1. Articles in category: Ophthalmology

    11305-11328 of 11410 « 1 2 ... 469 470 471 472 473 474 475 476 »
    1. Optical Coherence Tomography Findings in Persistent Diabetic Macular Edema: The Vitreomacular Interface

      Retina practice. Fifty-two normal eyes of 48 patients and 100 eyes of 80 patients with DME. We measured retinal thickness for nine zones and total macular volume using the 3.5-mm display of an optical coherence tomograph (OCT). We determined the normal ranges of values for zones, and then normal ranges of values for the difference in thickness between each pair of zones, termed comparisons. Frequencies of increased zonal thickness, increased total macular volume, and abnormalities in zonal compa
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    2. Optical coherence tomography characteristics of full-thickness traumatic macular holes

      Purpose The objective of this paper is to describe the optical coherence tomography (OCT) characteristics of patients with full-thickness traumatic macular hole (TMH) and to correlate them with biomicroscopy findings. Methods Twelve eyes of ten consecutive patients with full-thickness TMH participated in this observational retrospective multicentre study. Patients underwent biomicroscopic fundus examination, colour fundus photography, and OCT. Results Traumatic macular hole was documented with OCT in five women and five men. Mean (range) time between trauma and macular hole (MH) diagnosis was 8.1 (1–24) months. The shape of TMHs was round in 11 (91.7%) eyes. The posterior ...
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    3. Evaluation of potential image acquisition pitfalls during optical coherence tomography and their influence on retinal image segmentation

      The development of improved segmentation algorithms for more consistently accurate detection of retinal boundaries is a potentially useful solution to the limitations of existing optical coherence tomography (OCT) software. We modeled artifacts related to operator errors that may normally occur during OCT imaging and evaluated their influence on segmentation results using a novel segmentation algorithm. These artifacts included: defocusing, depolarization, decentration, and a combination of defocusing and depolarization. Mean relative reflectance and average thickness of the automatically extracted intraretinal layers was then measured. Our results show that defocusing and depolarization errors together have the greatest altering effect on all measurements ...
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    4. Retinal nerve fibre layer imaging compared with histological measurements in a human eye

      Purpose A feasibility study comparing retinal nerve fibre layer (RNFL) thickness values obtained with imaging devices against RNFL thickness measurements obtained histologically in a human eye. Design A single patient scheduled for orbital exenteration, who still possessed a healthy functioning eye. Methods Before surgery, the eye was imaged using optical coherence tomography (OCT) and scanning laser polarimetry (SLP). After orbital exenteration, the globe was sectioned, and 100 equidistant RNFL thickness measurements were obtained for each of four concentric rings centred on the optic disc, with diameters of 3.0, 3.5, 4.0, and 4.5 mm. Results RNFL thickness ...

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    5. Peripapillary intrachoroidal cavitation in high myopia: reappraisal

      Purpose To evaluate optical coherence tomography (OCT) and clinical findings of a peripapillary lesion in high myopia recently named peripapillary detachment in pathologic myopia (PDPM) or intrachoroidal cavitation. Methods Observational case report by chart review, analysis of colour fundus photography, fluorescein angiography, and OCT in 16 eyes of 12 patients with myopic degeneration and the presence of a slightly elevated, patchy peripapillary, yellow-orange lesion on the fundus. Results Patients were mean age 53.110.7 years, with a spherical-equivalent refractive error of -10.993.33 D and mean axial length of 27.341.44 mm. The mean best-corrected visual acuity ...
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    6. Method and apparatus for screening for retinopathy

      A method of screening for retinal disease including directing a first light at a first portion of the retina, directing a second light at a second portion of the retina, measuring a first pupillary response of the eye as a result of the first light and a second pupillary response as a result of the second light, and generating an indication of a severity level of the retinal disease using the first pupillary response and the second pupillary response. Also, an apparatus that implements this method including a light source for directing a first light at a first retinal portion ...
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    7. Enhanced optical coherence patterns of diabetic macular oedema and their correlation with the pathophysiology

      Enhanced optical coherence patterns of diabetic macular oedema and their correlation with the pathophysiology
      Purpose: To describe different patterns of diabetic macular oedema (DMO) using a computerized alignment and averaging of sequences in optical coherence tomography (OCT) B-scans and to show the correlation of these patterns with the pathophysiology of the condition. Methods: We carried out a prospective, uncontrolled study, including 46 human subjects with untreated DMO. Enhanced OCT images were produced. We correlated different OCT patterns of DMO with ETDRS visual acuity and with the thickness of the central 1-mm of the macula. We also correlated these patterns with theories of the pathophysiology of DMO. Results: Enhanced OCT images enabled us to examine ...
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    8. Technical Note: Method for estimating volume of subretinal fluid in cases of localized retinal detachment by OCT ophthalmoscopy

