LIGHT AND EYESIGHT

Waipa Post, Volume XXIV, Issue 1641, 14 May 1925, Page 2

LIGHT AND EYESIGHT

With the powerful lights used nowadays in homes and other buildings it is very necessary to institute safeguards and precautions against any injury to eyesight. The Eyesight Conservation Council of the United States has issued a series of hints -which are of interest and value from this standpoint. Some of the hints, quoted by the Illuminating Engineer, are as follow: — The light should shine on the object under gaze, but not lu the eyes of the observer. The first remedy is the use of the diffusing glass globes, reflectors, or shades. Localised lighting should be used only in conjunction with some general system of lighting, so as to avoid marked contrasts. Avoid the glare or reflection from polished surfaces. Both excessive illumination and inadequate illumination strain and fatigue the eye in order to obtain sharp definition. Intrinsic brilliancy of more than fivft candle-power per square inch should be reduced by a diffusing medium if the rays enter the eye at an angle below sixty degrees vlth the horizontal plane. Flickering, unsteady, or .streaked illumination strains the eye and produces irritation in the eye in its attempt to maintain vision. Special protective glasses should be used to protect the aye from the ultraviolet radiation in excess of that present in daylight as well as present radiation from high temperature molten surfaces. Windows should form as large a percentage of the total wall area as possible. Window shades usel indiscriminately are conducive to contrast glare effects. Translucent screens and shades are generally preferable. Ground glass and the like should be avoided in window-sashes which are below the level of the eye as they cause an increase of brightness in the retinal images thrown on a portion of retina unaccustomed to &uch brightness. Dark-coloured finished walls and ceilings should be avoided if eye comfort is desired, since they are likely to introduce glaring contrasts.