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Level Set Methods in Segmentation of SDOCT Retinal Images
Published in Ayman El-Baz, Jasjit S. Suri, Level Set Method in Medical Imaging Segmentation, 2019
N Padmasini, R Umamaheswari, Yacin Sikkandar Mohamed, Manavi D Sindal
As shown in Figure 5.2, the retina is a ten layered structure, viz., Nerve fiber layer (NFL), Ganglion cell layer (GCL), Inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), External limiting membrane (ELM), Ellipsoid zone (previously referred to as the IS/OS junction), Interdigitation zone, and Retinal pigment epithelium (RPE). Automatic detection of diabetic maculopathy from SDOCT retinal images is extremely important in analyzing the stage of diabetic retinopathy. Diabetic maculopathy is the condition of fluid being accumulated in between the retinal layers. As shown in Figure 5.3, SDOCT images provide more details about the intraretinal fluid and subretinal fluid present in the macula scan images.
Impact of Retinal Stimulation on Neuromodulation
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
A large amount of retinal processing occurs at synaptic junctions. The outer plexiform layer of the retina is where electrical signals from the photoreceptors interact with bipolar cells. This outer layer includes dendrites from bipolar and horizontal cells as well as axons from photoreceptors. The inner nuclear layer contains the cell nuclei of horizontal, bipolar, and amacrine cells. The inner plexiform layer contains axons of bipolar cells, many types of amacrine cells, and dendrites of ganglion cells (Roska et al. 2006). A web of filtered excitatory and inhibitory signals in the inner plexiform layer detects motion and suppresses eye movements (Baccus 2007). The combination of those signals affects judgments in space and time (Kim et al. 2014a, Robinson 2014) and results in the final exiting signal from the ganglion cell.
Fish-oil supplementation improves retinal injury induced by diabetes and hypercholesterolemia in male Wistar rats
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Hassan IH El-Sayyad, Doaa A. Ali, Mohamed E Hanafy
At the ultrastructural level, the control and those supplemented with fish oil showed normal retinal cell layers. The pigment epithelium is firmly attached to the Bruch’s membrane with underlying choriocapillaris lined by flattened endothelial cells. The apical cell surfaces have a fine arrangement of microvilli which takes as irregular-shaped structures. The basal cell membrane is irregular and in-folded (Figure 2(a)). The photoreceptors of outer segments are inter-digitated with microvilli of the pigment epithelium. Their cell bodies consist of frequently traversed regular-stacked thin membranes (Figure 2(b)). The outer nuclear layer is composed of closely packed nuclei of the photoreceptors and distinguished by its distinctive rosette-shaped thick heterochromatin and the very thin coat of cytoplasm (Figure 2(c)). Internally, the inner nuclear layer is distinguished by two major types of cells; horizontal and bipolar cells (Figure 2(d)). The ganglion cells vary in size with centrally located nuclei composed mainly of euchromatin. At its periphery and in between the ganglion cells, nerve fibers are distributed (Figure 2(e)).