DISEASES OF THE CORNEA 89 



and ciliary body, with an exudate in the anterior cham- 

 ber. This exudate may be purulent in character, when 

 it is called a hypopyon. The amount varies from a 

 slight hne, which can barely be seen, to a complete 

 filling of the chamber. The consistence of this exudate 

 also varies from a thin, watery fluid to a thick, pultaceous 

 mass. The former is readily absorbed, while the latter 

 may undergo a fibrinous change and cause adhesions be- 

 tween the iris and the cornea. 



Small spots of infiltration and superficial nebulae 

 can readily be detected by the use of obhque illumination 

 and a magnifying lens. Dense opacities can easily be 

 seen without these means. In a recent infiltration there 

 is a dull and clouded appearance over the area. In 

 case of an ulcer there is a loss of substance, seen in mild 

 cases, by a break in a reflected line on the surface of the 

 cornea. If the surface retains its luster the ulcer is a 

 clean one, but if there is a cloudiness over its area, it is 

 a foul or infected one. An opacity with a lustrous 

 surface indicates an old ulcer which has healed in, leav- 

 ing a cicatrix. 



The symptoms of keratitis are essentially the same 

 in all types. Pain, lacrimation, and photophobia are 

 nearly always present. Reflex contraction of the lid 

 (blepharospasm) is a common symptom, except in those 

 cases caused by paralysis of the fifth and seventh nerves. 

 In the former case there is no pain. 



Keratitis is divided into two principal types— the 



