A growing collection of reports confirms that the number of employees choosing to work past the conventional retirement age is escalating. An AARP (American Association of Retired Persons) survey shows that 70 percent of employees over the age of 50 intend to work for compensation after retiring from their current profession. The Bureau of Labor Statistics estimates that by 2012, workers over the age of 55 will make up 19 percent of the U.S. workforce. And a recent University of Michigan study indicates that the percentage of Baby Boomers planning to remain in the labor force past retirement age continues to climb - 57 percent of older men and 45 percent of older women expect to work beyond the age of 62.
Not only will these vibrant, able seniors be guests in your hotels, customers in your shopping centers, and patients in your healthcare facilities - they'll be occupants and tenants in your office buildings. Because they're choosing to continue with employment, suitable accommodations should be made to make certain that this group of workers can function comfortably in the office environment.
Adjusting lighting systems accordingly is one of the most significant changes that can be made to allow older occupants a pleasant work atmosphere. As people age, visual systems weaken; aged eyes begin to require lighting modifications to make up for this deterioration. But to understand the kinds of adjustments necessary to accommodate these changes in vision, you'll need a quick refresher in Biology 101. Light enters the eye via the cornea. Light then passes through the pupil (which changes its size to admit more or less light via iris muscles, as needed). Beyond the pupil is the crystalline lens; it's controlled by ciliary muscles to focus incoming light onto the retina at the very back of the eye. The retina is made up of rods and cones (rods help us see in dim light, and detect shades of gray; cones allow us to see in bright light, and also sense color and detail), and is light-sensitive. It's also responsible for sending messages to the brain about what you're looking at.
As time progresses, however, the eye inevitably changes - and these transformations make it harder to see. "In some ways, the aged eye has been compared to a computer screen with the brightness and contrast knobs turned down," explains Ace H. Rosenstein, vice president, marketing and business development, Sea Gull Lighting Products Inc., Riverside, NJ. Changes to the pupil and the lens occur as every eye ages. Pupils become smaller, allow less light transmission, and take longer to respond to changes in light level - which makes it more difficult for the aged eye to adapt to environments that move quickly from dark to light (or light to dark).
The lens loses its flexibility and transparency - it becomes yellow-tinted, may develop opacities, and iris muscles have to work harder to bring near objects into focus. Due to this loss of transparency, light coming through the lens becomes diffused and is scattered to unexpected places in the eye (reducing the ability to perceive contrast). These opacities don't allow as much light to reach the retina, and as a result, images aren't as sharp and clear as they are for younger eyes. "For a [75-year-old] person, the total amount of light that reaches the retina to form an image is only about 25 percent of that of a 25-year-old," explains Dawn De Grazio, manager of Holophane's Light and Vision Center, Newark, OH. "If less light is reaching the retina, then you're not seeing as well." As the lens turns yellow, it absorbs more of the blue wavelengths in the spectrum; because of this, color is harder to distinguish - especially pastels and shades close to each other on the color wheel. Edges and details become less distinct. The sensation of glare gets stronger, more intrusive, and ultimately blocks more in the field of view. "Floaters" in the eye (cellular debris) progressively get worse; and when light bounces off of them, images lose their preciseness. Peter Hugh, president, Hugh Lighting Design Inc. Oak Park, IL, explains that aged eyes also lose "three-dimensional vision due to contrast ratios within the foreground and background lighting," making it more difficult to tell how near or far away something is.
In some cases, central vision can become impaired as well - photoreceptors in the central part of the retina die and aren't able to pick up light. In other cases, the photoreceptors around the edge of the retina fail, causing loss of peripheral vision.
"The range of light that a [65-year-old] can work in, be comfortable in, and see in is narrowed compared to a younger person," emphasizes De Grazio.
After the preceding synopsis, you're familiar with how the eye works and which visual functions begin to decline with age. The challenge now is to create a lighting atmosphere that balances these predictable kinds of vision impairments.
Here are five things you can do today to accommodate the aged eye in an office environment:
Tip 1: Provide task lighting.
"We need to accommodate the middle-aged worker and the older worker," explains De Grazio. "And yet, if we provided enough light in the whole office that would be appropriate for the average 60-year-old, it would cost a lot more in energy, and it would be harder to meet today's energy codes. We're stuck between providing an appropriate amount of light and not going overboard on energy." She emphasizes that the average office lighting system should be designed for the average worker, and that older occupants should be provided with options to augment that existing system.
