I have a client with a call center office environment with very limited natural light. Several employees suffer from migraine headaches and one has a seizure disorder. There is concern that the lighting may be contributing to symptoms for these employees. The area has overhead flourescent lighting and the employees work in closely spaced cubicles. They have already attempted to reduce the amount of light by reducing some of the bulbs, but this resulted in the office being below the ANSI recommended standard and became a safety hazard. The employer is prepared to replace the existing lighting with full spectrum if that is the optimum solution for their employees. However they were also considering light diffusers. I would welcome any input or resources on the most effective ligthing solutions to specifically address migraines and seizure disorders.
Thank you for your assistance.
Cathy Bloome MS, OTR/L
Bloome Ergonomics Consulting
We came across a similar case here at the University of Washington and I talked to a Lighting Architect and a Nuerologist. If people did not have the problem prior to the worksite of interest, then that points to the lightng. Most migraines typically start when people are in their teens and development in the 30’s and 40’s isn’t the typical trajectory. There is some information that flourescents light may be associated with migranes, especially older flourecent lighting. The ballasts which are electrical devices which power the lights may be old, and older ballasts cause the light to flicker at a lower frequenct relative to newer flourescent lights. So a low cost soluton is to just update the ballasts. Hope this information helps.
Department of Environmantal and Occupationa Health Sciences
University of Washington=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Peter W. Johnson, Ph.D. University of Washington
I think that there are several things to take into consideration in addition to the lighting. Various things can contribute to migraines and I might be somewhat careful in making that attribution however there are aspects of the task and environment that bear a look:
-Glare – are they looking at screens/displays that present excessive glare or light contrast? Screen glare can be very fatiguing although again I caution against attributing migraines or seizures to it. Also consider the surfaces and features of the work area.
– General lighting – there are good IES and other human factors information on lighting. Indirect lighting at an appropriate level is often cited as being good for reading computer screens. Natural spectrum lighting may or may not be a big improvement in and of itself. Avoid glare is a priority (that is where indirect lighting can help along with diffusers and louvers, etc.) and the right level of light. Task lighting should be available for anyone who may need it.
– Other envirnmental aspects of the office – seating, monitor height, telelphone equipment, temperature, air movement – all of these can certainly have an effect on perceptions of comfort and best a look. Font sizing and orientation can be important. Again, there are very good guidelines out there. Start with some HFES publications.
Bob Fox GM global ergonomics
Are these employees using computers? If so, what type of display do they have? Flicker from older CDTs can cause problems with flicker.
Just using diffusers might not be enough- sounds like they need indirect lighting (having the light bounce off the ceiling); this will "soften" the light. They might also need task lighting for their desks.
Just a few thoughts….
JeffDr. Jeffrey Anshel
Corporate Vision Consulting
Cathy, I will simply echo some of the other excellent suggestions you have received, with some slight modifications and additions. First, I would check to be sure the task-relevant content on users’ computer screens is large and sharp enough so that no one suffers from simple visual acuity problems. If task content cannot be resolved easily (characters too small, due to being too small on the screen or the screen being placed too far away from the user), this can lead to headaches and bad postures–which of course lead to other aches & pains. Second, I would make sure the computer screens are current (particularly for users with complaints and/or headaches; refresh rates of at least 120 Hz). It would also be best if these screens were LCD’s; such screens are not quite as prone to glare as VDT’s. Third, I would make sure the fluorescent light fixtures all have electronic ballasts (this will usually ensure that the flicker rate remains above all users’ critical fusion frequency–although some particularly sensitive users may never fully adjust to fluorescent lighting [this is quite rare but not impossible]); and yes, they should also deliver indirect ambient light, and definitely should not deliver light directly opposite to users’ lines-of-site (shouldn’t shine into their eyes)–particularly while they are working on their computers. Fourth, I would make sure that everyone (having headaches or reporting vision problems) has user-adjustable task lighting to ensure adequate brightness for task-relevant materials. The reason for adjustability is to ensure that light does not shine directly into users’ eyes or parallel to their computer screens–thus "washing out" the information displayed on those screens. Finally, be sure that no furniture or other furnishings (carpets, etc.) are "off-gasing" (releasing VOC’s (Volatile Organic Compounds) into the indoor environment without adequate ventilation). It’s best to purchase low or zero VOC-emitting furnishings.
Best of luck! Jay Brand
Jay L. Brand, Ph.D. Cognitive Psychologist Haworth Holland, Michigan 616.835.1481
Cathy, the ergonomic suggestions so far are good, just a few clarifications.
1. Refresh rate for the computer screen only applies to CRT screens (the old tube type). Don’t increase the refresh rate of an LCD screen – it makes the screen blurry without any benefit.