      The volume of the subretinal fluid can be used to assess the condition of different types of retinal and macular disorders. The purpose of this report is to introduce a method to measure the volume of the subretinal fluid with the images of the optical coherence tomography (OCT) Ophthalmoscope in three cases of central serous chorioretinopathy and one case of retinal pigment epithelial detachment. We used the topography-mode program of the OCT Ophthalmoscope and measured the average height of the retinal detachment. By multiplying the size of the area of the retinal detachment and the average height of the retinal ...
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    9. Enzymatic vitreolysis with recombinant microplasminogen and tissue plasminogen activator

      Purpose To generate microplasmin (Plm) using recombinant microplasminogen (Plg) and recombinant tissue plasminogen activator (rt-PA) before intravitreous injection and to investigate the efficacy of Plm in inducing posterior vitreous detachment (PVD). Methods Forty-eight female or male New Zealand white rabbits were randomized into three groups. Recombinant human Plg was incubated with rt-PA with a 200:1 molar ratio at 37°C for 40 min. The right eyes of groups 1, 2, and 3, were injected with 0.5, 1.0, and 1.5 U Plm in 0.1 ml respectively, and 0.1 ml balanced salt solution (BSS) was injected ...

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      Mentions: Fudan University
    10. Method and an apparatus for the simultaneous determination of surface topometry and biometry of the eye

      An apparatus (10, 10') for detecting the surface topography of a cornea (24) of an eye (22) by dynamic or static projection of a pattern onto the surface of the cornea and detection of the pattern reflected by the cornea, providing preferably simultaneous detection of at least one optical property of a layer disposed beneath the cornea.
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      Mentions: Adolf F. Fercher
    11. Customized corneal profiling

      A customized corneal profile is provided by combining corneal topography data with captured wavefront aberration data to form a course of refractive treatment of the eye. In one embodiment, the captured wavefront data is employed within the area of a pupil, while the corneal topography data is employed in the area outside of the pupil. In other embodiments, the topography data is adjusted based on the wavefront data, a course of refractive treatment is simulated and displayed upon the topography data, and an initial evaluation of the suitability of a patient for treatment is performed based on the topography data.
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      Mentions: Bausch & Lomb
    12. Optical coherence tomography in anterior segment imaging

      Purpose: To evaluate the ability of optical coherence tomography (OCT), designed primarily to image the posterior segment, to visualize the anterior chamber angle (ACA) in patients with different angle configurations. Methods: In a prospective observational study, the anterior segments of 26 eyes of 26 patients were imaged using the Zeiss Stratus OCT, model 3000. Imaging of the anterior segment was achieved by adjusting the focusing control on the Stratus OCT. A total of 16 patients had abnormal angle configurations including narrow or closed angles and plateau irides, and 10 had normal angle configurations as determined by prior full ophthalmic examination ...
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    13. Optical coherence tomography evidence of rapid progression from vitreomacular traction to full thickness macular hole

      The authors present a case of a patient with idiopathic vitreomacular traction who subsequently developed a full thickness macular hole 3 weeks following the onset of metamorphopsia. Vitreomacular traction is a well described phenomenon and has been known to resolve spontaneously and in this patient the conservative approach was adopted initially. However, she progressed rapidly to a full thickness macular hole and therefore, the authors recommend close monitoring of such patients with a view to early vitrectomy to prevent progressive morbidity.
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    14. Measurement of gradient refractive index profile of crystalline lens of fisheye in vivo using optical coherence tomography

      Measurement of gradient refractive index profile of crystalline lens of fisheye in vivo using optical coherence tomography
      We report the use of optical coherence tomography (OCT) for noninvasive measurement of the refractive index profile of a crystalline lens of a fisheye. The approach exploits the fact that OCT provides a direct measurement of the optical path of the light traveled through the medium. The gradient refractive index profile for the crystalline lens was retrieved by iterative fitting of the optical path calculated by the ray tracing method with that experimentally measured using OCT. The estimated error in refractive index is approximately 1%. The measured gradient refractive index and Matthiessen’s ratio (ratio of focal length to lens ...
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    15. Glaucoma detection using different Stratus optical coherence tomography protocols

      Purpose: To examine and compare the diagnostic accuracy of retinal nerve fibre layer (RNFL) thickness measurements using different Stratus optical coherence tomography (OCT) scanning protocols. Methods: Stratus OCT data for 90 healthy subjects and 62 glaucoma patients with mild or moderate visual field loss were prospectively collected and analysed using four RNFL thickness protocols that differed in terms of image resolution and number of scans. Cut-off levels corrected for age and refractive error were defined by reference values derived from an independent normal database. Sensitivity and specificity were calculated for average RNFL thickness for the full circle scan, and for ...
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    16. Optical coherence tomography of chorioretinal and choroidal folds

      Purpose: To report the optical coherence tomography (OCT) findings in cases of chorioretinal and choroidal folds. Methods: Eight subjects with folds of the fundus of the eye were examined with fundus photography, fluorescein angiography, B-scan ultrasonography and Stratus OCT. Results: Two types patterns were found on OCT. Five cases showed undulating retinal as well as retinal pigment epithelial lines of normal thickness; these were defined as chorioretinal folds. The posterior vitreous surface often adhered to the crests of the folds only. Three cases exhibited a wavy appearance of the retinal pigment epithelium and a flat retinal surface; these were classified ...
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    17. MIT team takes high-res, 3-D images of eye

