46 Surgical Diseases and Surgery of the Dog 



the opening in the form of a small pouch (Keratocele). Should the 

 superficial layers remain intact, the pus infiltrates the deeper layers 

 and an abscess results. Such an abscess may undergo resolution, 

 but it tends to burst on the surface, or as sometimes happens, it dis- 

 charges inwardly into the anterior chamber (Hypopyon) and there 

 may inaugurate an acute ophthalmia. In rare instances, through 

 failure of an ulcer to heal, a fistula develops. In some cases the 

 ulcer becomes exuberant as in other parts of the body. As a result 

 of corneal ulceration and the consequent formation of scar tissue 

 an opacity remains which may vary in degree, receiving the name 

 Nebula, Macula, or Leucoma according to its intensity. Sometimes 

 the scar tissue formed after perforation fails to withstand the in- 

 traocular tension, and that portion of the cornea is forced forward 

 to form a pouch-like protrusion. This is termed a Staphyloma, 

 Ordinarily, a Nebula or Macula decreases little by little and finally 

 disappears, but dense Leucomas are usually a permanency. Kera- 

 titis is generally accompanied with more or less pericorneal injection 

 or conjunctivitis, but an asthenic type without manifest inflammatory 

 reaction is sometimes seen during the course of exhaustive diseases. 

 Symptoms and Diagnosis. The earliest symptoms are photo- 

 phobia, manifested by spasmodic closing of the lids, and increased 

 sensitiveness and lachrymation. The cornea becomes infiltrated and 

 opaque. This condition can last some weeks and be accompanied 

 with suppuration and new vessel formation. The process continu- 

 ing to the ulcerative stage, a grey or greyish white depressed or 

 excavated area appears, of variable breadth and depth, surrounded 

 by a zone of hazy cornea and sometimes vascularization. Threat- 

 ened perforation is recognized by bulging of the floor of the ulcer, 

 Kerectasia by a bulging opaque elevation, and Keratocele by a 

 translucent, hernia-like pouch surrounded by a border of opaque 

 cornea. Staphyloma is at first reddish, but later becomes densely 

 opaque. Abscess formation, which may be of variable eprtent and 

 occur at any portion of the cornea, is characterized by great photo- 

 phobia, secretion of tears, and pericorneal injection, and by a spot 

 which is at first grey but speedily grows yellow, and which may be 

 sharply defined by normal cornea or surrounded by a zone of 

 opacity. As already has been stated, an abscess, unless previ- 

 ously opened, discharges, as a rule, externally. When it empties 

 into the anterior chamber, the piis appears as a yellow mass within. 



