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Optic nerve head width and retinal nerve fiber layer changes are good indexes for validating the successful induction of experimental anterior ischemic optic neuropathy
摘要： Reproducible skills are essential for successful induction of a rat model of anterior ischemic optic neuropathy (rAION). We established an in vivo validation index by measuring the natural course of optic nerve head (ONH) width and retinal nerve fiber layer (RNFL) thickness in the rAION model using optical coherence tomography (OCT). The rAION model was induced by photodynamic operations. We measured the ONH width and RNFL thickness in the acute stage (<3 days), subacute stage (day 7 and day 14) and later stage (day 28) post-infarct by OCT. RNFL were measured by hematoxylin and eosin stain (HE) to confirm the OCT findings. The RGCs survival rate was determined by retrograde Fluoro-gold labeling, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks post-infarct. The ONH showed significant swelling in the acute stage, which also correlated with RNFL swelling. The swelling was reduced to normal within one-week post-infarct. The rAION group (0.51± 0.12 mm2) showed a significant RNFL thinning when compared with sham groups (0.92±0.15 mm2, p<0.05) on day-28 post-infarct. And HE-stained retina cross sections also showed RNFL thinning, which further confirmed our OCT Findings. The RGC density and P1-N2 amplitude were significantly reduced in rAION. Swelling, reduction of swelling, and atrophy of RNFL in acute, sub-acute, and later stage, respectively, are important events for confirming the successful induction of rAION. They suggest that the longitudinal OCT data provides a reliable index for validating the reproducibility and correct order of rAION.
关键词： optic nerve head (ONH),retinal ganglion cells (RGCs),optical coherence tomography (OCT),anterior ischemic optic neuropathy in rats (rAION),retina nerve fiber layer (RNFL)
更新于2025-09-04 15:30:14
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Influence of <i>Opa1</i> Mutation on Survival and Function of Retinal Ganglion Cells
摘要： PURPOSE. Mutations in the OPA1 gene cause autosomal dominant optic atrophy (ADOA), a visual disorder associated with degeneration of retinal ganglion cells (RGCs). Here, we characterized the disease progression in a homologous mouse model B6;C3-Opa1329-355del and asked whether the pronounced cell death affects certain RGC types more than others. METHODS. The in?uence of the Opa1 mutation was assessed by morphologic (retina and optic nerve histology) and functional (multielectrode array) methods. RESULTS. The RGC loss of approximately 50% within 18 months was signi?cantly more pronounced in RGCs with small-caliber axons. Small-caliber axon RGCs comprise a variety of functional RGC types. Accordingly, electrophysiological analyses of RGCs did not show a dropout of distinct functional RGC subgroups. However, the response properties of RGCs were affected signi?cantly by the mutation. Surprisingly, these functional changes were different under different luminance conditions (scotopic, mesopic, and photopic). Finally, melanopsin cells are known to be less susceptible to retinal insults. We found that these cells are also spared in the Opa1 mouse model, and demonstrated for the ?rst time that this resistance persisted even when the melanopsin gene had been knocked-out. CONCLUSIONS. Small-caliber axons show a higher vulnerability to the Opa1 mutation in our mouse model for ADOA. Luminance-dependent functional changes suggest an in?uence of the Opa1 mutation on the retinal circuitry upstream of RGCs. Photoresponsive RGCs are protected against cell death due to the Opa1 mutation, but not by melanopsin expression itself.
关键词： retinal ganglion cells,optic nerve,melanopsin,MEA recordings,optic neuropathy
更新于2025-09-04 15:30:14
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Comprehensive Three-Dimensional Analysis of the Neuroretinal Rim in Glaucoma Using High-Density Spectral-Domain Optical Coherence Tomography Volume Scans
摘要： To describe spectral-domain optical coherence tomography (OCT) methods for quantifying neuroretinal rim tissue in glaucoma and to compare these methods to the traditional retinal nerve fiber layer thickness diagnostic parameter. Neuroretinal rim parameters derived from three-dimensional (3D) volume scans were compared with the two-dimensional (2D) Spectralis retinal nerve fiber layer (RNFL) thickness scans for diagnostic capability. This study analyzed one eye per patient of 104 glaucoma patients and 58 healthy subjects. The shortest distances between the cup surface and the OCT-based disc margin were automatically calculated to determine the thickness and area of the minimum distance band (MDB) neuroretinal rim parameter. Traditional 150-lm reference surface–based rim parameters (volume, area, and thickness) were also calculated. The diagnostic capabilities of these five parameters were compared with RNFL thickness using the area under the receiver operating characteristic (AUROC) curves. The MDB thickness had significantly higher diagnostic capability than the RNFL thickness in the nasal (0.913 vs. 0.818, P ? 0.004) and temporal (0.922 vs. 0.858, P ? 0.026) quadrants and the inferonasal (0.950 vs. 0.897, P ? 0.011) and superonasal (0.933 vs. 0.868, P ? 0.012) sectors. The MDB area and the three neuroretinal rim parameters based on the 150-lm reference surface had diagnostic capabilities similar to RNFL thickness. The 3D MDB thickness had a high diagnostic capability for glaucoma and may be of significant clinical utility. It had higher diagnostic capability than the RNFL thickness in the nasal and temporal quadrants and the inferonasal and superonasal sectors.
