THE EFFECT OF STRONG LIGHT UPON THE EYE.

Otago Witness, Issue 1858, 1 July 1887, Page 36

THE EFFECT OF STRONG LIGHT UPON THE EYE.

The exposure of. the eye to intense light has beeri attended with many curious and unfortunate re£ults. ■ In the case of Professor J.' Plateau, of. the. University of Ghent, who, while trying to observe the effects of irritation of the retina gazed steadily at the sun for 20 seconds, a chronic irido-choroiditis developed, which ended eventually in total blindness. Dr J. A. Andrews, in an article upon this subject, collects a number of cases in j which choroiditis and retinitis occurred in persons who had observed an eclipse of the son. % The single flash of a. sun reflector has .been known to dause , retinitis, and other . temporary visual disturbances of a functional character have been frequently noted. 'M.> Reich has described a curious epedemic of snow blindness- which occurred among a body of labourers ; engaged in clearing a way through the masses of snow which obstructed the "road between Passanaur and Mleti, in the Caucasus. The rays of the sun, 'reflected from the vast, stretches pf snow on every side, produced an intense glare of light, which theunaccustomed eye could not support withont

the 'protection of dark glasses. A few of the sturdiest among the labourers were able 'to; work with , impunity, but the majority .suffered severely-, Among 70 stijongly marked cases, 30 were so severe that the men were absolutely unable to continue their .work or to find their way home. They were collected in a covered place, where Keich found them' on his arrival prone on their faces, striving to hide their eyes from the light, and crying out from pain. Eecoyery was gradual but complete.

W. O. Eockliffe records a case of acute conjunctivitis brought on by exposure of the eyes to 3000 candle-power electric Jight. It is estimated that exposure of the naked eye for one . minute to an arc light of 2000 candles will cause conjunctivitis. The violet or orange, lights are said to be less injurious than the normal white light.

The light of lightning is too transient to cause any injury from simple retinal overirritation; but it is known that cataracts sometimes follow lightning strokes, and these are believed to be produced by some physico-chemical influence. Glassblowers suffer from an opacity of the lens, brought on, riot by the light, but by the intense radiant heat (148deg. F.) to which they are exposed during their work. ' Of all forms of artificial illumination, the incandescent electric light, , so far as facts now go, is the best.- Among 1100 persons who worked by this light, Dr Andrews found not' a single case of. injury. „0n the other hand, many persons testified to the fact that they could work longer by it with less fatigue than with the gas or oil light. This is due, it is- found, to the steadiness, absence 1 of heat, and perhaps the greater proportion of violet ray's. " Short-sighted persons are, in particular, benefited by the use of the incandescent lamp. — Medical Record.