1. Articles in category: Ophthalmology

    11593-11616 of 11634 « 1 2 ... 481 482 483 484 485 »
    1. Arrangements for coherence topographic ray tracing on the eye

      Topographic measurement of eye structures based on short coherence interferometry is the subject of the invention. The problem occurring in this connection is that longitudinal and transverse eye movements during signal registration lead to errors in the measured structure. The influences of longitudinal eye movements are compensated in that the reference beam, independent from the measurement beam, is directed to the corneal vertex and is reflected at the latter. The influences of longitudinal eye movements are minimized in that the transverse position of the eye is monitored by means of a direction-dependent registration of the light reflected at the corneal ...
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    2. System and method for non-contacting measurement of the eye

      Combined equipment for non-contacting determination of axial length (AL), anterior chamber depth (VKT) and corneal curvature (HHK) of the eye are also important for the selection of the intraocular lens IOL to be implanted, particularly the selection of an intraocular lens IOL to be implanted, preferably with fixation of the eye by means of a fixating lamp and/or illumination through light sources grouped eccentrically about the observation axis.
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    3. Optical mapping apparatus with adjustable depth resolution and multiple functionality

      The present invention relates to a multiple channel optical mapping apparatus which can deliver one or simultaneously at least two images of different depth resolutions or sequentially, images with different depth resolutions, or a combination of these images, or a single image with adjustable depth resolution. The multiple channels could be either multiple confocal channel and one or two optical coherence tomography channel, or two optical coherence tomography channels, or two confocal channels. The channels, either OCT or confocal can operate on the same wavelength or on different wavelengths. The apparatus can display both transversal as well as longitudinal images ...
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    4. Methods for measuring retinal damage

      Methods for measuring retinal damage resulting from an injury include calculating the slope of retinal thickness from the injury site to the periphery of the site. A shallower slope of retinal thickness correlates with a greater degree of damage resulting from the injury. The methods may also be useful to screen pharmaceuticals for potential neuroprotective effects against retinal injuries.
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    5. Method and device for the photoablation of the cornea with a laser beam

      In a method for photoablation on the cornea with a laser beam with the aid of which a multiplicity of consecutive partial ablation operations are undertaken, the thickness of the cornea is determined with the aid of a measuring device co-operating with a Michelson interferometer before and after each partial ablation operation. By using the thickness values determined, the measuring device guides the laser beam, with intensity values appropriately adjusted by it, over the cornea in a controlled fashion so as not to undershoot a prescribed cornea thickness while complying with a prescribed cornea profile. The measuring device operates with ...
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    6. Tracking assisted optical coherence tomography

      One embodiment of the present invention is an optical coherence tomography ("OCT") application apparatus that performs an OCT application on an object. The OCT application apparatus includes: (a) an OCT scanning apparatus which outputs a scanning beam of OCT scanning radiation; and (b) an active tracking system that generates and projects a tracking beam of tracking radiation onto a region including a reference tracking feature; wherein the active tracking system further includes an analysis system that analyzes tracking radiation reflected from the region to detect movement of the object and to generate tracking signals, and applies the tracking signals (i ...
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    7. Optical Coherence Tomography of Ocular Diseases, Second Edition (Book)

      Optical Coherence Tomography of Ocular Diseases, Second Edition (Book)
      Optical Coherence Tomography of Ocular Diseases, Second Edition is a completely revised and updated version of this classic text. Incorporated within over 700 pages are a multitude of updated features unique to this edition including over 1,600 color images, state-of-the-art technology, and case presentations. These elements cohesively work together to successfully demonstrate the retina in normal and diseased states using the innovative Stratus OCTTM. Optical Coherence Tomography of Ocular Diseases, Second Edition is written with the clinician in mind. The text's primary objective is to illustrate the appearance of the eye in health and disease, comparing conventional clinical ...
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    8. Method of manufacturing customized intraocular lenses

      A method of manufacturing an intraocular lens that has been customized to provide optimum vision for an eye with prior corneal refractive surgery. Such a custom manufactured IOL will address not only optical correction requirements as currently met by spherical or toric-shaped IOLs, but will correct higher order optical aberrations using needed optimum customized shapes.
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    9. Method and apparatus for the simultaneous determination of surface topometry and biometry of the eye

      An apparatus (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
    10. Method and device configuration for determining the corneal thickness of an eye

      Proposed is a method and a device configuration for determining the corneal thickness of an eye, in particular of a human eye, by means of light rays. First light rays are projected onto and into the cornea, and second light rays, reflected by the cornea, are registered for determining the corneal thickness. A contact element, which is preferably plane-parallel, is placed on the contact area of the cornea, and the first light rays are projected through the contact element onto and into the cornea. The contact element is fixed on the cornea, for example. The first light rays are projected ...
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    11. Optical coherence tomography: evaluation and clinical application (Thesis)

      Optical coherence tomography: evaluation and clinical application (Thesis)
      The ability to examine the appearance of the retina is of paramount importance for the diagnosis and monitoring of ophthalmic disease and for the evaluation of treatment outcomes. Direct cross-sectional imaging of retinal structure could be useful for early diagnosis and more sensitive monitoring of a variety of retinal conditions such as macular oedema and glaucoma. The view of the fundus given by ophthalmoscopy provides very limited depth information and clinicians will often have to resort to additional techniques such as flourescein angiography or visual field testing for information on structural abnormalities within the retina. Other currently available imaging techniques ...
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    12. Method and apparatus for improving vision and the resolution of retinal images

      A method of and apparatus for improving vision and the resolution of retinal images is described in which a point source produced on the retina of a living eye by a laser beam is reflected from the retina and received at a lenslet array of a Hartmann-Shack wavefront sensor such that each of the lenslets in the lenslet array forms an aerial image of the retinal point source on a CCD camera located adjacent to the lenslet array. The output signal from the CCD camera is acquired by a computer which processes the signal and produces a correction signal which ...