      MIT team takes high-res, 3-D images of eye
      In work that could improve diagnoses of many eye diseases, MIT researchers have developed a new type of laser for taking high-resolution, 3-D images of the retina, the part of the eye that converts light to electrical signals that travel to the brain. The research will be presented at the Conference on Lasers and Electro-Optics and the Quantum Electronics and Laser Science Conference in Baltimore on May 10.
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    18. Assessment of macular retinal thickness and volume in normal eyes and highly myopic eyes with third-generation optical coherence tomography

      Purpose To compare the macular retinal thickness and macular volume between subjects with high myopia and non-myopia. Methods This prospective nonrandomized, comparative study recruited healthy subjects with high myopia subjects, defined as a spherical equivalence (SE) over - 6 dioptres (D) or AXL26.5 mm and the best corrected visual acuity better than 20/25, and subjects with non-myopia, defined as an with SE between 1.5D and - 1.5 D and the BCVA better than 20/25. Optical coherence tomography was performed in each eye. Results Eighty high myopic eyes and 40 non-myopic eyes were included. The mean age of ...
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    19. Optical Coherence Tomography of the Macula in Congenital Achromatopsia

      Optical Coherence Tomography of the Macula in Congenital Achromatopsia
      purpose. It is known that symptoms of congenital achromatopsia are caused by the lack of functioning cones, but there are very few published data on histologic changes in the retina in these cases. This study was conducted to examine in vivo the anatomic structure of the retina of patients with achromatopsia. methods. Fifteen eyes of eight patients with congenital achromatopsia and 18 eyes of nine control subjects were examined by optical coherence tomography. Radial 6-mm scans were taken of the macula. The thickness of the neuroretina was measured both automatically and manually. Measurements were taken at the foveola and at ...
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    20. Relation of optical coherence tomography and unusual angiographic leakage patterns in central serous chorioretinopathy

      Purpose To investigate the anatomic basis of atypical angiographic leaks in central serous chorioretinopathy (CSC) with optical coherence tomography (OCT). Methods Fluorescein angiography (FA) and OCT were performed in three eyes of three patients (two men, one woman) with CSC. The angiographic leaks were treated with transpupillary thermotherapy (TTT) in two patients with long-standing CSC. The investigations were repeated in the treated patients during follow-up visits. Results Clinically, all patients demonstrated typical CSC; the female patient had subretinal fibrin under the detachment. FA showed unusual leakage patterns and OCT revealed bridging tissue connecting the pigment epithelial detachment (PED) to the ...
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    21. Assessment of the posterior segment of the cat eye by optical coherence tomography (oct)

      Objectives To assess the feasibility of optical coherence tomography (OCT) for examining the cat ocular fundus, to provide normative data on retinal thickness in different fundus regions, and to demonstrate selected surgically induced vitreoretinal pathologies in the cat. Animal studied Forty-five eyes of 28 healthy domestic cats and two eyes of domestic cats that had undergone subretinal implantation surgery for a visual prosthesis were examined. Procedures An optical coherence tomograph (Zeiss-Humphrey) was used to examine the anesthetized animals. At least five vertical and five horizontal scans in regular distribution were recorded for each cat including (1) the peripapillary region, (2 ...
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    22. Optical coherence tomography in a patient with tobacco-alcohol amblyopia

      Aim To report optical coherence tomography (OCT) finding in a patient with tobacco-alcohol amblyopia. Methods A 45-year-old man presented with a gradual decrease in vision over 4 years. He had smoked a half to one pack of cigarettes per day and had consumed 350 cc of gin per day for 30 years. A detailed ophthalmologic examination was performed. Results His corrected visual acuities were 20/800 OD and 20/200 OS. A Goldmann visual field examination showed ceco-central scotomas in both eyes. OCT using a peripapillary Fast RNFL (retinal nerve fiber layer) programme showed a small decrease in the RNFL ...

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    23. Correlation between microaneurysm closure rate and reduction in macular thickness following laser photocoagulation of diabetic macular edema

      Aim To correlate the microaneurysmal closure rate measured on fundus fluorescein angiography (FFA) with reduction in macular thickness observed on optical coherence tomography (OCT) following laser photocoagulation of diabetic macular edema. Materials and methods A prospective observational case series. Fifty patients (50 eyes) of type II diabetes mellitus with clinically significant macular oedema (CSME) underwent focal/grid laser photocoagulation. OCT and FFA were performed at baseline and at 2 and 12 weeks following laser photocoagulation to measure the change in macular thickness and the number of leaking microaneurysms respectively. Statistical analysis was performed using paired-ttest and Pearson's correlation test ...
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      Mentions: Amod Gupta
    11305-11328 of 11410 « 1 2 ... 469 470 471 472 473 474 475 476 »
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