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Abstract #10417 Published in IGR 6-1
Normal-pressure glaucoma: a hypothesis of pathogenesis
Nesterov AP; Aliab'eva ZI; Lavrent'ev AVVestnik Oftalmologii 2003; 119: 3-6
Normal pressure glaucoma (NPG) is a heterogeneous pathology of the optic nerve and retina. Moreover, primary open-angle glaucoma (POAG) with high pressure also belongs to the heterogeneous group. The risk factors and pathogenesis stages of NPG and those of POAG do not completely coincide. A considerable number of NPG cases can be attributed to pseudo-normal pressure glaucoma. The individual norm of the intraocular pressure (IOP) does not coincide with statistical standards. At the same time, POAG with high pressure has, to a more or less extent, specific features peculiar to NPG. This is especially characteristic of POAG with moderately high IOP. NPG specific features peculiar to the majority of the patients examined were related to insufficient cerebral blood circulation caused by occlusive processes in the large and small vessels of the brain, by the nature of the collateral blood ,circulation and by dysfunction of the vascular endothelium due to exhaustion of the cerebral perfusion reserve. The latter is formed mainly at the cost of the vertrebobasilar basin. This 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, BNDF) with axonal transport to the retinal ganglion 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. Mechanical factors related to excavation cannot be ruled out either. NPG patients often have a relatively large optic nerve disc (OND), and therefore, their disc area is equally large. The pressure exerted on the OND is proportional, not only to IOP value, but also to disc area. Consequently, provided the IOP is identical, the mechanical forces exerted on the OND would differ with direct dependence on disc area. There is every reason to suggest that a considerable proportion of NPG cases is preconditioned by the cerebrovascular pathology and, therefore, not only an ophthalmologist, but also a neurologist should be involved in the diagnosis and treatment of such patients. LA: Russian
Classification:
9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)