SIMPLE OPHTHALMIA. 107 



injury, inflicted either directly or indirectly ; hence tli«^ 

 causes are legion. A few may be enumerated as foHows : 

 a blow from a whip in the hands of a careless or cruel 

 driver; the presence of a foreign body, as a grain of sand, 

 a hay-seed, a bit of chaff", etc. The presence of a foreign 

 body of minute size is sometimes very difficult to detect, 

 and, when it is found, requires very careful work to remove 

 it. Ammoniacal vapours or foul air ia stables will irritate 

 the eye and cause the trouble. Particularly does this cause 

 operate where one or two horses are stabled with a number 

 of cattle. A blow on the orbital arch will also sometimes 

 cause simple ophthalmia. Extremes of heat and cold, as 

 well as sudden alternations of temperature, excite or })ro- 

 duce the trouble. 



Sym])toms. — A partial or complete closure of the eye is 

 observed. There is a copious flow of tears. The eyelids 

 (particulaily the upper lid) are, in a large majority of cases, 

 swollen to a considerable extent. In some few cases it is 

 not swollen, but is much reddened and inflamed ; and in 

 other cases it becomes completely everted. On making an 

 examination of the eyeball, it is found to be retracted as 

 far as possible. The pupil is dilated, and the eye cannot 

 bear sudden exposure to light. The exudate, when the 

 condition occurs as the result of an injury, radiates from 

 the seat of the injury towards the circumference ; while in 

 periodic ophthalmia precisely the opposite takes place. 

 There is not much constitutional disturbance unless the 

 injury to the eye be a pretty severe one. Small bloodvessels 

 may be seen, as it were, forming in the conjunctiva. A 

 very slight irritation will often produce simple ophthalmia. 

 The flow of tears may, after a while, be followed by a dis- 

 charge of a purulent character, which ceases after a while, 

 and is in its turn succeeded by the appearance of an 

 exudate — a film which appears to be external to the cornea, 



