CHAPTER XV 



GLAUCOMA 



Glaucoma is characterized by an increase of the 

 intra-ocular tension — that is, the eyeball is harder than 

 normal, and its hardness may continue to increase until 

 there is absolute resistance to pressure by the finger- 

 tips. Make a practice of taking the tension in all dis- 

 eases of the eye as a part of the routine examination, 

 and acquaint yourselves with the normal tension of the 

 eyes of different animals. This is done by pressing the 

 eyeballs, above the cornea, over the closed lids, with 

 the tips of the index-fingers; first gently pressing with 

 one finger, and then with the other, as in testing for 

 fluctuation. There is an instrument devised for this 

 purpose, called a tenometer, but with practice and ex- 

 perience the finger-tips are reliable. 



The cause of increased tension is due to a damming 

 up or failure of the lymphatics to perform their func- 

 tion, the principal one being Schlemm's canal, located 

 in the sclera, just anterior and external to the spaces 

 of Fontana or the filtration angle of the anterior cham- 

 ber. This angle is adjacent to the anterior portion of the 

 ciliary body and the root of the iris. For this reason 



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