Light & Health

Lighting for Children

• Around children, I’d use only low watt (preferably frosted) incandescent bulbs. If frosted bulbs are unavailable in your country, try and find a combination lamp with a 20W or 33W mini halogen inner bulb and a frosted outer bulb, or a clear lamp behind a shade.

• Clear halogen lamps can get very hot and glaring and should only be used in lamps (luminaires) especially designed for children to prevent burns and glare.

• CFLs contain mercury vapour, which can be extremely toxic even in the smallest doses. CFLs should never be used if you are pregnant or have have children! 

Screenshot from the Austrian documentary Bulb Fiction

After sleeping in a room where a CFL had started leaking toxic mercury vapour, 
this young boy from Bavaria began losing his hair, eyelashes & eyebrows 
and developed tremor episodes and depression. He was later diagnosed with 
mercury poisoning.

• Naked CFL tubes can also emit unsafe UV radiation.

• White LEDs often contain a higher portion of blue light, which may be harmful to children's eyes which are more sensitive to blue light than adults, so LEDs are not recommended for children for that reason, even if they are nice and cool to the touch. Bright light and blueish light can also disrupt melatonin production and sleep rhythm.

• Also remember that a computer, e-book reader, smartphone and TV screen is a light source in itself. Either don't let children use the computer late in the evening - if you want them to be able to sleep - or download a free colour adjusting app (e.g. the f.lux) which automatically dims down the screen at night and makes it more red so as to not inhibit melatonin by too much blue-white light at night. Orange goggles are another option.

• Prevent unnecessary electro-smog in children's rooms by avoiding wireless electronics as much as possible, always making sure any cell phones are used with headphones and switched off at night, and by not using electrical wires or magnetic AC-transformers near children's sleep area (especially near the head).

• Avoid DECT wireless home phones as they transmit microwave radiation like a cell phone base station 24/7 whether in use or not.

• And avoid scented products and toxic household chemicals as some might trigger light sensitivity and allergies.

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Lighting for Seniors

Optimal colour rendition and contrast is even more important for seniors as the eye's ability to distinguish colours and contrasts diminishes with age.

At the same time, the eye gets more sensitive to glare due to microscopic scratches on the cornea (like the scratches on an old car windshield scattering the light to produce more glare than a new windshield).

Recommendation:

• A bright clear light source, in a glare-free luminaire (light fitting), is ideal, e.g. a 75 or 100 watt frosted incandescent lamp. If not available, a frosted halogen combination lamp or a clear halogen Eco lightbulb is the second and third best choice.

• Avoid fluorescent tubes, CFLs and LEDs.

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Lighting for Light Sensitive Conditions

Highly sensitive people in general, people with light sensitive eye- or skin conditions in particular, and other patient groups, tend to tolerate the different types of light in this order (from best to worst, with some variation between patient groups and individuals):

1. Candles or oil lamps
2. Incandescent light
3. Halogen eco bulbs 
4. 12V halogen (glare, in some cases slightly higher UV)
4. Warm-white LEDs (spectral imbalance, glare, sometimes flicker)
5. Cool-white LEDs (spectral imbalance, blue light, glare, sometimes flicker)
7. Covered CFL bulbs (spiky spectrum, unclear light, HF flicker)
8. Naked CFL tubes (spiky spectrum, UV radiation, HF flicker)

Patient Groups at Risk from CFLs

Idiopathic photodermatoses:

• Actinic prurigo (3.3% of the population) may be worsened by CFLs.

• Chronic actinic dermatitis is a condition where a subject's skin becomes inflamed due to a reaction to sunlight or artificial light. There is evidence that CFLs worsen the condition.

• Solar urticaria (3.1% of the population), a skin disorder affected by ultraviolet light. Some patients are directly affected by CFLs. Severely affected may be at risk from CFL and unfiltered halogen, some also to incandescent lamps.

• Polymorphous light eruption (10-20% in Europe) is a condition affecting the skin thought to be caused by an adverse reaction to ultraviolet light. Artificial light sources may provoke the condition, and CFLs have been shown to produce an eruption.

Genophotodermatoses (250 000 people in Europe). Unfiltered CFL light could be associated with increased disease activity:

• Bloom syndrome is a rare autosomal recessive disorder characterized by short stature and predisposition to the development of cancer.

• Rothmund-Thomson syndrome is a rare autosomal recessive skin condition. There have been several reported cases associated with osteosarcoma.

