502 DISEASES OF THE EYELIDS 



Symptoms. The position of the upper eyelid, which hangs 

 downward and partially covers the eyeball, is characteristic. 

 All movements of the animal indicate its inability to move 

 the eyelid to any degree. The most important thing to be 

 considered is the causative factor, and the examination should 

 be made to determine it, if possible. 



Treatment. The treatment should be applied to remove 

 the cause. If sympathetic and the lesion apparent an attempt 

 should be made to correct it. Very often the cause is central 

 and cannot be removed. Potassium iodid in small doses 

 is indicated. If of paralytic origin nerve stimulants, such 

 as strychnin sulphate (0.001 daily) may be tried. Tumor 

 formations on the eyelid should be removed conserving as 

 much of the lid as possible. 



Paralysis of the Orbicularis Nerve. Definition. Paralysis 

 of the facial nerve, probably of central origin, may be periph- 

 eral in which the eye is held open, the lower lid relaxed 

 falling away from the eyeball. 



Etiology. The cause of paralysis of the orbicularis may 

 be wounds or contusions of the nerve leading to temporary 

 or permanent paralysis. When of central origin it often 

 results from hemorrhages in contact with the nerve at the 

 point where it leaves the brain; or thrombus formation in the 

 left posterior cerebellar artery interfering with the nutrition 

 of the nucleus of the facial nerve. Tumors of the brain, and 

 chronic lesions resulting from distemper have also been 

 found to produce it. 



Symptoms. The lack of symmetry of the two sides of the 

 face is the most apparent symptom of facial paralysis. The 

 side paralyzed has a relaxed and drooped appearance. The 

 eyelid will be drooped to a degree and cover a portion of the 

 eyeball but cannot be closed producing a condition of lag- 

 ophthalmus. There is a very noticeable absence of winking 

 of the lids. Palpation of the lids will at once reveal their 

 condition. 



Prognosis. If of peripheral origin and resulting from simple 

 contusing a favorable termination may be looked for. How- 

 ever, if indications point to central origin the condition is 

 often permanent. The degree of injury to the nerve will 



