Providing Lighting for Older Clients
by Glenda Gilmore
With increasing age come bodily system changes that can affect an individual’s ability to live independently. Individuals who report difficulty with vision are also more likely to have difficulty with walking and going outside (Campbell et al., 1999) and are more likely to fall (National Center for Health Statistics, 2001). While the degree of change experienced varies widely among individuals, the nature of the changes is common. The eye is a sensory system very vulnerable to aging, and loss of vision is one of the most dreaded consequences of aging (Cogan, as cited in Verrillo & Verrillo, 1985). And, while many older persons maintain good visual acuity into their 70s and 80s, a research study conducted at the Smith-Kettlewell Eye Research Institute found that many older persons with good visual acuity are rendered effectively visually impaired while performing everyday tasks in the presence of low and changing light levels, low contrast and glare (Brabyn et al., 2001). The following is a discussion of changes taking place in the aging eye and information that interior designers can take into consideration when designing for seniors.
Increase Levels of Light
Because the pupil of the eye decreases in diameter and becomes less responsive with age, seniors need as much as three times more light than younger persons in order to perceive the shape and fine details of objects (Haight, 1993; Kallman & Kallman, 1989). The designer can provide an environment that is more easily perceived by the older client by greatly increasing the levels of ambient light and making sure that there is even greater illumination and/or task lighting at high-risk areas, such as stairs or areas where there is change in grade or incline, or where a client must perceive fine details to successfully complete the task at hand. It is also important to provide well lighted pathways to guide visitors through unfamiliar territory and provide well illuminated areas where directions and information are offered to the visitor to help them find their way to their destination.
Seniors also need more light to see well because both the lens and the vitreous humor become more opaque with age. However, instead of light passing directly through the lens and the vitreous humor to the optic nerve at the back of the eye, it tends to become scattered within the eye, a sensitivity which is called glare. Bright, sparkling light and small points of light can cause so many reflections within the eye that they become problematic for the older person (Goodman & Smith, 1992). So, while the amount of light provided within environments for older persons is very important, it is equally important to provide light sources that do not cause glare. All light fixtures should either be concealed or have shades and we should rarely use exposed lamps. Any exposed lamps must have opaque glass to diffuse the light.
Glare: Unshaded lamps or lamps made of clear glass create bright points of light that are often perceived as glare by the older eye.
Natural light is always welcome in interior spaces and the use of light filtering window treatments and use of glare filtering films on uncovered windows will reduce the likelihood of glare. Care should also be taken to select non-reflective surfaces and matte finishes to reduce the amount of reflected glare from those materials.
Adjust for Changes from Light to Dark
The older eye needs more time to respond to changes in light and dark. This is especially true when adjusting to changes from a bright environment to a dark one, such as the situation encountered when entering a dark movie theater or a dark home from the outside. Homes should have well illuminated entry areas with switching at the point of entry. Thoughtful designs for the elderly will also provide uniform light levels to avoid pools of light and darkness that could be dangerous for older persons to navigate through.
After age 40 individuals also begin to have difficulty with depth perception, a situation which can contribute to postural instability and the likelihood of falling among older adults (Verrillo & Verrillo, 1985). The combination of decreased depth perception and difficulty in adjusting between light and dark areas of an environment make circumstances where backlighting is present, such as a bright window at the end of a hall or stairwell, particularly dangerous. The older eye has difficulty accommodating for both light and dark areas. The result is a dangerous intermediate area filled with dark, poorly defined shapes.
Back-lighting: The eye adjusts to the brightest light, leaving the middle ground in darkness and filled with poorly defined shapes and dangerous obstacles.
Select Color Carefully
Another consideration for the designer is knowledge that light entering the eye must pass through the cornea and the vitreous humor. The lens has a tendency to become yellowish with age which affects color perception by filtering out blues and violets in the color spectrum (Haight, 1993). The lens may also become darker which causes a decrease in color vision, especially in the blue-green area of the spectrum. Consequently, elderly persons see yellow, orange and red more easily than other colors (Goodman & Smith, 1992).
Well thought-out use of color will help older occupants perceive their surroundings more clearly. In order for individuals to make correct color judgments it is important that the lamp used have a color rendering index (CRI) of 70 or greater. Additionally, it is important when designing color for the environments of older persons to use more highly saturated colors, especially when color is used as a cue within the environment (Hedge, 1996).
The designer should avoid monochromatic color schemes and provide high levels of contrast to assist the individual with low vision to identify the edges of objects.
A Monochromatic Color Scheme: Even though it is well illuminated, a monochromatic color scheme can create an environment in which it is difficult to distinguish shapes and objects.
And extensive use of dark materials and finishes can create a space that is very difficult to illuminate properly and in which it is difficult to differentiate between items.
Use of Dark Materials and Finishes: Use of dark materials and finishes can create an environment that is very difficult to illuminate properly even with multiple light sources.
An overwhelming majority of seniors want to remain in their homes as they get older. Interior designers have a valuable role in the lives of older persons by creating designs that support the occupants as they age in place.
Campbell, V. A., Crews, J. E., Moriarty, D. G., Zack, M. M., & Blackman, D. K. (1999). Surveillance for sensory impairment, activity limitations, and health-related quality of life among older adults - United States, 1993-1997 (Rep. No. 48(SS08)).
Brabyn, J., Schneck, M., Haegerstrom-Portnoy, G., & Lott, L. (2001). The Smith-Kettlewell Institute (SKI) longitudinal study of vision function and its impact among the elderly: An overview. Optometry and Vision Science, 78 (5), 254–269.
Goodman, R. J. & Smith, D. G. (1992). Retirement facilities: Planning, design, and marketing.
Haigh, R. (1993). The ageing process: A challenge for design. Applied Ergonomics, 24, 9-14.
Hedge, A.L. (1996). The effects of artificial light sources on color judgement by the aging eye. Family and Consumer Sciences Research Journal, 25 (2), 184-195.
Kallman, H. & Kallman, S. (1989). Accidents in the elderly population. In W.Reichel (Ed.), Clinical aspects of aging (pp. 547-558).
Verrillo, R. T. & Verrillo, V. (1985). Sensory and perceptual performance. In N.Charness (Ed.), Aging and human performance (pp. 1-46).