EYE DISEASES PROPER 



1999 



mia aegyptiaca; while Laveran, in 1880, announced that the same 

 fact applied to the conjunctivitis seen in Biskra; and Howe, in 1888, 

 stated that the number of cases of conjunctivitis in Egypt increased 

 in proportion with the increase of flies, and were more prevalent in 

 the Delta, where there were many flies, than in the Desert, where 

 there were few. Nuttall and Jephson consider the spread of 

 ophthalmia aegyptiaca by the agency of flies to be definitely proved. 

 The ' pink eye ' of school-children in Florida is believed to be spread 

 by minute flies of the genus Hippelates. 



That some other actor, in addition to those mentioned above, is 

 necessary to explain the epidemiology of trachoma is evident from 

 the fact that the disease does not often spread to the attendants 

 or to inhabitants of the same house as the infected person. This 

 other factor may be some local derangement, as, for example, a 

 slight attack of conjunctivitis ; or some general derangement, as, 

 for example, an attack of fever. 



Pathology. — The essential feature of the disease is a round-celled infiltration 

 into the conjunctiva associated with hypertrophy of the papillae of that 

 membrane. 



Morbid Anatomy. — The papillae of the conjunctiva are hypertrophied and 

 the trachoma granules are formed from accumulations of round cells which are 

 peripherally lymphocytes and centrally mononuclear leucocytes, with a few 

 macrophages. These cells are supported by a delicate connective tissue 

 which contains plasma cells. Pannus is a layer of new-formed connective 

 tissue which is rich in cells and bloodvessels. 



Symptomatology. — An acute attack may begin with acute inflam- 

 matory symptoms, oedema of the eyelids, great swelling of the con- 

 junctiva, and profuse purulent secretion. On examination, the 

 conjunctiva is studded with the typical nodules, but these may not 

 be apparent, and may even at first be absent. These acute attacks 

 may be complicated with corneal ulcers. 



A chronic attack often begins insidiously, the acute phase being 

 absent, very mild, or unnoticed, and usually the patient is not seen 

 until the eyesight is dimmed by the pannus over the cornea. In 

 other cases the disease sets in with photophobia, pain; and watering 

 of the eye; the lids stick together in the morning, and there is dim- 

 inution of visual acuity. The eye is not fully opened, partly because 

 of the photophobia, and partly because the upper lid is swollen and 

 heavy. On everting the lids, the tarsal and transitional conjunc- 

 tivae are found to be swollen and red, and either velvety in appear- 

 ance, or with distinct nodules which are most marked on the upper 

 lid. These nodules or granules are of considerable importance in 

 the differentiation between trachoma and ollicular conjunctivitis, 

 and it is to be specially noted that those of trachoma are larger in the 

 superior fornix than in the inferior fornix. It is therefore important 

 to examine the superior retrotarsal fold very carefully. On the 

 tarsal conjunctiva the granules are not so prominent, and are there- 

 fore less easily seen. A trachoma granule is typically a grey, 

 roundish, translucent granule, comparable to a grain of boiled sago 

 in appearance. Harston's sign is a linear groove running almost 



