748 OPERATIONS UPON THE EYE AND EAK. 



A. — The Extraction of Foreign Bodies on the Surface 

 OF the Globe. 



The presence of a foreign body between the lids and the globe 

 of the eye is just as painful to animals as to man, and may, if 

 allowed to remain, give rise to symptoms of irritation and inflam- 

 mation which, unless promptly relieved, may induce severe attacks 

 of diseases which may compromise the usefulness of the organ. 



Dust, insects, and small seeds of various kinds may indeed 

 find a lodgment in the eye, and resist the efforts made for their 

 removal, notwithstanding the excited function of the membrana 

 nictitans, or the super-excited flood of tears stimulated by their 

 presence. 



Immediate removal is the first indication. This may some- 

 times be effected by bringing the lids together and keeping them 

 temporarily closed until the stimulated collection of tears washes 

 out the offending substance. 



If this fails, cocaine must be apfdied upon the eye, and when 

 its full effect is obtained, careful examination must be made, if 

 necessary, with the assistance of a loup, by everting the lids, in 

 order to bring the entire surface of the cornea into view The 

 irritating body may be wiped out with the finger, a piece of cloth, 

 or a soft camel hair brush, or when the object is hard and angu- 

 lar, as a particle of metal or stone, which has become partly im- 

 bedded in the cornea, the forceps may be necessary. 



B. — Puncture, or Paracentesis of the Cornea. 



The object of this operation is to empty the anterior chamber 

 of the eye of its aqueous humor, of a collection of pus, or to effect 

 a release of a living intruder from the cavity of the eye, as, for 

 example, the -pax&sitic ^/ilaria oculi. 



The operation is simple, but the use of cocaine cannot be 

 omitted. The instruments necessary are a cataract knife, or a 

 lanceolated bistoury (Fig. 539). It is introduced obliquely through 

 the cornea, at a very short distance from the sclerotic, and its in- 



FlO. 539 —Lanceolated Bistoury. 



