EFFECTS OF RADIANT ENERGY ON THE EYE. 685 



eye was normal and had normal visual aeuty. Before the experiment 

 the pupil of the left eye was dilated with atropine, but the visual 

 acuity remained the same. The total exposure was less than in the 

 case of the monkeys, owing to the patient becoming somewhat fatigued, 

 and for the same reason also the exposure was not continuous, but 

 otherwise the conditions of the experiment were the same. 



The total exposure was 55 minutes, and the interval between the 

 separate exposures was about 1| minutes. The first three exposures 

 were 3, 9, 12 minutes respectively, the remainder were 5 minutes each. 

 At the beginning of each exposure the patient stated that the "light 

 was like the sun." At the end of the sixth exposure there was ery- 

 thropsia and the visual acuity was reduced to counting of fingers at 

 one foot. Within 2^ minutes after the last exposure the consensual 

 pupillary reaction was well marked, and the patient could with diffi- 

 culty count fingers at six feet. Three minutes after the last exposure 

 there was only slight erythropsia. Xanthopsia was not noted at any 

 time but may have been unrecognized by the patient. After 10 

 minutes the visual acuity was ^§q. There was an appearance of a 

 mist before the eye, but no erythropsia. After 1^ hours the visual 

 acuity was y§q, and a slight mist still persisted. After 3 hours the 

 visual acuity was ^q-\-, and a white surface seemed almost but not 

 quite as white as with the right eye. After 22 hours (in the morning), 

 the visual acuity was fg— as before the experiment. There was no 

 erythropsia, and central color vision was perfect for red, blue and 

 green. 24 hours after the exposure the eye was enucleated. On 

 microscopic examination the cornea, iris, lens epithelium (flat prepara- 

 tion), and retina were found to be normal. 



The result of this experiment confirms those obtained with the 

 monkeys. It is obvious that the retina could not have been injured 

 by abiotic action of light, since the visual acuity was fully restored 

 within 3 hours and remained so the following morning. The rapid- 

 ity with which the erythropsia disappeared was unexpected, and 

 indicates that duration of exposure is equally as important as its 

 intensity in the production of persistent erythropsia. 



