Circulatory disorders of the optic nerve.

Circulatory disorders of the optic nerve may be classified into acute and chronic lesions as well as into anterior and posterior ones. In general, anterior lesions clinically prevail; they are located around the lamina cribrosa and are pathogenetically explained as a consequence of decreased blood flow in the posterior ciliary arteries as well as in the perilaminar capillaries. The symptoms of the acute anterior lesions are described. The nerve head infarction may be induced by various circulatory disorders such as arteriosclerosis, diabetes, elevated blood pressure, giant cell arteritis or other collagen diseases, but also by others. The particular importance of giant cell arteritis is stressed. The prognosis of acute anterior ischemic optic neuropathy is poor, possibilities of treatment are discussed. The chronic anterior lesion is considered to be caused by an imbalance between intraocular pressure and the perfusion pressure in the posterior ciliary arteries and consequently in the perilaminar capillaries. The clinical signs ('low tension glaucoma') are described, the therapeutic measures, although limited, are outlined. The ischemic lesions of the posterior part of the optic nerve are less well defined. However, theoretical considerations as well as clinical experience suggest that such lesions occasionally occur taking either an acute or a chronic course.