Enter the task light: According to Naomi Miller, principal, Naomi Miller Lighting Design, Troy, NY, the average 65-year-old needs 2.5-times the amount of light that the average 20-year-old needs. Older employees, or those with special visual problems, may need up to 10 times that amount of light. Making sure that workstations are equipped with adjustable task lighting allows office spaces to be much more adaptable - you let individuals control their own lighting and customize it based on particular tasks. The Troy, NY-based Lighting Research Center estimates that at least 3-times more light is required for the aged eye to read, see fine details, and perform other visually intensive tasks. It recommends task lighting levels of at least 100 footcandles.
Task lighting in offices or cubicles with partitions and overhead cabinets are especially crucial, because these pieces of furniture tend to create shadows, which make it even harder for the aged eye to see. The task light should allow the occupant to "adjust the light level to the place where they need it," says Miller, "in some cases, 2- or 3-times higher than their younger neighbor might choose in order to make their visual tasks easier to perform." She also emphasizes that visual tasks do not include using computers. "Computer screens are a different matter, because the light is coming from the screen itself. It doesn't help to add light to the computer screen." Instead, increase the level of illumination on the desk area where paper tasks are performed.
A last piece of advice on task lighting: Make sure these lights shine down on what the aged eye is looking at - not up into the eyes - and that the lamp used in the fixture is completely shielded from view. Exposed lamps can reduce the ability to see details on the lighted page, and often contribute to painful glare.
Tip 2: Raise overall light levels.
A 25- to 50-percent increase in ambient light levels can overcome the loss of light transmission in the aged eye without adding glare. Instead of searching for new fixtures that will allow you to achieve an increased light level, Rosenstein recommends adding "extra layers" of light to your facilities' existing lighting systems as a much more cost-effective technique.
Indirect lighting is ideal for accommodating the aged eye. Go for luminaires that direct light toward ceilings, walls, tables, and artwork - not toward the eyes. Indirect lighting located in architectural features (in coves, soffits, etc.) can also work well, evening out light levels, getting rid of shadows, and providing overall illumination. Whenever possible, experts advise using additional fixtures to add more light to a space instead of relying on a single, bright fixture. "Don't make one ceiling fixture do all the work," says Rosenstein. He suggests investing in Energy Star®-qualified lighting fixtures and lamps when lighting spaces for the aged eye, since these products provide clean, crisp, bright light, and must meet strict U.S. Environmental Protection Agency criteria for efficacy, color rendition, and color temperature.
"Facilities that are more up-to-date may have ample quantity of illumination, and [may] need only to address issues of the quality of light. [For example,] fixtures may need to be retrofitted to reduce glare," says Hugh. He also explains that louvers can be a low-cost, "instant" fix to many of the glare problems in office spaces. "Older facilities, or ones that were designed for minimal performance values, may require additional fixtures [and] re-spacing of existing fixtures [as well]. In some cases, new fixtures to replace the existing [ones] may be needed to adequately address the task needs in the working environment."
Incorporating daylight into office spaces is another way to increase light levels - just make sure that the windows and skylights have appropriate solar control to filter and diffuse the sun's rays. "Useful daylighting is brought in through windows and skylights, which produce fairly diffuse light as uniformly as possible throughout the space," says Miller. She also stresses that in addition to useful lighting, it's important to provide "view" windows with clear glass to deliver information about the world outside.
Tip 3: Control glare.
Exposing the aged eye to glare "superimposes a haze over everything in its field of view," explains Miller. Concealing exposed lamps is the No. 1 way to avoid this problem. Make sure all lamps are hidden from view using luminaire components such as louvers, lenses, reflectors (make sure they're white, not shiny), baffles, and/or valances. As mentioned earlier, indirect lighting is fitting for office environments that need to provide illumination for the aged eye. It produces no glare, but successfully adds to the overall light level.
