Lighting level

Age-related visual impairments generate requirements for senior-friendly lighting. This concerns in particular

• lighting level,

• glare limitation,

• light colour,

• control of biological functions using light with an elevated blue component as well as

• limitation of differences in brightness.

Due to age-related debility of sight, the lighting level for residents of geriatric care and nursing homes must be significantly higher than defined by relevant standards such as EN 12464-1. Figure shows the relation of luminance and visual acuity in younger people compared to older people. A 75-year-old person requires roughly 20 times the luminance on a visual object to achieve the same visual acuity in the distance that a ca. 40-year-old person needs. The required lighting level for older people compared to younger people is illustrated in figure. Where e.g. a 30-year-old requires 300 lx for effortless vision, a 70-year-old needs about 500 lx, i.e. a value located one level higher on the illuminance scale.

The Kuratorium Deutsche Altenhilfe (KDA – German board of trustees for work with the elderly) has commissioned minimum illuminance values for geriatric care homes (table). In many cases, the values for comparable visual tasks are 1 or more levels higher than specified by EN 12464-1 for younger people. With higher levels of illuminance like these, it was possible to achieve a reduction in aggressive behaviour as well as improved moods particularly in people with dementia.

Generally, all rooms in geriatric care and nursing homes should feature high ceiling, wall and floor reflectance. The primary surfaces (walls and ceiling) should be illuminated sufficiently by the right choice and arrangement of luminaires. According to EN 12464-1, at an illuminance of ≥ 500 lx, walls should be illuminated with a minimum of 75 lx, and the ceiling with a minimum of 50 lx, with uniformity being ≥ 0,10 for both cases. Doubled values should be targeted for such applications.

Lighting uniformity must exceed the provisions of EN 12464-1 for work places. Dark spots and pronounced shadow effects cause anxiety in older people, intensify insecurities and increase the danger of falling down – not only in corridors or staircases. For communication with other people, a cylindrical illuminance Ez of at least 150 lx at 1,2 m above the floor with a uniformity of ≥ 0,10 required.