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There is more to lighting than meets the eye

Les Kacev is passionate about lighting education, measurement and the quality of light. He has run seminars, workshops and webinars for utilities, associations, universities, LED manufacturers, vendors, distributors, and conferences. A few examples follow

The human eye is truly our window to the world. Not only does it contain rods and cones which stimulate our vision, but it has recently been discovered that the eye contains a variety of intrinsically photosensitive retinal ganglion cells known as ipRGC which are involved in non-visual functions. Light and light quality play an immensely important role in stimulation of ipRGCs and in so doing determine our mood, sleep patterns, productivity, health and  general wellbeing. Light exposure plays an important part in our mental health.

Not only does light [natural and artificial] affect humans, but its impact on fauna and flora is only now being appreciated. Its influence on mammals, birds, bats, insects, fish and plant life has opened up a new branch of science.

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Introduction

The human eye is truly our window to the world. Not only does it contain rods and cones which stimulate our vision, but it has recently been discovered that the eye contains a variety of intrinsically photosensitive retinal ganglion cells known as ipRGCs which are involved in non-visual functions. Light and light quality play an immensely important role in stimulation of ipRGCs and in so doing determine our mood, sleep patterns, productivity, health and  general wellbeing. Light exposure plays an important part in our mental health.

CIRCADIAN SYSTEM

Light is in large part responsible for setting our body clocks and keeping us in sync with nature and the day night cycle. Exposure to light affects our circadian rhythms by stimulating or blocking the production of Melatonin and other hormones in our system. This is a complex process which is determined by many parameters such as color temperature and spectrum. Much research has been done, and there is much more to do. The advent of solid state lighting with its vast differences in characteristics and the ability to supply or “tune” lights to set specifications has opened up a new world to lighting professionals and their awareness of the principles of human centric lighting.

SEASONAL AFFECTIVE DISORDER [SAD], MOOD, DEPRESSION

It was found that people living in colder, darker climates were in general more susceptible to SAD and other mood related issues than people living in warmer climates with better natural light distributions. Starting around half a century ago, scientists pioneered treatment plans for SAD patients using light. Great strides have been made, but research in this field is ongoing.

What color temperature is best? At what intensity? For how long? How does the spectral power distribution play its part?

SLEEP

Before humans produced artificial light sources, we were awake during the day and slept at night. A purely natural phenomenon. But now we get exposed to all kinds of artificial light with different specification both during the day and at night. Some we can plan, like lighting within our own homes, and how and when we watch TV and work on our computers, smartphones and tablets. We have little control over the effects of street lighting, lighting in stores, parking lot lighting, etc., which may drastically alter our sleep patterns. Lack of sleep is a prime causation for poor work performance, loss of concentration, mood swings and other psychological disorders. In fact the symptoms of sleep deprivation are often confused with ADHD.

LIGHTING FOR SCHOOLS, UNIVERSITIES AND HOSPITALS

Hospitals that have introduced LED lighting in patient areas have discovered how important human centric lighting principles need to be understood and applied. Many hospitals introduced solid state lighting to reduce their utility bills. Some employed competent designers, whereas others ignored research and installed energy saving lamps with no regard to light quality. The demand for sleeping tablets sky-rocketed and doctors and nursing staff complained that their ability to work efficiently was curtailed.

It has been found that “tuning” lights during the daylight and evening hours can greatly improve concentration, productivity, motivation and mood. Further, alertness can be stimulated by changing color temperature rather than using caffeine or other drugs.

HEALTH

Can general wellbeing and specific diseases be treated and/or avoided by carefully planning lighting exposure. More research is needed, but current studies point to the fact that light can play a major role in health. Scientific research has shown:

  • Exposure to sunlight for 20 minutes in the early morning and late afternoon when it is less intense can improve natural production of vitamin E without fear of causing skin cancer.
  • Breast cancer cells have been shown to be light sensitive leading to research into prevention and treatment using natural sunlight and artificial clones.
  • Alzheimer’s researchers have had positive results stemming the onslaught of this mentally incapacitating disease using light therapy.
  • Light therapy has successfully been implemented to reduce or eliminate jet-lag.
  • The amount of light exposure that a pregnant women gets may affect her child’s IQ, need for spectacles and other health issues.
  • Light exposure can reduce face wrinkles, prevent suicide attempts, alleviate pain and reduce the incidence of cancer.