Lighting For The Aging Eye
One of many important facts significant to lighting designers is knowing how the eye sees at night. Safe, comfortable movement within an evening space begins with comfortable visual movement.
Equally as important, the lighting designers understanding and planning of proper lighting for the aging eye.
Life expectancy in the United States now approaches 80 years old and the number of people aged in the 65-80 category will double in the next ten years. With age, we undergo a natural process that reduces our visual abilities. Whether designing for an interior or exterior environment, proper lighting is an important issue for the older adults health, well-being and quality of life.
Lighting design does not start with the selection of fixtures, but with an evaluation of the clients' needs, visual and physical capabilities, age and lifestyle. It's a known fact that the older we get, the more light we need. A 55 year-old requires twice as much light as a 20 year-old. And, it is critical to understand what are appropriate light levels while allowing for the differences in how the aging eye sees and reacts with them.
A keen understanding of glare, illumination levels, adaptation and transient adaptation are important for the aging eye; Glare is, "any light over and above to see clearly and comfortably." Glare is mis-directed light. The elderly are particularly susceptible to discomfort glare and disability glare. Analogous to what an aging eye might momentarily experience would be a driver looking through their windshield in the direction of a setting sun. A dirty windshield can further complicate the vision process by creating a veiling reflection.
Adaptation is the eye's ability to adapt to changing light levels. Entering a darkened theater for a matinee portrays an excellent example of the eye's need and ability to adapt and lend to safe, comfortable movement in finding a seat.
Transient adaptation is the eye's ability to adapt when moving between places with differing levels of brightness. A problem these days might be for an older driver whose eyes have 'light-adapted' under an over lit gas station canopy. They complete their sale and then enter back onto a darkened street or highway. Before the eye can completely 'dark-adapt' the bright lights of an oncoming car completely confuses the eye's adaptation process.
The above information is especially important in designing good lighting within evening transition spaces. Good lighting makes the adjustment easier on the eyes when going between places with differing levels of brightness. An even light distribution that does not create deep shadows will make walkways easier to traverse. Comfortable pools of fill light can be used to emphasize hazards such as steps or changes in ground elevations.
A simple understanding of how the older eye sees takes into account the strengths and weaknesses of human vision. Quality, not quantity of lighting is what counts.
Glare-free evening environments and smooth transitions between lighting darker areas as well as creating uniform lighting can make important differences for the older adult's safe enjoyment of an evening space.
REFERENCES: International Dark-Sky (IDA) - Information Sheet #156 - The Aging Eye
Illuminating Engineering Society of North America (IESNA, 9th edition.)
Doug Alderman, LC
Nightscaping® by Loran, Inc.
958 Narcissus Ave.
Clearwater, FL 33767-1045
727-443-3906 office
727-442-6822 fax
727-510-7336 cell
dalderman@nightscaping.com
Equally as important, the lighting designers understanding and planning of proper lighting for the aging eye.
Life expectancy in the United States now approaches 80 years old and the number of people aged in the 65-80 category will double in the next ten years. With age, we undergo a natural process that reduces our visual abilities. Whether designing for an interior or exterior environment, proper lighting is an important issue for the older adults health, well-being and quality of life.
Lighting design does not start with the selection of fixtures, but with an evaluation of the clients' needs, visual and physical capabilities, age and lifestyle. It's a known fact that the older we get, the more light we need. A 55 year-old requires twice as much light as a 20 year-old. And, it is critical to understand what are appropriate light levels while allowing for the differences in how the aging eye sees and reacts with them.
A keen understanding of glare, illumination levels, adaptation and transient adaptation are important for the aging eye; Glare is, "any light over and above to see clearly and comfortably." Glare is mis-directed light. The elderly are particularly susceptible to discomfort glare and disability glare. Analogous to what an aging eye might momentarily experience would be a driver looking through their windshield in the direction of a setting sun. A dirty windshield can further complicate the vision process by creating a veiling reflection.
Adaptation is the eye's ability to adapt to changing light levels. Entering a darkened theater for a matinee portrays an excellent example of the eye's need and ability to adapt and lend to safe, comfortable movement in finding a seat.
Transient adaptation is the eye's ability to adapt when moving between places with differing levels of brightness. A problem these days might be for an older driver whose eyes have 'light-adapted' under an over lit gas station canopy. They complete their sale and then enter back onto a darkened street or highway. Before the eye can completely 'dark-adapt' the bright lights of an oncoming car completely confuses the eye's adaptation process.
