528 DISEASES OF THE CORNEA 



solution of silver nitrate will be found useful to change the 

 type of inflammation and to act as an antiseptic and astrin- 

 gent. Daily examination and treatment must be carried out 

 until the opacity disappears. 



Vascular Keratitis. — Pannus.— Definition.— The formation 

 of new vascular tissue extending over the cornea just under- 

 neath the epithelial covering. Pannus is not frequent in 

 small animals; it is seen occasionally in dogs. 



Etiology.— Pannus occurs in most instances from irritation 

 of a severe form extending over a long period of time. In 

 dogs it commonly results from chemical irritation, when 

 strong chemical agents, such as alum, mercury, etc., are used 

 in treating opacities and chronic conjunctivitis. It may be 

 due to trichiasis or districhiasis, and is also a sequel to chronic 

 conjunctivitis, or may occur during the course of dog dis- 

 temper. 



• Symptoms. — Pannus usually begins with photophobia and 

 v lacrimation. This is soon followed by a gray or white 

 opacity, traversed by numerous bloodvessels which can be 

 easily seen extending over the cornea in the form of reddish, 

 radiating lines. Later, when the cause is removed, the new 

 tissue becomes organized and appears as a white opacity of 

 varying density. 



Prognosis.— Complete recovery is difficult to attain in all 

 cases. The prognosis should be guarded as complications 

 may follow. 



Treatment.— A careful history of the case should be 

 obtained in order to determine the cause, which should be 

 removed, if possible. If opacity is present a solution of 

 succus cineraria maritima compositus (50 per cent.) is recom- 

 mended, using a few drops once or twice daily. Some of the 

 various ophthalmic ointments might also be tried. Operative 

 procedure is recommended in case the ordinary treatment 

 fails. The pannus may be removed by first giving the 

 patient a general or local anesthetic, dilating the lids with an 

 eye speculum, and carefully curetting the surface with a 

 rather dull curette. Care must be taken to prevent curetting 

 too deep. After operating apply antiseptics, and in severe 

 cases cover the eye with sterile gauze held in place by a head 

 bandage. Daily dressing is recommended. 



