EFFECTS OF RADIANT ENERGY ON THE EYE. 781 



Martin ^^^ in 1912, with a single high intensity exposure, — one half 

 to two hours at a distance of one inch from a Kroraayer water-cooled 

 mercury vapor lamp, found the lens capsule changes as described by 

 Hess. Because the interposition of a benzol cell prevented these 

 changes they were ascribed to ultra violet light. "With repeated 

 exposures of moderate intensity without lid retractors — at a distance 

 of 4 inches to 3 ft. at intervals of 1 to 2 weeks over a period of 2| to 12 

 months exposure times varying from 1 to 3 hours, the following 

 changes were noted. In one rabbit of this latter series exposed every 

 10 days at 4 in. distance for 1 hour over a period of 3 to 12 months lens 

 changes somewhat as described by Hess were found, but differed in 

 that the "wall" was wider, the central cells were uninjured, and 

 proliferation was 2 or 3 cells thick. There was present in all of this 

 series slight corneal opacities. Others of the series, less severely 

 exposed, had no corneal opacities or lens trouble, while those more 

 severely exposed, — 3 hours every 2 weeks at 4 inches for 3 to 11 

 months, — showed dense corneal opacities which had undergone vas- 

 cularization but the lenses were clear and capsule normal, supposedly 

 protected by the dense corneal opacities. 



Sharply to be distinguished from these are cataracts experimentally 

 produced by exposure to light, are those resulting from the actual 

 transit of the electric current through or near the eye. Leber ^^^ 

 in 1882 first explained, the long noted tendency to cataract in people 

 struck by lightning, as due to the electro-chemical reaction. This 

 was experimentally demonstrated by Hess ^^^ in 1888 who made an 

 electric spark to impinge in the supraorbital region of a rabbit. He 

 noted a central destruction of lens epithelium and vacuolization of 

 lens fibres w^ith a marked secondary peripheral mitosis and prolifera- 

 tion of the lens epithelium resulting in the formation of equatorial 

 cataracts. Likewise Kiribuchi ^°^ in 1900 using the Ley den condenser 

 spark produced the same results. Clinically many cases of cataract 

 after lightning stroke or short circuit have been reported as due to 

 ultra violet rays but really must be included in this last group. Birch- 

 Hirschfeld^^ in 1909 found, in a study of all such cases reported up to 

 that time, injuries such as burns and cicatricial formations or impair- 

 ment of nutrition or nerve suppl}', which would readily account for 

 cataract formation. These cataracts are further distinguished by 

 the fact that clinically and experimentally they do not appear centrally 

 as do those in purely blinding experiments but peripherally. Again 

 on an experimental basis the length of exposure time is seldom if ever 

 long enough. No cases of lens trouble from lightning without bodily 



