There's More to Light Than Meets the Eye

Creating the proper lighting environment involves taking into account the workers' health and visual demands.

WE'VE all heard the jokes . . . "Q: How many gorillas does it take to change a light bulb? A: One, but it takes a really large box of light bulbs." Here's a more serious question, however. Q: How many people does it take to change the way we light the workspace? A: All of us!

I have worked in the field of vision care for more than 34 years. The number one visual complaint over most of those years has been the headaches and eyestrain caused by fluorescent lighting. Somewhere along the line, someone said, "If a little bit of light is good, then a lot of light must be great!" Nothing could be further from the truth. Making the visual system work harder to compensate for the glare is never smarter.

Fluorescent lighting has enjoyed more than 50 years as our predominant source of artificial light. The reason is simple: These lights last longer and use one-fourth the energy of their predecessor, the incandescent light bulb. However, there is one area that still needs to be refined: the effect of fluorescent lighting on human health and productivity.

It is important at this point to understand just how a fluorescent light bulb works. A glass envelope is coated on the inside with phosphors. Within the tube is a small amount of mercury and Argon gas. As a beam of electricity shoots back and forth, the mercury atoms convert into rays of ultraviolet radiation (UVR.) It is this UVR that excites the phosphors and makes them fluoresce, giving off light.

It is important to understand this because only a fraction of the UVR produced is necessary to make the phosphors glow. A portion of the excess UVR passes through the glass and affects objects in their path. UV rays not only cause fabrics, paintings, and carpets to fade, but also they affect our health. Ultraviolet rays affect our very DNA. While some DNA can repair itself, not all of it does. Because of this, UVR can cause allergic skin reactions, cataract formation, and even skin cancer. Several studies link occupational exposure to domestic fluorescent light and cutaneous malignant melanoma (skin cancer.) On top of this, there are more than 150 commonly prescribed medications that cause you to become photosensitive to UV. These include tranquilizers, antibiotics, heart drugs, and diuretics.

other health issue suffered by 1.5 to 2 million Americans is Lupus Erythematosus. Lupus is an autoimmune disease that can affect the skin, joints, heart, blood, lungs, kidneys, and brains. With lupus, the body's immune system cannot distinguish between foreign substances and its own tissues and cell. The body therefore creates antibodies that attack itself, causing inflammation, pain, and organ damage. Lupus patients commonly take a medication that makes the body very sensitive to UVR.

I have personally spoken with lupus patients who can be under fluorescent lighting for only 20 to 30 minutes before they "pass out." Others will develop rashes and blisters on the skin that is exposed to the fluorescent light--typically, their arms and scalps. Obviously, if they are to continue to be able to work, lupus patients must avoid UV exposure by wearing protective clothing and slathering on high SPF sunblock.

Artificial lighting plays a significant role in our daily lives. It enables us to live, work, shop, and play in places that would otherwise be pitch dark. Light, whether solar or artificial, helps to regulate hormone production in out bodies and helps to regulate our biological clock and sleeping habits, as well.

Our Preference for Bluer Light
The color of light is measured in Kelvin (K) temperature. For instance, a warm white light is about 3500K, cool white light is 4100K, and full spectrum light starts at about 5000K. White light found in sunlight is actually a mix of red, orange, yellow, green, blue, indigo, and violet light.

Scientists have determined that our biological clock prefers selected colors within white light. The results of a five-year study showed that the biological clock is most responsive to bluer light. Blue light increases serotonin (the "wake-up" hormone) in our blood. Serotonin is crucial in suppressing melatonin (the drowsy hormone).

Recent studies also demonstrate that subjective drowsiness is higher under 3000K light than 5900K light. Office workers who spend more than 90 percent of their day indoors do not receive the higher color-temperature light. That is why offices that have replaced 3500K lamps with 5000K+ lamps report not only energy savings, but also improved visual acuity and productivity. A drowsy workforce isn't very motivated or productive, after all.

That is also why doctors routinely use 5000K light to combat a condition called Seasonal Affective Disorder, or S.A.D. The light sources used in this therapy are much bluer in color than commonly found in offices. S.A.D. patients number in the millions in the United States, and many of them receive tremendous relief from this form of phototherapy.
The key to providing optimal workplace lighting is to create a glare-free, UV-safe, color-corrected environment that is as close to natural sunlight as possible. [OHS endbug]

Kevin A. Kirschner, inventor of the NaturaLux™ Filter, was trained to be an optometric assistant while serving in the U.S. Air Force. While stationed at Mountain Home AFB, Idaho, Kirschner became proficient in performing refractions, biomicroscopy, lensometry, tonometry, and fitting contact lenses. After his tour of duty, he studied at the University of Iowa, the University of Southern California's Estelle Doheny Eye Institute, and UCLA's Jules Stein Eye Institute. Since 1980, he has owned a mobile diagnostic ophthalmic laboratory in Southern California, examining patients from Los Angeles to San Diego.

This article originally appeared in the September 2007 issue of Occupational Health & Safety.

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