlier. ICGA showed hypofluorescent areas corresponding to the scotoma delineated by visual field testing. The pattern of this recurrence clearly corresponded to MFC. Conclusion: This case illustrates an overlap between two entities, MEWDS and MFC in two sequential episodes. FA and fundus autofluorescence accounted for the lesions and optical coherence tomography showed damage to the photoreceptor outer segments, but only ICGA correlated well with functional evolution. PMID:22737390

  14. Exudative retinal detachment following strabismus surgery in Sturge–Weber syndrome

    PubMed Central

    Kim, Yu Cheol; Lee, Se Yeop; Kim, Kwang Soo

    2015-01-01

    A 15-year-old boy with Sturge–Weber syndrome underwent strabismus surgery (oculus sinister [OS]) for the treatment of exotropia. The patient's visual acuity (OS) decreased to hand motion 10 days after the surgery. One month after the surgery, the patient's visual acuity decreased to light perception, and a fundus examination showed total exudative retinal detachment (OS). PMID:26265655

  15. H2S, a novel gasotransmitter, involves in gastric accommodation

    PubMed Central

    Xiao, Ailin; Wang, Hongjuan; Lu, Xin; Zhu, Jianchun; Huang, Di; Xu, Tonghui; Guo, Jianqiang; Liu, Chuanyong; Li, Jingxin

    2015-01-01

    H2S is produced mainly by two enzymes:cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), using L-cysteine (L-Cys) as the substrate. In this study, we investigated the role of H2S in gastric accommodation using CBS+/− mice, immunohistochemistry, immunoblot, methylene blue assay, intragastric pressure (IGP) recording and electrical field stimulation (EFS). Mouse gastric fundus expressed H2S-generating enzymes (CBS and CSE) and generated detectable amounts of H2S. The H2S donor, NaHS or L-Cys, caused a relaxation in either gastric fundus or body. The gastric compliance was significantly increased in the presence of L-Cys (1 mM). On the contrary, AOAA, an inhibitor for CBS, largely inhibited gastric compliance. Consistently, CBS+/− mice shows a lower gastric compliance. However, PAG, a CSE inhibitor, had no effect on gastric compliances. L-Cys enhances the non-adrenergic, non-cholinergic (NANC) relaxation of fundus strips, but AOAA reduces the magnitude of relaxations to EFS. Notably, the expression level of CBS but not CSE protein was elevated after feeding. Consistently, the production of H2S was also increased after feeding in mice gastric fundus. In addition, AOAA largely reduced food intake and body weight in mice. Furthermore, a metabolic aberration of H2S was found in patients with functional dyspepsia (FD). In conclusion, endogenous H2S, a novel gasotransmitter, involves in gastric accommodation. PMID:26531221

  16. Histopathologic Findings in the Areas of Orange Pigment Overlying Choroidal Melanomas

    PubMed Central

    Garcia, Maria D.; Salomao, Diva R.; Marmorstein, Alan D.; Pulido, Jose S.

    2016-01-01

    Purpose Orange pigment is an important sign of malignancy in melanocytic tumors. There is a question as to whether the pigment accumulation is inside of macrophages or retinal pigment epithelial (RPE) cells. We investigated which cells are involved with this color alteration. Methods We examined enucleated specimens from two patients with choroidal melanoma and dense orange pigment on fundus examination. Color fundus and fundus autofluorescence (FAF) photographs were reviewed followed by examination with fluorescent microscopy, electron microscopy, and immunohistochemistry of enucleated eyes for the specific areas corresponding to the orange pigment. Results Orange pigment was observed on color fundus photography and correlated with areas of hyperautofluorescence on FAF. Fluorescent microscopy of sections of the enucleated eyes showed autofluorescence in the RPE, which were most pronounced where there was a localized retinal detachment and reactive hyperplasia of the RPE. Immunohistochemical studies were done with keratin (OSCAR and AE1/AE3) and S-100 stained RPE cells, which still were attached to Bruch's membrane. Histiocytes present in the detached retina stained with anti-CD163 antibody and did not show autofluorescence. Electron microscopy studies of the same areas showed the presence of lipofuscin and melanolipofuscin within the clustered RPE cells. Conclusions Orange pigment in choroidal melanocytic lesions originates from the RPE cells, rather than macrophages, and is most abundant where there is proliferation of the RPE. Translational Relevance The orange pigment tumoral biomarker arises and is in the retinal pigment epithelium. PMID:27190699

  17. 21 CFR 886.1250 - Euthyscope.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... inspect the interior of the eye) that projects a bright light encompassing an arc of about 30 degrees onto the fundus of the eye. The center of the light bundle is blocked by a black disk covering the...

  18. Spectral OCT techniques in eye imaging

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Andrzej; Wojtkowski, Maciej

    2002-02-01

    This contribution presents examples of images of eye in vitro obtained by spectral optical tomography (OCT). Particular interest was focused on obtaining clear images of the corneo-scleral angle and images of fundus which are both essential for diagnosing and planning of a treatment of glaucoma.

  19. Suspected macular degeneration in a captive Western lowland gorilla (Gorilla gorilla gorilla).

    PubMed

    Steinmetz, Andrea; Bernhard, Andreas; Sahr, Sabine; Oechtering, Gerhard

    2012-09-01

    The case of a 31-year-old captive female Western lowland gorilla (Gorilla gorilla gorilla) with decreased near vision but good distance vision is presented. Examination of the fundus revealed drusen-like bodies in the macula presumably because of an age-related macular degeneration (AMD). PMID:22702721

  20. Application of adaptive optics in retinal imaging: a quantitative and clinical comparison with standard cameras

    NASA Astrophysics Data System (ADS)

    Barriga, E. S.; Erry, G.; Yang, S.; Russell, S.; Raman, B.; Soliz, P.

    2005-04-01

    Aim: The objective of this project was to evaluate high resolution images from an adaptive optics retinal imager through comparisons with standard film-based and standard digital fundus imagers. Methods: A clinical prototype adaptive optics fundus imager (AOFI) was used to collect retinal images from subjects with various forms of retinopathy to determine whether improved visibility into the disease could be provided to the clinician. The AOFI achieves low-order correction of aberrations through a closed-loop wavefront sensor and an adaptive optics system. The remaining high-order aberrations are removed by direct deconvolution using the point spread function (PSF) or by blind deconvolution when the PSF is not available. An ophthalmologist compared the AOFI images with standard fundus images and provided a clinical evaluation of all the modalities and processing techniques. All images were also analyzed using a quantitative image quality index. Results: This system has been tested on three human subjects (one normal and two with retinopathy). In the diabetic patient vascular abnormalities were detected with the AOFI that cannot be resolved with the standard fundus camera. Very small features, such as the fine vascular structures on the optic disc and the individual nerve fiber bundles are easily resolved by the AOFI. Conclusion: This project demonstrated that adaptive optic images have great potential in providing clinically significant detail of anatomical and pathological structures to the ophthalmologist.

  1. Children's Color Perception in Relation to Habitat and Skin Color.

    ERIC Educational Resources Information Center

    Gaines, Rosslyn; Powell, Gloria J.

    1981-01-01

    Developmental color perception of 278 four- and eight-year-old Black and White children in three societies was examined in relation to the theories that proximity to the equator and that fundus pigmentation (as measured by skin color) reduce shortwave (blue-green) in comparison to long-wave perception. (Author/MP)

  2. Glaucoma screening as part of the routine physical examination. What to look for and how to use the Schiotz tonometer.

    PubMed

    Pabalan, F J; Weingeist, T A

    1985-05-01

    Glaucoma is a leading cause of visual loss in the United States. The primary care physician can effectively screen patients at risk by performing Schiotz tonometry, checking the visual fields, and examining the fundus. Patients with elevated intraocular pressure, grossly abnormal visual fields, or abnormal optic disks should be referred to an ophthalmologist for confirmation of diagnosis and for therapy. PMID:3991383

  3. Computer-Assisted Instruction in Medicine: A German View.

    ERIC Educational Resources Information Center

    Voss, Gunnar; And Others

    The following seven American programs of Computer Assisted Instruction in Medicine are among 20 implemented at the University of Bonn: OPHTHA and FUNDUS (programs of the tutorial mode), CARDI (presents information via three media on the clinical alterations of Mitral and Aortic Stenosis as well as Mitral and Aortal Incompetence), CARDIOPULMONARY…

  4. Intravenously administered phosphodiesterase 4 inhibitors dilate retinal blood vessels in rats.

    PubMed

    Miwa, Tomoyo; Mori, Asami; Nakahara, Tsutomu; Ishii, Kunio

    2009-01-01

    In the present study, we examined effects of intravenously administered inhibitors of phosphodiesterase 4 (rolipram and 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro-20-1724)) and non-selective inhibitor of phosphodiesterases (theophylline) on diameter of retinal blood vessel and fundus (retinal/choroidal) blood flow in rats. Male Wistar rats (8- to 10-week-old) were treated with tetrodotoxin (50 microg/kg, i.v.) to eliminate any nerve activity and prevent the eye movement under artificial ventilation. Methoxamine was used to maintain adequate systemic circulation. Ocular fundus images were captured with an original high-resolution digital fundus camera for small animals. Diameters of retinal blood vessels contained in the digital images were measured using image-processing softwares on a personal computer. Fundus blood flow was measured using a laser Doppler flow meter. Both rolipram (0.01-10 microg/kg/min, i.v.) and Ro-20-1724 (0.01-10 microg/kg/min, i.v.) increased diameters of retinal blood vessels in a dose-dependent manner without significant effect on systemic blood pressure, heart rate and fundus blood flow. The effects of phosphodiesterase 4 inhibitors on retinal arterioles were greater than those on retinal venules. Similarly, theophylline (0.1-10 mg/kg/min, i.v.) dilated retinal blood vessels, whereas it decreased blood pressure and increased heart rate markedly. These results suggest that phosphodiesterase 4 contributes to maintenance of retinal vascular tone. Inhibitors of phosphodiesterase 4 could be considered as a candidate for therapeutic drugs to treat diseases associated with disorders of retinal circulation without severe cardiovascular side-effects. PMID:19027003

  5. Selexipag: a selective prostacyclin receptor agonist that does not affect rat gastric function.

    PubMed

    Morrison, Keith; Ernst, Roland; Hess, Patrick; Studer, Rolf; Clozel, Martine

    2010-10-01

    Selexipag [2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide] is an orally available prostacyclin (PGI(2)) receptor (IP receptor) agonist that is chemically distinct from PGI(2) and is in clinical development for the treatment of pulmonary arterial hypertension. Selexipag is highly selective for the human IP receptor in vitro, whereas analogs of PGI(2) can activate prostanoid receptors other than the IP receptor. The goal of this study was to determine the impact of selectivity for the IP receptor on gastric function by measuring 1) contraction of rat gastric fundus ex vivo and 2) the rates of gastric emptying and intestinal transport in response to selexipag in comparison with other PGI(2) analogs. The rat gastric fundus expresses mRNA encoding multiple prostanoid receptors to different levels: prostaglandin E receptor 1 (EP(1)) > prostaglandin E receptor 3 (EP(3)), IP receptor > prostaglandin D(2) receptor 1, thromboxane receptor. Selexipag and metabolite {4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (ACT-333679) did not contract gastric fundus at concentrations up to 10(-3) M. In contrast, the PGI(2) analogs iloprost and beraprost evoked concentration-dependent contraction of gastric fundus. Contraction to treprostinil was observed at high concentration (10(-4) M). Contraction to all PGI(2) analogs was mediated via activation of EP(3) receptors, although EP(1) receptors also contributed to the contraction of gastric fundus to iloprost and beraprost. Antagonism of IP receptors did not affect responses. Oral selexipag did not significantly alter gastric function in vivo, as measured by rates of stomach emptying and intestinal transport, whereas beraprost slowed gastrointestinal transport. The high functional selectivity of selexipag and ACT-333679 for the IP receptor precludes a stimulatory action on gastric smooth muscle and may help minimize gastric side effects such as nausea and vomiting. PMID:20660124

  6. Noninflammatory upregulation of nerve growth factor underlies gastric hypersensitivity induced by neonatal colon inflammation.

    PubMed

    Li, Qingjie; Winston, John H; Sarna, Sushil K

    2016-02-01

    Gastric hypersensitivity is one of the key contributors to the postprandial symptoms of epigastric pain/discomfort, satiety, and fullness in functional dyspepsia patients. Epidemiological studies found that adverse early-life experiences are risk factors for the development of gastric hypersensitivity. Preclinical studies found that neonatal colon inflammation elevates plasma norepinephrine (NE), which upregulates expression of nerve growth factor (NGF) in the muscularis externa of the gastric fundus. Our goal was to investigate the cellular mechanisms by which NE upregulates the expression of NGF in gastric hypersensitive (GHS) rats, which were subjected previously to neonatal colon inflammation. Neonatal colon inflammation upregulated NGF protein, but not mRNA, in the gastric fundus of GHS rats. Western blotting showed upregulation of p110γ of phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K), phosphoinositide-dependent kinase-1 (PDK1), pAKT(Ser473), and phosphorylated 4E-binding protein (p4E-BP1)(Thr70), suggesting AKT activation and enhanced NGF protein translation. AKT inhibitor MK-2206 blocked the upregulation of NGF in the fundus of GHS rats. Matrix metalloproteinase 9 (MMP-9), the major NGF-degrading protease, was suppressed, indicating that NGF degradation was impeded. Incubation of fundus muscularis externa with NE upregulated NGF by modulating the protein translation and degradation pathways. Yohimbine, an α2-adrenergic receptor antagonist, upregulated plasma NE and NGF expression by activating the protein translation and degradation pathways in naive rats. In contrast, a cocktail of adrenergic receptor antagonists suppressed the upregulation of NGF by blocking the activation of the protein translation and degradation pathways. Our findings provide evidence that the elevation of plasma NE induces NGF expression in the gastric fundus. PMID:26608656

  7. Ácaros del mango

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Los ácaros constituyen un grupo abundante y diverso que ocupa diferentes hábitats en árboles frutales y la estructura y disposición del follaje y ramas del mango, contribuyen significativamente a que se presente gran diversidad de ácaros benéficos y dañinos asociados a esta especie frutal. En Colomb...

  8. Accidentes en plantas nucleares de electricidad y el riesgo de cáncer

    Cancer.gov

    Hoja informativa acerca de los riesgos del cáncer asociados con accidentes en plantas nucleares de electricidad. Incluye información para pacientes con cáncer que viven en una zona que puede haber sido afectada por un accidente en una planta nuclear.

  9. Hoja informativa del alcohol y el riesgo de cáncer

    Cancer.gov

    Hoja informativa que resume la comprobación de la relación entre el consumo de alcohol y el riesgo de varios cánceres. Incluye información de los factores que afectan el riesgo de cánceres asociados con el alcohol, como son los genes y el uso de tabaco.

  10. Unwanted reflections during slit lamp assisted binocular indirect ophthalmoscopy

    NASA Astrophysics Data System (ADS)

    Sheehan, Matthew; Goncharov, Alexander

    2011-11-01

    Binocular indirect ophthalmoscopy is a routine ophthalmic examination procedure. Two different apparatus setups are commonly employed; the head/spectacle mounted designs of Schepens and slit lamp assisted ophthalmoscopy, both typically performed through a fundus lens of high positive power. It can be difficult for clinicians to avoid unwanted back reflections primarily emanating from the fundus lens and the pre-corneal tear film, particularly when initially learning the skills required to perform the examination. In this investigation the illumination system of a slit lamp was modified to include a variety of obscuration designs optically conjugate to surfaces responsible for creating unwanted reflections. The modified apparatus was then used to perform binocular indirect ophthalmoscopy on an artificial eye and on real eyes. Clinicians used questionnaires to score the appearance of reflections. The mean scores were similar across all trials, including the control unmodified trial, indicating general consensus that the modified illumination system provided no substantial effect on the perception of these unwanted reflections.

  11. Congenital retinal macrovessel: atypical presentation using optical coherence tomography.

    PubMed

    Ceylan, Osman M; Gullulu, Gulay; Akin, Tugrul; Bilen, Harun

    2011-02-01

    To describe a congenital retinal macrovessel with macular thickening. This case was investigated using fundus photography, fluorescein angiography, Spectralis optical coherence tomography and a 10-2 visual field test. A 23-year-old man was referred to our clinic with decreased vision in the right eye. Fundus examination of the right eye revealed a congenital retinal macrovessel that originated inferior to the superotemporal branch of the central retinal vein. Using fluorescein angiography, early filling and delayed emptying of the aberrant vein were observed. Spectralis optical coherence tomography demonstrated macular thickening and was supported by a 10-2 visual field test that revealed a relative scotoma corresponding to the same location. At the 18-month follow-up, visual acuity remained stable. Although rare, this case demonstrated that macular thickening can cause decreased visual acuity in the presence of a congenital retinal macrovessel. PMID:20922460

  12. Snapshot retinal imaging Mueller matrix polarimeter

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Kudenov, Michael; Kashani, Amir; Schwiegerling, Jim; Escuti, Michael

    2015-09-01

    Early diagnosis of glaucoma, which is a leading cause for visual impairment, is critical for successful treatment. It has been shown that Imaging polarimetry has advantages in early detection of structural changes in the retina. Here, we theoretically and experimentally present a snapshot Mueller Matrix Polarimeter fundus camera, which has the potential to record the polarization-altering characteristics of retina with a single snapshot. It is made by incorporating polarization gratings into a fundus camera design. Complete Mueller Matrix data sets can be obtained by analyzing the polarization fringes projected onto the image plane. In this paper, we describe the experimental implementation of the snapshot retinal imaging Mueller matrix polarimeter (SRIMMP), highlight issues related to calibration, and provide preliminary images acquired from the camera.

  13. Preliminary Evaluation Of Charge-Coupled Device (CCD) Multispectral Analysis In Ophthalmology

    NASA Astrophysics Data System (ADS)

    Launay, Francoise; Fauconnier, Thierry; Fort, Bernard; Cailloux, Mireille; Bonnin, Paul; Bloch-Michel, Etienne

    1986-05-01

    The work described was originally aimed at providing a new diagnostic technique for the early detection of malignant ocular tumors through their spectral signature. The instrument developed comprises a modified fundus camera, a Charge-coupled device (CCD) camera and a 16 bit microcomputer equipped with floppy disk drives and a 512 x 512X 8-bit display device. The system allows the recording of digitized fundus or iris reflectance pictures in eight spec-tral bands between 500 and 1100 nm. After calibration and preprocessing of the data, a multi-spectral analysis is performed by means of a VAX computer. The image processing methods are described and their ability to characterize pigmented lesions or other ocular anatomical fea-tures through their spectral signature is evaluated.

  14. Faces in Motion: Selectivity of Macaque and Human Face Processing Areas for Dynamic Stimuli

    PubMed Central

    Polosecki, Pablo; Moeller, Sebastian; Schweers, Nicole; Romanski, Lizabeth M.; Tsao, Doris Y.

