CAUSES OF FAILING EYESIGHT.

Dunstan Times, Issue 1164, 20 June 1884, Page 4

CAUSES OF FAILING EYESIGHT.

The causes to which deterioration of e esight. has been attributed are alleged to be cross liiihta from opposite windows, light shining directly on the face, insufficient light, .small print, and to the posi ion of the desk, forcing the scholar to bend over and bring ihe eyes too close to the book or writing paper, etc. But (says 1 Popular Science' for January), were all the defectsremedied, the integrity of the eye would not be restored no- its deterioration prevented. The chief caus-s of the evil would still remain. These are colors of the paper and ink. White paper a d black ink are ruining the eyesight of all reading nai ions. Tho “ rays of the sun,” says Lord Uacon, < are roll icted by » while body, and are absorbed by a black one ” No one dissents from this opinion; but, despite these indications of imtu«-e nil( j (l p plnioso hy, we print our books and write our letters in direct opposition to the suggestions of optical science. When we read a book printed in the existing made, we do not see the letters which, being 1.1 hA, am n..n reflective. The shapes reach the ie i;„t. but they are not. nceived by a spontaneous, direct action of that organ. Tho white surface of the paper is reflected, hub the lerters are detected only by a discriminative effort of the optic nerves. This eftort annoys the nerves, and when long continued, exansts their suspectibility. The human eye cannot long sustain the broad glare of a whi;e surface without injury. The author

of * Sjtiinish Vistas,” in * Harper's Magazine’ Bjy« of Cartagena, that “ liliml people seem to bo numerous there, a fact which may bo owing to the excessive dazzle of the sunlight ana t\ie absence of verdure.” Air Seward, in his tour around the world, observed that “ in Kgypt ophthalmia is universal,” attributing it to the same “ cxci'ssive dazzle” ol the wide areas of white sand ; and the British soldiers in the late campaign in that country, exhibited symptoms of the same disease. In the Smithsonian re port for : 877, it is staled, in a paper on “ Color Blindness," that M. Chevreul has produced 14,420 distinguishable tints of the elementary colors, from which the paper manufacturers could select colors more agreeable to the eye than the dazzling white, so weakening and Jaceratiugto the nerves of that delicate organ.