2. 85 Hertz refresh rate on a CRT screen is enough for nearly everyone although the very rare person might benefit from 95 to 100 Hertz. I havent met anyone who needs a higher refresh rate (and it also depends on screen size and distance, and the amount of the screen that is white). The fine detail (eg the text) on the screen will start to go blurry if you push refresh rate too high. It’s trial and error – go as high as the display will support, and see if it’s still sharp (it probably won’t be).
3. Electronic ballasts for fluorescent lamps – even though they switch at 20,000 Hertz or more, they let some 60 Hertz flicker through. Some are better than others. A solid manufacturer will be able to tell you the percentage modulation at the mains frequency. Otherwise just buy a brand that advertises low flicker (I have used Helvar and Philips but there would be others).
4. Emotional factors – feeling put down, unrewarded, angry, resentful, hostile, depressed – are just as likely to be the cause. Both visual and emotional factors can trigger headaches.
5. Task factors include angry customers (eg if the call centre worker is the fall guy for an organisation’s poor product or service); and the ability of the call centre worker to do anything positive to resolve the problem.
6. The responsiveness of the computer system – does it provide relevant information quickly and easily, can the user do things quickly and easily to make a difference
Just walking around can tell you a lot. Are the faces tired and drawn? Are people squinting at the screen, craning their necks forward, slumping…
David Brown, B.Sc. M.A.
Fellow, Human Factors and Ergonomics Society of Australia
David Brown, workplace psychologist and ergonomics consultant, Sydney Australia
I don’t know if you’re still looking for a solution, but my company just renovated our offices. We had several people who were getting migranes from the fluorescent lighting also and so they bought light diffusers. They do a great job at taking away the glare and they also have cloud or tree designs on them that make you feel like you’re seeing the sky when you look up.
I have heard that my coworkers don’t have the migranes they used to, so that’s definitely a credit to these diffuser panels. I asked the manager and he said they’re something like "skypanels" or something, but he did some shopping around on google to find them.
Let me know if this helps! Good luck!
You have some great solutions suggested to you by these interested professionals which is great.
One cautionary note and one of the assumptions which is not based on good science; there is no solid, peer reviewed research which shows links between fluorescent lighting and migraines. This has been an oft repeated assumption on the part of employees and as such has taken on a "truth" of its own.
To zero in on solutions in the absence of evidence for cause makes for bad science. Migraine causation is mutifactorial in nature and is still not well understood in the medical literature.
My suggestion therefore is to take a holistic look at this while at the same time informing employees of the facts; migraines are not caused by the workplace. The solution lies in having employees by all means being set up and using their equipment and lighting properly. It also lies in the employee determining the other triggers for their migraines (and don’t forget many people mislabel their headaches as migraines and often this is NOT the case) such as foods, stressors, lack of exercise.
There is great new evidence published in a few top level medical journals for effective treatment of bona fide migraines; plain and simple use of aspirin. Maybe adding a water fountain (to rehydrate), removing chocolate and coffee vending machines) and adding an aspirin vending machine would be the better solution!
JE Sleeth Sr Ergonomic Consultant & Orthopaedic Physiotherapist
Very well said. Just yesterday I had a patient call me with a complaint of "spots" in front of her eyes after 60 minutes in front of a computer. More inquiry found out that she had a history of migraines but she assumed that the computer use brought them on. Unlikely….
However, while I’m sure aspirin has it’s place in migraine mitigation, I do know of several sufferers who can’t take enough of it when they get symptoms. In aspirin- as with everything- more is not necessarily better….
and then there is the diet issue!!
Dr. Jeffrey Anshel
Corporate Vision Consulting
In my opinion, the best idea would be to retrofit your fluorescent lights, which means changing the magnetic ballasts that have a lower frequency (a lower frequency means that the light will flicker more slowly). Replace the magnetic ballasts with electronic ballasts that these days basically eliminate light flicker. When you replace a magnetic ballast with an electronic one, you must replace the lamps, or bulbs. Magnetic ballasts use a T12 fluorescent bulb, and electronic ballasts require a newer, T8(recomend) or T5(don’t recomend) bulbs. Sometimes, changing the light color or color rendering index (CRI) may effect things in a good way. The light color is measured in Kelvin temperature–the lower the number, the more red, or more yellow the light will be, and the higher the temperature, the bluer, or whiter the light will be. Changing the CRI basically means that the colors in the room are going to be truer as the CRI number goes up (which is good for the eyes). I usually recomend somewhere around 4100k color for office environments, which is kind of in the middle of the spectrum, and and 840 CRI. If there’s windows in the office, light harvesting can be used to ease the fluorescent light intensity. Light harvesting will dim the lights as it gets brighter outside (wal-mart does this).
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