FACTS OF LIGHT
“Light is like food. The wrong kind can make us ill and the right kind can keep us healthy.” In our Spring issue we reviewed some of the research behind this simple, common-sense prescription from pioneer photobiologist John Nash Ott.
In this issue, we’ll sift through the often conflicting information on the many full-spectrum lights available, all of whose manufacturers promise us health and happiness with a mere flick of the light switch.
Full-Spectrum Fluorescent Tubes
Those who go to their local store in search of full-spectrum fluorescent lights usually come home with the Vita-LiteT brand. Though Dr. Ott invented it years ago, he no longer endorses it. Instead, he has been associated with two companies that produce higher quality, more expensive brands: OTTbioLIGHTSYSTEMS of Santa Barbara, California that sells bioLIGHTsT, and Environmental Lighting Concepts of Tampa, Florida that sells Ott-LitesT. Though the two Ott-named companies are now rivals, their products are similar and differ from Vita-LitesT in two key ways: in the number and quality of their phosphors and in the use of lead shielding on the ends of the tubes.
Phosphors, as the name suggests, are phosphorescent substances that coat the interior of fluorescent tubes. They emit light when excited by radiation. Inexpensive full-spectrum fluorescents have three phosphors, whereas higher quality tubes have four. Each phosphor has its own special characteristic and the art lies in the careful mixing and matching of the phosphors. The goal is to produce a true, natural, perfectly balanced white light that simulates sunlight.
Although many manufacturers claim to have accomplished this, consumers may want to ask for proof. It is among the manufacturer’s specifications and known as the Color Rendition Index (CRI). To be full spectrum, the rating must be 90 or above. Of the well-known brands, Verilux shines with ratings between 93.5-94.5. Not surprisingly, its clear, beautiful full-spectrum lights have been used for grading diamonds for 25 years. The CRI of Vita-LitesT, Ott-LitesT and OTTbioLIGHTsT range from 91-93. However, the Vita-LitesT have a lower lumen level, meaning they are less bright.
Consumers should also think about phosphors because they degrade at different speeds. This means that the light’s balance is affected well before the bulb actually burns out. Unfortunately, full-spectrum lights do not stay full spectrum for long, a fact not known to the average consumer, who assumes that he or she is benefiting from full-spectrum light right up until the time that the tubes or bulbs die.
How quickly the degradation occurs varies from product to product. It occurs fairly quickly with the inexpensive brands, but even higher priced products dim in time. Upon request, all manufacturers will provide guidelines for replacement, generally in the range of 18-24 months, depending on how much they are used. This, of course, vastly complicates calculations of both energy savings and economics and means that fluorescent lights are not quite the ideal energy saving solution that environmentalists believe them to be.
Lead Shielding
Another feature to consider is whether the ends of the fluorescent bulbs should be shielded with lead. While growing geraniums for the film On a Clear Day You Can See Forever starring Barbra Streisand, Dr. Ott noticed that the plants growing under the ends did poorly. He concluded that this was due to low-level X-rays emitted from the ends of the cathodes and decided to rectify the problem by shielding the ends of the tubes with lead.
Not everyone agrees that this safety feature is necessary. “I think the lead shielding is a marketing angle,” says Nicholas Harmon, President of Verilux, who believes lead should be avoided because it is a hazardous material. “It could be outgassing when heated up. There are also environmental issues related to disposal.”
UV Or Not To UV
The biggest controversy, of course, is the matter of UV. Many people fear UV light and recommend that it should be filtered out of full-spectrum bulbs altogether. Accordingly, Verilux sells two lines of fluorescent tubes, one that emits UV and one that blocks it with a polymer coating.
Dr. Ott, on the other hand, reveres UV light to such an extent that he recommends light fixtures that deliver an extra dose. These fixtures house two fluorescent tubes plus a small ultraviolet black light in the center. Although his full-spectrum fluorescent tubes emit ultraviolet light, Dr. Ott believes the extra UV tube is the key to good health.
Light Bytes
Computer manufacturers claim that sitting in front of a cathode ray tube — the heart of the computer’s monitor — poses no threat to health. Dr. Ott begs to differ. “When a drop of human blood is placed on an ultraviolet transmitting microscope slide and then placed directly in front of a video display terminal for five minutes, it will cause long chain clumping of the red blood cells known as “Rouleau.” That clumping, Dr. Ott theorizes, causes a restriction of blood flow, a diminished supply of oxygen to the brain and problems with headaches, eyestrain, fatigue and irritability.
Dr. Ott’s research shows that the clumping will be broken up within five minutes if the slide with the blood sample is placed directly in front of a special full-spectrum light that is radiation shielded and provides a separate ultraviolet black light. Therefore, Dr. Ott recommends that computer stations be set up either with a 2′ x 2′ overhead model, which hangs six to seven feet from the floor between the VDT and the user, or a 1′ x 2′ table fixture, designed to be positioned next to a CRT computer screen and angled to shine into the user’s eyes. Note that these are large — and not very attractive — light fixtures. They differ substantially from the little Ott task lights owned by many computer users. The task lights provide good clean light but little or no therapeutic benefit.
An alternative for those who fear UV light is the Verilux “Happy LightT,” a compact 1′ x 1 1/2′ panel. There is no extra UV socket and all UV has been filtered out. “We do not want to risk causing injury to anyone,” says Verilux’s president. “We believe that people would prefer not to sit inches from UV light.”
Don’t Be Sad
Dr. Ott’s 1′ by 2′ computer lights, Verilux’s 1′ x 1 1/2′ “Happy LightT” and similar products are smaller versions of the larger, full-spectrum light panels designed to help the five million Americans affected each year by Seasonal Affective Disorder (SAD) and the 25 million others afflicted with a milder version that is commonly known as the “winter blues.” Depression, PMS and other mental health problems have also been linked to SAD.
