CHAPTER XI 



DISEASES OF THE OPTIC NERVE 



The optic nerve is subject to inflammation at any 

 point along its course. When it occurs in the anterior 

 portion it may gradually ascend along the trunk, and 

 when the initial trouble is along the trunk it may descend 

 to the optic disk, and will be followed by atrophy in many 

 cases. When the disk is inflamed the retina is nearly al- 

 ways involved, when it is known as neuroretinitis. The 

 causes are traumatism, inflammation of adjacent struc- 

 tures, tumors, hemorrhages, and diseases of the central 

 nervous system. A portion of the fibers only may be 

 affected, when vision will be partly retained, but if ah 

 the fibers are involved and atrophy follows, vision wifl 

 be entirely lost. When one eye only is affected the 

 cause Hes anterior to the optic chiasm. 



Papillitis is an inflammation of the optic nerve head 

 or papilla. It is usually bilateral, and is due either to 

 pressure upon the nerves or tracts or to effusion within 

 the sheaths or fibers. The papillae are edematous and 

 swollen, larger than normal, and may be reddish, gray, 

 pale, or even white, and the outlines are very indistinct. 

 The arteries are small, while the veins are large and 



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