EFFECTS OF RADIANT ENERGY ON THE EYE. 713 



therefore, the red comes easily and quickly into activity and unites 

 with the residual blue to produce very marked erythropsia of a dis- 

 tinctly rosy tinge. This lasts for some minutes, while traces of the 

 disturbance of the blue and green vision may still be found after pro- 

 longed exposure for a period of several hours, and this like other forms 

 of color fatigue takes place whenever the light which affects the three 

 primary sensations has been active, quite irrespective of whether 

 the ultra violet is present or absent. 



As to the aphakic eye Wydler*^^ has noted the probable effect of 

 coloration of the lens in this connection. When an eye has been 

 shielded, often for years, against any strong access of the blue and 

 violet and against the extreme end of the green sensation as well and 

 is then after recovery from cataract operation exposed to strong day- 

 light, it is merely a phenomenon to be expected if there is predominant 

 red vision after fatigue. It would not be surprising, for that matter, 

 if after long disuse of the color sensations toward the blue end of the 

 spectrum fatigue were easier and recovery less prompt than in the 

 normal eye. Aphakic patients in whom the pupil is often greatly 

 enlarged as a result of iridectomy are likely to receive extraordinarily 

 intense illumination on the retina, and hence may show the phenome- 

 non of color fatigue to an exceptionally great extent. Exposed in the 

 open the color fatigue is very marked, and w^hen this wears off after 

 the exposure ceases, the return of the red sensation may very naturally 

 be accompanied by some degree of erythropsia for this reason alone. 

 One of us has recently examined a case in which erythropsia so pro- 

 duced was a characterisitc condition. 



Vernal Catarrh. 



Spring catarrh is an uncommon disease of the conjunctiva that 

 most often affects the upper lid, much less often the bulbar conjunc- 

 ti\'a around the corneal limbus, and almost never the two together. 

 It is extremely chronic, lasting from 3 to 20 years, and is associated 

 with the formation of peculiar granulation tissue, infiltrated with 

 eosinophilic leucocytes to an unusual degree, containing downgrowths 

 of epithelium from the surface. In the case of the conjunctiva of 

 the lid, the new tissue forms within the papillae, thus giving rise to 

 large flat papillary growths. The symptoms of irritation, photophobia, 

 lacrimation, and itching, are most marked in the spring and warm 