SAD lights generally come in 2′ x 4′ floor models or 2′ by 2′ table models and produce 10,000 lux (lux is the measurement of light intensity). In contrast, the smaller computer panels are generally in the 2,500 lux range. Typically, SAD patients are told to spend 30 minutes each morning “sunbathing” in front of the big light boxes.
Although OTTbioLIGHT systems, Environmental Lighting Concepts and Verilux all sell SAD lights, the leader in the field is the SunBox Company, whose SunboxT was used in the initial research on SAD by Norman Rosenthal, M.D., at the National Institute of Mental Health in the early 1980s. The SunBox and Verilux models filter out UV light, whereas OTTbioLIGHTs and Environmental Technology Concept’s provide an added dose through the extra UV socket.
A more novel product for SAD sufferers is the Bio-Brite Light VisorT. Worn on the head, it delivers constant, consistent illumination to the eyes and allows users to go about their daily work without sitting directly in front of a light source. The light intensity is adjustable and can deliver between 500 and 3,000 lux from a distance of two inches from the eyes. It uses full-spectrum white light with the UV filtered out.
Now that light therapy is accepted as mainstream psychiatric treatment, more and more SAD sufferers are finding that their insurance will cover the cost of a full-spectrum light system. Even so, many sufferers ask, “Why can’t I just replace all the light bulbs in my house with full-spectrum lights?” Dr. Rosenthal replies, “This is not feasible. Intensity, not spectrum, is the variable most critical for obtaining an antidepressant effect.”
The Goods on Compact Fluorescents
Over the past decade, Real Goods and other companies interested in protecting the environment have been selling odd-shaped, twisting little fluorescent bulbs that are geared to the home market. Though these once required special fixtures or adapters, more and more of them now fit standard lamp fixtures. Those that don’t can be adapted with a “harp” sold at most lighting stores. Although they save greatly on energy bills, none of the models on the market are full-spectrum. Even the two Ott companies and Verilux only offer “broad spectrum” bulbs, with CRI ratings of 85. Full-spectrum bulbs must have a CRI rating of 90 or above.
Full-Spectrum Incandescents
These bulbs look like Tom Edison’s light bulb and screw into standard fixtures. The best are manufactured in Europe using handblown glass that contains neodymium. This rare earth element — number 60 on the Table of Periodic Elements — is commonly used in space and laser technology because of its ability to filter out the yellow-green part of the spectrum. Thus, it is useful in helping an incandescent bulb (with a low CRI rating of 78-80) to approximate a balanced full-spectrum light.
ChromaluxT, the most widely available brand, was developed a quarter of a century ago when the Finnish government pressed for vision improvement in schools, nursing homes and hospitals. The lights were then commercialized and have been available in the United States for a decade. Verilux and the two Ott companies offer a similar product. Both emit white light without glare and boast crisp, clear color rendition. Users report better concentration, better visual acuity, higher comfort, greater relaxation and reduced eye stress. Unhappily, there is no truth to the claim made in some mail-order catalogues that these bulbs can help prevent SAD; they are not nearly bright enough to do so. Although these incandescent bulbs cost three times more than standard bulbs, they last four to six times longer, depending on who is counting — and how.
Windows of Opportunity
When Dr. Ott built his home in Sarasota, Florida, he chose UV-transmitting plastic in lieu of UV-blocking window glass. Since then, many of the companies that once sold UV-transmitting plastic sheets have discontinued their lines, a result perhaps of consumer fear of UV. A company producing such glass is called CYRO in Mt. Arlington, NJ. The Ott company fixtures are covered with UV-transmitting plastic.
Despite reports of good health for humans and spectacular growth for houseplants, not everyone puts UV-transmitting plastic windows on their wish list. Certainly it hastens the fading of curtains, rugs, paint and artworks. One point photobiologists do agree on is that sleek urban skyscrapers with smoky brown and gray windows are terrible for the health and morale of workers. Tinted windows in cars can also lead to light deprivation.
For a complete list of manufacturer’s names, addresses and phone numbers, write the author c/o Right Spin Health Education, 525 Cortez Street, Santa Fe, New Mexico. Or call 505-984-2093.
Editor’s Note: David Getoff, CNC, ND, PPNF Advisory Board member, has the following additional comments to add regarding full spectrum lighting: The four foot fluorescent bulb which we use in our homes is powered by a special transformer which is called a ballast. The ballast supplies the initial high voltage to energize or fire-up the gasses inside the fluorescent tube, and then drops down to a lesser voltage to keep the tube lit. Although most people cannot see it happening, fluorescent tubes are actually going on and off 60 times a second like a strobe light. This flicker, while not usually visible, may cause the same kind of harmful effects as partial spectrum lighting. The best way to avoid these problems and to make your lighting beneficial rather than detrimental is to have your bulbs installed along with a special electronic ballast which completely eliminates the flicker by changing the 60 cycle strobe problem to 25,000 cycles. An additional benefit is that they eliminate the buzz or hum which many of us find bothersome from fluorescent lighting. My own personal favorite electronic ballast is manufactured by Motorola.
Another problem is that all glass and most plastic effectively filter out most, and in some cases all, of the beneficial ultraviolet portion of the spectrum. However, special UV transmitting plastics can eliminate most of these problems. I highly recommend that the plastic diffuser panels which cover the bulbs be replaced with the special clear prismatic UV transmitting type, or eliminated completely. The Ott company fixtures are covered with UV-transmitting plastic. Another alternative cover is called egg crate.