    2013-01-01

    Face recognition mechanisms need to extract information from static and dynamic faces. It has been hypothesized that the analysis of dynamic face attributes is performed by different face areas than the analysis of static facial attributes. To date, there is no evidence for such a division of labor in macaque monkeys. We used fMRI to determine specializations of macaque face areas for motion. Face areas in the fundus of the superior temporal sulcus responded to general object motion; face areas outside of the superior temporal sulcus fundus responded more to facial motion than general object motion. Thus, the macaque face-processing system exhibits regional specialization for facial motion. Human face areas, processing the same stimuli, exhibited specializations for facial motion as well. Yet the spatial patterns of facial motion selectivity differed across species, suggesting that facial dynamics are analyzed differently in humans and macaques. PMID:23864665

  15. A simple integrated system for electrophysiologic recordings in animals

    PubMed Central

    Slater, Bernard J.; Miller, Neil R.; Bernstein, Steven L.; Flower, Robert W.

    2009-01-01

    This technical note describes a modification to a fundus camera that permits simultaneous recording of pattern electroretinograms (pERGs) and pattern visual evoked potentials (pVEPs). The modification consists of placing an organic light-emitting diode (OLED) in the split-viewer pathway of a fundus camera, in a plane conjugate to the subject’s pupil. In this way, a focused image of the OLED can be delivered to a precisely known location on the retina. The advantage of using an OLED is that it can achieve high luminance while maintaining high contrast, and with minimal degradation over time. This system is particularly useful for animal studies, especially when precise retinal positioning is required. PMID:19137347

  16. Gastric lipase: localization of the enzyme in the stomach

    SciTech Connect

    DeNigris, S.J.; Hamosh, M.; Hamosh, P.; Kasbekar, D.K.

    1986-03-05

    Isolated gastric glands prepared from human and rabbit stomach secrete lipase in response to secretagogues. They have investigated the localization of this enzyme in three species (rabbit, baboon, guinea pig). Gastric mucosa was sampled from the cardia (C), fundus-smooth (FS), fundus-ruggae (FR) and the antral area (A). Lipase activity was measured in mucosal homogenates using /sup 3/H-triolein as substrate and is expressed in units (U) = nmols free fatty acid released/min/mg wet weight. The localization of lipase is compared with that of pepsin (measured by hydrolysis of 2% hemoglobin at pH 1.8 and expressed in I.U.). Lipase is localized in a well defined area in the rabbit and is diffusely distributed in both guinea pig and baboon. The distribution of lipase and pepsin containing cells differs in all three species. The cellular origin of gastric lipase remains to be determined.

  17. Ultra-High Resolution Optical Coherence Tomography Imaging of Unilateral Drusen in a 31 Year Old Woman

    PubMed Central

    de Carlo, Talisa E; Adhi, Mehreen; Lu, Chen D; Duker, Jay S; Fujimoto, James G; Waheed, Nadia K

    2016-01-01

    We report a case of widespread unilateral drusen in a healthy 31 year old Caucasian woman using multi-modal imaging including ultra-high resolution optical coherence tomography (UHR-OCT). Dilated fundus exam showed multiple drusen-like lesions in the posterior pole without heme or fluid. Fundus auto fluorescence demonstrated hyperautofluorescent at the deposits. Fluorescein angiography revealed mild hyperfluorescence and staining of the lesions. Spectral-domain optical coherence tomography (SD-OCT) OS showed accumulations in the temporal macula at Bruch’s membrane. UHR-OCT provided improved axial resolution compared to the standard 5 μm on the commercial SD-OCT and confirmed the presence of deposits in Bruch’s membrane, consistent with drusen. The retinal layers were draped over the excrescences but did not show any disruption. PMID:27398405

  18. The problem of macular sparing after unilateral occipital lesions.

    PubMed

    Sugishita, M; Hemmi, I; Sakuma, I; Beppu, H; Shiokawa, Y

    1993-11-01

    Whether or not unilateral occipital damage produces sparing of central vision, namely macular sparing, is controversial. We tested two subjects with left occipital lesions by means of fundus perimetry combined with fundus image analysis. This method made it possible to measure the distance of the stimulus projected on the retina from the foveal centre defined as the centre of the foveal reflex. The results indicated that macular sparing, if it exists, must be less than 0.4 degree wide. Two of the four eyes during the stimulus presentation often but not always showed eccentric fixation of a small magnitude, whose mean was less than 0.6 degree from the foveal centre in the right hemiretina. PMID:8138815

  19. Retinal oximetry with a multiaperture camera

    NASA Astrophysics Data System (ADS)

    Lemaillet, Paul; Lompado, Art; Ibrahim, Mohamed; Nguyen, Quan Dong; Ramella-Roman, Jessica C.

    2010-02-01

    Oxygen saturation measurements in the retina is an essential measurement in monitoring eye health of diabetic patient. In this paper, preliminary result of oxygen saturation measurements for a healthy patient retina is presented. The retinal oximeter used is based on a regular fundus camera to which was added an optimized optical train designed to perform aperture division whereas a filter array help select the requested wavelengths. Hence, nine equivalent wavelength-dependent sub-images are taken in a snapshot which helps minimizing the effects of eye movements. The setup is calibrated by using a set of reflectance calibration phantoms and a lookuptable (LUT) is computed. An inverse model based on the LUT is presented to extract the optical properties of a patient fundus and further estimate the oxygen saturation in a retina vessel.

  20. MTF measurements on real time for performance analysis of electro-optical systems

    NASA Astrophysics Data System (ADS)

    Stuchi, Jose Augusto; Signoreto Barbarini, Elisa; Vieira, Flavio Pascoal; dos Santos, Daniel, Jr.; Stefani, Mário Antonio; Yasuoka, Fatima Maria Mitsue; Castro Neto, Jarbas C.; Linhari Rodrigues, Evandro Luis

    2012-06-01

    The need of methods and tools that assist in determining the performance of optical systems is actually increasing. One of the most used methods to perform analysis of optical systems is to measure the Modulation Transfer Function (MTF). The MTF represents a direct and quantitative verification of the image quality. This paper presents the implementation of the software, in order to calculate the MTF of electro-optical systems. The software was used for calculating the MTF of Digital Fundus Camera, Thermal Imager and Ophthalmologic Surgery Microscope. The MTF information aids the analysis of alignment and measurement of optical quality, and also defines the limit resolution of optical systems. The results obtained with the Fundus Camera and Thermal Imager was compared with the theoretical values. For the Microscope, the results were compared with MTF measured of Microscope Zeiss model, which is the quality standard of ophthalmological microscope.

  1. Lens design with suppressed first order reflections

    NASA Astrophysics Data System (ADS)

    Buchheister, Jan; Weth, Christopher

    2010-08-01

    Optical systems with a reflected light condition, e.g. microscopes with reflected light illumination or fundus cameras, need to have weak first order ghosts or even to be completely free from them. Sequential ray tracing can be used to control optical performance and reflections on a ray basis during optimization. This is significantly more efficient in computation time and convergence than the usual approaches with non-sequential ray tracing or reconfigured optical systems to cover all critical ghosts. An ophthalmic lens for a fundus camera was designed with first order reflections stripped out by applying sequential ray tracing. The merit-function only had to be completed under certain conditions guaranteeing the absence of any reflections. No additional reconfiguration of the optical system in the design software was necessary.

  2. Optic disc detection using ant colony optimization

    NASA Astrophysics Data System (ADS)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  3. AUTOMATIC RETINA EXUDATES SEGMENTATION WITHOUT A MANUALLY LABELLED TRAINING SET

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Tobin Jr, Kenneth William; Chaum, Edward

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy which can be assessed by detecting exudates (a type of bright lesion) in fundus images. In this work, two new methods for the detection of exudates are presented which do not use a supervised learning step and therefore do not require ground-truthed lesion training sets which are time consuming to create, difficult to obtain, and prone to human error. We introduce a new dataset of fundus images from various ethnic groups and levels of DME which we have made publicly available. We evaluate our algorithm with this dataset and compare our results with two recent exudate segmentation algorithms. In all of our tests, our algorithms perform better or comparable with an order of magnitude reduction in computational time.

  4. The relative activities of some tryptamine analogues on the isolated rat stomach strip preparation

    PubMed Central

    Vane, J. R.

    1959-01-01

    The relative potencies of analogues of tryptamine and 5-hydroxytryptamine have been determined on the rat fundus preparation. This tissue had an amine oxidase activity, which, in the homogenate, was able to inactivate both tryptamine and 5-hydroxytryptamine to about the same degree. Amine oxidase inhibitors potentiated the action of tryptamine and many analogues on the isolated rat fundus preparation, but not the action of 5-hydroxytryptamine or of other hydroxytryptamines. This suggested that, in the isolated organ, the amine oxidase was unable to inactivate 5-hydroxytryptamine, but could inactivate tryptamine, 5-methoxytryptamine and many others. These results may be explained if it is supposed that tryptamine entered the cell, but because of the polar hydroxyl group 5-hydroxytryptamine did not. This hypothesis is supported by the oil/water partition coefficients. The structure/activity of the various tryptamine derivatives is discussed in the light of this assumption. PMID:13651584

  5. Genetic study in a tunisian family revealed IVS1+1G>A mutation in the CHM gene.

    PubMed

    Ben Charfeddine, Ilhem; Ben Lazreg, Taheni; Ben Rayana, Narjes; Amara, Abdelbasset; Mamaï, Ons; Knani, Leila; Mili, Amira; M'sakni, Ahlem; Saad, Ali; Ben Hadj Hamida, Fafani; Gribaa, Moez

    2015-01-01

    Choroideremia is a rare X-linked recessive, hereditary retinal pigment epithelial dystrophy, characterized by night blindness and progressive constriction of the visual fields leading to blindness in young adulthood. In this study, we reported three cases of choroideremia belonging to a Tunisian family. Patients complained of vision loss and night blindness. Fundus examination revealed diffused chorioretenal atrophy. In all cases, there was a visual field constriction and an undetectable electroretinography. Direct sequencing of the CHM gene detected a guanine to adenine transition (G>A) into the donor splice site of intron 1 leads to aberrantly spliced mRNA producing a premature stop codon and therefore functional loss of the CHM gene product, REP-1. The diagnosis should be considered in patients with a suitable family history and fundus findings. PMID:26411914

  6. Imaging retinal densitometry with a confocal Scanning Laser Ophthalmoscope.

    PubMed

    van Norren, D; van de Kraats, J

    1989-01-01

    We describe a novel use of the Scanning Laser Ophthalmoscope (SLO), viz. as an imaging retinal densitometer. In our SLO a helium-neon or an argon laser beam is moved in a raster pattern over the retina; the reflected light is descanned (confocal SLO) and collected by a photomultiplier. Images of the fundus subtending 22 by 18 deg are displayed on a TV monitor. Single frames taken with 514 nm light were stored in a computer in arrays of 256 by 256 pixels and density differences between dark adapted and bleached images were calculated. With a full bleach density differences of about 0.35 were found in the center of the fovea; at retinal eccentricities of 15-20 deg we found 0.15. After selective bleaching with 633 nm light substantial density differences were only seen in the foveal area. We conclude that the confocal SLO is a very suitable instrument for imaging fundus reflectometry. PMID:2631402

  7. Chandelier retroillumination-assisted cataract surgery during vitrectomy.

    PubMed

    Bilgin, S; Kayikcioglu, O

    2016-08-01

    PurposeTo present an alternative cataract surgical technique in patients with cataract and intravitreal hemorrhage.MethodsTwelve cases with poor fundus reflex caused by severe vitreus hemorrhage were included in the study. All patients underwent combined phaco surgery and 23-gauge vitrectomy. Chandelier retroillumination was inserted into the infusion trochar during the cataract operations and was used with low power (50-75%) in necessary steps.ResultsWe did not experience phaco complications or complications due to technique during surgery. Retroillumination assistance was especially useful during final stages of cataract surgery, particularly irrigation-aspiration of cortical material.ConclusionRetroillumination in absence of red fundus reflex may be helpful and can be practiced more often in cataract surgery combined with vitrectomy. PMID:27256306

  8. Tracing retinal blood vessels by matrix-forest theorem of directed graphs.

    PubMed

    Cheng, Li; De, Jaydeep; Zhang, Xiaowei; Lin, Feng; Li, Huiqi

    2014-01-01

    This paper aims to trace retinal blood vessel trees in fundus images. This task is far from being trivial as the crossover of vessels are commonly encountered in image-based vessel networks. Meanwhile it is often crucial to separate the vessel tree structures in applications such as diabetic retinopathy analysis. In this work, a novel directed graph based approach is proposed to cast the task as label propagation over directed graphs, such that the graph is to be partitioned into disjoint sub-graphs, or equivalently, each of the vessel trees is traced and separated from the rest of the vessel network. Then the tracing problem is addressed by making novel usage of the matrix-forest theorem in algebraic graph theory. Empirical experiments on synthetic as well as publicly available fundus image datasets demonstrate the applicability of our approach. PMID:25333171

  9. Hyperbaric Oxygen Therapy in Branch Retinal Artery Occlusion in a 15-Year-Old Boy with Methylenetetrahydrofolate Reductase Mutation

    PubMed Central

    Kadayifcilar, Sibel; Eldem, Bora

    2015-01-01

    Purpose. To report the efficacy of hyperbaric oxygen (HBO) therapy in a case of branch retinal artery occlusion (BRAO) in a 15-year-old boy. Methods. We report a 15-year-old boy with sudden loss of vision due to BRAO. Examination included laboratory evaluation for systemic risk factors. Follow-up exams included visual acuity, fundus examination, fundus fluorescein angiography, and visual field testing. HBO therapy was employed for treatment. Results. Medical history was positive for isolated glucocorticoid deficiency. Laboratory evaluation disclosed hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) mutation. The visual acuity 0.05 at presentation improved to 0.8 after 20 days of HBO therapy. There was no change on visual fields. Conclusion. In this pediatric case, HBO therapy was useful in the treatment of BRAO. PMID:25722905

  10. The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo

    NASA Technical Reports Server (NTRS)

    Laing, R. A.; Danisch, L. A.; Young, L. R.

    1975-01-01

    The Choroidal Eye Oximeter is an electro-optical instrument that noninvasively measures the oxygen saturation of choroidal blood in the back of the human eye by a spectrophotometric method. Since choroidal blood is characteristic of blood which is supplied to the brain, the Choroidal Eye Oximeter can be used to monitor the amount of oxygen which is supplied to the brain under varying external conditions. The instrument consists of two basic systems: the optical system and the electronic system. The optical system produces a suitable bi-chromatic beam of light, reflects this beam from the fundus of the subject's eye, and onto a low-noise photodetector. The electronic system amplifies the weak composite signal from the photodetector, computes the average oxygen saturation from the area of the fundus that was sampled, and displays the value of the computed oxygen saturation on a panel meter.

  11. Texton-based segmentation of retinal vessels.

    PubMed

    Adjeroh, Donald A; Kandaswamy, Umasankar; Odom, J Vernon

    2007-05-01

    With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE5370, 648 (2004)]. PMID:17429484

  12. Texton-based segmentation of retinal vessels

    NASA Astrophysics Data System (ADS)

    Adjeroh, Donald A.; Kandaswamy, Umasankar; Odom, J. Vernon

    2007-05-01

    With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE5370, 648 (2004)].

  13. Fluorescein angiography findings in a case of Rubinstein-Taybi syndrome.

    PubMed

    Jacobs, David J; Sein, Julia; Berrocal, Audina M; Grajewski, Alana L; Hodapp, Elizabeth

    2012-01-01

    The purpose of this report is to describe the fluorescein angiography findings in a case of Rubinstein-Taybi syndrome. Fundus photography and fluorescein angiography were performed on a 6-year-old male with Rubinstein-Taybi syndrome due to CREB binding protein gene mutation. Fundus photography showed glaucomatous cupping and diffusely attenuated retinal vasculature. Choroidal vasculature was prominent due to diffuse retinal atrophy with scattered focal retinal pigment epithelial changes. Fluorescein angiography showed retinal vascular attenuation, prolonged arteriovenous transit time with delayed venous filling, late small vessel leakage, and 360 degrees of peripheral avascularity. Peripheral retinal avascularity and retinal vascular inflammation evidenced by late small vessel leakage can be demonstrated by fluorescein angiography in the retinal dystrophy of Rubinstein-Taybi syndrome. PMID:22942640

  14. [Photocoagulation in diabetes mellitus--our results].

    PubMed

    Stankiewicz, A; Szczuka, A; Bakunowicz-Lazarczyk, A; Zywalewski, B

    1989-01-01

    Fifty six diabetic patients aged 25-74 were under ophthalmological control in the period 1984-87. The mean time of duration of diabetes amounted 14 years. In 29 persons diabetes was insulinodependent and in the remaining insulino-independent. In 11 eyes the fundus exhibited diabetic changes with characteristics of angiopathy, in 43 eyes--of exudative retinopathy and in 58 eyes of proliferative retinopathy. Photocoagulation with a xenon-arc lamp of the diabetic changes was performed in all the patients. In dependence of the extent of the changes one used either a focused or a panretinal photocoagulation. In the majority of cases one could stop the progress of the diabetic changes on the fundus and preserve a fair visual acuity. PMID:2638444

  15. Retrieving clinically relevant diabetic retinopathy images using a multi-class multiple-instance framework

    NASA Astrophysics Data System (ADS)

    Chandakkar, Parag S.; Venkatesan, Ragav; Li, Baoxin

    2013-02-01

    Diabetic retinopathy (DR) is a vision-threatening complication from diabetes mellitus, a medical condition that is rising globally. Unfortunately, many patients are unaware of this complication because of absence of symptoms. Regular screening of DR is necessary to detect the condition for timely treatment. Content-based image retrieval, using archived and diagnosed fundus (retinal) camera DR images can improve screening efficiency of DR. This content-based image retrieval study focuses on two DR clinical findings, microaneurysm and neovascularization, which are clinical signs of non-proliferative and proliferative diabetic retinopathy. The authors propose a multi-class multiple-instance image retrieval framework which deploys a modified color correlogram and statistics of steerable Gaussian Filter responses, for retrieving clinically relevant images from a database of DR fundus image database.

  16. Three-dimensional segmentation and reconstruction of the retinal vasculature from spectral-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Guimarães, Pedro; Rodrigues, Pedro; Celorico, Dirce; Serranho, Pedro; Bernardes, Rui

    2015-01-01

    We reconstruct the three-dimensional shape and location of the retinal vascular network from commercial spectral-domain (SD) optical coherence tomography (OCT) data. The two-dimensional location of retinal vascular network on the eye fundus is obtained through support vector machines classification of properly defined fundus images from OCT data, taking advantage of the fact that on standard SD-OCT, the incident light beam is absorbed by hemoglobin, creating a shadow on the OCT signal below each perfused vessel. The depth-wise location of the vessel is obtained as the beginning of the shadow. The classification of crossovers and bifurcations within the vascular network is also addressed. We illustrate the feasibility of the method in terms of vessel caliber estimation and the accuracy of bifurcations and crossovers classification.

  17. Clinical results of fluorescence lifetime imaging in ophthalmology

    NASA Astrophysics Data System (ADS)

    Schweitzer, D.; Quick, S.; Klemm, M.; Hammer, M.; Jentsch, S.; Dawczynski, J.; Becker, W.