The above information is especially important in designing good lighting within evening transition spaces. Good lighting makes the adjustment easier on the eyes when going between places with differing levels of brightness. An even light distribution that does not create deep shadows will make walkways easier to traverse. Comfortable pools of fill light can be used to emphasize hazards such as steps or changes in ground elevations.
A simple understanding of how the older eye sees takes into account the strengths and weaknesses of human vision. Quality, not quantity of lighting is what counts.
Glare-free evening environments and smooth transitions between lighting darker areas as well as creating uniform lighting can make important differences for the older adult's safe enjoyment of an evening space.
REFERENCES: International Dark-Sky (IDA) - Information Sheet #156 - The Aging Eye
Illuminating Engineering Society of North America (IESNA, 9th edition.)
Doug Alderman, LC
Nightscaping® by Loran, Inc.
958 Narcissus Ave.
Clearwater, FL 33767-1045
727-443-3906 office
727-442-6822 fax
727-510-7336 cell
dalderman@nightscaping.com
Photo courtesy of Seth Petree of Night Designs, Inc. Contractor of the Week Seth Petree
Night Designs, INC is Knoxville's premier landscape lighting company. With over 9 years in the landscape lighting industry, owner Seth Petree has a knack for understanding client needs and lifestyles when putting together a holistic lighting plan.
His design expertise often incorporates a lighting technique known as 'down lighting.' Seth uses this most natural of lighting techniques frequently when designing for his older clients. "Their property is part of their home, and we try to enhance it rather than compete with it by lending a natural evening feel."
We are pleased to introduce Seth Petree and show his lighting expertise. One of Tennessee's top lighting contractors, he is a true reflection of Nightscaping® lighting professionals world-wide.
His design expertise often incorporates a lighting technique known as 'down lighting.' Seth uses this most natural of lighting techniques frequently when designing for his older clients. "Their property is part of their home, and we try to enhance it rather than compete with it by lending a natural evening feel."
We are pleased to introduce Seth Petree and show his lighting expertise. One of Tennessee's top lighting contractors, he is a true reflection of Nightscaping® lighting professionals world-wide.
Moonlighting
Bob Cooper
Bob Cooper Sales Group INC
Apex, NC 27502
919-782-4432 Busn
919-341-8693 Fax
bcoopersales@mindspring.com
Bob Cooper Sales Group INC
Apex, NC 27502
919-782-4432 Busn
919-341-8693 Fax
bcoopersales@mindspring.com
Photo courtesy of Seth Petree of Night Designs, Inc.
Do You Know How To Extend or Shorten A Lamp's Life? Are you new to the lighting industry and wondering what a lamp is and how it has life - just as Bill once wondered how colors could compliment each other? Lamps, also known as light bulbs, come with a rated life expectancy determined by the approximate number of hours at which it will operate when supplied with 12.0 volts of electricity. Lamps can vary anywhere between 500 to 18,000 hours, while some lamps lie outside the given range. The chart below demonstrates what will happen to the average life expectancy of a lamp when the voltage supplied to it is either above or below 12.0 volts, in addition to the associated candlepower that it puts out.
|
Effect of Voltage on Lamp Life & Light Output | ||
|
Voltage at Lamp |
Lamp Life Expectancy |
% of Rate Candlepower |
|
13.2 |
2/3 rated life |
350 |
|
12.6 |
3/4 rated life |
180 |
|
12.0 |
as rated |
100 |
|
11.5 |
2 x rated life |
80 |
|
11.0 |
3 x rated life |
75 |
|
10.75* |
4 x rated life |
70 |
|
10.50 |
5 x rated life |
65 |
|
10.0 |
9 x rated life |
50 |
Voltage Calculator
Although most of you don't work in the field with a computer next to you, it may still be valuable to mention the Voltage Calculator that Nightscaping® has available on our website. It is a calculator that computes 4 factors: Wattage on run, Length of run, Size of wire, and Voltage Drop. You can either enter wattage, length of run, and size of wire to compute voltage drop, or you can enter any three factors to calculate the forth. You can either go to Nightscaping's® Home Page, Technical, Help On, Voltage Calculator, or you can click on our Voltage Calculator Link.