Home About us Contact
|
Home About us Contact | ||
|
|
||
Optic Nerve Damage (optic + nerve_damage)
Selected AbstractsExpression of glial fibrillary acidic protein and glutamine synthetase by Müller cells after optic nerve damage and intravitreal application of brain-derived neurotrophic factorGLIA, Issue 2 2002Hao Chen Abstract Müller glia play an important role in maintaining retinal homeostasis, and brain-derived neurotrophic factor (BDNF) has proven to be an effective retinal ganglion cell (RGC) neuroprotectant following optic nerve injury. The goal of these studies was to investigate the relation between optic nerve injury and Müller cell activation, and to determine the extent to which BDNF affects the injury response of Müller cells. Using immunocytochemistry and Western blot analysis, temporal changes in the expression of glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) were examined in rats after optic nerve crush alone, or in conjunction with an intravitreal injection of BDNF (5 ,g). GFAP protein levels were normal at 1 day post-crush, but increased ,9-fold by day 3 and remained elevated over the 2-week period studied. Müller cell GS expression remained stable after optic nerve crush, but the protein showed a transient shift in its cellular distribution; during the initial 24-h period post-crush the GS protein appeared to translocate from the cell body to the inner and outer glial processes, and particularly to the basal endfeet located in the ganglion cell layer. BDNF alone, or in combination with optic nerve crush, did not have a significant effect on the expression of either GFAP or GS compared with the normal retina, or after optic nerve crush alone, respectively. The data indicate that although BDNF is a potent neuroprotectant in the vertebrate retina, it does not appear to have a significant influence on Müller cell expression of either GS or GFAP in response to optic nerve injury. GLIA 38:115,125, 2002. © 2002 Wiley-Liss, Inc. [source] Optic radiation changes after optic neuritis detected by tractography-based group mappingHUMAN BRAIN MAPPING, Issue 3 2005Olga Ciccarelli Abstract Postmortem data suggest that trans-synaptic degeneration occurs in the lateral geniculate nucleus after optic nerve injury. This study investigated in vivo the optic radiations in patients affected by optic neuritis using fast marching tractography (FMT), a diffusion magnetic resonance imaging (MRI) fiber tracking method, and group mapping techniques, which allow statistical comparisons between subjects. Seven patients, 1 year after isolated unilateral optic neuritis, and ten age and gender-matched controls underwent whole-brain diffusion tensor MR imaging. The FMT algorithm was used to generate voxel-scale connectivity (VSC) maps in the optic radiations in each subject in native space. Group maps of the left and right optic radiations were created in the patient and control group in a standardized reference frame using statistical parametric mapping (SPM99). The reconstructed optic radiations in the patient group were localized more laterally in the posterior part of the tracts and more inferiorly than in the control group. Patients showed reduced VSC values in both tracts compared with controls. These findings suggest that the group mapping techniques might be used to assess changes in the optic radiations in patients after an episode of optic neuritis. The changes we have observed may be secondary to the optic nerve damage. Hum Brain Mapp, 2005. © 2005 Wiley-Liss, Inc. [source] Ocular Changes after Intravitreal Injection of Methanol, Formaldehyde, or Formate in RabbitsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2001Yoriko Hayasaka One hundred ,l of 1% methanol, 1% or 0.1% formaldehyde, or 1% formate was injected in the vitreous cavity of the right eyes of rabbits. The eyes were examined by biomicroscopy and ophthalmoscopy weekly. One month after injection, the eyes were enucleated and examined histologically. One week after treatment the animals that received 0.1% formaldehyde showed retinal vessel dilation, and the rabbits that received 1% formaldehyde showed mild posterior subcapsular cataract and retinal vessel dilation and haemorrhages. One month after treatment, the animals that received 0.1% or 1% formaldehyde developed mild posterior subcapsular cataract and retinal lesions. Animals that received 1% methanol or 1% formate showed nearly normal optical media and fundi. Histologically disorganized retina and optic nerve were seen in eyes that received 0.1% or 1% formaldehyde. Eyes that received 1% methanol or 1% formate appeared histologically normal. Our findings indicate that intravitreal injection of formaldehyde causes retinal and optic nerve damage, while methanol and formate are