LIGHT AND EYESIGHT.

Te Aroha News, Volume XLI, Issue 6604, 26 May 1925, Page 6

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. Thg 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 in 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 lhore than five candle-power per square inch should be reduced by a diffusing me--dium if the rays enter the eye at an angle below sixty degrees with 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 eye from the ultraviolet radiation in excess of that sent ,ifi 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 used indiscriminately are conducive to contrast glare effects. Translucent screens and shades are generally preferable. - Ground glass and the like should be avoided in window shashes 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 such brightness. Dark-coloured finished walls and ceilings should be avoided if eye comfort is desired, since they are likely to introduce glaring contrasts.'