CHAPTER XIX. 



DISEASES OF THE EYE. 



EYELIDS AND LACHRYMAL APPARATUS. 



Hsematoma. The areolar tissue of the eyelid is so loose that 

 it readily becomes infiltrated with blood after a blow, leading to 

 a characteristic " black eye " ; or with inflammatory products in 

 septic conditions in the neighbourhood ; or with air in fracture 

 of the nasal bones or of the frontal bone over the sinus. 



Ciliary Blepharitis. The large hair follicles, and the associated 

 sebaceous or Meibomian glands, are frequently the site of invasion 

 by bacteria, with resulting acute or chronic inflammation. In 

 consequence of this there may follow a certain amount of ectro- 

 pion, together with scarring of the edge of the lid. The duct 

 of one of the glands may become blocked, and a chalazion or 

 Meibomian cyst result. This is placed between the conjunctiva 

 and the tarsal cartilage, but it may cause some thinning of the 

 latter, and so present as a swelling which can be seen through 

 the skin of the lid. 



A stye, or hordeolum, is a localised septic inflammation 

 occurring in a hair follicle or Meibomian gland, and the sup- 

 purating contents can often be readily evacuated by pulling out 

 the lash from the aft'ected follicle. 



Ptosis may be due to paralysis of the third nerve, the levator 

 palpebrae superioris becoming inactive, or to paralysis of the 

 seventh nerve producing a relaxation of the palpebral portion of 

 the orbicular muscle. 



Entropion. Granular conjunctivitis and spasm of the orbicu- 

 laris palpebrarum are the two most common causes of inversion 

 of the eyelids. The usual result of entropion is trichiasis, or 

 turning in of the cilia. This will lead to the surface of the 