not or less toxic to ocular tissues. [source] 2151: Interaction of vascular and biomechanical aspects of glaucomaACTA OPHTHALMOLOGICA, Issue 2010M LESK Purpose In an attempt to understand some of the reasons why some optic nerves appear to be sensitive to IOP and others not, I will review studies describing the interaction between vascular and biomechanical factors in open angle glaucoma. Methods Studies using biomechanical modelling, epidemiologic data, measurements of ocular or systemic blood flow, measurment of peripheral vasospasticity, and measurement of ocular biomechanical parameters will be reviewed. Hypotheses will be presented regarding the interpretation of these data. Results Studies suggest that the optic nerves of vasospasctic patients may be more IOP-sensitive than those of non-vasospastic patients. Non-invasive measurements of ocular blood flow suggest that this pressure-sensitivity may be related to IOP-sensitive optic nerve blood flow. Biomechanical modelling suggests that scleral and lamina cribrosa elasticity, axial length, and eye wall thickness contribute to optic nerve head stress and strain. Cross-sectional clinical data supports the role of increased ocular elasticity in the susceptibilty of the optic nerve to glaucoma damage, especially in vasospastic patients. Some promising new avenues for research in this area will be presented. Conclusion There is increasing evidence that biomechanical and vascular ocular factors interact leading to an elevated susceptibilty of the optic nerve to glaucomatous optic nerve damage. Commercial interest [source] 2163: Identification of novel disease gene for primary congenital glaucoma (PCG) through homozygosity mapping and next-generation sequencing strategies in a large consanguineous pedigreeACTA OPHTHALMOLOGICA, Issue 2010H VERDIN Purpose Primary congenital glaucoma (PCG) is caused by developmental anomalies of the trabecular meshwork and the anterior chamber angle resulting in an increased ocular pressure (IOP) and optic nerve damage. In general PCG displays an autosomal recessive inheritance pattern and is genetically heterogeneous. To date, three PCG loci are known, namely GLC3A, GLC3B and GLC3C, and two causal genes have been identified, CYP1B1 located in the GLC3A locus and LTPB2 located at 1.3 MB proximal to the GLC3C locus. The purpose of the current study is to identify the causal disease gene in a large consanguineous family with PCG, originating from Jordany. CYP1B1 mutations and linkage to the LTBP2, GLCB3 and GLCC3 locus were previously excluded. Methods In a first step, DNA from members from the consanguineous family will be genotyped by 250K GeneChip Mapping Affymetrix arrays. Homozygosity mapping will be applied to identify potential disease loci, using a homemade Perl script. Next, microsatellite analysis will be performed in order to confirm findings and to narrow down candidate regions. Subsequently, candidate regions of interest will be captured (Agilent) and sequenced on the Illumina Genome Analyser IIx (GAIIx). Gene and variant prioritization will be done using in-house developed software, followed by segregation analysis and screening in control individuals. At last, a cohort of 30 molecularly unsolved PCG patients will be screened for mutations in the newly identified disease. Conclusion The identification of a new disease gene for PCG may lead to better insights into the molecular pathogenesis of glaucoma, and might uncover novel therapeutic strategies. [source] Disease mechanisms leading to impaired blood flow in glaucomaACTA OPHTHALMOLOGICA, Issue 2009D GHERGHEL Purpose SIS lecture Methods Literature search Results Although primary open-angle glaucoma (POAG), is associated more closely with elevated intraocular pressure (IOP), other risk factors already implicated in the aetiology of this disease and especially in the aetiology of normal-tension glaucoma are: abnormal ocular circulation, ocular and systemic vascular dysregulation, as well as systemic blood pressure (BP) alterations. Oxidative stress, which occurs as a result of an imbalance between generation of reactive oxygen species (ROS) and antioxidant defence mechanisms and is implicated in the pathogenesis of disorders ranging from atherosclerosis to neurodegenerative disorders, diabetes and aging, may also contribute to the general vascular disturbances observed in glaucoma. Moreover, increasing evidence shoes that oxidative stress plays a role in promoting endothelial dysfunction, which is a key factor in progression of vascular diseases. Indeed, glaucomatous optic nerve damage has been related to endothelial damage/dysfunction. This presentation explores the role of various ocular and systemic circulatory factors in the pathogenesis of glaucomatous