• Xeroderma pigmentosum (XP) is an autosomal recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet (UV) light is deficient. In extreme cases, all exposure to sunlight must be avoided, no matter how small. Should to avoid all UVB/A light sources incl. CFLs, unfiltered halogen and possibly even incandescent lamps.

• Phytophotodermatitis (photosensitivity from certain plant chemicals) may be aggravated by the additional levels of ultraviolet light emitted by naked CFLs.

• The autoimmune disease Lupus (especially SLE) can be exacerbated from CFLs and unfiltered halogen lamps.

• Medication-induced photosensitivity (e.g. amiodarone, derivatives of phenothiazine & fluoroquinolone antibiotics). With photofrin, photosensitivity might be expected to occur with CFL and LED to a greater extent than with incandescent lighting.

• Patients undergoing photodynamic therapy are at additional risk of adverse photosensitive reactions caused by CFLs.

• Photophobia  5 to 20% of the population) is a symptom of excessive sensitivity to light may be affected by CFLs. No studies have been conducted into the effect of CFLs on sufferers of photophobia but there is the possibility for CFLs to affect sufferers.

• Cataracts can be caused by is exposure to ultraviolet light, such as naked CFLs close to the eyes.

• The inner-ear condition Ménière's disease can be aggravated by flicker. Sufferers of vertigo are recommended to not use fluorescent lights.

• Photosensitive epilepsy. There is evidence that flicker can cause seizures, but there has yet to be any evidence to date attributing seizures to CFLs.

• Migraine can be induced by flicker [and bright light].

• Dyslexia. Self-reporting suggests fluorescent lamps aggravate the condition.

• Autism spectrum, including Asperger's syndrome (self-reported). Deleterious effects on sufferers of autism or Asperger Syndrome from CFLs cannot be dismissed.

Sources: 
Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), “Health Effects of Artificial Light” (2012)
Fluorescent lamps and health (Wikipedia summary of 2008 SCENIHR report)
Health effects of CFLs, LEDs and halogen lamps (summary of both original and updated reports)

Potential LED Risks 

Risks related to blue light 

The photochemical risk is associated with blue light (high proportion of blue light in white LEDs) and depends on the accumulated dose as a result of low intensity exposure repeated over long periods. There is a high level of proof of such a risk.

Three groups especially at risk:

• Children (because of the transparency of their crystalline lens) and both aphakics (with no crystalline lens) and pseudophakics (with artificial crystalline lenses) who consequently either cannot or can only insufficiently filter short wavelengths (particularly blue light)

• Light-sensitive patients suffering from certain eye (e.g. age-related macular degeneration ARMD) and skin diseases, patients taking photosensitising substances, etc., for whom blue light may aggravate their condition.

• Workers highly exposed to LEDs (those installing lighting systems, theatre and film industry professionals, etc.) which are subjected to high-intensity lighting, and are therefore likely to be exposed to large quantities of blue light,
Risk related to glare

Because the emission surfaces of LEDs are highly concentrated point sources, the luminance of each individual source can be 1000 times higher than the discomfort level.

Source: French Agency for Food, Environmental and Occupational Health & Safety (ANSES), “Opinion in response to 'Health effects of lighting systems using light-emitting diodes (LEDs)'” (2010) 

Flicker

All lamps powered by alternating current flicker (turns on and off 100 times per second or more). Flicker has been associated with eye strain, headaches and fatigue. Some highly sensitive people can see flicker that is above the point where most people can no longer see it.

In incandescent and halogen incandescent lamps, the tungsten filament keeps glowing between pulses, creating a softer modulation than fluorescent lights and LEDs.

CFLs often have electronic ballasts which increase the flicker rate to 20 000 Hz or higher, which gives the impression of a more even light flow. But some sensitive people still report negative reactions to it.

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Lighting for Animals

• As animals often have much more sensitive senses than humans, flicker invisible to most humans may be perceived by pets as strobe lights! 

So, if you have pets, the most animal-friendly light is probably incandescent light. 

• If you have birds, avoid teflon coated Rough Service incandescent lamps. (Note: most Rough Service are not teflon coated.)  

Source: Teflon Coated Light Bulbs Deadly to Chickens

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Overview

Note: This table is only a very rough guide, based on available research. There may be big differences between individuals what types of light is best tolerated. 

Always consult your doctor if you have a serious UV-sensitive eye- or skin condition and use your own discrimination. 

For those who are just sensitive in general, try different lamps and trust your body. If it doesn't feel good, it probably isn't - for you.