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Vision loss is one of the most common problems of later life. Our built environments should be designed to enable people of all ages to carry out their activities with relative ease, safety, and comfort. Sadly, the needs of older eyes are not always met. The changes in vision due to aging are different than the changes due to specific eye diseases in younger disabled people. The loss of focus is a natural part of aging. Aging eyes need more light and more contrast to see. Color perception is also affected.
Aging eyes adjust more slowly to changes in illumination levels. When moving from a normally illuminated room into bright sunlight, or entering a dimly lit space from bright sunlight, the dramatic change results in temporary blindness as the eyes adjust. The three most common types of vision loss in older adults are overall blurred vision, central vision loss, and peripheral vision loss. Those with overall blurred vision experience increased sensitivity to light, a marked decrease in the intensity of color, and due to lack of contrast, they may experience particular difficulty being outside. For those with central vision loss, images appear distorted and segments of words may be missing in type, there’s an increased sensitivity to light, altered color vision, and faces may be hard to recognize. Window coverings and lighting can be adjusted to reduce bright sunlight. Peripheral vision loss causes a fear of moving around, so it’s important not to rearrange furniture. In people with dementia, all the above normal vision problems caused by aging are even worse. There is a disproportionate impairment in the discrimination of colors on the cool (blue) side of the color wheel, and they have difficulty distinguishing between blue and green and blue and violet. While these colors may be very calming to the general population, these colors are not the best choices for dementia settings. People with dementia also experience depressed contrast sensitivity in all colors.
Lighting needs for the elderly are quite different from those of a younger person, and designers have a big challenge to understand appropriate lighting for long-term care facilities. Vision begins to decline as early as age 40. A 60-year old person may require two to three times as much light as a 20-year old and the amount of light required doubles each 13 years after the age of 20. One of the most important design considerations in the design of senior housing facilities is lighting. Key design goals for senior housing projects are as follows:
1. Provide a higher level of illumination compared to most spaces designed for the general public. A combination of low-brightness, direct fixtures, and indirect light fixtures is one reliable approach for general illumination. Using indirect fixtures that provides a uniform ceiling brightness and down lighting with the same luminance as the ceiling is key. A uniformly bright ceiling is defined as one that has no areas four times brighter than the area between fixtures; however, because of the extreme sensitivity to glare for older adults, a 3:1 ratio is preferable.
2. Provide consistent, even light levels. Pendant indirect lighting and cove lighting provide the most even illumination and provide a high level of ambient lighting without glare. Chandeliers and sconces look nice and provide a homelike feel, which is important, but on their own, can’t supply the amount of light needed for aging eyes. Recessed down lights also provide poor light distribution and produce both direct and reflective glare.
3. Eliminate glare. There are two types of glare: direct glare and reflected glare. Direct glare comes from inappropriately shielded light sources such as sunlight streaming in from windows or skylights in a dimly lit hallway. Daylight should be balanced and controlled, but should definitely be utilized. When light bulbs are exposed in light fixtures without proper deflectors or diffusers, it can be especially harsh for the elderly. Reflected glare comes from strong light bouncing off a smooth reflective surface such as vinyl flooring, appearing as “hot spots”. Reflected glare can be controlled by a skillful selection of paint, wallcovering, countertops, and other surface materials with matte finishes. Polished surfaces and high gloss paint are not recommended.
4. Provide access to natural daylight. Access to interior courtyards, indoor atriums and greenhouse windows offer greater access to natural daylight. People who rarely see natural light suffer from illness as well as visual deterioration. Sunlight stimulates the nervous system, improving appetite and mental attitude, and induces better sleep. This is true not only for the general public, but for elderly people and people with dementia. Daylight and views to the outdoors are critical for wellbeing. Yet, it’s important to control bright sunlight and glare coming through windows. Horizontal and vertical blinds can create light patterns that can be visually disturbing for the elderly. Semi-translucent shades are a better choice. A wide range of flame-resistant fabrics and finishes are available. Drapes add a home-like feel, but should be used with shades since they aren’t great at controlling the amount of light that enters the space. Traditional drapery hardware should be replaced with a break-away wall or ceiling mounted curtain hanging system.
5. Provide gradual changes in light levels. Transition areas should be provided from spaces with bright daylight to areas of lower light levels or vice versa. Changes in floor level should not occur until the eyes have had enough time to adjust. A seating area in an entry vestibule, for example, gives the older person a place to rest while their eyes adjust.
6. Provide focused task lighting. Lamps in the 3,500 to 4,000 degree Kelvin range are best for task lighting. Avoid direct glare from the light source. If no local task lighting is available, the general lighting should provide illumination of about 300 lux (30 footcandles) to 750 lux (75 footcandes) at a work surface.
7. Improve color rendition from lights. Cool-white fluorescent lamps are deficient in both the red and blue-violet areas of the spectrum, and result in color devoid of warmth and aliveness giving skin a lifeless pallor. Choose lighting that more accurately the true color of people and objects. 8. Using natural light. The illumination level for indoor lighting is typically equivalent to that of twilight. These light levels are barely adequate to see and not sufficient to send an effective signal to the biological clock for the regulation of hormones and circadian rhythms. Daylighting refers to design solutions that gather, direct, and reflect natural light deep into buildings. High ceilings, large windows, and north-facing skylights to maximize natural light while minimizing direct light are all good strategies. Providing adjustable window coverings to control natural light is important to reduce glare.