neuropathy. [source] The influence of age, sex, race, refractive error and optic disc parameters on the sensitivity and specificity of scanning laser polarimetryACTA OPHTHALMOLOGICA, Issue 4 2004Vital P. Costa Abstract. Purpose:,To evaluate the influence of age, sex, race, refractive error and optic disc topography on the sensitivity and specificity of scanning laser polarimetry (SLP) in the diagnosis of glaucoma. Methods:,A total of 88 normal individuals and 95 glaucoma patients were included in this study. Glaucoma was defined on the basis of both optic nerve damage and visual field defects. Scanning laser polarimetry, optic disc topography, automated perimetry and refractometry were performed in all subjects. The sensitivity and specificity of SLP were assessed applying a previously calculated cut-off to a previously described linear discriminant function (LDF). Results:,The sensitivity and specificity of SLP in the study population were 82% and 83%, respectively. Sensitivity and specificity were not affected by age, sex, race, average disc diameter or disc area. The sensitivity of SLP tended to be higher in myopes (93%) than in emmetropes (80%) and hyperopes (71%) (p = 0.08). Sensitivities were higher in individuals with cup areas > 0.96 mm2 (89%), rim areas , 1.36 mm2 (92%), and cup area/disc area ratios > 0.45 (89%) (p < 0.05). Stepwise logistic regression analysis indicated that the presence of a cup area > 0.96 mm2 and a rim area < 1.36 mm2 significantly increased the sensitivity of the LDF, whereas a cup area/disc area ratio , 0.45 significantly increased the specificity of the LDF. Conclusion:,The sensitivity and specificity of SLP may be influenced by refractive error and optic disc parameters that are affected by glaucomatous damage (cup area, rim area and cup area/disc area ratio). These parameters must be considered in studies evaluating the sensitivity and specificity of optic nerve/retinal nerve fibre layer imaging technologies. [source] Frequency doubling technology and high-pass resolution perimetry in glaucoma and ocular hypertensionACTA OPHTHALMOLOGICA, Issue 3 2003Lada Kalaboukhova Abstract. Purpose:, To study the correlation between frequency doubling technology perimetry (FDT) and high-pass resolution perimetry (HRP) in eyes with primary open-angle glaucoma, suspect glaucoma, ocular hypertension, and in normal eyes. Patients and Methods:, Ninety-four patients (162 eyes) were studied. Visual fields were assessed by HRP, FDT screening C-20,5 and FDT threshold C-20 programs. In eyes with a discrepancy between the test results, a comprehensive clinical examination was performed, including optic disc photography and Heidelberg retinal tomography (HRT). Results:, There was a strong correlation between HRP global deviation and the FDT mean deviation (for FDT threshold C-20 test), and between HRP score and FDT score (for FDT screening C-20,5 ). The correlation coefficients were r = ,0.83 and r = 0.77, respectively. In all, 75 eyes (46.3%) had normal HRP and FDT screening results, while 67 eyes (41.4%) showed abnormal results in both tests. In 12 eyes (7.4%) HRP was within normal limits while FDT screening was abnormal. Seven of these eyes were judged to have glaucoma; three of them had converted from ocular hypertension to glaucoma. In eight eyes (4.9%) HRP was abnormal while FDT screening was normal. Three of these were judged to have glaucoma. Thus, the sensitivity and specificity of the FDT screening test for the detection of glaucoma were 91.7% and 87.8%, respectively. Conclusion:, There was a strong correlation between FDT threshold C-20, FDT screening C-20,5 and HRP test results. Frequency doubling technology perimetry C-20,5 represents a good screening test for the detection of optic nerve damage in open-angle glaucoma. [source] Posner-Schlossman syndrome (glaucomatocyclitic crisis)CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 1 2007Ralph J Green DipAppSc(Optom) Posner-Schlossman syndrome (PSS) or glaucomatocyclitic crisis is a rare, typically unilateral recurrent inflammatory ocular hypertensive disease in which diagnosis can be challenging. An acute elevation of intraocular pressure is accompanied by or followed within a few days by a mild, often symptomless uveal inflammation. The mild nature of the uveitis at presentation of the first attack may go undetected. Medical treatment is indicated to prevent pressure-related optic nerve damage and to reduce inflammation. This report details a patient with Posner-Schlossman syndrome whose unilateral pressure elevation was initially treated as acute angle-closure glaucoma. He subsequently had several episodes of increased pressure over a two-year period. Diagnostic difficulties in this case are discussed. [source] | |||||||||||||