EFFECTS OF RADIANT ENERGY ON THE EYE. 7Q9 



The Aqueous and Vitreous Humors. 



The humors of the eye seem to be the most silent regions as far as 

 response to insult from ultra violet light sources is concerned. Since 

 they have an absorptive power, never greater, and often less than that 

 of the cornea, the latter apparently protects them from the action of 

 the injurious rays. 



Bonders ^^ who made the first attempt to measure the absorptive 

 power of vitreous humor alone was not aware of the fact that the 

 containing vessel must be made of thin quartz glass, so that his re- 

 sults were of no value. After him Soret ^*^ in 1879 reported the first 

 reliable results. He found the vitreous humor able to absorb rays 

 of lengths less than 294.8 fxfj, in thicknesses of 1 cm. and still smaller 

 values for thinner layers. The values of de Chardonet^^ in 1883 

 were still lower. He found the absorptive value to lie between the 

 310 MM and 304 mm lines. 



Birch-Hirschfeld ^* in 1909 found that the vitreous humor in 1 cm. 

 layers has an absorptive power, practically constant for all animals, 

 of ravs less than 300 fi/j. thus being the same as common glass. Schanz 

 and Stockhausen^oa, Vogt^^^, Hess^^s, Ogneff ^59^ Birch-Hirschfeld 3^- 

 and all recent observers have also confirmed this value for 1 cm. layers 

 of vitreous humor. Parsons ^^^ for thinner layers, — j^ of an inch, — 

 found absorption to begin at 280 fxfjL and become complete at 270 mm- 

 Martin ^^^ in 1912 confirmed the later results and found no change in 

 the absorptive power of eye media as long as 8 hours after death. 



The Iris. 



The iris and uveal tr.act have long been noted to suffer in severe 

 exposures to short wave lengths. Martin ^^^ and Nodier^^^ in 1881 

 noted inflammation of the iris in severe cases, confirmed by Terrier ^^* 

 in 1888. The very short exposure with light rays by Czerny ^^ in 1867, 

 Deutschman ^^ in 1898 and Herzog ^^^ in 1898 gave no notable iris 

 changes beyond slight hyperaemia. Hess ^^^ in 1888 by use of the 

 electric spark impinging in the supraorbital region, and Kiribuchi ^°^ 

 in 1900 with the Ley den jar spark were both able to produce marked 

 uveitis. Gardner ^^'^ in 1871, Berlin ^2 1888, and Ewald ^^^ 1891, have 

 reported hyperemic and swollen iris in snow blinding. 



Widmark*^^ in 1889 noted microscopically in cases of 2-4 hours- 



