346 DISEASES OF THE EYES. 



introduce a huuian iris forceps, with which he seizes and removes 

 the worm. These instruments sliould be disinfected (p. 70) before 

 use. 



Worms under the Eyelids {Extra-ocular Filariasis). 



The presence of tliread-worms between the internal surface of 

 the eyelids and the ball of the eye, sometimes causes considerable 

 irritation of the part ; the chief symptoms being weeping, in- 

 tolerance of light, opacity of the cornea, and tenderness. In old- 

 standing cases, the cornea may become rough and scaly. The 

 worm in question (filaria palpebralis) varies from ^ to f inch in 

 length. It is occasionally found in the canal (lachrymal canal) 

 through which the watery fluid of the eye escapes into the nostril. 



TREATMENT naturally consists in the removal of the worm, or 

 worms, which may be done by opening the eyelids, gently 

 syringing the part with warm saltish water (a teaspoonful to the 

 pint), or with a warm solution of boracic acid and water (5 grains 

 to the ounce of water), a,nd picking out the worms when they 

 come into view. The manipulation in this case will be aided by 

 placing in the affected eye a few drops of a 5 per cent, solution 

 of cocaine, which, in about ten minutes, will render the surface of 

 the eye insensible to pain, for several minutes. 



Amaurosis, or Glass Eye. 



This is not a disease of the eye itself ; but is the condition of an 

 eye in which there is loss of function of the optic nerve, which form 

 of paralysis renders the jetina insensible to the action of light. 

 It may be due to some affection of this nerve, when it will be 

 incurable, or to sympathetic causes, and will probably disappear 

 when the original disease is relieved. The functions of the optic 

 nerve may become arrested by pressure on it from tumours in the 

 brain, or by the loss of its blood-supply from the blocking up of 

 the small artery which is in the centre of this nerve. A blow, a 

 sudden shock, or a flash of lightning close to the eye may, also, 

 render it amaurotic. 



In the majority of cases, both eyes are affected. The presence 

 of the disease can be known by the fact of the pupil remaining 

 dilated and immovable under the influence of light. The interior 

 of the eye looks bright, healthy, and somewhat clearer than natural 

 — in fact, it looks glassy; hence its common name. 



The eyelids are opened wide; and when both eyes are affected, 

 the animal's action and appearance denote that he is blind. 



