DISEASES OF THE EYE. 273 



STAPHYLOMA. 



This consists in a bulging forward of the cornea at a given point 

 by the saccular yielding and distention of its coats, and it may be 

 either transparent or opaque and vascular. In the last form the iris 

 has become adherent to the back of the cornea, and the whole struc- 

 ture has become filled with blood vessels. In the first form the bulg- 

 ing cornea is attenuated ; in the last it may be thickened. The best 

 treatment is by excision of a portion of the rise so as to relieve the 

 intraocular pressure. 



PAEASITES IN THE EYE. 



Acari in the eye have been incidentally alluded to under inflamma- 

 tion of the lids. 



Filaria palpebralis is a white worm, one-half to 1 inch long, which 

 inhabits the lachrymal duct and the underside of the eyelids and haw 

 in the horse, producing a verminous conjunctivitis. The first step in 

 treatment in such cases is to remove the worm with forceps, then treat 

 as for external inflammation. 



Filaria equina is a delicate, white, silvery-looking worm, which I 

 have repeatedly found 2 inches in length (a length as great as 5 inches 

 has been reported). It invades the aqueous humor, where its constant 

 active movements make it an object of great interest, and it is fre- 

 quently exhibited as a " snake in the eye." It is found also in other 

 internal cavities of the horse, to which it undoubtedly makes its way 

 from the food, and especially the water swallowed, and its prevention 

 is therefore to be sought mainly in the supply of pure water from 

 closed, deep wells. When present in the eye it causes inflammation 

 and has to be removed through an incision made with the lancet in 

 the upper border of the cornea close to the sclerotic, the point of the 

 instrument being directed slightly forward to avoid injury to the iris. 

 Then apply cold water or astringent antiseptic lotions. 



Filaria conjunctivw, resembling Filaria equina very much in size 

 and general appearance, is another roundworm which has been found 

 in the eye of the horse. 



The echinococcus, the cystic, or larval, stage of the echinococcus 

 tapeworm of the dog, has been found in the eye of the horse, and a 

 cysticercus {Gysticercus -fistularisf) is also reported. 



H. Doc. 795, 59-2 18 



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