关键词： neuroretinal rim,spectral-domain optical coherence tomography,glaucoma,optic disc,optic nerve
更新于2025-09-04 15:30:14
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[IEEE 2018 International Joint Conference on Neural Networks (IJCNN) - Rio de Janeiro (2018.7.8-2018.7.13)] 2018 International Joint Conference on Neural Networks (IJCNN) - Study of Clinical Staging and Classification of Retinal Images for Retinopathy of Prematurity (ROP) Screening
摘要： Retinopathy of Prematurity (ROP) is a disease which requires immediate precautionary measures to prevent blindness in the infants, and this condition is prevalent in premature babies in all the underdeveloped, developing, and in the developed countries as well. This paper proposes a tool by which the stage and zones of Retinopathy of Prematurity in infants can be diagnosed easily. This tool takes the input from the Retcam and detects the stage, zone, and gives a rating of 1 to 9 for classifying the severity of the disease in the infants. This is achieved by extracting the optic disc, marking the ridge, and the distance of the optic nerve. This tool can be easily used by nurses and paramedics, unlike the existing technologies which require the guidance of a specialist to come to a conclusion.
关键词： Retina,Retcam,Zones,Retinopathy,Stage,Optic disc,Optic nerve
更新于2025-09-04 15:30:14
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Evaluation of Ocular Perfusion in Alzheimer’s Disease Using Optical Coherence Tomography Angiography
摘要： Background: There is increasing evidence for the involvement of cerebrovascular factors in Alzheimer’s disease (AD). Objective: To evaluate retinal and optic nerve head perfusion in patients with AD using optical coherence tomography angiography (OCTA), and to analyze the correlations of quantitative OCTA metrics with AD pathology and vascular cerebral lesions in AD patients. Methods: 36 eyes of 36 patients with AD (study group) and 38 eyes of 38 healthy subjects (control group) were prospectively included in this study. OCTA was performed using RTVue XR Avanti with AngioVue. In addition, patients underwent a detailed ophthalmological and neurological examination including Mini-Mental State Examination, cerebral magnetic resonance imaging, and amyloid-β (Aβ) and tau levels in the cerebrospinal fluid (CSF). Results: The flow density in the superficial retinal OCT angiogram of the macula in the study group was significantly lower compared to the control group (p = 0.001). There was a significant correlation between the flow density in the superficial retinal OCT angiogram of the macula, as measured using OCTA, and the Fazekas scale (Spearman’s correlation coefficient = –0.520; p = 0.003). There was no significant correlation between the Aβ or tau levels in the CSF and the flow density data. Conclusion: Patients with AD showed a reduced flow density in the radial peripapillary capillaries layer and in the superficial retinal OCT angiogram when compared with healthy controls. The reduced retinal flow density measured using OCTA is not specifically associated with AD pathology but is associated with the vascular cerebral lesions in AD.
关键词： optical coherence tomography angiography,retinal and optic nerve head perfusion,Alzheimer’s disease,flow density
更新于2025-09-04 15:30:14
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Spatiotemporal Expression Changes of PACAP and Its Receptors in Retinal Ganglion Cells After Optic Nerve Crush
摘要： Pituitary adenylate cyclase-activating polypeptide (PACAP) has been demonstrated to play a crucial part in protecting retinal ganglion cells (RGCs) from apoptosis in various retinal injury animal models. PACAP has two basic groups of receptors: PACAP receptor type 1 (PAC1R) and vasoactive intestinal polypeptide/PACAP receptors (VPAC1R and VPAC2R). However, few studies illustrated the spatial and temporal expression changes of endogenous PACAP and its receptors in a rodent optic nerve crush (ONC) model. In this study, a significant upregulation of PACAP and PAC1R in the retina after ONC was observed in both protein and RNA levels. The peak level of PACAP and PAC1R expression could be found on the fifth day following ONC. In addition, immunofluorescent labeling indicated that PACAP and PAC1R were localized mainly in RGCs. On the contrary, VPAC1R and VPAC2R were hardly detected in the retina. Collectively, the spatiotemporal expression of PACAP and its high-affinity receptor PAC1R were remarkably changed after ONC, and mainly expressed in the ganglion cell layer of the retina. This suggested that the upregulation of PACAP and PAC1R may play a vital role in RGC death after ONC.
关键词： PACAP,Receptors,Rat,Retinal ganglion cells,Optic nerve crush
更新于2025-09-04 15:30:14
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Optic nerve and retinal electrostimulation in rats: direct activation of the retinal ganglion cells
摘要： Visual prosthesis is competing with biological approaches to restore vision to the blind. Understanding and developing the ability to replicate the neural code of the retina are key factors that can bring bionic vision significant advantage. Here, electrically evoked potentials were recorded in anesthetized rats from the dorsal surface of the superior colliculus. Electrical stimuli of different amplitudes were delivered at the retina and the optic nerve. An evoked potential appeared in both cases within the first 5 ms post-stimulus suggesting that this component of the response was initiated by direct activation of the retinal ganglion cells. However, in the case of retinal neurostimulation, a second evoked potential occurred 9.0 ± 3.4 ms after the stimulus delivery. Because this component was not present in the case of optic nerve electrostimulation, it is expected to be originated by the activation of other cells in the retinal network.
关键词： superior colliculus,visual prosthesis,electrostimulation,retinal ganglion cells,optic nerve
更新于2025-09-04 15:30:14