    2009-07-01

    A laser scanner ophthalmoscope was developed for in vivo fluorescence lifetime measurements at the human retina. Measurements were performed in 30 degree fundus images. The fundus was excited by pulses of 75 ps (FWHM). The dynamic fluorescence was detected in two spectral channels K1(490-560nm), K2(560-700 nm) by time-correlated single photon counting. The decay of fluorescence was three-exponentially. Local and global alterations in lifetimes were found between healthy subjects and patients suffering from age-related macular degeneration, diabetic retinopathy, and vessel occlusion. The lifetimes T1, T2, and T3 in both channels are changed to longer values in AMD and diabetic retinopathy in comparison with healthy subjects. The lifetime T2 in K1 is most sensitive to metabolic alterations in branch arterial vessel occlusion.

  18. Automated static perimetry to evaluate diabetic retinopathy.

    PubMed Central

    Federman, J L; Lloyd, J

    1984-01-01

    The Octopus automated static perimeter was used to evaluate patients with early diabetic retinopathy. It showed islands of threshold sensitivity depression that were equal to areas of nonperfusion seen on fluorescein angiography. The geographic area of the fundus at risk of developing these field defects was found to be between 20 and 45 degrees, representing the central area of the midperiphery. This procedure has potential as an excellent screening test for early diabetic retinopathy. Images FIGURE 1 (Cont'd) C PMID:6549516

  19. Late onset Leber's optic neuropathy: a case confused with ischaemic optic neuropathy.

    PubMed Central

    Borruat, F X; Green, W T; Graham, E M; Sweeney, M G; Morgan-Hughes, J A; Sanders, M D

    1992-01-01

    A case is reported of a 63-year-old man with progressive central visual loss in one eye followed 11 months later by involvement of the fellow eye. A diagnosis of chronic ischaemic optic neuropathy was considered. However, despite a negative family history, the absence of electrocardiographic abnormalities, and minimal fundus changes a diagnosis of Leber's optic neuropathy was made on the basis of magnetic resonance imaging findings and the mitochondrial DNA mutation at base pair 11778. Images PMID:1420066

  20. Atypical Presentation of Ocular Toxoplasmosis: A Case Report of Exudative Retinal Detachment and Choroidal Ischemia

    PubMed Central

    Al-Zahrani, Yahya A.; Al-Dhibi, Hassan A.; Al-Abdullah, Abdulelah A.

    2016-01-01

    A 24-year-old healthy male presented with a chief complaint of blurred vision in the right eye for 1-week. Fundus examination indicated right exudative retinal detachment and choroidal ischemia. The patient responded well to anti-toxoplasmosis medications and steroids. Exudative retinal detachment and choroidal ischemia are atypical presentations of ocular toxoplasmosis. However, both conditions responded well to anti.parasitic therapy with steroid. PMID:26957857

  1. Asymmetric severity of diabetic retinopathy in Waardenburg syndrome.

    PubMed

    Kashima, Tomoyuki; Akiyama, Hideo; Kishi, Shoji

    2011-01-01

    A 30-year-old female patient was referred to our institution due to vitreous hemorrhage. Best corrected visual acuity of her right and left eyes at her initial visit was 10/20 and 20/20, respectively. Although hypochromic iris was observed in the superior iris between the 10 and 2 o'clock positions in her right eye, her entire left eye exhibited hypochromic iris. Hypopigmentation of the fundus was seen in the superior part of her right eye. This eye also had a huge neovascularization on the optic disc that was 7 discs in diameter. Conversely, her left fundi showed hypopigmentation of the fundus in the entire region of the left eye, and dot hemorrhages were observed all over the left fundi, although no neovascularization could be seen microscopically. Fluorescein angiography showed a huge neovascularization in the right eye and a tiny neovascularization in the left eye. Gene analysis revealed the presence of the PAX3 gene homeobox domain mutation, which led to her being diagnosed as Waardenburg syndrome type 1. Magnetic resonance angiography showed there was no obstructive region at either of the internal carotid arteries and ophthalmic arteries. The severity of the diabetic retinopathy appeared to be correlated with the degree of hypopigmentation in the posterior fundus. We speculate that hypopigmentation of the fundus in Waardenburg syndrome may be responsible for the reduction in retinal metabolism, which led to a reduction in oxygen consumption and prevented further aggravation of the diabetic retinopathy. Only laser treatments using short wavelengths was effective in this case. While the extinction coefficient for hemoglobin when using green light is higher than when using yellow light, the differences between these wavelengths tend to disappear when oxygenated hemoglobin is present. To the best of the authors' knowledge, this is the first case report of a patient with Waardenburg syndrome and diabetic retinopathy. PMID:22205830

  2. [Hypertensive retinopathy].

    PubMed

    Genevois, Olivier; Paques, Michel

    2010-01-20

    Acute hypertensive retinopathy should be distinguished from retinal arteriolosclerosis. The presence of microvascular abnormalities in the ocular fundus increases the risk of heart and/or brain attack. At the clinical level, the current classification of chronic hypertensive retinopathy is based on the long-term risk of stroke. In research, a great number of studies are focused on the predictive value of retinal vascular diameters related to the general micro- and macrovascular disease. PMID:20222306

  3. Dual-modal whole eye photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Wu, Ning; Ren, Qiushi; Li, Changhui

    2014-09-01

    We developed a prototype dual-modal ocular imaging system integrating optical-resolution photoacoustic microscopy and high-frequency ultrasound imaging modalities. This system can perform high-resolution ocular imaging from the anterior region down to the fundus area. The novel system successfully imaged the murine eyes in vivo, including iris, lens, retina, and retinal pigment epithelium. Our results demonstrated that this system has a great potential in the diagnosis of ophthalmic diseases.

  4. Imaging Single Cells in the Living Retina

    PubMed Central

    Williams, David R.

    2011-01-01

    A quarter century ago, we were limited to a macroscopic view of the retina inside the living eye. Since then, new imaging technologies, including confocal scanning laser ophthalmoscopy, optical coherence tomography, and adaptive optics fundus imaging, transformed the eye into a microscope in which individual cells can now be resolved noninvasively. These technologies have enabled a wide range of studies of the retina that were previously impossible. PMID:21596053

  5. Continuous monitoring of the stimulated area in multifocal ERG.

    PubMed

    Seeliger; Narfstrom; Reinhard; Zrenner; Sutter

    2000-01-01

    INTRODUCTION: Multifocal electroretinography (MF-ERG) is widely used in the detection of local retinal dysfunction. However, the position of the stimulus on the retina and the stability of fixation are usually not directly accessible. Thus, devices have been designed for a continuous fundus visualization during recording. METHODS: MF-ERGs were recorded with a RetiScan system connected to two different Scanning-laser ophthalmoscopes (SLOs) that use either a red (633 nm) or green (415 nm) laser for stimulation, and a VERIS 4 system connected to a piggyback stimulator prototype that added the stimulus to the optical pathway of the SLO by means of a wavelength-sensitive mirror. Fundus visualization was achieved with the infrared lasers of the SLOs (780 and 835 nm). RESULTS: The most extensive study so far with a green laser stimulus in a cat model of retinal degeneration demonstrated the capability of the device to detect retinal landmarks and the different stages of degeneration. Also, the advantages of exactly reproducible stimulus positioning for averaging within and comparison between disease groups became apparent. The results with the same setup in transgenic mice suggest a pure cone origin of the responses. In humans, recordings show that fixation is sufficiently good in most subjects. It is not clear yet whether red or green laser stimulation (or both) is preferable. The results with the prototype were very similar to the MF-ERGs obtained with a standard CRT screen. CONCLUSIONS: All three devices allowed us to record MF-ERGs with continuous fundus monitoring. Although further refinements are necessary, it is obvious that fundus controlled methods will improve the reliability of MF-ERG in future research on glaucoma, transplantation studies, and evaluation of gene therapy. PMID:11117444

  6. Late-onset Stargardt-like macular dystrophy maps to chromosome 1p13

    SciTech Connect

    Kaplan, J.; Gerber, S.; Rozet, J.M.

    1994-09-01

    Stargardt`s disease (MIM 248200), originally described in 1909, is an autosomal recessive condition of childhood, characterized by a sudden and bilateral loss of central vision. Typically, it has an early onset (7 to 12 years), a rapidly progressive course and a poor final outcome. The central area of the retina (macula) displays pigmentary changes in a ring form with depigmentation and atrophy of the retinal pigmentary epithelium (RPE). Perimacular yellowish spots, termed fundus flavimaculatus, are observed in a high percentage of patients. We have recently reported the genetic mapping of Stargardt`s disease to chromosome 1p13. On the other hand, considering that fundus flavimaculatus (MIM 230100) is another form of fleck fundus disease, with a Stargardt-like retinal aspect but with a late-onset and a more progressive course, we decided to test the hypothesis of allelism between typical Stargardt`s disease and late-onset autosomal recessive fundus flavimaculatus. Significant pairwise lod scores were obtained in each of four multiplex families (11 affected individuals, 12 relatives) with four markers of the 1p13 region (Z = 4.79, 4.64, 3.07, 3.16 at loci D1S435, D1S424, D1S236, and D1S415, respectively at {theta} = 0). Multipoint analysis showed that the best estimate for location of the disease gene is between D1S424 and D1S236 (maximum lod score of 5.20) as also observed in Stargardt`s disease. Our results are consistent with the location of the gene responsible of the late-onset Stargardt-like macular dystrophy in the 1p13 region and raise the hypothesis of either allelic mutational events or contiguous genes in this chromosomal region. The question of possible relationship with some age-related macular dystrophies in now open to debate.

  7. Intraocular involvement with subretinal pigment epithelium infiltrates by mycosis fungoides.

    PubMed Central

    Erny, B. C.; Egbert, P. R.; Peat, I. M.; Shorrock, K.; Rosenthal, A. R.

    1991-01-01

    We report a case of intraocular mycosis fungoides in a 48-year-old man. The patient presented with decreased visual acuity, white subretinal lesions, and vitritis. Post-mortem histopathology revealed malignant T cell infiltrates consistent with mycosis fungoides in the retina, vitreous, and between the retinal pigment epithelium (RPE) and Bruch's membrane Focal atrophy of the RPE, along with the sub-RPE infiltrates, correlated with the clinically visible fundus lesions. Images PMID:1751471

  8. Cross-Coupled Eye Movement Supports Neural Origin of Pattern Strabismus

    PubMed Central

    Ghasia, Fatema F.; Shaikh, Aasef G.; Jacobs, Jonathan; Walker, Mark F.

    2015-01-01

    Purpose. Pattern strabismus describes vertically incomitant horizontal strabismus. Conventional theories emphasized the role of orbital etiologies, such as abnormal fundus torsion and misaligned orbital pulleys as a cause of the pattern strabismus. Experiments in animal models, however, suggested the role of abnormal cross-connections between the neural circuits. We quantitatively assessed eye movements in patients with pattern strabismus with a goal to delineate the role of neural circuits versus orbital etiologies. Methods. We measured saccadic eye movements with high-precision video-oculography in 14 subjects with pattern strabismus, 5 with comitant strabismus, and 15 healthy controls. We assessed change in eye position in the direction orthogonal to that of the desired eye movement (cross-coupled responses). We used fundus photography to quantify the fundus torsion. Results. We found cross-coupling of saccades in all patients with pattern strabismus. The cross-coupled responses were in the same direction in both eyes, but larger in the nonviewing eye. All patients had clinically apparent inferior oblique overaction with abnormal excylotorsion. There was no correlation between the amount of the fundus torsion or the grade of oblique overaction and the severity of cross-coupling. The disconjugacy in the saccade direction and amplitude in pattern strabismics did not have characteristics predicted by clinically apparent inferior oblique overaction. Conclusions. Our results validated primate models of pattern strabismus in human patients. We found no correlation between ocular torsion or oblique overaction and cross-coupling. Therefore, we could not ascribe cross-coupling exclusively to the orbital etiology. Patients with pattern strabismus could have abnormalities in the saccade generators. PMID:26024072

  9. High-Resolution Field-Of Widening in Human Eye Retina Imaging - Oral Paper

    NASA Astrophysics Data System (ADS)

    Dubinin, Alexander V.; Cherezova, Tatyana Yu.; Kudryashov, Alexey V.

    2008-01-01

    In this paper we investigate methods of widening high resolution area in fundus cameras equipped with adaptive optics. We first considered average phase correction method. It was found out that this method leads to isoplanatic patch increasing but residual error of correction between the reference sources increases. We also investigated the performance of an adaptive system with five reference sources and two correctors. For optimal corrector and reference sources positions we obtained approximately two times enlargement of isoplanatic patch area.

  10. MILES device: ocular hazard evaluation. Interim report, 1 May-30 September 1979

    SciTech Connect

    Zuclich, J.A.; Tredici, T.J.; Mikesell, G.W. Jr.; Gibbons, W.D.; Schmidt, R.E.

    1980-03-01

    This report describes an attempt to find ocular effects in the primate eye as a result of exposure to a MILES (Multiple Integrated Laser Engagement System) laser transmitter for a M16A1 rifle. The MILES device incorporates a pulsed gallium arsenide laser operating in the near infrared. For the exposure parameters reported, no ocular alterations could be detected with either a fundus camera or a direct ophthalmoscope.

  11. Quantitative television fluoroangiography - the optical measurement of dye concentrations and estimation of retinal blood flow

    SciTech Connect

    Greene, M.; Thomas, A.L. Jr.

    1985-06-01

    The development of a system for the measurement of dye concentrations from single retinal vessels during retinal fluorescein angiography is presented and discussed. The system uses a fundus camera modified for TV viewing. Video gating techniques define the areas of the retina to be studied, and video peak detection yields dye concentrations from retinal vessels. The time course of dye concentration is presented and blood flow into the retina is estimated by a time of transit technique.

  12. In vivo and in vitro investigations of retinal fluorophores in age-related macular degeneration by fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Hammer, M.; Quick, S.; Klemm, M.; Schenke, S.; Mata, N.; Eitner, A.; Schweitzer, D.

    2009-02-01

    Ocular fundus autofluorescence imaging has been introduced into clinical diagnostics recently for the observation of the age pigment lipofuscin, a precursor of age-related macular degeneration (AMD). However, a deeper understanding of the generation of single compounds contributing to the lipofuscin as well as of the role of other fluorophores such as FAD, glycated proteins, and collagen needs their discrimination by fluorescence lifetime imaging (FLIM). FLIM at the ocular fundus is performed using a scanning laser ophthalmoscope equipped with a picosecond laser source (448nm or 468nm respectively, 100ps, 80 MHz repetition rate) and dual wavelength (490-560nm and 560-7600nm) time-correlated single photon counting. A three-exponential fit of the fluorescence decay revealed associations of decay times to anatomical structures. Disease-related features are identified from alterations in decay times and-amplitudes. The in-vivo investigations in patients were paralleled by experiments in an organ culture of the porcine ocular fundus. Photo-oxidative stress was induced by exposure to blue light (467nm, 0.41 mW/mm2). Subsequent analysis (fluorescence microscopy, HPLC, LC-MS) indicated the accumulation of the pyridinium bis-retinoid A2E and its oxidation products as well as oxidized phospholipids. These compounds contribute to the tissue auto-fluorescence and may play a key role in the pathogenesis of AMD. Thus, FLIM observation at the ocular fundus in vivo enhances our knowledge on the etiology of AMD and may become a diagnostic tool.

  13. Atypical Presentation of Ocular Toxoplasmosis: A Case Report of Exudative Retinal Detachment and Choroidal Ischemia.

    PubMed

    Al-Zahrani, Yahya A; Al-Dhibi, Hassan A; Al-Abdullah, Abdulelah A

    2016-01-01

    A 24-year-old healthy male presented with a chief complaint of blurred vision in the right eye for 1-week. Fundus examination indicated right exudative retinal detachment and choroidal ischemia. The patient responded well to anti-toxoplasmosis medications and steroids. Exudative retinal detachment and choroidal ischemia are atypical presentations of ocular toxoplasmosis. However, both conditions responded well to anti.parasitic therapy with steroid. PMID:26957857

  14. Cystic endosalpingiosis presenting as chronic back pain, a case report

    PubMed Central

    2013-01-01

    A 48-year old woman presented with chronic back pain. Previous examinations had been inconclusive. Gynaecological examination revealed large cystic masses on the fundus uteri and left adnexa. Laparoscopy and histopathology showed unusually extensive cystic endosalpingiosis covering the serosa-coated uterine surface as well as the adnexa on both sides. After uneventful laparoscopic-assisted vaginal hysterectomy the patient quickly recovered and was relieved of her chronic backache. Virtual slides http://www.diagnosticpathology.diagnomx.eu/vs/1501709091077524. PMID:24299296

  15. An examination of the relation between intraocular pressure, fundal stretching and myopic pathology.

    PubMed

    McMonnies, Charles W

    2016-03-01

    Pathological myopia is one of the leading causes of visual impairment worldwide. Myopic development and progression is biomechanical and dominated by axial elongation. This clinical perspective examines some of the stretch-related fundal changes, which are associated with axial elongation and myopic pathology. The biomechanics of stretching of the fundus appears to depend on genetically and/or visual experience-based scleral changes, which reduce its thickness and elastic modulus so that it becomes more susceptible to the distending forces of intraocular pressure. These changes include reduced collagen synthesis, altered collagen fibres, tissue loss, altered proteoglycans and increased matrix metalloproteinase activity. Such changes are associated with reduced scleral rigidity and related increased potential to stretch in response to intraocular pressure. As axial elongation progresses, the sclera appears likely to continue to reduce in thickness and in its capacity to resist intraocular pressure, especially when pressure becomes elevated. Tessellation, lacquer cracks, myopic crescents, staphylomata, chorioretinal atrophy and retinal detachment are examined within a model for stretching of the fundus. Age, refractive error and axial length, for example, are associated with increased pathological progression. Myopic pathological progression can become dominated by vascular changes and include a greater risk of loss of acuity and blindness. Measures to control myopic pathology, which successfully slow or prevent stretching of the fundus, appear to be key factors in reducing or even avoiding permanent visual loss associated with this condition. For example, limiting axial elongation and related myopic fundus pathology by inhibiting changes which reduce the elastic modulus of scleral tissue is a desirable outcome from interventions to control myopia. Similarly, reducing exposure to the distending stress of elevated intraocular pressure appears to be a desirable form of

  16. Optimal Prenatal Care

    PubMed Central

    Reynolds, J. L.

    1982-01-01

    Optimal prenatal care begins before conception, when health habits can be reviewed. The most important task of the initial prenatal assessment is establishing dates. Ongoing assessments should emphasize measurement of symphisis to fundus height, maternal nutrition and screening, especially for urinary tract infection and gestational diabetes. Prenatal care is an excellent opportunity for patient education and involvement of the family. Good prenatal care is today's best health investment. PMID:21286515

  17. Tuberculosis of the oral cavity: a case report.

    PubMed

    de Aguiar, M C; Arrais, M J; Mato, M J; de Araújo, V C

    1997-11-01

    Tuberculosis of the oral mucosa was associated with pulmonary tuberculosis in a 38-year-old white man. The patient presented with multiple oral ulcerations with an irregular periphery and a granular vegetative fundus. The oral lesions antedated the findings of primary pulmonary tuberculosis, and the diagnosis was initially established histologically. Through the differential diagnosis of oral ulcerations, the dentist can play a role in the early detection of tuberculosis. PMID:9573865

  18. [Effectivity of different methods for disinfection of applanation tonometer prisms (author's transl)].

