iio />'y^y:.i.W:A i>j- J nil iiVE 



Li^htniu^, by means of its ultia-violt'i rnvs. may result in 

 blindness tliroii^h : — 



1 lie heat rays produtin^^ burns. 

 Hlectrolytic action. 



Concussion causing a disturbance of the circulation. 

 .Sunlight is al.so said to cau.se a spring catarrh which dis- 

 appears in autumn and winter. 

 (6) Wind and Dust. These will cause: — 



Pitiguccuhi, a yellow thickening of the outer conjunctiva: 



opposite to the palpebral fissure. 

 Ptervf^ium, an extension of a triangular va.scular fold of 



conjunctiva spreading lo the cornea. 

 Ophthalmic irritation and microbic infection. 



(3) Habits. &c. 



Xerosis among debilitated children is very common, esf)ecially 

 in the Mast, where famine, cholera and dysentery are pre- 

 valent. 



Keratomuhichi, an ulci rative condition, may ensue from the 

 same cause. 



Cataract in India is chiefly senile, although diabetes is common 

 amongst vegetarians. 



I'lonorrhaeal conjunctivitis is common as a result of unclean 

 habits. Inflammatory conditions arise as a result of pilgrims 

 bathing in infected water. 



Toxic amblyopia is caused by excessive smoking and drinking, 

 as also is misty vision. Tiiere is a central colour scotoma 

 for red and green especially. There must be immediate 

 cessation of the causiitive factor. 



(4) Insects and Parasites. 

 (a) Insects. 



.Stings cause ix'dema of the lids and conjunctive'^. 

 Irritating secretions are troublesome, e.g., the eye-fly of 



India, the great-ant of Senegal, &c. 

 Pediculis pubis may occur on the eyelaslies. 

 Sarcopleri invade the free edges of the eyelids by burrowing 



beneath the skin. It is not uncommon in .San Domingo. 

 Larva." may be deposited in or about the eye by Musca 



vomitoria, Dermatobia noxalis and cyaniventris, Sarco- 



phaga magnitica. 

 Hairs or horns mav find a resting place here. Ophthalmia 



nodosi is due to the liairs of liombyx rubi. 

 Infective discharge is not uncommonly carried to the eye 



as by .Musca domestica. 

 Irritating pollen may cause vesicular eruption. 