Blinds, light shelves, overhangs, awnings, and curtains can help direct and distribute incoming daylight to only the places where it's wanted. "Glare control is a must," says Hugh. "The eye wants to focus on the brightest area within the visual field, thus bright lenses or exposed lamps present problems." He also explains that when eliminating glare, facilities professionals need to pay attention to the fact that people see both vertically (walls, shelving, etc.) and horizontally (desk surfaces, flooring, etc.). If fixtures are too shielded and the light is pointed straight down on the horizontal plane, the aged eye loses some of its ability to discern detail in the vertical field of vision.
Tip 4: Establish uniformity of light.
Avoid creating dark corners and other shadowy places: Bounce large amounts of light from walls and ceilings to make lighting levels more constant throughout the space (including corridors and stairways, to eliminate confusion and possible trips or falls). Intensify the usefulness of indirect lighting by using light-colored finishes on floors, ceilings, and walls that reflect - not absorb - bounced light. Rosenstein emphasizes that facilities professionals should never use only downlights to illuminate hallways, waiting areas, meeting rooms, or other spaces: This technique alone will create a cave-like effect and cause confusion or disorientation.
Try to avoid abrupt changes in lighting levels as well: Leaving a bright office and heading out to a dark parking lot at the end of the day is hard on aged eyes. Consider offering some sort of transition from dark spaces to light spaces, and vice versa. For example: Miller suggests dimming lobby light levels at night and increasing lobby light levels during the day to give the aged eye a chance to adjust when heading into (or out of) the outdoors. It's also recommended that in-between two areas with different levels of brightness, lobby space is provided to give occupants time to wait for visual systems to adjust.
While light-level uniformity is easier on aged eyes and allows for better vision, Hugh emphasizes that if the visual field is perfectly uniform, "there are no brightness cues to assist [the aged eye] in the distinctions of distance. If light is too uniform, it equates to being in a 'light fog,' and the sense of three dimensions becomes compromised."
Tip 5: Improve contrast.
Contrast is important in the workplace - it makes going up and down stairs safer and hallway navigation easier for older occupants. Lamps with greater blue content (high-quality, warm-colored fluorescents or compact fluorescents) help aged eyes distinguish between certain colors more clearly, and improve color perception.
Good color rendering lamps may help enhance color discrimination as well. Color characteristics are measured in two ways: CCT (correlated color temperature) and CRI (color rendering index). CCT is a measure of the color of illumination produced by the lamp. Warm lamps have a low CCT (yellowish-white) and cool lamps have a high CCT (bluish-white). CRI characterizes how well the lamp's illumination makes objects appear "natural." For good color rendering, the Lighting Research Center recommends that lamps have a CCT of 2,700 to 3,500 Kelvin and a CRI of at least 80. Of note:
Incandescent lamps have a low CCT and a high CRI.
Fluorescent lamps can have nearly any CCT and have a medium to high CRI.
Metal halide lamps have a high CCT and a medium to high CRI.
Making improvements to your buildings' lighting systems not only assists the aged eye with everyday tasks; these modifications could very well improve the lighting environment for all building occupants. "There is nothing that you would do for the older eye that wouldn't also help the younger eye," explains Miller.
Leah B. Garris (firstname.lastname@example.org) is associate editor at Buildings magazine.
To Learn More ...
Lighting for the aged eye takes practice and experience. Enlisting the help of a professional (or two) isn't a bad idea:
Illuminating Engineering Society of North America (IESNA)
With its Lighting for the Aged & Partially Sighted Committee, IESNA reviews available information on the special lighting requirements of older eyes and people with defective vision, and has developed lighting design recommendations to optimize seeing and comfort. Its Recommended Practice 28 (RP-28) document, titled Lighting and the Visual Environment for Senior Living, is currently available to members and non-members for a small fee.
International Association of Lighting Designers (IALD)
This internationally recognized organization's members are a tremendous resource of innovative, practical, and economically viable lighting solutions - including solutions for the aged eye. Its professionals can help you make appropriate decisions for accommodating older eyes in the office environment.
Lighting Research Center (LRC)
A university-based research center devoted to lighting, the LRC investigates lighting issues. Its programs cover a range of activities including both laboratory testing of lighting products, and real-world demonstration and evaluation of lighting products and designs. The LRC has developed lighting principles for older adults and tested those principles in two assisted living facilities. A special publication, Lighting the Way: A Key to Independence, provides helpful information to facilities professionals.