    PubMed

    Wizemann, A

    1980-01-01

    In 13,440 bacteriological investigations the effectivity of different methods for desinfection of Goldmann tonometer prisms (merfen, pantasept, sekusept steril, UV sterilizer Sklar) is tested. Sekusept steril and UV sterilizer show the quickest and most sufficient results. They cause no damage to corneal epithelium or to plastic objects. We can recommend them for desinfection of applanation tonometer prims, Goldmann's gonioscopy and fundus contact lenses as routine methods. PMID:7207970

  19. Optical coherence tomographic imaging of sub-retinal pigment epithelium lipid.

    PubMed

    Mukkamala, Sri Krishna; Costa, Rogerio A; Fung, Adrian; Sarraf, David; Gallego-Pinazo, Roberto; Freund, K Bailey

    2012-12-01

    OBJECTIVE To describe an optical coherence tomographic finding of layered hyperreflective bands beneath the retinal pigment epithelium (RPE), the so-called onion sign believed to represent lipid within a vascularized pigment epithelial detachment. METHODS This retrospective observational case series involved reviewing clinical histories of patients with the onion sign. Imaging studies analyzed included spectral-domain optical coherence tomography, color and red-free photographs, near infrared reflectance, fundus autofluorescence, and blue-light fundus autofluorescence. RESULTS A total of 22 eyes of 20 patients with sub-RPE hyperreflective bands were identified. There were 15 women and 5 men with a mean patient age of 76 years (range, 60-92 years). Snellen best-corrected visual acuities ranged from 20/25 to counting fingers, with a median of 20/80. Two patients had bilateral involvement, and 3 of 17 eyes had multifocal onion signs in the same eye. All eyes had neovascular age-related macular degeneration, with type 1 (sub-RPE) neovascularization. In all patients, the onion sign correlated with areas of yellow-gray exudates seen clinically that appeared bright on red-free and near infrared reflectance imaging. No specific fundus autofluorescence or blue-light fundus autofluorescence pattern was identified. CONCLUSIONS The onion sign refers to layered hyperreflective bands in the sub-RPE space usually associated with chronic exudation from type 1 neovascularization in patients with age-related macular degeneration. With an associated bright near infrared reflectance, these bands may correspond to lipid, collagen, or fibrin. Because the onion sign colocalizes to areas of exudation that are known to consist of lipoprotein, we propose that this finding may represent layers of precipitated lipid in the sub-RPE space. To our knowledge, this is the first report of lipid detected in the sub-RPE space on clinical examination. PMID:22892986

  20. 64Cu-ATSM Hypoxia Positron Emission Tomography for Detection of Conduit Ischemia in an Experimental Rat Esophagectomy Model

    PubMed Central

    Park, Seong Yong; Kang, Won Jun; Cho, Arthur; Chae, Ju Ri; Cho, Ye Lim; Kim, Jung Young; Lee, Ji Woong; Chung, Kyung Young

    2015-01-01

    Background We designed a hypoxia-imaging modality to detect ischemia of the gastric conduit after esophagectomy. Materials and Methods A rat esophagectomy model was created using 12-16-week-old, 300-350 g male Sprague-Dawley rats. In the operation group (n=6), partial gastric devascularization was performed by ligating the left gastric artery and the short gastric arteries and an esophagogastric anastomosis was performed. In the control group (n=6), the esophageal-gastric junction was incised and suturing was performed without gastric devascularization. Positron emission tomography (PET) images were taken using a microPET rodent model scanner, 24 h after the initial operation, after injection of 200 μCi 64Cu-diacetyl-bis (N4-methylsemicarbazone) (64Cu-ATSM) and pimonidazole 120 mg/kg. After microPET imaging, autoradiography and immunohistochemistry were performed. Results The PET image revealed 64Cu-ATSM uptake at the fundus in the operation group 3 h after 64Cu-ATSM injection. The maximum percentage of the injected dose per gram of tissue was higher in the operation group (0.047±0.015 vs. 0.026±0.006, p=0.021). The fundus/liver ratio was also higher in the operation group (0.541±0.126 vs. 0.278±0.049, p=0.002). Upon autoradiography, 64Cu-ATSM uptake was observed in the fundus in the operation group, and was well-correlated to that observed on the PET image. Upon immunohistochemistry, expression of hypoxia-inducible factor 1a and pimonidazole were significantly increased at the fundus and lesser curvature compared to the greater curvature in the operation group. Conclusion Hypoxia PET imaging with 64Cu-ATSM can detect ischemia in a rat esophagectomy model. Further clinical studies are needed to verify whether hypoxia imaging may be useful in humans. PMID:26098420

  1. A portable monocular indirect ophthalmoscopic technique.

    PubMed

    Sislowitz, M J

    1975-01-01

    A simple, inexpensive, and portable method of monocular indirect ophthalmoscopy is used as the physician's examining eye is aligned in the axis of the patient's eye, a flashlight is held against the examiner's malar area beneath the dominant eye, and the beam of the flashlight is directed to the patient's eye. A plus 30 lens is then interposed 1 or 2 inches in front of the patient's eye and the fundus viewed. PMID:1110195

  2. Evidence for VIP1/PACAP receptors in the afferent pathway mediating surgery-induced fundic relaxation in the rat

    PubMed Central

    Boeckxstaens, G E; Hollmann, M; Heisterkamp, S H; Robberecht, P; de Jonge, W J; van den Wijngaard, R M J G J; Tytgat, G N J; Blommaart, P J E

    2000-01-01

    We previously reported activation of an inhibitory adrenergic and a non-adrenergic non-cholinergic (NANC) pathway during abdominal surgery relaxing the rat gastric fundus. In the present study, we investigated the possible role of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) in the NANC part of the surgery-induced fundic relaxation. The effect of the NO biosynthesis inhibitor NG-nitro-L-arginine (L-NOARG), the non-selective VIP receptor antagonist [D-p-Cl-Phe6,Leu17]-VIP and the selective VIP1 receptor antagonist [Acetyl-His1,D-Phe2,Lys15,Arg16,Leu17]-VIP was investigated on the non-adrenergic fundic relaxation induced by manipulation of the small intestine followed by resection of the caecum. Guanethidine partly reduced the manipulation-induced fundic relaxation. Addition of L-NOARG reduced this non-adrenergic component, whereas the non-selective VIP receptor antagonist had no significant effect. Combination of L-NOARG and the non-selective VIP antagonist however further reduced the relaxation to manipulation. The selective VIP1 receptor antagonist reduced the mean and maximal relaxation induced by abdominal surgery in the presence of guanethidine. When combined with L-NOARG, the relaxation of the gastric fundus was almost completely abolished. The VIP1 receptor antagonist alone had no significant effect on the mean and maximal relaxation, but enhanced recovery of fundic tone. In conclusion, as VIP1 receptors are not present in the rat gastric fundus, these results suggest that the NANC inhibitory pathway activated during abdominal surgery involves VIP1 receptors, most likely in the afferent limb. The inhibitory neurotransmitters released at the level of the gastric fundus smooth muscle are NO and a substance different from VIP. PMID:11030719

  3. Pharmacological action of DA-9701 on the motility of feline stomach circular smooth muscle.

    PubMed

    Nguyen, Thanh Thao; Song, Hyun Ju; Ko, Sung Kwon; Sohn, Uy Dong

    2015-03-01

    DA-9701, a new prokinetic agent for the treatment of functional dyspepsia, is formulated with Pharbitis semen and Corydalis tuber. This study wasconducted to determine the pharmacological action of DA-9701 and to identify the receptors involved in DA-9701 -induced contractile responsesin the feline gastric corporal, fundic and antral circular smooth muscle. Concentration-response curve to DA-9701 was established. The tissue trips were exposed to methylsergide, ketanserin, ondansetron, GR 113808, atropine and dopamine before administration of DA-9701. The contractile force was determined before and after administration of drugs by a polygraph.DA-9701 enhanced the spontaneous contractile amplitude of antrum, corpus and fundus. However, it did not change the spontaneous contractile frequency of antrum and corpus, but concentration-dependently reduced that of fundus. In the fundus, DA-9701 -induced tonic contractions were inhibited by dopamine, methylsergide, ketanserine, ondansetron or GR 113808 respectively, but not by atropine, indicating that the contractile responses are mediated by multiple receptors: 5-HT2, 5-HT3, 5-HT4, and dopamine receptors. In the corpus, DA-9701-induced contractions were blocked by atropine, dopamine or GR 113808, but not by methysergide, ketanserin or ondansetron, indicating that they are involved in receptors on both, smooth muscles and neurons: 5-HT4 and dopamine receptors. However, contractile responses to DA-9701 are mainly mediated by dopamine receptors in the antrum. These results suggest that DA-9701 has important roles in gastric accommodation by enhancing tonic activity of fundus, and in gastric emptying and gastrointestinal transit by phasic contractions of corpus and antrum mediated by multiple receptors. PMID:25980179

  4. Prevalence, distribution and pattern of gastric lesions in slaughtered pigs in south-western Nigeria.

    PubMed

    Omotosho, Oladipo O; Emikpe, Benjamin O; Lasisi, Olalekan T; Jarikre, Theophilus A

    2016-01-01

    Gastric lesions, especially ulceration, cause significant economic losses in the swine industry worldwide. The study was designed to assess its prevalence, distribution and pattern in pigs in south-western Nigeria. Slaughter house surveys were conducted on three government-established abattoirs in Lagos, Ogun and Oyo states. Stomachs from 480 pigs were assessed for gross lesions, which were graded using a modification of a standard technique. Tissues from different regions of the stomach were routinely stained to assess histopathologic changes. Data were presented as frequency counts and analysed using analysis of variance and chi-square technique. Significance was determined at p ≤ 0.05. Gastric lesions were encountered across the four regions of the stomach with a point prevalence of 57.29%. The prevalence of lesions in the non-glandular region was 32.9%, with severe hyperkeratosis (13.13%) being most frequently observed (p < 0.05). Erosions were significantly higher in the cardia (8.54%) (p < 0.05), followed by fundus (8.33%). Gastric ulcers were significantly higher in the fundus (19.58%) (p < 0.05). Scars of healed ulcers and lacerations were also observed in the fundus (5.42%) (p < 0.05). The gastric lesion distribution across the four regions of the stomach and the occurrence of ulceration in the fundus showed an unusual pattern, which is rarely reported in other parts of the world. The reason for these findings in pigs in Nigeria is not fully understood; therefore, further studies are required to identify and manage these factors for increased productivity, improved animal welfare and enhanced food security. PMID:27247073

  5. Enhanced sympathetic nerve activity induced by neonatal colon inflammation induces gastric hypersensitivity and anxiety-like behavior in adult rats.

    PubMed

    Winston, John H; Sarna, Sushil K

    2016-07-01

    Gastric hypersensitivity (GHS) and anxiety are prevalent in functional dyspepsia patients; their underlying mechanisms remain unknown largely because of lack of availability of live visceral tissues from human subjects. Recently, we demonstrated in a preclinical model that rats subjected to neonatal colon inflammation show increased basal plasma norepinephrine (NE), which contributes to GHS through the upregulation of nerve growth factor (NGF) expression in the gastric fundus. We tested the hypothesis that neonatal colon inflammation increases anxiety-like behavior and sympathetic nervous system activity, which upregulates the expression of NGF to induce GHS in adult life. Chemical sympathectomy, but not adrenalectomy, suppressed the elevated NGF expression in the fundus muscularis externa and GHS. The measurement of heart rate variability showed a significant increase in the low frequency-to-high frequency ratio in GHS vs. the control rats. Stimulus-evoked release of NE from the fundus muscularis externa strips was significantly greater in GHS than in the control rats. Tyrosine hydroxylase expression was increased in the celiac ganglia of the GHS vs. the control rats. We found an increase in trait but not stress-induced anxiety-like behavior in GHS rats in an elevated plus maze. We concluded that neonatal programming triggered by colon inflammation upregulates tyrosine hydroxylase in the celiac ganglia, which upregulates the release of NE in the gastric fundus muscularis externa. The increase of NE release from the sympathetic nerve terminals concentration dependently upregulates NGF, which proportionately increases the visceromotor response to gastric distention. Neonatal programming concurrently increases anxiety-like behavior in GHS rats. PMID:27151940

  6. Frequency Domain Optical Coherence Tomography Techniques in Eye Imaging

    NASA Astrophysics Data System (ADS)

    Wojtkowski, M.; Kowalczyk, A.; Targowski, P.; Gorczyñska, I.

    2000-12-01

    This contribution presents an application of frequency-domain optical tomography to ophthalmology. Essential theoretical foundations of time-domain and frequency-domain optical tomography are presented. Images of sections through the anterior chamber, the corneo-scleral angle and fundus of the eye are reconstructed from the spectral fringes. The morphological information gained by tomograms is important for diagnosing and planning of a treatment of glaucoma.

  7. Acute gastric volvulus associated with wandering spleen in an adult treated laparoscopically after endoscopic reduction: a case report.

    PubMed

    Omata, Jiro; Utsunomiya, Katsuyuki; Kajiwara, Yoshiki; Takahata, Risa; Miyasaka, Nobuo; Sugasawa, Hidekazu; Sakamoto, Naoko; Yamagishi, Yoji; Fukumura, Makiko; Kitagawa, Daiki; Konno, Mitsuhiko; Okusa, Yasushi; Murayama, Michinori

    2016-12-01

    A 43-year-old female was referred to our hospital for sudden onset of abdominal pain, fullness, and vomiting. Physical examination revealed abdominal distension with mild epigastric tenderness. Abdominal radiography showed massive gastric distension and plain computed tomography (CT) a markedly enlarged stomach filled with gas and fluid. A large volume of gastric contents was suctioned out via a nasogastric (NG) tube. Contrast-enhanced CT showed a grossly distended stomach with displacement of the antrum above the gastroesophageal junction, and the spleen was dislocated inferiorly. Upper gastrointestinal (GI) series showed the greater curvature to be elevated and the gastric fundus to be lower than normal. Acute mesenteroaxial gastric volvulus was diagnosed. GI endoscopy showed a distortion of the gastric anatomy with difficulty intubating the pylorus. Various endoscopic maneuvers were required to reposition the stomach, and the symptoms showed immediate and complete solution. GI fluoroscopy was performed 3 days later. Initially, most of the contrast medium accumulated in the fundus, which was drawn prominently downward, and then began flowing into the duodenum with anteflexion. Elective laparoscopic surgery was performed 1 month later. The stomach was in its normal position, but the fundus was folded posteroinferiorly. The spleen attached to the fundus was normal in size but extremely mobile. We diagnosed a wandering spleen based on the operative findings. Gastropexy was performed for the treatment of gastric volvulus and wandering spleen. The patient remained asymptomatic, and there was no evidence of recurrence during a follow-up period of 24 months. This report describes a rare adult case of acute gastric volvulus associated with wandering spleen. Because delay in treatment can result in lethal complications, it is critical to provide a prompt and correct diagnosis and surgical intervention. We advocate laparoscopic surgery after endoscopic reduction because

  8. Light microscopy and scanning electron microscopy study on microstructure of gallbladder mucosa in pig.

    PubMed

    Prozorowska, Ewelina; Jackowiak, Hanna

    2015-03-01

    The present light microscopy (LM) and scanning electron microscopy (SEM) studies on porcine gallbladder mucosa provide a description of the microstructures of great functional importance such as mucosal folds, the epithelium, glands, and lymphatic nodules. The results showed the regional structural differences of the porcine gallbladder wall. Depending on the part of the gallbladder, three types of mucosal structures were described: simple and branched folds and mucosal crypts. An important structural feature found in the mucosa is connected with the structural variety of type of mucosal folds, which change from simple located in the neck, to most composed, i.e., branched or joined, in the polygonal crypts toward the fundus of the gallbladder. The morphometric analysis showed statistically significantly differences in the form and size of the folds and between the fundus, body, and neck of the gallbladder. Differences in the size of mucosal epithelium are discussed in terms of processes of synthesis and secretion of glycoproteins. Regional, species-specific differences in morphology of mucosal subepithelial glands, i.e., their secretory units and openings, and intensity of mucus secretion were described. Our results on the pig gallbladder show adaptation and/or specialization in particular areas of the mucosa for (1) secretion of mucus in the neck or body of gallbladder and (2) for cyclic volume changes, especially in the fundus of gallbladder. The description of the microstructures of mucosa in the porcine gallbladder could be useful as reference data for numerous experiments on the bile tract in the pig. PMID:25604381

  9. The Diabetic Retinopathy Screening Workflow: Potential for Smartphone Imaging.

    PubMed

    Bolster, Nigel M; Giardini, Mario E; Bastawrous, Andrew

    2015-01-01

    Complications of diabetes mellitus, namely diabetic retinopathy and diabetic maculopathy, are the leading cause of blindness in working aged people. Sufferers can avoid blindness if identified early via retinal imaging. Systematic screening of the diabetic population has been shown to greatly reduce the prevalence and incidence of blindness within the population. Many national screening programs have digital fundus photography as their basis. In the past 5 years several techniques and adapters have been developed that allow digital fundus photography to be performed using smartphones. We review recent progress in smartphone-based fundus imaging and discuss its potential for integration into national systematic diabetic retinopathy screening programs. Some systems have produced promising initial results with respect to their agreement with reference standards. However further multisite trialling of such systems' use within implementable screening workflows is required if an evidence base strong enough to affect policy change is to be established. If this were to occur national diabetic retinopathy screening would, for the first time, become possible in low- and middle-income settings where cost and availability of trained eye care personnel are currently key barriers to implementation. As diabetes prevalence and incidence is increasing sharply in these settings, the impact on global blindness could be profound. PMID:26596630

  10. Gastric Wall Thickness in Sleeve Gastrectomy Patients: Thickness Variation of the Gastric Wall.

    PubMed

    van Rutte, Pim W J; Naagen, Bertus J; Spek, Marinus; Jakimowicz, Jack J; Nienhuijs, Simon W

    2015-11-01

    The sleeve gastrectomy has been accepted as a primary bariatric procedure. One of the most feared complications is staple line leakage. It is important to use the right staple sizes to minimize the risk of leak. Knowledge of gastric thickness is important. The goal of this study was to measure the thickness of the gastric wall after elimination of the gastric folds in the mucosa. An electronic thickness gauge was developed that measured the anterior and posterior wall of the fresh stomach specimen together at 5 points at a pressure based on the finger pressure necessary to flatten the gastric folds. Thirty-three fresh specimens were measured. The mean compression pressure was 714 grams, and no difference was found between the 5 measure points. There was a significant difference in stomach wall thickness. The gastric antrum was more than 1 mm thicker than the fundus. No difference was found between BMI groups <40 Kg/m2, 40-50 Kg/m2, or >50 Kg/m2. No bleeding occurred, leakage occurred in 1 case. There is a significant difference in thickness of the stomach wall between the gastric fundus and the antrum. A pressure 2.5 times lower than applied in prior studies was necessary to achieve full tissue compression. Choosing thinner staple sizes for the gastric fundus might be the optimal technique for compression. However, there are several additional factors that influence the risk of staple line leaks. PMID:26680415

