This is the most versatile form of light therapy, has been used not only for skin but ailments elsewhere, even the ears and head. It is non-invasive (skin is not pierced) and non-ablative (tissue is not burnt). Ultra low level light therapy (ULLLT) should be treated as part of low level light therapy (LLLT). In either case light of different colors is used to cure various disorders.

 

Laser therapy is ablative (can burn tissue), and more in the nature of surgery.  It is not really light therapy. The acronym LASER stands for Light Amplification Using Stimulated Emission of Radiation. The theory of laser is rather complex for this platform. What results is a narrow beam of intense monochromatic light. Monochromatic means all energy is at a single wavelength. Light composed of many wavelengths like daylight spreads because different wavelengths tend to bend differently when travelling through a practical medium like air. The advantage of monochromatic light is that all energy goes straight or bends together. Once collimated (made into a parallel beam), it does not spread. Thus the energy density can be very high even though the total power be in milliwatts.  Because of this concentration of light energy it can burn target tissue. Do you recall the school-days pastime of focusing sunlight onto a piece of paper and setting it afire? Laser is used for military, scientific, and medical purposes.

 

Color therapy does not really depend on levels of light. Rather, it has a psychological effect, and hence will be most effective on mood disorders.

 

The term chromotherapy has been applied to both color therapy, and to low level light therapy. Only context will tell what type of therapy we are talking about. ‘Chrom-‘means color, and therapy means cure or treatment. Hence the word chromotherapy can be used to describe healing with the help of colors. Normally colored lights are used, as direct radiation, or through irradiated liquids like water, to cause the desired healing effect. Yellow is one of the seven natural colors in the rainbow, and hence, use of yellow light therapy to heal is a part of chromotherapy.  That way red light therapy would also be a close kin of yellow light therapy, and both would be branches of chromotherapy.  Chromotherapy, uses selected colors of light to produce various healing effects on human body, while a general use of light as a healing medium would be called phtotherapy. Please recall that ambient light affects ones state of mind, other than through the skin. For light effect through the skin alone, multiple “pathways” have been described. The subsequent discussion will be mainly confined to LLLT.

 

Is It Really a Therapy?

 

Modern medical science, with its observable success in most areas of treatment especially surgery, has somehow overshadowed the various healing practices of the past. Further, by chance or by design, practitioners of modern medicine, being in favor with the powers that be, have relegated the older healing practices to the status of ‘arts’, or even, baseless myth. That is where they have gone wrong, and may be doing grave harm to humanity by cutting out on a large base of useful knowledge which if filtered and developed, could not only supplement modern medical practices, but in certain areas, even better them.

 

Their main objection against these ancient healing practices is that there is no logical explanation for its working. I would rather say that there is no reason to deny the presence of logic in these ancient practices. The truth is that we do not understand it yet, and unfortunately, some of us at the helm of affairs in the health field seem to have decided not even to try. I ask the reader as an impartial judge: How many of us know how our digestive system works?  Or how many of us know how our hearing works? How do we give meaning to a pressure wave that hits our ear drums? Does it mean that those who don’t know their digestive systems do not work? Or they cannot hear?  The fact is: absence of understanding of a thing or a phenomenon does not mean it does not exist. There is a very serious flaw in the thinking of some people who profess to be “scientific”. They do not believe in what they cannot explain or measure.

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Hysenberg’s Uncertainty Principle

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People forget Hysenberg’s Uncertainty Principle taught at school these days. In simple words it says: you (son of Adam) cannot measure anything completely and accurately.  All my scientific minded friends have studied this law and believe in it, may be more than they do in the Bible and Quran. Yet they do not seem to have derived a lesson from it. The Uncertainty Principle implies that we do not know everything that exists. We cannot explain everything. Is it wise to deny those things we cannot explain? That is a mistake a section of humanity has always committed. Unfortunate people even denied presence of God because they could not see him or feel him.

