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Optical Coherence Tomography (Oct) and Fundus Fluorescein Angiography (FFA) in Neuro-Ophthalmology
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Ramandeep Singh, Deeksha Katoch, Mohit Dogra, Basavaraj Tigari, Simar Rajan Singh, Sahil Jain, Bruttendu Moharana, Sabia Handa, Mangat R. Dogra
She presented after 3 years with sudden-onset progressive loss of vision in both eyes (R>L) for 1 week. She presented to the neurology department, and the diagnosis of relapse of NMOSD was made. On examination, her best-corrected visual acuity (BCVA) was counting finger 1 m in the right eye and 20/160 in the left eye. Fundus examination (Figure 3A.3e and f) showed bilateral temporal disc pallor (R>L) in both eyes. OCT macula (Figure 3A.3g and h) showed some changes in the inner nuclear layer (red arrowhead) in the right eye with the otherwise normal foveal contour in both the eyes. GCA analysis (Figure 3A.3i and j) revealed bilateral thinning. The ganglion cell loss was more evident in the right eye (Figure 3A.3i) (darker the color, thinner is the ganglion cell layer). OCT pRNFL in the right eye (Figure 3A.3k) showed thinning of retinal nerve fiber layer of around the entire optic disc. In the left eye (Figure 3A.3l), only temporal and inferior pRNFL was thinned out.
Comparative Anatomy and Physiology of the Mammalian Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The optic nerve is comprised of the axons of the ganglion cells of the retina, myelin, blood vessels, glial cells, and the three meningeal sheaths of the central nervous system (dura, arachnoid, and pia). The optic nerve fibers originate from the ganglion cells of the retina which give rise to the nerve fiber layer, the innermost layer of the retina. These fibers take an arcuate course, merge, and exit the eye at the posterior pole at an area that can be seen clinically as the optic disc. Depending on the species, this intraocular portion of the optic nerve may or may not be myelinated and varies in size and shape. The nerve then courses posteriorly past the choroid, where it is surrounded by astrocytes, and the sclera where both astrocytes and scleral collagen surround the nerve, comprising the lamina cribrosa. As the nerve exits the globe it acquires its meningeal covering, travels craniad, and leaves the orbit via the bony optic foramen. The right and left optic nerve meet at the optic chiasm and, depending on the species, a percent of the fibers will decussate (Table 7).3
Related Works
Published in Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza, Computer-Aided Glaucoma Diagnosis System, 2020
Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza
Pachiyappan et al. (2012) proposed a technique for Glaucoma diagnosis utilizing fundus images of the eye and the optical coherence tomography (OCT). The Retinal Nerve Fiber Layer (RNFL) can be classified into anterior boundary, which is the top layer of RNFL, the posterior boundaries (bottom layer of RNFL), and also the distance in between the two boundaries. glaucomatous and non-glaucomatous classification depends on the thickness of the nerve fiber layer, which is nearly 105 μm. This approach provided optical disc detection with a 97.75% accuracy.
Investigation of Retinal Alterations in Patients Recovered from COVID-19: A Comparative Study
Published in Ocular Immunology and Inflammation, 2023
Mehmet Özbaş, Bengi Demirayak, Aslı Vural, Yunus Karabela, Fadime Ulviye Yigit
All patients underwent biomicroscopic anterior and posterior segment evaluation. Fundus photography was done using a fundus camera (Kowa VX-20, Kowa, Tokyo, Japan). OCT and OCTA, using the split-spectrum amplitude decorrelation angiography (SSADA) algorithm (RTVue XR Avanti with Angio Vue, Optovue Inc., Fremont, CA, USA), were performed for all participants. Macular 6x6-mm scans were used. Each scan was automatically segmented by the software to visualize the SCP and DCP of the retina. The whole, foveal, and parafoveal vessel density (as a percentage) of the SCP, DCP, and FAZ area (in millimeters squared) were analyzed. In addition, retinal nerve fiber layer thickness and subfoveal thickness (in microns) were measured and compared. Only the right eyes of the patients and participants in the control group were included in the study. This was done to eliminate similarities of the measurements in the same person as a confounding factor. The status of hospitalization, level of oxygen saturation, medical treatment used, and presence of pneumonia of the thorax were recorded via computerized tomography (CT).
A Case of Presumed Bonsai-induced Severe Toxic Optic Neuropathy
Published in Neuro-Ophthalmology, 2022
Erdogan Yasar, Hatice Suhan Tomac, Ugur Gurlevik
A 32-year-old man presented with gradually worsening vision in both eyes for the last 2 years. He reported that he had been completely normal vision 2 years ago. He said that there had been no serious eye disease in his family. He had a visual acuity of counting fingers at 1 m in each eye. His pupils were mid-dilated with a feeble reaction to light. No pathology was found in the anterior segment during the examination. During fundus examination, both optic discs were diffusely covered with a black pigment and the optic nerves below were atrophic. Retinal nerve fibre layer thinning was observed. The vessels appeared to have disappeared below the pigmentation (Figures 1 and Figures 2). Due to cognitive and behavioural impairment and his poor visual acuity he could not co-operate to allow optical coherence tomography (OCT) or visual field testing. In addition, there were no previous fundus photographs available to compare with.
The Correlation of Inflammation and Microvascular Changes with Diabetic Retinal Neurodegeneration
Published in Current Eye Research, 2021
Tuna Celik Buyuktepe, Sibel Demirel, Figen Batıoğlu, Emin Özmert
All SD-OCT image sets contained a minimum of 13 B-scans distributed in a horizontal raster pattern, with a scan speed of 27,000 A-scans/second, a scan depth of 2.00 mm, axial resolution of 5 µm, and transverse resolution of 15 µm. After pupillary dilation, each subject was seated in front of the OCT scanner, and their head was stabilized on the chin rest. An internal fixation target was used to avoid eye movement. Retinal layers and thickness analysis were recorded in the foveal area (1-mm zone centered on the fovea as defined by the Early Treatment Diabetic Retinopathy Study, ETDRS). The automatic segmentation of the retinal layers was performed, and the segmentation lines were manually adjusted if needed. The thicknesses of the following layers were recorded: 1) the retinal nerve fiber layer (RNFL), 2) the ganglion cell layer (GCL), 3) the inner plexiform layer (IPL), 4) the inner nuclear layer (INL), 5) the outer plexiform layer (OPL), 6) the outer nuclear layer (ONL), and 7) the retinal pigment epithelium (RPE). The total retinal thickness was defined as the distance between the vitreoretinal interface and the anterior surface of the RPE along each A-scan. The “inner retina” was defined as the space lying between the inner aspect of the internal limiting membrane and the inner border of the OPL, whereas the “outer retina” was defined as the space lying between the inner border of the OPL and the inner aspect of the RPE.