  11. Association between Blood Lead Levels and Age-Related Macular Degeneration

    PubMed Central

    Hwang, Ho Sik; Lee, Seung Bum; Jee, Donghyun

    2015-01-01

    Purpose To investigate the association between blood lead levels and prevalence of age-related macular degeneration (AMD). Methods A nationwide population-based cross-sectional study included 4,933 subjects aged over 40 years who participated in the 2008–2012 Korean National Health and Nutrition Examination Survey, and for whom fundus photographs were available. All participants underwent a standardized interview, evaluation of blood lead concentration, and a comprehensive ophthalmic examination. Digital fundus photographs (45°) were taken of both eyes under physiological mydriasis. All fundus photographs were graded using an international classification and grading system. Results Mean blood lead levels were 3.15 μg/dL in men and 2.27 μg/dL in women (P < 0.001). After adjusting for potential confounders including age, gender, smoking status, total cholesterol levels, triglyceride levels, heart problems and strokes, the adjusted odds ratio (OR) in women for any AMD was 1.86 (95% Confidence Interval [CI], 1.03–3.36) and for early AMD was 1.92 (95% CI, 1.06–3.48), for those in the highest quintile of lead level compared with the lowest quintile. In men, however, blood lead level was not significantly associated with AMD. Conclusions Blood lead levels were higher in men, but were only associated with AMD in women. Increased levels of blood lead may be involved in the pathogenesis of AMD development in women. PMID:26252225

  12. Advances in retinal imaging for diabetic retinopathy and diabetic macular edema.

    PubMed

    Tan, Colin Siang Hui; Chew, Milton Cher Yong; Lim, Louis Wei Yi; Sadda, Srinivas R

    2016-01-01

    Diabetic retinopathy and diabetic macular edema (DME) are leading causes of blindness throughout the world, and cause significant visual morbidity. Ocular imaging has played a significant role in the management of diabetic eye disease, and the advent of advanced imaging modalities will be of great value as our understanding of diabetic eye diseases increase, and the management options become increasingly varied and complex. Color fundus photography has established roles in screening for diabetic eye disease, early detection of progression, and monitoring of treatment response. Fluorescein angiography (FA) detects areas of capillary nonperfusion, as well as leakage from both microaneurysms and neovascularization. Recent advances in retinal imaging modalities complement traditional fundus photography and provide invaluable new information for clinicians. Ultra-widefield imaging, which can be used to produce both color fundus photographs and FAs, now allows unprecedented views of the posterior pole. The pathologies that are detected in the periphery of the retina have the potential to change the grading of disease severity, and may be of prognostic significance to disease progression. Studies have shown that peripheral ischemia may be related to the presence and severity of DME. Optical coherence tomography (OCT) provides structural detail of the retina, and the quantitative and qualitative features are useful in the monitoring of diabetic eye disease. A relatively recent innovation, OCT angiography, produces images of the fine blood vessels at the macula and optic disc, without the need for contrast agents. This paper will review the roles of each of these imaging modalities for diabetic eye disease. PMID:26953028

  13. Ultrahigh-speed imaging of the rat retina using ultrahigh-resolution spectral/Fourier domain OCT

    NASA Astrophysics Data System (ADS)

    Liu, Jonathan J.; Potsaid, Benjamin; Chen, Yueli; Gorczynska, Iwona; Srinivasan, Vivek J.; Duker, Jay S.; Fujimoto, James G.

    2010-02-01

    We performed OCT imaging of the rat retina at 70,000 axial scans per second with ~3 μm axial resolution. Three-dimensional OCT (3D-OCT) data sets of the rat retina were acquired. The high speed and high density data sets enable improved en face visualization by reducing eye motion artifacts and improve Doppler OCT measurements. Minimal motion artifacts were visible and the OCT fundus images offer more precise registration of individual OCT images to retinal fundus features. Projection OCT fundus images show features such as the nerve fiber layer, retinal capillary networks and choroidal vasculature. Doppler OCT images and quantitative measurements show pulsatility in retinal blood vessels. Doppler OCT provides noninvasive in vivo quantitative measurements of retinal blood flow properties and may benefit studies of diseases such as glaucoma and diabetic retinopathy. Ultrahigh speed imaging using ultrahigh resolution spectral / Fourier domain OCT promises to enable novel protocols for measuring small animal retinal structure and retinal blood flow. This non-invasive imaging technology is a promising tool for monitoring disease progression in rat and mouse models to assess ocular disease pathogenesis and response to treatment.

  14. Pattern of blood vessels in eyes with coloboma

    PubMed Central

    Lingam, Gopal

    2013-01-01

    Background: Choroidal coloboma, especially with optic disc involvement affects the blood vessel (BV) pattern in the fundus. Aim: The aim of this study was to report the observations on the pattern of retinal BVs in eyes with fundus coloboma. Design: Retrospective observational study. Materials and Methods: Twenty four eyes of 19 patients with fundus coloboma and the disc involvement in the coloboma was classified according to a previous publication. Results: Four varieties of BVs were identified in the area of coloboma - BVs that were continuous with those arising from the optic disc; vessels emanating from the floor of coloboma whose continuity with central retinal artery or its branches could be indirectly established; and those emanating from the floor of coloboma whose continuity with central retinal artery could not be established. In addition, extraocular BVs were visible through the thinned sclera. The retinal BVs often traversed the coloboma to reach the normal retina. The disc itself was found to be small and had no physiological cup (if not colobomatous). Conclusions: One should be aware of the major BVs transgressing the coloboma while performing relaxing cuts in the intercalary membrane, during the surgery for retinal detachments in eyes with coloboma. Physiological cup is usually absent (when the disc is not colobomatous). Hence, any cupping in such eyes should be viewed with suspicion. PMID:24413826

  15. Bietti crystalline retinal dystrophy with subfoveal neurosensory detachment and congenital tortuosity of retinal vessels: case report.

    PubMed

    Padhi, Tapas Ranjan; Kesarwani, Siddharth; Jalali, Subhadra

    2011-06-01

    A 34-year-old man presented with reduction and distortion of vision in both the eyes. The best-corrected vision was 20/20 parts, N6 in either eye. The external and slit lamp examination of both the eyes was unremarkable. The fundus examination showed multiple intraretinal crystalline deposits at the posterior pole, extending up to midperiphery, tortuous retinal blood vessels with S-shaped deflections, and absent foveal reflex in both the eyes. There were no corneal crystals, and the color vision was defective in both the eyes. Fundus autofluorescence and fundus fluorescein angiogram (FFA) were suggestive of geographic areas of retinal pigment epithelium (RPE) and choriocapillary (CC) loss. OCT revealed subfoveal neurosensory detachment. Flash ERG and EOG were normal except for a slight decrease in amplitude and delay in latency of pattern ERG waveforms. The Humphrey's visual field showed paracentral scotoma with reduction in the amplitude of waveforms from the corresponding area in the multifocal ERG in both the eyes. Systemic evaluation for crystalline retinopathy was unremarkable. He was diagnosed to be a case of Bietti crystalline retinopathy (local/regional variant). The subfoveal neurosensory detachment could represent early RPE dysfunction caused by these crystals and could account for the mild visual disturbance in both the eyes. Retinal vascular tortuosity and neurosensory detachment seen in this case is the first time to be reported in literature. PMID:21611771

  16. A YAC contig encompassing the recessive Stargardt disease gene (STGD) on chromosome 1p

    SciTech Connect

    Anderson, K.L.; Lewis, R.A.; Chinault, A.C.

    1995-12-01

    Stargardt disease (STGD) and fundus flavimaculatus are infrequent autosomal recessive conditions characterized by a juvenile macular dystrophy and variable degrees of peripheral retinal changes. Linkage analysis performed in 47 STGD/fundus flavimaculatus families demonstrated significant linkage to 13 polymorphic DNA markers on chromosome 1p. The maximum combined two-point lod score was 32.7 (maximum recombination fraction [{theta}{sub max}] = .006) with the polymorphic marker D1S188. Our data demonstrate that STGD and fundus flavimaculatus are the same disorder clinically and genetically and provide further evidence for genetic homogeneity of this phenotype. Analysis of recombination on disease chromosomes placed the STGD gene within a 4-cM interval between markers D1S435 and D1S236. A physical map was constructed of a YAC contig flanking STGD, from markers D1S500 to D1S495, and includes the critical interval delineated by historical recombinants. This contig spans {approximately}31 cM, with one gap (3-5 cM) that is outside the 4-cM critical region. Localization of STGD to a single YAC contig will facilitate its positional cloning. 75 refs., 3 figs., 21 tabs.

  17. Training simulator for retinal laser photocoagulation: a new approach for surgeons' apprenticeships

    NASA Astrophysics Data System (ADS)

    Dubois, Patrick; Meseure, Philippe; Peugnet, Frederic; Rouland, Jean-Francois

    1998-06-01

    Retinal laser photocoagulation is a current practice in many eye diseases therapy. Its mastering requires a specific training usually made on actual patients with some risks. The authors present a new device aimed to deliver a complete training separated from the therapeutic practice. This training simulator is built around the actual instrument to comply with the required realism. The instrumental functionalities of the device give the residents the same operating conditions as in the actual practice. The eye fundus visualization is simulated by virtual images, based on actual fundus pictures. They are computed at the rate of 10-12 frames/second according to the adjustments and manipulations of the 3-mirror lens made by the operator. All the pictures are combined in a fundus database planned to collect a wide variety of pathologies. The pedagogical functionalities are gathered in the user's interface. The two major guidelines of the developed software was to achieve an easy to use interface and to enforce no 'school dependent' rules of valuation. This new pedagogical instrument runs on PC micro-computers which allows a low- cost technology and could provide a practical training to retinal photocoagulation without the patient. A clinical validation of its pedagogical efficiency is submitted in another abstract.

  18. Indirect ophthalmoscopic stereo video system using three-dimensional LCD

    NASA Astrophysics Data System (ADS)

    Kong, Hyoun-Joong; Seo, Jong Mo; Hwang, Jeong Min; Kim, Hee Chan

    2009-02-01

    Binocular indirect ophthalmoscope (BIO) provides a wider view of fundus with stereopsis contrary to the direct one. Proposed system is composed of portable BIO and 3D viewing unit. The illumination unit of BIO utilized high flux LED as a light source, LED condensing lens cap for beam focusing, color filters and small lithium ion battery. In optics unit of BIO, beam splitter was used to distribute an examinee's fundus image both to examiner's eye and to CMOS camera module attached to device. Captured retinal video stream data from stereo camera modules were sent to PC through USB 2.0 connectivity. For 3D viewing, two video streams having parallax between them were aligned vertically and horizontally and made into side-by-side video stream for cross-eyed stereoscopy. And the data were converted into autostereoscopic video stream using vertical interlacing for stereoscopic LCD which has glass 3D filter attached to the front side of it. Our newly devised system presented the real-time 3-D view of fundus to assistants with less dizziness than cross-eyed stereoscopy. And the BIO showed good performance compared to conventional portable BIO (Spectra Plus, Keeler Limited, Windsor, UK).

  19. High resolution retinal image restoration with wavefront sensing and self-extracted filtering

    NASA Astrophysics Data System (ADS)

    Yang, Shuyu; Erry, Gavin; Nemeth, Sheila; Mitra, Sunanda; Soliz, Peter

    2005-04-01

    Diagnosis and treatment of retinal diseases such as diabetic retinopathy commonly rely on a clear view of the retina. The challenge in obtaining high quality retinal image lies in the design of the imaging system that can reduce the strong aberrations of the human eye. Since the amplitudes of human eye aberrations decrease rapidly as the aberration order goes up, it is more cost-effective to correct low order aberrations with adaptive optical devices while process high order aberrations through image processing. A cost effective fundus imaging device that can capture high quality retinal images with 2-5 times higher resolution than conventional retinal images has been designed [1]. This imager improves image quality by attaching complementary adaptive optical components to a conventional fundus camera. However, images obtained with the high resolution camera are still blurred due to some uncorrected aberrations as well as defocusing resulting from non-isoplanatic effect. Therefore, advanced image restoration algorithms have been employed for further improvement in image quality. In this paper, we use wavefront-based and self-extracted blind deconvolution techniques to restore images captured by the high resolution fundus camera. We demonstrate that through such techniques, pathologies that are critical to retinal disease diagnosis but not clear or not observable in the original image can be observed clearly in the restored images. Image quality evaluation is also used to finalize the development of a cost-effective, fast, and automated diagnostic system that can be used clinically.

  20. Parapapillary atrophy and optic disc region assessment (PANDORA): retinal imaging tool for assessment of the optic disc and parapapillary atrophy

    NASA Astrophysics Data System (ADS)

    Lu, Cheng-Kai; Tang, Tong Boon; Laude, Augustinus; Dhillon, Baljean; Murray, Alan F.

    2012-10-01

    We describe a computer-aided measuring tool, named parapapillary atrophy and optic disc region assessment (PANDORA), for automated detection and quantification of both the parapapillary atrophy (PPA) and the optic disc (OD) regions in two-dimensional color retinal fundus images. The OD region is segmented using a combination of edge detection and ellipse fitting methods. The PPA region is identified by the presence of bright pixels in the temporal zone of the OD, and it is segmented using a sequence of techniques, including a modified Chan-Vese approach, thresholding, scanning filter, and multiseed region growing. PANDORA has been tested with 133 color retinal images (82 with PPA; 51 without PPA) drawn randomly from the Lothian Birth Cohort (LBC) database, together with a "ground truth" estimate from an ophthalmologist. The PPA detection rate is 89.47% with a sensitivity of 0.83 and a specificity of 1. The mean accuracy in defining the OD region is 81.31% (SD=10.45) when PPA is present and 95.32% (SD=4.36) when PPA is absent. The mean accuracy in defining the PPA region is 73.57% (SD=11.62). PANDORA demonstrates for the first time how to quantify the OD and PPA regions using two-dimensional fundus images, enabling ophthalmologists to study ocular diseases related to PPA using a standard fundus camera.

  1. Decreased choroidal thickness in eyes with secondary angle closure glaucoma. An aetiological factor for deep retinal changes in glaucoma?

    PubMed Central

    Kubota, T.; Jonas, J. B.; Naumann, G. O.

    1993-01-01

    A decreased count of retinal photoreceptors all over the fundus and a loss of retinal pigment epithelium cells mainly in the parapapillary region have been reported to be associated with glaucoma. This study addressed the question whether this cell loss in the deep retinal layers may be connected with a change of the choroidal thickness in glaucomatous eyes. Histological sections of 12 eyes with secondary angle closure glaucoma due to a malignant melanoma of the ciliary body and 20 eyes with a malignant choroidal melanoma and normal intraocular pressure were histomorphometrically evaluated. Before enucleation the intraocular pressure was significantly higher in the glaucoma group compared with the control group. Thickness of the choroid was measured at 12 locations from the posterior pole to the fundus periphery. The choroid was significantly thinner in the glaucoma group than in the control group. The decreased choroidal thickness was mainly due to a diminished choroidal vessel diameter. The differences were more marked at the optic disc border than in the fundus periphery. The decreased choroidal thickness in the glaucomatous eyes suggests a reduced choroidal perfusion. It fits with the reported lack of autoregulation of the choroidal blood circulation. Considering the diminished choroidal thickness especially in the parapapillary region, it may be one among other factors explaining the changes of the deep retinal layers in eyes with glaucoma. It indicates that thinning of the choroid, besides the chorioretinal atrophy in the parapapillary region, should be added to the panoply of histological changes in glaucoma. Images PMID:8343472

  2. Serous retinal detachment following panretinal photocoagulation (PRP) using Pattern Scan Laser (PASCAL) photocoagulator

    PubMed Central

    Azar, Georges; Wolff, Benjamin; Cornut, Pierre-Loïc; Mauget-Faÿsse, Martine

    2012-01-01

    Objective: To report a case of serous retinal detachment after Pattern Scan Laser (PASCAL) treatment in a diabetic woman. Methods: A 34-year-old diabetic woman presented with florid diabetic retinopathy after a miscarriage during the 20th week of pregnancy. Her Best Corrected Visual Acuity (BCVA) was 20/40 right eye (OD) and 20/30 left eye (OS). Fundus exam showed multiple microaneurysms, large blot hemorrhages and venous dilation both eyes (OU). Fundus fluorescein angiography (FFA) revealed large areas of capillary nonperfusion and panretinal neovascularisation in all quadrants OU. Macular Spectral-Domain Optical Coherence Tomography scan (SD-OCT) did not show any foveal thickening. Panretinal photocoagulation (PRP) was immediately performed OU during the same day. Results: Two days after PASCAL treatment, her BCVA decreased to 20/80 OU and worsened to Count Fingers (CF) during the following days. Fundus exam revealed an extensive serous retinal detachment confirmed on SD-OCT. 2 sub-conjunctival injections of 0.1 ml Betamethasone were done OU. One month later, BCVA improved to 20/30 and SD-OCT confirmed regression of retinal detachment. Conclusions: PASCAL is considered to be a safe treatment, but one has to be aware of its potential side effects. It has to be used with caution in pregnant women.