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    13. Nondestructive Quantification of Analyte Diffusion in Cornea and Sclera Using Optical Coherence Tomography

      PURPOSE. Noninvasive functional imaging, monitoring, and quantification of analytes transport in epithelial ocular tissues are extremely important for therapy and diagnostics of many eye diseases. In this study the authors investigated the capability of optical coherence tomography (OCT) for noninvasive monitoring and quantification of diffusion of different analytes in sclera and cornea of rabbit eyes. METHODS. A portable time-domain OCT system with wavelength of 1310 ± 15 nm, output power of 3.5 mW, and resolution of 25 µm was used in this study. Diffusion of different analytes was monitored and quantified in rabbit cornea and sclera of whole eyeballs. Diffusion ...
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    14. System and method for determining birefringence of anterior segment of a patient's eye

      The magnitude and axial orientation of birefringence of the anterior and the posterior segments of the human eye are determined. The anterior segment includes essentially the combined birefringence of the cornea and the crystalline lens, and the posterior segment includes regions at the fundus. The optical axis and the magnitude of the birefringence of the anterior segment is first determined, then the birefringence of the posterior segment is nulled by a variable retarder. The birefringence of the posterior segment is then determined without interference of the birefringence of the anterior segment. The apparatus and method are applicable to the measurement ...
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    15. Retinal tracking assisted optical coherence tomography

      One embodiment of the present invention is an optical coherence tomography ("OCT") application apparatus that performs an OCT application on an object. The OCT application apparatus includes: (a) an OCT scanning apparatus which outputs a beam of OCT scanning radiation; (b) an active tracking system that generates and projects a beam of tracking radiation onto a region including a reference tracking feature, which active tracking system includes a tracking optical system that is disposed to intercept the beam of tracking radiation and the beam of OCT scanning radiation; and (c) wherein the active tracking system analyzes tracking radiation reflected from ...
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    16. Evaluation of macular holes by optical coherence tomography in Chinese patients

      Evaluation of macular holes by optical coherence tomography in Chinese patients

      Aim: To evaluate the diagnostic significance of optical coherence tomography for macular holes. Materials and methods: From October 1999 to February 2000, forty six eyes of 40 patients with clinically diagnosed or suspected macular holes had optical coherence tomography performed via dilated pupils in both eyes. All images were measured and analyzed. Results: The optical coherence tomography technique showed lamellar macular holes in 11 eyes of 9 patients with partial neural epithelium defect. The average remaining retinal thickness of the macular area was 108 mm (standard deviation, 42.5 mm). Thirty eyes of 27 patients had full-thickness macular holes. The ...

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    17. Method and apparatus for diagnosing and monitoring eye disease

      Embodiments of the present invention provide method and apparatus for diagnosing and monitoring eye disease such as, for example, glaucoma. In particular, embodiments of the present invention analyze OCT scans of a retina to determine one or more of the following measures for diagnosing and monitoring glaucomatous retinal nerve fiber layer ("NFL") change: an NFL thickness; a ratio of NFL thickness in a vertical quadrant (superior and inferior quadrants in an OCT scan are combined in a vertical average) and a horizontal quadrant (nasal and temporal quadrants in the OCT scan are combined in a horizontal average); and an NFL ...
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    18. Ocular microcirculation examination and treatment apparatus

      Ophthalmologic examination apparatus comprises a light source, illumination means for directing light from the source along an illumination path and into the fundus of an eye of a patient, imaging means for directing fluorescence from the fundus of the patient along an imaging path to enable an image of the eye to be viewed, wherein the illumination and imaging paths are arranged as a confocal microscope adapted to focus on the fundus of the eye. A method of diagnosis of disease in an eye of a patient comprises providing in the ocular circulation of the patient: a first dye which ...
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    19. Method and apparatus for recording three-dimensional distribution of light backscattering potential in transparent and semi-transparent structures

      An apparatus is disclosed for generating data representative of a three-dimensional distribution of the light backscattering potential of a transparent or semi-transparent object such as a human eye. The apparatus includes an interferometer, both the reference beam and measurement beam of which are directed toward the object and reflected by respective reference and measurement sites thereof, such that axial motion of the object during measurement affects both beams equally. The measurement beam is raster scanned transversely across each measurement site for which data is obtained. Also, the frequency of one of the beams is shifted by a non-moving frequency shifter ...
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    20. Method and apparatus for improving vision and the resolution of retinal images

      A method of and apparatus for improving vision and the resolution of retinal images is described in which a point source produced on the retina of a living eye by a laser beam is reflected from the retina and received at a lenslet array of a Hartmann-Shack wavefront sensor such that each of the lenslets in the lenslet array forms an aerial image of the retinal point source on a CCD camera located adjacent to the lenslet array. The output signal from the CCD camera is acquired by a computer which processes the signal and produces a correction signal which ...

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    21. Process and arrangement for examining a section of the eye

      Systems, methods, and apparatus are provided for deriving the relative position of an eye by tracking a boundary of the eye such as the limbus (i.e., the interface between the white sclera and the colored iris). A technique for tracking the position of the eye of patient comprises directing light to an annular region of the eye between the sclera and the iris and receiving reflected light from that region. The intensity of the reflected light is then measured to determine a relative position of the eye. In some embodiments, the measured region is scanned around the boundary. In ...
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    11593-11616 of 11634 « 1 2 ... 481 482 483 484 485 »
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