Abstract:

A survey carried out by the Royal National Institute for the Blind (RNIB) in 1991, suggested that about one million people in the U.K. suffer from some form of visual handicap involving central or peripheral vision, or the whole visual field. While some impairements like macular degeneration may bring about a loss of acuity in central vision, for others, such as glaucoma, visual acuity in central vision is relatively unimpaired but peripheral sensitivity to coarse moving patterns is reduced. In both conditions, colour discrimination is impaired. A further survey, carried out by the RNIB in 1993, showed that five particular impairments namely, macular degeneration, cataract, glaucoma, retinitis pigmentosa and diabetic retinopathy represent the ones suffered by approximately 80% of the visually impaired population in the UK. As such, it was decided that people with these impairments would form the basis of any test groups. Preliminary research by the University of Reading, showed that whilst knowledge exists within various medical fields regarding how the perception of colour is affected by such eye impairments, very little of this knowledge has been related to decisions made within the construction profession. When selecting colours, designers and managers of buildings can have a major impact on the ability of visually impaired people to use buildings. Unfortunately, in lieu of detailed information, the obvious response is to maximise colour and luminance contrast between different objects, or to cover walls with coarse high contrast patterns. However, both of these solutions will probably produce an environment which is unacceptable to designers and the fully sighted user of the building. Another approach may be to use subtle variations of colour and texture but again, uncertainty often exists regarding which combinations are useful to the visually impaired in coping with the general internal environment of a building, identifying localised features such as doors, or essential utility items such as light switches and sockets. The research project, with value of approximately £349,000, was carried out under the LINK Construction Maintenance and Refurbishment (LINK CMR) Programme and, as such, is collaborative research funded by industrial partners, the Department of the Environment (DOE) and the Engineering and Physical Sciences Research Council (EPSRC). The Industrial Partners in the project, who provided over 50% of the funding, are the RNIB, the Guide Dogs for the Blind Association (GDBA), and ICI Paints. The research was undertaken by the Departments of Construction Management & Engineering and Psychology at the University of Reading. The project, which had a duration of two years (48 man months), involved the following: (1) an investigation of existing medical and applied psychological research data to establish the effect that colour and luminance difference plays in the visual perception of people with varying visual impairments (2) the selection of an existing system for specifying colour and luminance, undertaking a 1500 person questionnaire/interview survey to identify what visually impaired people perceive as their major problems when interacting with the built environment and to identify the colour luminance contrast combinations which they feel hinder or assist in their search and navigation tasks in buildings (3) using a panel of fifty visually impaired and fully sighted people in real world tests, to measure the acceptability of various colour/luminance combinations (4) the preparation of a Design Guide.