DISEASES OF THE EYE, 347 



rheumatic inflammation of the optic nerve, or from extension of deep 

 inflammation of the eye involving the retina. It sometimes occurs 

 as the result of excessive loss of blood or of great debility. 



SymptOTns. — In this disease observation is seldom made until the 

 animal in its gait and by its action indicates blindness. Generally 

 both eyes are affected. The eyeball remains clear, and the pupil is 

 permanently dilated. No response to light is manifested. 



Treatment. — If caused by debility, loss of blood, or associated with 

 rheumatism, general blood tonics may be given in the feed, namely, 

 powdered sulphate of iron, 1 dram; gentian, 2 drams; nux vomica, 

 one-half dram; to be given twice a day. In cases of rheumatism, 

 one-half ounce of saltpeter may be added. 



FILARIA OCULI (WORM IN THE EYE). 



Filaria oculi (provisionally taken as the larva of F. cervina) is a 

 small white worm, found swimming in the aqueous fluid in the ante- 

 rior chamber. It may be apparently harmless for a long time, but 

 will eventually induce keratitis with inflammatory exudations. 



Treatment. — The cornea may be punctured at its upper and outer 

 margin, and the worm squeezed out with the aqueous humor. The 

 latter will be formed again. This operation results disastrously 

 unless the greatest care and skill are employed. 



CORNEAL DERMATOMA (HAIRY TUMOR ON THE EYEBALL). 



In a few instances this has been seen as a congenital growth. The 

 tumor arises from the cornea or the sclerotic, covered by its respective 

 membrane, with a growth of hair upon its surface. These tumors 

 may be quite prominent or flattened, and are dark in color; the hair 

 may protrude between the eyelids, giving the animal the appearance 

 of having a double eyelid. 



Treatment. — A surgical operation becomes necessary for their re- 

 moval — one requiring a skilled operator. 



STRABISMUS (SQUINTING). 



This is a very rare affection among cattle. Strabismus may be 

 either single or double — affecting one eye or both. It is caused by a 

 paralysis, or a weakening of one of the straight muscles of the eye- 

 ball. Generally it is a congenital defect, and the squinting is toward 

 the nose — strabismus convergens. It is best not to attempt to remedy 

 the defect, as the risk in an operation is greater than the chances of 

 success warrant. 



PTERYGIUM. 



This term is applied to a flesh-colored membrane, triangular in 

 form, which most frequently grows from the inner angle of the eye 



