Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fluorescein angiography, visual field and retinal nerve fiber layer defects (RNFLD) in 23 patients (35 eyes) with low tension glaucoma (LTG) showed that there was a marked positional correspondency between the fluorescein filling defect of the optic disc and the RNFLD (91.4%) or the visual field defect (77.1%). Besides, the rate of positional correspondent between the RNFLD and visual field defect was 80.0%. The study indicated that RNFLD and visual field defect of LTG are related to ischemia of the optic disc.
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PMID:[The relation of fluorescein angiography in low tension glaucoma with retinal nerve fiber layer defect and visual field damage]. 224 74

A case of arteriosclerotic posterior ischemic optic neuropathy without optic disc edema is described and documented photographically. The development of optic disc cupping and pallor with ischemia in this patient supports the vascular basis for development of similar cupping and pallor in open angle glaucoma and low tension glaucoma.
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PMID:Development of cupping and pallor in posterior ischemic optic neuropathy. 688 56

The endothelium influences local vascular tone by releasing endothelium-derived relaxing factors such as nitric oxide, prostacyclin and a putative hyperpolarizing factor. In isolated ophthalmic arteries and the perfused eye, all endothelial factors importantly contribute to vascular regulation. In larger ophthalmic vessels, this is due to their effects on vascular smooth muscle cells; in smaller vessels, pericytes can be influenced as well. Contracting factors formed include peptide endothelin-1 and cyclooxygenase products, such as thromboxane A2 and prostaglandin H2. In the peripheral circulation endothelial dysfunction occurs under pathological conditions, both in conduit arteries and the microcirculation. An imbalance of endothelium-derived relaxing and contracting factors could be important for the development of vascular ophthalmic complications like hypertension, diabetes, arteriolosclerosis and retinal ischemia. Endothelial dysfunction may also contribute to vasospastic events in retinal migraine and some forms of low tension glaucoma associated with Raynaud phenomenon and migraine.
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PMID:The vascular endothelium as a regulator of the ocular circulation: a new concept in ophthalmology? 780 Dec 20

Normal pressure glaucoma (NPG) is a heterogeneous pathology of the optic nerve and retina. Besides, primary open-angle glaucoma (POAG) with high pressure belongs equally to the heterogeneous group. The risk factors and pathogenesis stages of NPG and those of POAG do not coincide completely. A considerable number of the NPG cases can be attributed to the glaucoma of pseudo-normal pressure. The individual norm of the intraocular pressure (IOP) does not coincide with the statistical standards. At the same time, POAG with high pressure has, to a more or less extent, the specific features peculiar to NPG. This is especially characteristic of POAG with moderately high IOP. The NPG specific features peculiar to a majority of the examined patients were related with an insufficient cerebral blood circulation caused by occlusive processes in the great and small vessels of the brain, by the nature of the collateral blood circulation and by a dysfunction of the vascular endothelium due to an exhaustion of the cerebral perfusion reserve. The latter is formed mainly at the cost of the vertrebobasilar basin. The mentioned basin supplies blood to the visual tract, as well as to the cerebral centers of the visual analyzer and of the midbrain. Ischemia of the upper corpus bigeminum and of the optic nucleus of the corpus geniculate laterale reduces the formation and supply of neurotrophines (in particular, of BNDF) with the axonal transport to the retinal ganglionic cells, which leads to their apoptosis. Cavernous dystrophy of the optic nerve is a factor preconditioning the occurrence of excavation of the optic nerve head. The mechanic factor related with excavation cannot be ruled out, either. NPG patients often have a relatively large size of the optic nerve disk (OND), therefore, their disk area is equally large. The pressure exerted on the OND is proportional not only to an IOP value, it is also proportional to a disk area. Consequently, provided the IOPs are identical, the mechanical forces exerted on the OND would differ with direct dependence on a disk area. There is every reason to suggest that a considerable share of NPG cases are preconditioned by the cerebrovascular pathology and, therefore, not only the ophthalmologist but also the neurologist must be involved in the diagnostics and treatment of such patients.
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PMID:[Normal-pressure glaucoma: a hypothesis of pathogenesis]. 1367 95