LIGHT AND EYESIGHT.

Hauraki Plains Gazette, Volume XXXVI, Issue 4831, 18 May 1925, Page 2

LIGHT AND EYESIGHT.

PROTECTION AGAINST INJURY.

HINTS OF VALUE.

With the powerful lights used nowadays in homes and other buildings it is very necessary to institute safeguards and precaution's against any injury to eyesight. The Eyesight Conservation Council of the United States has'issued a scries of hints which are of interest and value from this standpoint. Some of the hints, quoted by the Illuminating Engineer, are as follows

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 diffuisiiig glass globes,' reflectors, or shades.

Localised lighting should be used only in conjunction with some general system of lighting, so is to avoid marked contrasts.

Avoid the glare or reflection from polished surfaces.

Both excessive illumination and inadequate illumination strain 1 and fatigue the eye in order to obtain sharp definition.

Intrinsic briliancy of mere than five candle-power per square inch should be reduced by a diffusing medium if the enter the eye at an angde below sixty degrees with the horizontal plane.

nickering, unsteady, or streaked jllumination straisn 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 ultra-violet radiation in excess of that present in daylight as well as present radiation from high temperature molten surfaces.

Windows whould form as large a percentage of the total wall area as possible.

Window shades used indiscriminate’y arc conducive to contrast glare effects. Translucent screens and shades are generally preferable. Ground glass and th'c like should be avoided in window-sashes which ;are 'below the level of the eye, as they cluse an increase of brightness in the retinal images thrown on a povtioj! of retina unaccustomed to such b. : ghtnew.

Dark-coloured finished .walls hnd ceilings should be avoided if eye comfort is desired, since they are likely to introduce glaring 1 contrasts.