  3. A YAC contig encompassing the recessive Stargardt disease gene (STGD) on chromosome 1p.

    PubMed Central

    Anderson, K L; Baird, L; Lewis, R A; Chinault, A C; Otterud, B; Leppert, M; Lupski, J R

    1995-01-01

    Stargardt disease (STGD) and fundus flavimaculatus are infrequent autosomal recessive conditions characterized by a juvenile macular dystrophy and variable degrees of peripheral retinal changes. Linkage analysis performed in 47 STGD/fundus flavimaculatus families demonstrated significant linkage to 13 polymorphic DNA markers on chromosome 1p. The maximum combined two-point lod score was 32.7 (maximum recombination fraction [phi max] = .006) with the polymorphic marker D1S188. Our data demonstrate that STGD and fundus flavimaculatus are the same disorder clinically and genetically and provide further evidence for genetic homogeneity of this phenotype. Analysis of recombination events on disease chromosomes placed the STGD gene within a 4-cM interval between markers D1S435 and D1S236. A physical map was constructed of a YAC contig flanking STGD, from markers D1S500 to D1S495, and includes the critical interval delineated by historical recombinants. This contig spans approximately 31 cM, with one gap (3-5 cM) that is outside the 4-cM critical region. Localization of STGD to a single YAC contig will facilitate its positional cloning. Images Figure 3 PMID:8533764

  4. Comprehensive automatic assessment of retinal vascular abnormalities for computer-assisted retinopathy grading.

    PubMed

    Joshi, Vinayak; Agurto, Carla; VanNess, Richard; Nemeth, Sheila; Soliz, Peter; Barriga, Simon

    2014-01-01

    One of the most important signs of systemic disease that presents on the retina is vascular abnormalities such as in hypertensive retinopathy. Manual analysis of fundus images by human readers is qualitative and lacks in accuracy, consistency and repeatability. Present semi-automatic methods for vascular evaluation are reported to increase accuracy and reduce reader variability, but require extensive reader interaction; thus limiting the software-aided efficiency. Automation thus holds a twofold promise. First, decrease variability while increasing accuracy, and second, increasing the efficiency. In this paper we propose fully automated software as a second reader system for comprehensive assessment of retinal vasculature; which aids the readers in the quantitative characterization of vessel abnormalities in fundus images. This system provides the reader with objective measures of vascular morphology such as tortuosity, branching angles, as well as highlights of areas with abnormalities such as artery-venous nicking, copper and silver wiring, and retinal emboli; in order for the reader to make a final screening decision. To test the efficacy of our system, we evaluated the change in performance of a newly certified retinal reader when grading a set of 40 color fundus images with and without the assistance of the software. The results demonstrated an improvement in reader's performance with the software assistance, in terms of accuracy of detection of vessel abnormalities, determination of retinopathy, and reading time. This system enables the reader in making computer-assisted vasculature assessment with high accuracy and consistency, at a reduced reading time. PMID:25571442

  5. NEW BEST1 MUTATIONS IN AUTOSOMAL RECESSIVE BESTROPHINOPATHY

    PubMed Central

    FUNG, ADRIAN T.; YZER, SUZANNE; GOLDBERG, NAOMI; WANG, HAO; NISSEN, MICHAEL; GIOVANNINI, ALFONSO; MERRIAM, JOANNA E.; BUKANOVA, ELENA N.; CAI, CAROLYN; YANNUZZI, LAWRENCE A.; TSANG, STEPHEN H.; ALLIKMETS, RANDO

    2015-01-01

    Purpose To report the ocular phenotype in patients with autosomal recessive bestrophinopathy and carriers, and to describe novel BEST1 mutations. Methods Patients with clinically suspected and subsequently genetically proven autosomal recessive bestrophinopathy underwent full ophthalmic examination and investigation with fundus autofluorescence imaging, spectral domain optical coherence tomography, electroretinography, and electrooculography. Mutation analysis of the BEST1 gene was performed through direct Sanger sequencing. Results Five affected patients from four families were identified. Mean age was 16 years (range, 6–42 years). All affected patients presented with reduced visual acuity and bilateral, hyperautofluorescent subretinal yellowish deposits within the posterior pole. Spectral domain optical coherence tomography demonstrated submacular fluid and subretinal vitelliform material in all patients. A cystoid maculopathy was seen in all but one patient. In 1 patient, the location of the vitelliform material was seen to change over a follow-up period of 3 years despite relatively stable vision. Visual acuity and fundus changes were unresponsive to topical and systemic carbonic anhydrase inhibitors and systemic steroids. Carriers had normal ocular examinations including normal fundus autofluorescence. Three novel mutations were detected. Conclusion Three novel BEST1 mutations are described, suggesting that many deleterious variants in BEST1 resulting in haploinsufficiency are still unknown. Mutations causing autosomal recessive bestrophinopathy are mostly located outside of the exons that usually harbor vitelliform macular dystrophy–associated dominant mutations. PMID:25545482

  6. Non-responsiveness to intravitreal aflibercept treatment in neovascular age-related macular degeneration: implications of serous pigment epithelial detachment

    PubMed Central

    Nagai, Norihiro; Suzuki, Misa; Uchida, Atsuro; Kurihara, Toshihide; Kamoshita, Mamoru; Minami, Sakiko; Shinoda, Hajime; Tsubota, Kazuo; Ozawa, Yoko

    2016-01-01

    The prognosis of neovascular age-related macular degeneration (AMD) has been improved by anti-vascular endothelial growth factor treatments, including intravitreal aflibercept (IVA) treatment. However, many patients remain incurable. In this study, we retrospectively evaluated non-responsiveness to IVA monotherapy at 12 months in 133 eyes of 133 AMD patients. Sixty-two patients were initially treatment-naive, and 71 had received other treatments before IVA (the treatment-switched group). Mean best-corrected visual acuity (BCVA) was improved in the treatment-naive group but not in the treatment-switched group, although mean central retinal thickness (CRT) decreased in both groups. The respective percentages of non-responders as determined by worsened BCVA in the treatment-naive and treatment-switched groups were 8.1% and 15.5%, and via fundus findings, they were 12.9% and 8.5%. Multivariate analyses adjusted for age, gender, CRT, and greatest linear dimension showed that serous pigment epithelial detachment (PED) at baseline was associated with non-responsiveness in both groups as determined by BCVA and by fundus findings, and fibrovascular PED measurements indicated no response as determined by fundus findings in the treatment-switched group. The results reported herein may assist the formulation of appropriate treatment protocols for AMD patients. PMID:27403807

  7. An adaptive threshold based image processing technique for improved glaucoma detection and classification.

    PubMed

    Issac, Ashish; Partha Sarathi, M; Dutta, Malay Kishore

    2015-11-01

    Glaucoma is an optic neuropathy which is one of the main causes of permanent blindness worldwide. This paper presents an automatic image processing based method for detection of glaucoma from the digital fundus images. In this proposed work, the discriminatory parameters of glaucoma infection, such as cup to disc ratio (CDR), neuro retinal rim (NRR) area and blood vessels in different regions of the optic disc has been used as features and fed as inputs to learning algorithms for glaucoma diagnosis. These features which have discriminatory changes with the occurrence of glaucoma are strategically used for training the classifiers to improve the accuracy of identification. The segmentation of optic disc and cup based on adaptive threshold of the pixel intensities lying in the optic nerve head region. Unlike existing methods the proposed algorithm is based on an adaptive threshold that uses local features from the fundus image for segmentation of optic cup and optic disc making it invariant to the quality of the image and noise content which may find wider acceptability. The experimental results indicate that such features are more significant in comparison to the statistical or textural features as considered in existing works. The proposed work achieves an accuracy of 94.11% with a sensitivity of 100%. A comparison of the proposed work with the existing methods indicates that the proposed approach has improved accuracy of classification glaucoma from a digital fundus which may be considered clinically significant. PMID:26321351

  8. Changes in quantitative 3D shape features of the optic nerve head associated with age

    NASA Astrophysics Data System (ADS)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2013-02-01

    Optic nerve head (ONH) structure is an important biological feature of the eye used by clinicians to diagnose and monitor progression of diseases such as glaucoma. ONH structure is commonly examined using stereo fundus imaging or optical coherence tomography. Stereo fundus imaging provides stereo views of the ONH that retain 3D information useful for characterizing structure. In order to quantify 3D ONH structure, we applied a stereo correspondence algorithm to a set of stereo fundus images. Using these quantitative 3D ONH structure measurements, eigen structures were derived using principal component analysis from stereo images of 565 subjects from the Ocular Hypertension Treatment Study (OHTS). To evaluate the usefulness of the eigen structures, we explored associations with the demographic variables age, gender, and race. Using regression analysis, the eigen structures were found to have significant (p < 0.05) associations with both age and race after Bonferroni correction. In addition, classifiers were constructed to predict the demographic variables based solely on the eigen structures. These classifiers achieved an area under receiver operating characteristic curve of 0.62 in predicting a binary age variable, 0.52 in predicting gender, and 0.67 in predicting race. The use of objective, quantitative features or eigen structures can reveal hidden relationships between ONH structure and demographics. The use of these features could similarly allow specific aspects of ONH structure to be isolated and associated with the diagnosis of glaucoma, disease progression and outcomes, and genetic factors.

  9. Two-dimensional segmentation of the retinal vascular network from optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Rodrigues, Pedro; Guimarães, Pedro; Santos, Torcato; Simão, Sílvia; Miranda, Telmo; Serranho, Pedro; Bernardes, Rui

    2013-12-01

    The automatic segmentation of the retinal vascular network from ocular fundus images has been performed by several research groups. Although different approaches have been proposed for traditional imaging modalities, only a few have addressed this problem for optical coherence tomography (OCT). Furthermore, these approaches were focused on the optic nerve head region. Compared to color fundus photography and fluorescein angiography, two-dimensional ocular fundus reference images computed from three-dimensional OCT data present additional problems related to system lateral resolution, image contrast, and noise. Specifically, the combination of system lateral resolution and vessel diameter in the macular region renders the process particularly complex, which might partly explain the focus on the optic disc region. In this report, we describe a set of features computed from standard OCT data of the human macula that are used by a supervised-learning process (support vector machines) to automatically segment the vascular network. For a set of macular OCT scans of healthy subjects and diabetic patients, the proposed method achieves 98% accuracy, 99% specificity, and 83% sensitivity. This method was also tested on OCT data of the optic nerve head region achieving similar results.

  10. Automated Detection of Microaneurysms Using Scale-Adapted Blob Analysis and Semi-Supervised Learning

    SciTech Connect

    Adal, Kedir M.; Sidebe, Desire; Ali, Sharib; Chaum, Edward; Karnowski, Thomas Paul; Meriaudeau, Fabrice

    2014-01-07

    Despite several attempts, automated detection of microaneurysm (MA) from digital fundus images still remains to be an open issue. This is due to the subtle nature of MAs against the surrounding tissues. In this paper, the microaneurysm detection problem is modeled as finding interest regions or blobs from an image and an automatic local-scale selection technique is presented. Several scale-adapted region descriptors are then introduced to characterize these blob regions. A semi-supervised based learning approach, which requires few manually annotated learning examples, is also proposed to train a classifier to detect true MAs. The developed system is built using only few manually labeled and a large number of unlabeled retinal color fundus images. The performance of the overall system is evaluated on Retinopathy Online Challenge (ROC) competition database. A competition performance measure (CPM) of 0.364 shows the competitiveness of the proposed system against state-of-the art techniques as well as the applicability of the proposed features to analyze fundus images.

  11. Advances in retinal imaging for diabetic retinopathy and diabetic macular edema

    PubMed Central

    Tan, Colin Siang Hui; Chew, Milton Cher Yong; Lim, Louis Wei Yi; Sadda, Srinivas R

    2016-01-01

    Diabetic retinopathy and diabetic macular edema (DME) are leading causes of blindness throughout the world, and cause significant visual morbidity. Ocular imaging has played a significant role in the management of diabetic eye disease, and the advent of advanced imaging modalities will be of great value as our understanding of diabetic eye diseases increase, and the management options become increasingly varied and complex. Color fundus photography has established roles in screening for diabetic eye disease, early detection of progression, and monitoring of treatment response. Fluorescein angiography (FA) detects areas of capillary nonperfusion, as well as leakage from both microaneurysms and neovascularization. Recent advances in retinal imaging modalities complement traditional fundus photography and provide invaluable new information for clinicians. Ultra-widefield imaging, which can be used to produce both color fundus photographs and FAs, now allows unprecedented views of the posterior pole. The pathologies that are detected in the periphery of the retina have the potential to change the grading of disease severity, and may be of prognostic significance to disease progression. Studies have shown that peripheral ischemia may be related to the presence and severity of DME. Optical coherence tomography (OCT) provides structural detail of the retina, and the quantitative and qualitative features are useful in the monitoring of diabetic eye disease. A relatively recent innovation, OCT angiography, produces images of the fine blood vessels at the macula and optic disc, without the need for contrast agents. This paper will review the roles of each of these imaging modalities for diabetic eye disease. PMID:26953028

  12. Long-lasting, dense scotoma under light-adapted conditions in patient with multiple evanescent white dot syndrome.

    PubMed

    Kuniyoshi, Kazuki; Sakuramoto, Hiroyuki; Sugioka, Koji; Matsumoto, Chota; Kusaka, Shunji; Shimomura, Yoshikazu

    2016-08-01

    To report the light- and dark-adapted perimetric findings in a patient with multiple evanescent white dot syndrome (MEWDS). The patient was a 25-year-old Japanese woman who underwent comprehensive ophthalmological examinations including measurements of the visual acuity, dilated ophthalmoscopy, Goldmann kinetic perimetry, electroretinography (ERG), indocyanine green fundus angiography (ICGA), and optical coherence tomography (OCT). Kinetic perimetry was performed under light- and dark-adapted conditions. The patient was diagnosed with MEWDS by the fundus and visual field findings, and the ICGA abnormalities. Light-adapted perimetry showed an enlargement of the blind spot; however, the size of the blind spot was normalized with dark-adaptation. Amplitude of cone ERG was more reduced than that of rod ERG in the affected eye. The OCT images showed multiple disruptions of the ellipsoid and interdigitation zones. These abnormalities were still present 9 months after the onset although the fundus appeared normal. These findings indicate a persistent cone-dominated dysfunction in a patient with MEWDS. PMID:26678272

  13. Spectral-Domain Optical Coherence Tomography Findings in Lipemia Retinalis.

    PubMed

    Özturk, Banu Turgut; Bozkurt, Banu; Meşen, Ali; Gonul, Saban; İpekci, Süleyman Hilmi

    2016-06-01

    Severe hypertriglyceridemia can give rise to a fundus appearance with whitish-colored retinal vessels called lipemia retinalis. A 52-year-old man with hypertriglyceridemia presented with a best-corrected visual acuity of 20/20 in both eyes and creamy-white retinal vessels on fundus. Spectral-domain optical coherence tomography (SD-OCT) revealed hyperreflective and engorged retinal vessels and white dots mainly accumulated in the inner nuclear and ganglion cell layer. Follow-up fundus examination after plasmapheresis sessions revealed normal retinal vessels. The hyperreflective appearance of the retinal vessels in OCT reversed rapidly 5 days after the treatment, whereas hyperreflective dots in retina disappeared slowly in 3 months. OCT is useful in demonstrating inner retinal changes associated with lipemia retinalis at histopathological level. The hyperreflective dots in inner retina associated with leakage from superficial retinal capillaries attested the correlation of their location with their origin. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:589-592.]. PMID:27327291

  14. Application of higher-order spectra for automated grading of diabetic maculopathy.

    PubMed

    Mookiah, Muthu Rama Krishnan; Acharya, U Rajendra; Chandran, Vinod; Martis, Roshan Joy; Tan, Jen Hong; Koh, Joel E W; Chua, Chua Kuang; Tong, Louis; Laude, Augustinus

    2015-12-01

    Diabetic macular edema (DME) is one of the most common causes of visual loss among diabetes mellitus patients. Early detection and successive treatment may improve the visual acuity. DME is mainly graded into non-clinically significant macular edema (NCSME) and clinically significant macular edema according to the location of hard exudates in the macula region. DME can be identified by manual examination of fundus images. It is laborious and resource intensive. Hence, in this work, automated grading of DME is proposed using higher-order spectra (HOS) of Radon transform projections of the fundus images. We have used third-order cumulants and bispectrum magnitude, in this work, as features, and compared their performance. They can capture subtle changes in the fundus image. Spectral regression discriminant analysis (SRDA) reduces feature dimension, and minimum redundancy maximum relevance method is used to rank the significant SRDA components. Ranked features are fed to various supervised classifiers, viz. Naive Bayes, AdaBoost and support vector machine, to discriminate No DME, NCSME and clinically significant macular edema classes. The performance of our system is evaluated using the publicly available MESSIDOR dataset (300 images) and also verified with a local dataset (300 images). Our results show that HOS cumulants and bispectrum magnitude obtained an average accuracy of 95.56 and 94.39% for MESSIDOR dataset and 95.93 and 93.33% for local dataset, respectively. PMID:25894464

  15. Response of canine lower esophageal sphincter to gastric distension.

    PubMed

    Franzi, S J; Martin, C J; Cox, M R; Dent, J

    1990-09-01

    The aim of this study was to localize the region of the stomach responsible for triggering distension-induced transient lower esophageal sphincter relaxation (TLESR). The canine stomach was partitioned into subsegments by a row of buttressed sutures. This separated either the fundus from the lesser curve or the proximal stomach from the antrum. After 1 mo each region was progressively distended while gastroesophageal pressures were monitored. At the time of the first TLESR, gastric wall tension was estimated from the bag pressure and volume. Distension of the intact stomach, lesser curve, or proximal stomach in 12 dogs produced a progressive increase in lower esophageal sphincter (LES) pressure, which was interrupted at low gastric wall tension (29, 35, and 40 mmHg.cm, respectively) by a superimposed TLESR. Background LES pressure fell progressively with distension of the antrum but was unchanged by distension of the fundus alone. Both the fundus and antrum had significantly higher thresholds for triggering TLESR (96 and 105 mmHg.cm). In another two dogs truncal vagotomy performed at the time of gastric partitioning prevented both the change in background LES pressure, and the triggering of TLESR, associated with proximal gastric and antral distension. We conclude that the subcardiac region of the stomach is primarily responsible for triggering TLESR induced by distension and that the effect on background LES pressure depends on the region distended. PMID:2399982

  16. Compound Danshen Dripping Pill for Treating Early Diabetic Retinopathy: A Randomized, Double-Dummy, Double-Blind Study

    PubMed Central

    Luo, Dan; Qin, Yali; Yuan, Wei; Deng, Hui; Zhang, Youhua; Jin, Ming

    2015-01-01

    This randomized, double-dummy, double-blind study was to observe the therapeutic effects of compound Danshen dripping pill (CDDP) in treating early diabetic retinopathy (DR). All the 57 type 2 diabetes cases in nonproliferative diabetic retinopathy (NPDR) stage were divided into two groups randomly: 28 cases treated with CDDP as the treated group and 29 cases treated with calcium dobesilate as the control group. The best corrected visual acuity (BCVA) in the treated group was significantly improved after treatment when compared to that before treatment (P < 0.05). Mean defect (MD) of visual field, hemorrhage area of the fundus, microaneurysm number, fluorescent leakage area, and capillary nonperfusion area evaluated by visual field, fundus photography, and fundus fluorescein angiography in the treated group had the same results as BCVA. However, there was no statistical difference in each index between the two groups. No obvious adverse events with clinical significance occurred. Our present study showed that CDDP has a similar improvement and safety to calcium dobesilate for NPDR. In future DR treatments, CDDP may function as the auxiliary drug. PMID:26457110

  17. Determinación de la orientación global SAO-Hipparcos mediante una expansión en armónicos vectoriales

    NASA Astrophysics Data System (ADS)

    Cionco, R. G.; Vucetich, H.; Orellana, R.; Arias, E. F.

    En base a las diferencias de posición y movimientos propios de 101352 estrellas con posición SAO observadas por HIPPARCOS y utilizando la naturaleza vectorial de esas diferencias, determinamos 6 parámetros de orientación global (3 de rotación y 3 de desplazamiento axial), para los sistemas de referencia asociados a los marcos mencionados, mediante una descomposición en serie de armónicos vectoriales ortogonales.

