نتایج جستجو برای: retinal image
تعداد نتایج: 453049 فیلتر نتایج به سال:
Purpose To demonstrate a novel technique for capturing optical coherence tomography images of peripheral retina and its application in identifying rhegmatogenous retinal detachments within bullous retinoschisis. Observations We report two patients presenting with bullous retinoschisis noted on clinical examination. After performing optical coherence tomography studies utilizing our image acqu...
Effect of image quality, color, and format on the measurement of retinal vascular fractal dimension.
PURPOSE Fractal dimension of retinal vasculature is a global summary measure of retinal vascular network pattern and geometry. This study was conducted to examine the effect of variations in image color, brightness, focus, contrast, and format on the measurement of retinal vascular fractal dimension. METHODS A set of 30 retinal images from the Blue Mountains Eye Study was used for a series of...
Interocular differences in apparent size (aniseikonia) are typically associated with interocular differences in refractive error (anisometropia). Aniseikonia is generally thought to reflect disparities in retinal image size that often accompany anisometropia. This assumption was examined with seven highly anisometropic subjects who were tested under conditions in which no substantial retinal im...
Retinal exudates are typically manifested as spatially random yellow/white patches of varying sizes and shapes. They are a characteristic feature of retinal diseases such as diabetic maculopathy. An automatic method for the detection of exudate regions is introduced comprising image colour normalisation, enhancing the contrast between the objects and background, segmenting the colour retinal im...
Computerized screening of diabetic retinopathy employing blood vessel segmentation in retinal images
Diabetic retinopathy is a severe sight threatening disease which causes blindness among working age people. This research work presents a retinal vessel segmentation technique, which can be used in computer based retinal image analysis. This proposed method could be used as a prescreening system for the early detection of diabetic retinopathy. The algorithm implemented in this work can be effec...
Optical coherence tomography (OCT) has revolutionises the diagnosis of retinal disease based on the detection of microscopic rather than subcellular changes in retinal anatomy. However, currently the technique is limited to the detection of microscopic rather than subcellular changes in retinal anatomy. However, coherence based imaging is extremely sensitive to both changes in optical contrast ...
This study was conducted to demonstrate a new scan method for retinal vessel structure measurement in a specific region of fundus (zone B) using spectral-domain optical coherence tomography (SD-OCT), and to assess its reliability. One temporal superior retinal vessel pair passing through a concentric ring (zone B), which was defined between half and one disc distance from the optic disc border,...
PURPOSE To present a method for image segmentation and generation of enface thickness maps and reflectance images of retinal layers in healthy and diabetic retinopathy (DR) subjects. METHODS High density spectral domain optical coherence tomography (SDOCT) images were acquired in 10 healthy and 4 DR subjects. Customized image analysis software identified 5 retinal cell layer interfaces and ge...
A fundamental challenge for the visual system is to extract the 3D spatial structure of the environment. When an observer translates without moving the eyes, the retinal speed of a stationary object is related to its distance by a scale factor that depends on the velocity of the observer's self-motion. Here, we aim to test whether the brain uses vestibular cues to self-motion to estimate distan...
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