340 DISEASES OF THE EYES. 



of the eye ; but in simple ophthalmia, only the membrane covering 

 the ©ye is afiected. It is generally confined to one eye. 



SYMPTOMS AND COUKSE.— The symptoms come on suddenly, 

 and resemble those of simple ophthalmia, except that the interior 

 of the eye assumes a dim, dull, amber-coloured appearance ; and 

 the cornea becomes clouded. At first the pupil is contracted. In 

 conjunctivitis (p. 338) the inflammation is confined to the surface 

 of the eye. 



Usually the intensity of the symptoms begins to abate after 

 about a week, and the cornea and conjunctiva gradually assume 

 their normal condition more or less. The first attacks are usually 

 the longest, and their duration diminishes, as a rule, with their 

 recurrence. During the progress of apparent recovery a relapse is 

 not infrequent, and the term may be thus indefinitely lengthened. 

 The interval between the attacks is, on an average, about sixty 

 days. The eye may seem quite clear during the intermission ; but 

 it has not returned to its normal condition. The outline of the 

 upper eyelid is usually altered. It presents a slight bend in its 

 internal part, so that the upper joins the lower lid, at the inner 

 angle, by a right, in place of an acute, angle. This is best marked 

 after several severe attacks, and gives a triangular outline to the 

 opening between the lids. There may be recurrent attacks after 

 the horse has become totally blin'd. 



The upper lid and eyebrow assume a peculiarly wrinkled or 

 furrowed appearance. The eye appears smaller than it would do 

 in health, and looks dull and weak. In confirmed cases, the haw 

 is prominent ; the cornea, more or less opaque ; and the iris and 

 aqueous humour, changed in colour. These indications would 

 probably be of use to an intending purchaser. This disease 

 generally terminates in cataract ; although the latter affection may 

 come on independently of the former. 



TREATMiKNT.— Puncturing the cornea (p. 344) is strongly 

 recommended for periodic ophthalmia, if the operation is indicated 

 after testing the tension of the eyeballs, which is a useful and 

 important guide in determining whether to operate or not. In 

 testing the eyes, the most practical way is to exert alternating 

 pressure of two fingers placed on the upper lid, testing both eyes 

 at onoe, using the index and middle fingers of both hands on the 

 eyes. In this way, a slight variation of the tension of the two 

 eyes can be determined. If found harder than normal, the opera- 

 tion is indicated ; but, if softer, most emphatically contraindicated, 

 for surgical interference means an early and incurable blindness. 

 It is well to remember that, when one eye is afiected with this 