  18. Minimizing camera-eye optical aberrations during the 3D reconstruction of retinal structures

    NASA Astrophysics Data System (ADS)

    Aldana-Iuit, Javier; Martinez-Perez, M. Elena; Espinosa-Romero, Arturo; Diaz-Uribe, Rufino

    2010-05-01

    3D reconstruction of blood vessels is a powerful visualization tool for physicians, since it allows them to refer to qualitative representation of their subject of study. In this paper we propose a 3D reconstruction method of retinal vessels from fundus images. The reconstruction method propose herein uses images of the same retinal structure in epipolar geometry. Images are preprocessed by RISA system for segmenting blood vessels and obtaining feature points for correspondences. The correspondence points process is solved using correlation. The LMedS analysis and Graph Transformation Matching algorithm are used for outliers suppression. Camera projection matrices are computed with the normalized eight point algorithm. Finally, we retrieve 3D position of the retinal tree points by linear triangulation. In order to increase the power of visualization, 3D tree skeletons are represented by surfaces via generalized cylinders whose radius correspond to morphological measurements obtained by RISA. In this paper the complete calibration process including the fundus camera and the optical properties of the eye, the so called camera-eye system is proposed. On one hand, the internal parameters of the fundus camera are obtained by classical algorithms using a reference pattern. On the other hand, we minimize the undesirable efects of the aberrations induced by the eyeball optical system assuming that contact enlarging lens corrects astigmatism, spherical and coma aberrations are reduced changing the aperture size and eye refractive errors are suppressed adjusting camera focus during image acquisition. Evaluation of two self-calibration proposals and results of 3D blood vessel surface reconstruction are presented.

  19. Retinal Phenotypes in Patients Homozygous for the G1961E Mutation in the ABCA4 Gene

    PubMed Central

    Burke, Tomas R.; Fishman, Gerald A.; Zernant, Jana; Schubert, Carl; Tsang, Stephen H.; Smith, R. Theodore; Ayyagari, Radha; Koenekoop, Robert K.; Umfress, Allison; Ciccarelli, Maria Laura; Baldi, Alfonso; Iannaccone, Alessandro; Cremers, Frans P. M.; Klaver, Caroline C. W.; Allikmets, Rando

    2012-01-01

    Purpose. We evaluated the pathogenicity of the G1961E mutation in the ABCA4 gene, and present the range of retinal phenotypes associated with this mutation in homozygosity in a patient cohort with ABCA4-associated phenotypes. Methods. Patients were enrolled from the ABCA4 disease database at Columbia University or by inquiry from collaborating physicians. Only patients homozygous for the G1961E mutation were enrolled. The entire ABCA4 gene open reading frame, including all exons and flanking intronic sequences, was sequenced in all patients. Phenotype data were obtained from clinical history and examination, fundus photography, infrared imaging, fundus autofluorescence, fluorescein angiography, and spectral domain-optical coherence tomography. Additional functional data were obtained using the full-field electroretinogram, and static or kinetic perimetry. Results. We evaluated 12 patients homozygous for the G1961E mutation. All patients had evidence of retinal pathology consistent with the range of phenotypes observed in ABCA4 disease. The latest age of onset was recorded at 64 years, in a patient diagnosed initially with age-related macular degeneration (AMD). Of 6 patients in whom severe structural (with/without functional) fundus changes were detected, 5 had additional, heterozygous or homozygous, variants detected in the ABCA4 gene. Conclusions. Homozygous G1961E mutation in ABCA4 results in a range of retinal pathology. The phenotype usually is at the milder end of the disease spectrum, with severe phenotypes linked to the presence of additional ABCA4 variants. Our report also highlights that milder, late-onset Stargardt disease may be confused with AMD. PMID:22661473

  20. A new imaging technique for retinal vessel oximetry: principles and first clinical results in patients with retinal arterial occlusion and diabetic retinopathy

    NASA Astrophysics Data System (ADS)

    Hammer, M.; Riemer, T.; Vilser, W.; Gehlert, S.; Schweitzer, D.

    2009-02-01

    The oxygen saturation of blood inside retinal vessels is an essential measure for the estimation of oxygen supply to the tissue as well as its oxygen consumption. In the current approach, the blood oxygenation is measured by a dual-wavelength technique. Using a fundus camera, equipped with a special dual wavelength transmission filter and a color CCD camera, two monochromatic fundus images at 548 nm and 610 nm were recorded simultaneously. The optical densities of retinal vessels for both wavelengths and their ratio, which is known to be proportional to the oxygen saturation, were calculated. From a health control population, mean arterial and venous oxygen saturations were measured of 98+/-10.1% and 65+/-11.7% with reproducibility of 2.52% and 3.25% respectively. In 10 patients with arterial occlusion, a reduction of the arterial oxygen saturation to 78 +/-17% (mean +/- standard deviation, branch arterial occlusion) and 91+/-11% (central arterial occlusion) respectively was found in the occluded vessel. After 5 days on pentoxifilin therapy, the arterial saturation increased to an average of 93+/-12% or 103 +/-6% respectively. In 70 eyes of 42 patients suffering from diabetic retinopathy, an increase of the venous oxygen saturation with the severity of the retinopathy was found (mild nonproliferative retinopathy: 68.4+/-8.2%, moderate non-proliferative retinopathy: 70.5+/-6.8%, severe non-proliferative retinopathy: 72.4+/-7.6%, proliferative retinopathy 75.7+/-8.3%) due to vessel shunting and diabetic changes of the permeability of vessel walls. These first clinical results demonstrate the ability of an accurate measurement of retinal vessel oxygenation with a very simple setup just requiring a special filter in the illumination path of a fundus camera and dedicated software.

  1. Homozygosity Mapping in Leber Congenital Amaurosis and Autosomal Recessive Retinitis Pigmentosa in South Indian Families

    PubMed Central

    Srilekha, Sundaramurthy; Arokiasamy, Tharigopala; Srikrupa, Natarajan N.; Umashankar, Vetrivel; Meenakshi, Swaminathan; Sen, Parveen; Kapur, Suman; Soumittra, Nagasamy

    2015-01-01

    Leber congenital amaurosis (LCA) and retinitis pigmentosa (RP) are retinal degenerative diseases which cause severe retinal dystrophy affecting the photoreceptors. LCA is predominantly inherited as an autosomal recessive trait and contributes to 5% of all retinal dystrophies; whereas RP is inherited by all the Mendelian pattern of inheritance and both are leading causes of visual impairment in children and young adults. Homozygosity mapping is an efficient strategy for mapping both known and novel disease loci in recessive conditions, especially in a consanguineous mating, exploiting the fact that the regions adjacent to the disease locus will also be homozygous by descent in such inbred children. Here we have studied eleven consanguineous LCA and one autosomal recessive RP (arRP) south Indian families to know the prevalence of mutations in known genes and also to know the involvement of novel loci, if any. Complete ophthalmic examination was done for all the affected individuals including electroretinogram, fundus photograph, fundus autofluorescence, and optical coherence tomography. Homozygosity mapping using Affymetrix 250K HMA GeneChip on eleven LCA families followed by screening of candidate gene(s) in the homozygous block identified mutations in ten families; AIPL1 – 3 families, RPE65- 2 families, GUCY2D, CRB1, RDH12, IQCB1 and SPATA7 in one family each, respectively. Six of the ten (60%) mutations identified are novel. Homozygosity mapping using Affymetrix 10K HMA GeneChip on the arRP family identified a novel nonsense mutation in MERTK. The mutations segregated within the family and was absent in 200 control chromosomes screened. In one of the eleven LCA families, the causative gene/mutation was not identified but many homozygous blocks were noted indicating that a possible novel locus/gene might be involved. The genotype and phenotype features, especially the fundus changes for AIPL1, RPE65, CRB1, RDH12 genes were as reported earlier. PMID:26147992

  2. Whole exome sequencing identifies a novel NRL mutation in a Chinese family with autosomal dominant retinitis pigmentosa

    PubMed Central

    Gao, Meng; Zhang, Su; Liu, Chunjie; Qin, Yayun; Archacki, Stephen; Jin, Ling; Wang, Yong; Liu, Fei; Chen, Jiaxiang; Liu, Ying; Wang, Jiuxiang; Huang, Mi; Liao, Shengjie; Tang, Zhaohui; Guo, An Yuan; Liu, Mugen

    2016-01-01

    Purpose To investigate the genetic basis and its relationship to the clinical manifestations in a four generation Chinese family with autosomal dominant retinitis pigmentosa. Methods Ophthalmologic examinations including fundus photography, fundus autofluorescence imaging, fundus fluorescein angiography, optical coherence tomography, and a best-corrected visual acuity test were performed to define the clinical features of the patients. We extracted the genomic DNA from peripheral blood samples. The proband’s genomic DNA was submitted to the whole exome sequencing. Results Whole exome sequencing and the subsequent data analysis detected six candidate mutations in the proband of this pedigree. The novel c.146 C>T mutation in NRL was found to be the only mutation that co-segregated with the disease in this pedigree. This mutation resulted in a substitution of proline by a leucine at position 49 of NRL protein (p.P49L). Most importantly, the proline residue at position 49 of NRL is highly conserved from zebrafish to humans. The c.146 C>T mutation was not observed in 200 control individuals. What’s more, we performed the luciferase activity assay to prove that this mutation we detected alters the NRL protein function. Conclusions The c.146 C>T mutation in NRL gene causes autosomal dominant retinitis pigmentosa for this family. Our finding not only expands the mutation spectrum of NRL, but also demonstrates that whole-exome sequencing is a powerful strategy to detect causative genes and mutations in RP patients. This technique may provide a precise diagnosis for rare heterogeneous monogenic disorders such as RP. PMID:27081294

  3. Characterization of a Spontaneous Retinal Neovascular Mouse Model

    PubMed Central

    Hasegawa, Eiichi; Sweigard, Harry; Husain, Deeba; Olivares, Ana M.; Chang, Bo; Smith, Kaylee E.; Birsner, Amy E.; D’Amato, Robert J.; Michaud, Norman A.; Han, Yinan; Vavvas, Demetrios G.; Miller, Joan W.; Haider, Neena B.; Connor, Kip M.

    2014-01-01

    Background Vision loss due to vascular disease of the retina is a leading cause of blindness in the world. Retinal angiomatous proliferation (RAP) is a subgroup of neovascular age-related macular degeneration (AMD), whereby abnormal blood vessels develop in the retina leading to debilitating vision loss and eventual blindness. The novel mouse strain, neoretinal vascularization 2 (NRV2), shows spontaneous fundus changes associated with abnormal neovascularization. The purpose of this study is to characterize the induction of pathologic angiogenesis in this mouse model. Methods The NRV2 mice were examined from postnatal day 12 (p12) to 3 months. The phenotypic changes within the retina were evaluated by fundus photography, fluorescein angiography, optical coherence tomography, and immunohistochemical and electron microscopic analysis. The pathological neovascularization was imaged by confocal microscopy and reconstructed using three-dimensional image analysis software. Results We found that NRV2 mice develop multifocal retinal depigmentation in the posterior fundus. Depigmented lesions developed vascular leakage observed by fluorescein angiography. The spontaneous angiogenesis arose from the retinal vascular plexus at postnatal day (p)15 and extended toward retinal pigment epithelium (RPE). By three months of age, histological analysis revealed encapsulation of the neovascular lesion by the RPE in the photoreceptor cell layer and subretinal space. Conclusions The NRV2 mouse strain develops early neovascular lesions within the retina, which grow downward towards the RPE beginning at p15. This retinal neovascularization model mimics early stages of human retinal angiomatous proliferation (RAP) and will likely be a useful in elucidating targeted therapeutics for patients with ocular neovascular disease. PMID:25188381

  4. Activity of sap from Croton lechleri on rat vascular and gastric smooth muscles.

    PubMed

    Froldi, G; Zagotto, G; Filippini, R; Montopoli, M; Dorigo, P; Caparrotta, L

    2009-08-01

    The effects of red sap from Croton lechleri (SdD), Euphorbiaceae, on vascular and gastric smooth muscles were investigated. SdD, from 10 to 1000 microg/ml, induced concentration-dependent vasoconstriction in rat caudal arteries, which was endothelium-independent. In arterial preparations pre-constricted by phenylephrine (0.1 microM) or KCl (30 mM), SdD also produced concentration-dependent vasoconstriction. To study the mechanisms implicated in this effect we used selective inhibitors such as prazosin (0.1 microM), an antagonist of alpha(1)-adrenoceptors, atropine (0.1 microM), an antagonist of muscarinic receptors, and ritanserin (50 nM), a 5-HT(2A) antagonist; none of these influenced vasoconstriction caused by SdD. Likewise, nifedipine (50 nM), an inhibitor of L-type calcium channels, did not modify the action of SdD. Capsaicin (100 nM), an agonist of vanilloid receptors, also did not affect vasoconstriction by SdD. We also investigated the action of SdD (10-1000 microg/ml) on rat gastric fundus; per se the sap slightly increased contractile tension. When the gastric fundus was pre-treated with SdD (100 microg/ml) the contraction induced by carbachol (1 microM) was increased, whereas that by KCl (60mM) or capsaicin (100 nM) were unchanged. The data shows that SdD increased contractile tension in a concentration-dependent way, both on vascular and gastric smooth muscles. The vasoconstriction is unrelated to alpha(1), M, 5-HT(2A) and vanilloid receptors as well as L-type calcium channels. SdD increased also contraction by carbachol on rat gastric fundus. Thus for the first time, experimental data provides evidence that sap from C. lechleri owns constricting activity on smooth muscles. PMID:19406630

  5. Comparison of time-resolved autofluorescence in the eye-ground of healthy subjects and patients suffering from age-related macular degeneration

    NASA Astrophysics Data System (ADS)

    Schweitzer, Dietrich; Schweitzer, Frank; Hammer, Martin; Schenke, Stefan; Richter, Sandra

    2005-08-01

    Age-related macular degeneration (AMD) is the most frequent cause for blindness for person older than 65 years in western countries. Besides the subjective pain, it is also an economic problem in the ageing population. As the pathomechanism is unknown, no curative treatment is possible. International research for discovering of early age-related alterations at the fundus is directed on in vivo measurements of autofluorescence. One way is the measurement of fluorescence spectra. Unfortunately, any selective excitation of fluorophores is excluded by the absorption edge of the ocular media at 400 nm. Furthermore, the shape of fluorescence spectra is influenced by the spectral absorption of layers in front of the emitting fluorophore. Weakly emitting fluorophores are covered by intensive emitting substances. The most serious limitation in fluorescence measurements of the living human fundus is the maximal permissible exposure. For that reason, fluorescence spectra of the fundus can not be detected with a high spatial resolution. The detection of dynamic fluorescence provides substance-specific lifetimes Ti, amplitudes Ai, and information about the relative contribution Qi of components in fluorescence images. As these parameters are calculated for each image point, diagrams of Ti vs. Tj, Ai vs. Aj, and Qi vs. Qj can be drawn, in which specific clusters appear for healthy subjects or AMD - patients. The projection of lifetime - clusters onto corresponding axis represents histogram of the considered lifetime. The slope in the correlation between Ai and Aj can also be used as a discriminating mark. Considering image lines as intersection through characteristic anatomical structures (optic disc, macula) profiles of Ti, Ai, or Qi show changes of these parameters (e.g. depigmentation) as function of location, which might be specific for AMD.

  6. Inter- and Intrafractional Tumor and Organ Movement in Patients With Cervical Cancer Undergoing Radiotherapy: A Cinematic-MRI Point-of-Interest Study

    SciTech Connect

    Chan, Philip; Dinniwell, Robert; Haider, Masoom A.; Cho, Y.-B.; Jaffray, David; Lockwood, Gina; Fyles, Anthony; Milosevic, Michael

    2008-04-01

    Purpose: Internal tumor and organ movement is important when considering intensity-modulated radiotherapy for patients with cancer of the cervix because of the tight margins and steep dose gradients. In this study, the internal movement of the tumor, cervix, and uterus were examined using serial cinematic magnetic resonance imaging scans and point-of-interest analysis. Methods and Materials: Twenty patients with Stage IB-IVA cervical cancer underwent pelvic magnetic resonance imaging before treatment and then weekly during external beam radiotherapy. In each 30-min session, sequential T{sub 2}-sagittal magnetic resonance imaging scans were obtained. The points of interest (cervical os, uterine canal, and uterine fundus) were traced on each image frame, allowing the craniocaudal and anteroposterior displacements to be measured. The mean displacements and trends were analyzed using mixed linear models. Prediction intervals were calculated to determine the internal target margins. Results: Large interscan motion was found for all three points of interest that was only partially explained by the variations in bladder and rectal filling. The intrascan motion was much smaller. Both inter- and intrascan motion was greatest at the fundus of the uterus, less along the canal, and least at the cervical os. The isotropic internal target margins required to encompass 90% of the interscan motion were 4 cm at the fundus and 1.5 cm at the os. In contrast, smaller margins of 1 cm and 0.45 cm, respectively, were adequate to encompass the intrascan motion alone. Conclusion: Daily soft-tissue imaging with correction for interfractional motion or adaptive replanning will be important if the benefits of intensity-modulated radiotherapy are to be maximized in women with cervical cancer.

  7. Quantitative analysis of macular contraction in idiopathic epiretinal membrane

    PubMed Central

    2014-01-01

    Background We aimed to quantify the displacement of macular capillaries using infrared fundus photographs and image processing software (ImageJ) in patients with idiopathic epiretinal membrane (ERM) who have undergone vitrectomy and to analyze the correlation between vessel displacement and retinal thickness. Methods This prospective study included 16 patients who underwent vitrectomy for idiopathic ERM. Ophthalmic examination and optical coherence tomography (OCT) were performed before and 3 months after surgery. The length of radial vessel segment included in each area (VLA) and the length from the foveola to the vessel branching point (FBL) depending on the superior, inferior, nasal, and temporal areas of the macula were measured using infrared fundus images and image processing software (ImageJ). Preoperative and postoperative parameters were compared and correlations between VLA, FBL, macular thickness, and visual acuity were assessed. Results The VLA of superior, inferior, and temporal areas showed a significant postoperative reduction. VLA differences showed a positive correlation with differences in macular thickness, which corresponded to the superior, inferior, and temporal areas; however, no correlation was observed in the nasal area. The FBL of the superior and inferior areas was significantly increased postoperatively. A positive correlation was observed between FBL differences and macular thickness differences in the superior area. Postoperative change in VLA and FBL did not show a significant correlation with postoperative best corrected visual acuity (BCVA) and BCVA differences. Conclusions Infrared fundus photographs and image processing software can be useful for quantifying progressive changes in retinal surface distortion after surgical removal of ERM. Macular edema and vascular distortion showed significant improvement after surgery. Furthermore, a correlation was observed between topographic and tomographic changes. PMID:24735324

  8. Direct ophthalmoscopy on YouTube: analysis of instructional YouTube videos’ content and approach to visualization

    PubMed Central

    Borgersen, Nanna Jo; Henriksen, Mikael Johannes Vuokko; Konge, Lars; Sørensen, Torben Lykke; Thomsen, Ann Sofia Skou; Subhi, Yousif

    2016-01-01

    Background Direct ophthalmoscopy is well-suited for video-based instruction, particularly if the videos enable the student to see what the examiner sees when performing direct ophthalmoscopy. We evaluated the pedagogical effectiveness of instructional YouTube videos on direct ophthalmoscopy by evaluating their content and approach to visualization. Methods In order to synthesize main themes and points for direct ophthalmoscopy, we formed a broad panel consisting of a medical student, junior and senior physicians, and took into consideration book chapters targeting medical students and physicians in general. We then systematically searched YouTube. Two authors reviewed eligible videos to assess eligibility and extract data on video statistics, content, and approach to visualization. Correlations between video statistics and contents were investigated using two-tailed Spearman’s correlation. Results We screened 7,640 videos, of which 27 were found eligible for this study. Overall, a median of 12 out of 18 points (interquartile range: 8–14 key points) were covered; no videos covered all of the 18 points assessed. We found the most difficulties in the approach to visualization of how to approach the patient and how to examine the fundus. Time spent on fundus examination correlated with the number of views per week (Spearman’s ρ=0.53; P=0.029). Conclusion Videos may help overcome the pedagogical issues in teaching direct ophthalmoscopy; however, the few available videos on YouTube fail to address this particular issue adequately. There is a need for high-quality videos that include relevant points, provide realistic visualization of the examiner’s view, and give particular emphasis on fundus examination. PMID:27574393

  9. Multimodal Assessment of Microscopic Morphology and Retinal Function in Patients With Geographic Atrophy

    PubMed Central

    Panorgias, Athanasios; Zawadzki, Robert J.; Capps, Arlie G.; Hunter, Allan A.; Morse, Lawrence S.; Werner, John S.

