Studies of Lighting and Vision in Schools

Abstract

An investigation into the problem of school lighting and vision has been made, in four stages:—

• (a)

A study was made of the distribution of visual acuity in a random sample of London school children, in relation to the influence of illumination level and chalkboard reflection factor. The distribution was found to agree with a distribution measured in 1928 on a similar sample. Increased illumination was found to provide the greatest benefit to those children with indifferent visual acuity.

(b)

More detailed studies of the effect of illumination and contrast on visual acuity and on ease and speed of reading, were made on a selection of adults with visual acuity varying from very good (Snellen 6/4.5) to poor (Snellen 6/60).

(c)

The factors which influence glare have been investigated.

(d)

An analysis of visual tasks in schools was made by the M.R.C. investigators under the direction of Mr. H. C. Weston, and this analysis (of size, contrast, etc., of lettering on chalkboards) has been drawn upon, with Mr. Weston's kind permission.

The present standard of illumination prescribed by the Ministry of Education (10-ft.c., that is, 10 lumens/sq. ft.) is found to be an adequate minimum standard provided chalkboard letters are large and children sit near the chalkboard. Improvements in ease of reading result from increased illumination levels, but these increases must be substantial. Under some average conditions the improvement in ease of reading which results from the child moving four feet nearer the chalkboard is matched only by an increase of 30: 1 in illumination level. The results of the experiment throw into sharp relief the need for the integration of the lighting with the design of school classrooms.

The paper is a study of visual conditions associated mainly with formal teaching from fixed chalkboards. Educationists are, however, advocating the replacement of such methods, in infants' schools, by informal teaching in groups, using mobile chalkboards distributed round the room. In secondary schools the present methods will probably continue for some time. The studies reported in the paper are, of course, applicable to this new approach by educationists, but further work directly concerned with group teaching may be of value at a later stage.