164 SPECIFIC OPHTHALMIA. 



SPECIFIC OPHTHALMIA, OR MOON-BLINDNESS. 

 Should three or four days pass, and the inflammation not be abated, we may 

 begin to suspect that it is the Ophthalmia, especially if the eye is very impatient 

 of light, and the cornea is considerably clouded. The aqueous humour then often 

 loses its transparency— even the iris changes its colour, and the pupil is exceed- 

 ingly contracted. The veterinary surgeon has now an obstinate disease to com- 

 bat, and one that will generally maintain its ground in spite of all his efforts. 

 For three, or four, or five weeks, the inflammation will remain undiminished; or 

 if it appears to yield on one day, it will return with redoubled violence on the 

 next. At length, and often unconnected with any of the means that have been 

 used, the eye begins to bear the light, the redness of the membrane of the lid 

 disappears, the cornea clears up, and the only vestige of disease which remains 

 is a slight thickening of the lids, and apparent uneasiness when exposed to a 

 very strong light. 



If the owner imagines that he has got rid of the disease, he will be sadly dis- 

 appointed, for, in the course of six weeks or two months, either the same eye 

 undergoes a second and similar attack, or the other one becomes affected. All 

 again seems to pass over, except that the eye is not so perfectly restored, and a 

 slight, deeply-seated cloudiness begins to appear; and after repeated attacks, and 

 alternations of disease from eye to eye, the affair terminates in opacity of the 

 lens or its capsule, attended with perfect blindness either of one eye or both. 

 This affection was formerly known by the name of moon-blindness, from its peri- 

 odical return, and some supposed influence of the moon. That body, however, 

 has not, and cannot have anything to do with it. 



What is the practitioner doing all this while ? He is an anxious and busy, 

 but almost powerless spectator. He foments the eyes with warm water, or 

 applies cold lotions with the extract of lead or opium, or poultices to which these 

 drugs may be added ; he bleeds, not from the temporal artery, for that does not 

 supply the orbit of the eye, but from the angular vein at the inner corner of the eye, 

 or he scarifies the lining of the lid, or subtracts a considerable quantity of blood 

 from the jugular vein. The scarifying of the conjunctive, whichmay be easily ac- 

 complished without a twitch, by exposing the inside of the lids, and drawing a keen 

 lancet slightly over them, is the most effectual of all ways to abate inflammation, 

 for we are then immediately unloading the distended vessels. He places his setons 

 in the cheek, or his rowels under the jaw ; and he keeps the animal low, and 

 gives physic or fever medicine (digitalis, nitre, and emetic tartar). The disease, 

 however, ebbs and flows, retreats and attacks, until it reaches its natural termi- 

 nation, blindness of one or both eyes. 



The horse is more subject to this disease from the age of four to six years 

 than at any other period. He has then completed his growth. He is full of 

 blood, and liable to inflammatory complaints, and the eye is the organ attacked 

 from a peculiar predisposition in it to inflammation, the nature or cause of which 

 cannot always be explained. Every affection of the eye appearing about this age 

 must be regarded with much suspicion. 



It is a common opinion that black horses are more subject to blindness than 

 others. There is considerable doubt about this, or rather it is probable that 

 that colour has no influence either in producing or aggravating the disease. 



As this malady so frequently destroys the sight, and there are certain periods 

 when the inflammation has seemingly subsided and the inexperienced person 

 would be deceived into the belief that all danger is at an end, the eye should be 

 most carefully observed at the time of purchase, and the examiner should be 

 fully aware of all the minute indications of previous or approaching disease. 