    2013-01-01

    Purpose. To correlate retinal function and visual sensitivity with retinal morphology revealed by ultrahigh-resolution imaging with adaptive optics–optical coherence tomography (AO-OCT), on patients with geographic atrophy. Methods. Five eyes from five subjects were tested (four with geographic atrophy [66.3 ± 6.4 years, mean ± 1 SD] and one normal [61 years]). Photopic and scotopic multifocal electroretinograms (mfERGs) were recorded. Visual fields were assessed with microperimetry (mP) combined with a scanning laser ophthalmoscope for high-resolution confocal retinal fundus imaging. The eye tracker of the microperimeter identified the preferred retinal locus that was then used as a reference for precise targeting of areas for advanced retinal imaging. Images were obtained with purpose-built, in-house, ultrahigh resolution AO-OCT. Fundus autofluorescence (FAF) and color fundus (CF) photographs were also acquired. Results. The AO-OCT imaging provided detailed cross-sectional structural representation of the retina. Up to 12 retinal layers were identified in the normal subject while many severe retinal abnormalities (i.e., calcified drusen, drusenoid pigment epithelium detachment, outer retinal tubulation) were identified in the retinae of the GA patients. The functional tests showed preservation of sensitivities, although somewhat compromised, at the border of the GA. Conclusions. The images provided here advance our knowledge of the morphology of retinal layers in GA patients. While there was a strong correlation between altered retinal structure and reduction in visual function, there were a number of examples in which the photoreceptor inner/outer segment (IS/OS) junctions lost reflectivity at the margins of GA, while visual function was still demonstrated. This was shown to be due to changes in photoreceptor orientation near the GA border. PMID:23696601

  10. The appearance of newly identified intraocular lesions in Gaucher disease type 3 despite long-term glucocerebrosidase replacement therapy

    PubMed Central

    Sawicka-Gutaj, Nadia; Machaczka, Maciej; Kulińska-Niedziela, Izabela; Bernardczyk-Meller, Jadwiga; Gutaj, Paweł; Sowiński, Jerzy; Ruchała, Marek

    2016-01-01

    Background Gaucher disease (GD) is an autosomal recessive lipid storage disorder caused by the deficient activity of the lysosomal enzyme glucocerebrosidase. The presence of central nervous system disease is a hallmark of the neuronopathic forms of GD (types 2 and 3). Intraocular lesions (e.g. corneal clouding, retinal lesions, and vitreous opacities) have been infrequently reported in GD type 3 (GD3). Moreover, there are virtually no published data on the occurrence and natural course of intraocular lesions in GD3 patients treated with enzyme replacement therapy (ERT). Case presentation We describe the case of a 26-year-old Polish male with L444P homozygous GD3 (mutation c.1448T > C in the GBA1 gene) who developed fundus lesions despite 10 years of ERT. At the age of 23 years, a spectral domain optical coherence tomography (OCT) examination was performed which disclosed the presence of discrete lesions located preretinally, intraretinally in the nerve fiber layer, and in the vitreous body. A 3-year follow-up OCT examination has not shown any significant progression of the fundus lesions. Conclusions To the best of our knowledge, this is the first published report describing the occurrence of newly identified retinal and preretinal lesions occurring during long-term ERT in GD3. We recommend that a careful ophthalmic assessment, including a dilated fundus examination, should be included as part of annual follow-up in patients with GD3. Further studies are needed to understand the nature and clinical course of these changes and whether or not these intraocular findings have any predictive value in the context of neurologic and skeletal progression in GD3. PMID:27064303

  11. Evaluation of ocular findings in patients with vitiligo.

    PubMed

    Karadag, Remzi; Esmer, Oktay; Karadag, Ayse S; Bilgili, Serap Gunes; Cakici, Ozgur; Demircan, Yuhanize Tas; Bayramlar, Huseyin

    2016-03-01

    In this study, we aimed to investigate ocular manifestations in patients with vitiligo. Sixty-one patients with vitiligo were included in the study. From the patients who referred for examination to the dermatology and ophthalmology clinic, 57 patients without any systemic disease were taken as the control group. In both groups, otorefractometry, keratometry, visual acuity test, intraocular pressure measurement, anterior segment, and fundus examinations of the eye with slit lamp, Schirmer test, and perimetry were carried out. The mean age was 24.54 ± 11.90 years and 23.03 ± 8.72 years in the patients and control group, respectively. The mean Schirmer test results were as follows: 16.74 ± 9.11 mm and 17.64 ± 9.41 mm for the right and left eyes of the patients, and 21.96 ± 12.51 mm and 23.42 ± 12.51 mm for the right and left eyes of controls, respectively. Of the patients, 36 eyes showed lenticular findings. However, only 12 eyes of the controls have some lenticular findings. Twenty-nine eyes in the vitiligo group and four in the controls showed some fundus findings. When the two groups were compared with each other, there was a statistically significant difference between them in terms of Schirmer test results, lens, and fundus findings (P < 0.05 for all). However, there was no significant difference in terms of age, gender, visual acuity, refraction, keratometry, intraocular pressure, perimetry, and corneal findings (P > 0.05 for all). Patients with vitiligo may have more lenticular and retinal findings than normal. They can be more prone to dry eye syndrome as well. PMID:26235484

  12. Value of optical coherence tomography in the detection of macular pathology before the removal of silicone oil

    PubMed Central

    Rashad, Mohammad Ahmad; Mohamed, Ahmed Abdel Aliem; Ahmed, Asmaa Ismail

    2016-01-01

    Purpose To assess the pathological macular changes with optical coherence tomography (OCT) before the removal of silicone oil (SiO) in eyes that had undergone pars plana vitrectomy for complicated forms of retinal detachment (RD). Patients and methods Subjects included 48 patients (51 eyes) with complicated RD including proliferative vitreoretinopathy, proliferative diabetic retinopathy, recurrent RD, penetrating trauma, uveitis, giant retinal tears, and macular holes. All the eyes had undergone SiO injection. Furthermore, all eyes had been planned for the removal of SiO 6–12 months after the primary surgery. Finally, all eyes had a fundus examination and OCT examination before the silicone oil removal. Results OCT findings indicated epiretinal membrane in 41% of the eyes, macular edema in 17%, macular detachment in 13.5%, macular thinning in 13.5%, macular holes in 10%, and subretinal membranes in 2%. Preoperative OCT was normal in only 12% of the eyes, while a clinical fundus examination was normal in 43% (P<0.001). Eyes with normal OCT had significantly better mean logMAR (0.35) than eyes with pathological changes detected through OCT (1.28; P<0.001). Surgical modifications were made during the removal of SiO in 74.5% of the eyes. Conclusion OCT detected significantly more pathological changes than a clinical fundus examination. This had an impact on both surgical step modification during the removal of SiO and predictability of visual outcome after the removal of SiO. PMID:26855558

  13. Automated Detection of Malarial Retinopathy-Associated Retinal Hemorrhages

    PubMed Central

    Joshi, Vinayak S.; Maude, Richard J.; Reinhardt, Joseph M.; Tang, Li; Garvin, Mona K.; Sayeed, Abdullah Abu; Ghose, Aniruddha; Hassan, Mahtab Uddin; Abràmoff, Michael D.

    2012-01-01

    Purpose. To develop an automated method for the detection of retinal hemorrhages on color fundus images to characterize malarial retinopathy, which may help in the assessment of patients with cerebral malaria. Methods. A fundus image dataset from 14 patients (200 fundus images, with an average of 14 images per patient) previously diagnosed with malarial retinopathy was examined. We developed a pattern recognition–based algorithm, which extracted features from image watershed regions called splats (tobogganing). A reference standard was obtained by manual segmentation of hemorrhages, which assigned a label to each splat. The splat features with the associated splat label were used to train a linear k-nearest neighbor classifier that learnt the color properties of hemorrhages and identified the splats belonging to hemorrhages in a test dataset. In a crossover design experiment, data from 12 patients were used for training and data from two patients were used for testing, with 14 different permutations; and the derived sensitivity and specificity values were averaged. Results. The experiment resulted in hemorrhage detection sensitivities in terms of splats as 80.83%, and in terms of lesions as 84.84%. The splat-based specificity was 96.67%, whereas for the lesion-based analysis, an average of three false positives was obtained per image. The area under the receiver operating characteristic curve was reported as 0.9148 for splat-based, and as 0.9030 for lesion-based analysis. Conclusions. The method provides an automated means of detecting retinal hemorrhages associated with malarial retinopathy. The results matched well with the reference standard. With further development, this technique may provide automated assistance for screening and quantification of malarial retinopathy. PMID:22915035

  14. Photobleaching and Fluorescence Recovery of RPE Bisretinoids

    PubMed Central

    Liu, Zhao; Ueda, Keiko; Kim, Hye Jin; Sparrow, Janet R.

    2015-01-01

    The autofluorescence of the retina that originates primarily from lipofuscin fluorophores in retinal pigment epithelial cells, is observed to undergo photobleaching during the acquisition of fundus autofluorescence images. Bisretinoid fluorophores isolated from retinal pigment epithelial cells have the spectral characteristics consistent with their being the source of fundus autofluorescence. Clinically relevant experiments were designed to better understand conditions in the micromilieu of bisretinoid fluorophores that can influence fluorescence efficiencies, photobleaching, and subsequent fluorescence recovery of this fluorophore. The consumption of the bisretinoid A2E due to photooxidation-induced degradation was quantified in solvent systems of variable relative permittivity (formerly called dielectric constant), in micelles, and in phospholipid vesicles of varying composition. Reorganization within biphasic systems was also examined. A2E content was measured by high performance liquid chromatography (HPLC) and fluorescence intensity was quantified spectroscopically. As solvent polarity was increased, A2E fluorescent spectra exhibited red-shifted maxima and reduced intensity. A2E was depleted by light irradiation and the loss was more pronounced in less polar solvents, lower concentrations of anionic surfactant, and in gel- versus fluid-ordered phospholipid liposomes. Conditions that permit A2E aggregation promoted photooxidation/photodegradation, while movement of A2E between bisphasic systems was associated with fluorescence recovery after photobleaching. The fluorescence characteristics of A2E are subject to environmental modulation. Photooxidation and photodegradation of bisretinoid can account for fundus autofluorescence photobleaching. Return of fluorescence intensity after photobleaching likely occurs due to redistribution of A2E fractions amongst co-existing heterogeneous microdomains of the lysosomal compartment. PMID:26366866

  15. A dynamic opto-physiological model to effectively interpret retinal microvascular circulation

    NASA Astrophysics Data System (ADS)

    Hassan, Harnani; Hu, Sijung; Dwyer, Vincent M.

    2015-03-01

    The demand of non-invasive ocular screening is rapidly growing due to an increase of age related eye diseases worldwide. An indeed in-depth understanding of optical properties is required to elucidate nature of retinal tissue. The research aims to investigate an effective biomedical engineering approach to allow process region of interests (ROIs) in eyes to reveal physiological status. A dynamic opto-physiological model (DOPM) representing retinal microvascular circulation underlying a diffusion approximation to solve radiative transport theorem (RTT) has being developed to interpret patho-physiological phenomena. DOPM is being applied in imaging photoplethysmography (iPPG) to extract PPG signals from a series of 2D matrix images to access blood perfusion and oxygen saturation distributions. A variation of microvascular circulation could be mapped for an effectively diagnostic screening. The work presents mathematical modelling based ten layers of ocular tissue tested with four set of controlled parameters demontrated detection ratio between normal tissue damage or abnormal tissue and significant change of AC signal amplitude in these tissues. The result shows signicant change of AC signal amplitude in abnormal tissue. The preliminary results show extractable PPG signals from eye fundus video; experimented at five ROIs: whole fundus, optical disk, main vein vessel, lesion area and affected area. The outcome shows optical disk region gave a better performance compared to whole fundus region and main vein vessel. The robustness, miniaturization and artefact reduction capability of DOPM to discriminate oxygenation levels in retina could offer a new insight to access retinal patho-physiological status.

  16. Effects of short term changes in the blood glucose level on the autofluorescence lifetime of the human retina in healthy volunteers

    NASA Astrophysics Data System (ADS)

    Klemm, Matthias; Nagel, Edgar; Schweitzer, Dietrich; Schramm, Stefan; Haueisen, Jens

    2016-03-01

    Purpose: Fluorescence lifetime imaging ophthalmoscopy (FLIO) provides in vivo metabolic mapping of the ocular fundus. Changes in FLIO have been found in e.g. diabetes patients. The influence of short term metabolic changes caused by blood glucose level changes on is unknown. Aim of this work is the detection of short-term changes in fundus autofluorescence lifetime during an oral glucose tolerance test. Methods: FLIO was performed in 10 healthy volunteers (29+/-4 years, fasting for 12h) using a scanning laser ophthalmoscope (30° fundus, 34μm resolution, excitation with 473nm diode laser with 70 ps pulses at 80 MHz repetition rate, detection in two spectral channels 500-560nm (ch1) and 560-720nm (ch2) using the timecorrelated single photon counting method). The blood glucose level (BGL) was measured by an Accu-Chek® Aviva self-monitoring device. Before and after a glucose drink (300ml solution, containing 75g of glucose (Accu-Chek® Dextrose O.G.T.), BGL and FLIO were measured every 15min. The FLIMX software package was applied to compute the average fluorescence lifetime τ on the inner ring of the ETDRS grid using a modified 3-exponential approach. Results: The results are given as mean +/- standard deviation over all volunteers in ch1. Baseline measurement: BGL: 5.3+/-0.4 mmol/l, τ1: 49+/-6ps. A significant reduction (α=5% Wilcoxon rank-sum test) in τ1 is detected after 15min (BGL: 8.4+/-1.1 mmol/l, τ1: 44+/-5ps) and after 90min (BGL: 6.3+/-1.4 mmol/l, τ1: 41+/-5ps). Results of ch2 show smaller reductions in the fluorescence lifetimes over time.

  17. The Association Between Subretinal Drusenoid Deposits in Older Adults in Normal Macular Health and Incident Age-Related Macular Degeneration

    PubMed Central

    Huisingh, Carrie; McGwin, Gerald; Neely, David; Zarubina, Anna; Clark, Mark; Zhang, Yuhua; Curcio, Christine A.; Owsley, Cynthia

    2016-01-01

    Purpose Subretinal drusenoid deposits (SDD) have been associated with the progression to late age-related macular degeneration (AMD). To determine whether SDD in eyes in normal macular health increases risk for early AMD, this study examined the association between presence of SDD at baseline in a cohort of older adults in normal macular health and incident AMD 3 years later. Methods Subjects enrolled in the Alabama Study on Early Age-Related Macular Degeneration (ALSTAR) were assessed for the presence of SDD using color fundus photos, infrared reflectance and fundus autofluorescence images, and spectral-domain optical coherence tomography volumes. The study sample included 799 eyes from 455 participants in normal macular health per grading of color fundus photographs using the 9-step Age-Related Eye Disease Study (AREDS) classification system. Age-related macular degeneration was defined as eyes having an AREDS grade ≥2 at the 3-year follow-up. Results Twenty-five percent of participants had SDD in one or both eyes at baseline. At follow-up visit, 11.9% of eyes in the sample developed AMD. Compared to eyes without SDD, those with SDD were 2.24 (95% confidence interval [CI] 1.36–3.70) times more likely to have AMD at follow-up. After adjusting for age, C-reactive protein quartile, and family history of AMD, the association persisted. Conclusions Results suggest that SDD in older eyes with normal macular health as defined by the AREDS scale is a risk factor for the development of early AMD. Older adults in seemingly normal macular health yet having SDD may warrant closer clinical monitoring for the possible onset of early AMD. PMID:26906160

  18. Non-Mydriatic Confocal Retinal Imaging Using a Digital Light Projector.

    PubMed

    Muller, Matthew S; Elsner, Ann E; Ozawa, Glen Y

    2013-03-26

    A digital light projector is implemented as an integrated illumination source and scanning element in a confocal non-mydriatic retinal camera, the DLP-Cam. To simulate scanning, a series of illumination lines are rapidly projected on the retina. The backscattered light is imaged onto a 2-dimensional rolling shutter CMOS sensor. By temporally and spatially overlapping the illumination lines with the rolling shutter, confocal imaging is achieved. This approach enables a low cost, flexible, and robust design with a small footprint. Qualitative image comparison with commercial non-mydriatic SLOs and fundus cameras shows comparable fine vessel visibility and contrast. PMID:24236225

  19. Bladder Endometriosis and Endocervicosis: Presentation of 2 Cases with Endoscopic Management and Review of Literature

    PubMed Central

    Fuentes Pastor, Javier; Ballestero Diego, Roberto; Correas Gómez, Miguel Ángel; Torres Díez, Eduardo; Fernández Flórez, Alejandro; Ballesteros Olmos, Gerardo; Gutierrez Baños, Jose Luis

    2014-01-01

    Urinary tract endometriosis and endocervicosis are an uncommon pathologic finding, with a common embryological origin. We present 2 cases of female patients with bladder mass. The first one was a finding of a nodular formation in the bladder during study of a nonviable foetus and the second was an incidental finding of a neoformation in the fundus of the bladder during the realization of an ultrasound. In both cases, we performed a surgical management with transurethral resection. Histopathological examination revealed a bladder endometrioma in the first case and endocervicosis with associated endometriosis in the second. PMID:25184072

  20. Autosomal dominant vitreoretinochoroidopathy (ADVIRC).

    PubMed Central

    Blair, N P; Goldberg, M F; Fishman, G A; Salzano, T

    1984-01-01

    We report the second family recognised to have autosomal dominant vitreoretinochoroidopathy. The clinical features were (1) autosomal dominant inheritance; (2) peripheral, coarse pigmentary degeneration of the fundus for 360 degrees, with a relatively discrete posterior border in the equatorial region (this finding may be pathognomonic); (3) superficial punctate yellowish-white opacities in the retina; (4) various vascular abnormalities; (5) breakdown of the blood-retinal barrier; (6) retinal neovascularisation; (7) vitreous abnormalities; and (8) choroidal atrophy. Visual reduction was mainly due to macular oedema or vitreous haemorrhage. Images PMID:6689931