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Neuropathology Of Neuro-Ophthalmic Disorders
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
The neuropathological findings in LHON involve retinal ganglion cell layer. There is sparing of retinal pigment layer and photoreceptor layer. A significant cell body and axonal degeneration are noticeable. These changes are accompanied by demyelination and atrophy, which may extend from the optic nerve to the lateral geniculate body. Since the point mutations in LHON are related to respiratory chain dysfunction, there is reduced ATP production, energy failure and degeneration of the retinal ganglion cells.17
Retinal Prostheses Current Approaches, Challenges, and Outlook
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
Luke Theogarajan, John Wyatt, Joseph Rizzo
The retina is often referred to as an approachable part of the brain [1] and is composed of exquisite neural circuitry that performs an amazing level of processing. Hence, the greatest chance of building a successful retinal prosthesis is to start with diseases that leave much of the retinal architecture intact. There are two such diseases that affect only the sensory transduction layer, the photoreceptor layer, of the retina. The first is AMD and the second is retinitis pigmentosa; both these diseases result in a loss of photoreceptors (see Figure 9.1).
Retinal image enhancement and analysis for diabetic retinopathy assessment
Published in Ahmad Fadzil Mohamad Hani, Dileep Kumar, Optical Imaging for Biomedical and Clinical Applications, 2017
Ahmad Fadzil Mohamad Hani, Hanung Nugroho, Lila Iznita Izhar, Nor Fariza Ngah
The photoreceptor layer, which is also called the visual pigment, is composed of light-sensitive cells called rods and cones, characterized by different sensitivity to light. The cones are smaller and very highly concentrated in the fovea, the part of the retina on the visual axis and responsible for central vision. In addition, the layers of other cells and blood vessels covering the peripheral retina, thin out and disappear over the fovea, allowing uninterrupted exposure of the image. There are no rods in the fovea. However, rods dominate peripheral (non-central) vision. Under the photoreceptors is a dark layer known as RPE. The RPE contains melanin granules that absorb excess light and transport oxygen, nutrients and cellular wastes between the photoreceptors and the choroid.
A comparative study between the possible protective role of melatonin versus its combination with adipose derived-mesenchymal stem cells on experimentally induced diabetic retinopathy in adult male albino rats (Histological and immunohistochemical study)
Published in Ultrastructural Pathology, 2023
Samar Reda, Ghada A Elsammak, Tamer G Elsayed, Samar Abdelaziz Mostafa
H&E-stained sections from rat's retina of control group revealed the retinal layers from outside inwards; the retinal pigmented epithelium, photoreceptor layer, outer limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, and inner limiting membrane (Figure 2a), the diabetic group (II) showed apparent decrease of retinal thickness. Vacuoles in photoreceptor layer and inner plexiform layer were observed. Focal widening of intercellular spaces of the inner nuclear layer and the outer nuclear layer were seen. GCL had some ganglionic cells with shrunken darkly stained nuclei. Congested blood vessel was also noticed (Figure 2b), the diabetic rats treated with melatonin (group III) showed partially preserved histological structure of the retinal layers. There were many vacuoles in photoreceptor layer. Ganglionic cells appeared with shrunken nuclei and vacuolated cytoplasm. Congested blood capillary in ganglion cell layer was noticed (Figure 2c), while the diabetic rats treated with melatonin and stem cells (group IV) showed structure nearly similar to the control group. There were some vacuoles in photoreceptor layer (Figure 2d).
Fabrication of nanostructured lipid carriers ocugel for enhancing Loratadine used in treatment of COVID-19 related symptoms: statistical optimization, in-vitro, ex-vivo, and in-vivo studies evaluation
Published in Drug Delivery, 2022
Rehab Abdelmonem, Inas Essam Ibrahim Al-Samadi, Rasha M. El Nashar, Bhaskara R. Jasti, Mohamed A. El-Nabarawi
Histological examination, shown in Figure 8 of the control cornea, illustrated the outer epithelium, inner endothelium, and intermediate stroma, the three layers that made up the cornea. The stroma, which made up most of the cornea, was made up of collagenous fibers in continuous lamellae. Keratocytes were flattened cells found in between the stromal lamellae. The cornea's inner endothelium was composed of a single layer of flattened cells connected by a thick Descemet's membrane. Iris and the ciliary body had no symptoms of cellular invasion. The retinal pigment epithelium, the photoreceptor layer (rod and cone cells), the outer and inner nuclear layers, and the outer and inner plexiform layers were all visible in the control retina. The ganglion cell layer was made up of variously sized rounded cells.
Patterns of ellipsoid zone change associated with visual outcome for diabetic macular oedema
Published in Clinical and Experimental Optometry, 2022
Diabetic macular oedema is a complex disease and has remained one of the most important causes of visual loss worldwide.1 Production of endothelial growth factors, inflammatory cytokines, and more recently, systemic body fluid expansion have been implicated in the pathogenesis of diabetic macular oedema.2,3 While anti-vascular endothelial growth factors have been the mainstay of treatment recently, vision may not always improve as effectively as resolution of oedema in a significant portion of cases.4,5 Good vision at baseline, presence of submacular fluid, and photocoagulation naïve, were predictors for better vision after ranibizumab treatment for diabetic macular oedema.6 Larger visual improvement after treatment was associated with younger age, less severe retinopathy and absence of retinal surface wrinkling.7 Disorganisation of inner retinal layers, hyperreflective foci, and disruption of external limiting membrane and photoreceptors have been identified as useful OCT biomarkers to predict treatment response.8–13 Macular ischaemia has been one of the reasons for the discrepancy between visual and anatomical improvement. Previous studies have demonstrated the significant correlations between macular perfusion and the integrity of photoreceptors, and that the disruption of the photoreceptor may lead to worse visual outcomes.14,15 The connection is further strengthened by optical coherence tomography angiography, which provides more direct visualisation of deep capillary plexus responsible for photoreceptor layer oxygenation.16