 

Daily Observations

 

Do you feel happy when something happens according to your wish? Do you feel sad when things do not go according to your wish? Do you enjoy the smell of a flower, the taste of fruit and food, the sight of a beautiful child? Do you feel sad when your spouse is about to travel abroad without you? Do you feel better when you know of his / her return plans?

 

Why do we call a cloudy, cold, dark and damp evening a gloomy evening? Why a sunny day is called a bright day? That is because one depresses your mood, while the other elevates it, and stimulates you.  Why does the presence of some people electrify you while you just cannot stand some other people? 

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The fact is that humans, and to some extent, all living beings get affected by stimuli external to themselves. Some will sooth you, stimulate you, and electrify you into action. Others will depress you, deject you, may even make you sick.

 

Five Senses and More

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It is said that humans have five physical senses. We can smell with our noses; we can see with our eyes; we can taste with our tongues; we can hear with our ears; and we can feel with our skin. When you bump your head accidentally into something, does your hand not go automatically to your head to massage or rub that place?  That is touch therapy. You massage that area lightly, and it causes at least two effects. The sensation of touch causes a feeling which overrides or detracts from the pain.  Secondly, the stimulation of the skin by the touch causes more blood to flow and take whatever corrective action nature has taught your body to take.  Of course, a harder massage also helps by promoting blood flow further. How do you pacify an annoyed baby? Quite often by a candy or lollypop in his mouth! You are treating the baby through its sense of taste. (Of course the lollypop also has the physical capacity to shut an open mouth!).  Similarly, people listen to slow music to relax, and fast music to stimulate them.  That is music therapy. So why should not light therapy, and within that, red light therapy work.

 

How Does Light Therapy Work?

 

How does it exactly work? No one knows for sure, and no one can ever know for sure. But there are un-understood issues even in physical phenomena which are much more measurable and much more deterministic. We have seen established physical theories crumble under the evidence of new discoveries. Hence, no one can give a final verdict on whether, and how exactly, light therapy including yellow light therapy works. We shall try to make a simple understandable explanation which we may expand on later, or even modify.  Please note that human knowledge improves.  Such things have happened in science before. Do you recall the discussion about whether light was wave or particle? Currently scientists believe it is both, adopting one form according to circumstances. So the bottom line is human knowledge is limited. Many things exist which we do not know about, or if we know about them cannot explain them.

 

That much for those friends who insist on seeking an explanation of everything! And now we try to make simple explanation.

 

A Simple Explanation

 

One of the simplest explanations is that light (of all colors) gives its photons to mitochondria in the skin cells which generate additional adenosine triphosphate (ATP). Formation of ATP can be compared with storage of energy in the electrical battery. Creation of ATP is like adding charging an already charged or partially charged battery. This energy is readily available for use.  Availability of energy raises vitality and the system is better able to fight against disease. The list of conditions for which light therapy is being utilized or explored is long and expanding. At some later stage I will try to give a list of such conditions for which light therapy has shown utility. For the time being, it is sufficient to say that light therapy is being used for a very wide range of ailments through a number of helpful mechanisms. Apart from treatment of skin conditions, there are reports about treatment of tinnitus (ringing in the ear), mental and psychological conditions, as well as many other unconnected areas. We reproduce an extract of a paper converted to simple language  which shows how the biological systems are ‘let loose’ to cure the body:

 

‘Light therapy of tissue causes an increase in mitochondrial outputs such as ATP, NADH, protein, and RNA-83 (Wait till I explain these! For the time being, these are beneficial biological products), produces Reactive Oxygen Species (Again wait!), and resultantly, enhanced oxygen consumption (with obvious benefits). Cellular respiration is up-regulated (brought to a higher level) when mitochondria are exposed to illumination.’

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When the system is activated, it better able to fight the disease whether from inside or outside.

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Is our system intelligent enough to fight disease?

 

Yes, it is. We recover from minor ailment before we have reacted to them. Our skin starts repairing itself the moment it gets cut. When doctors cannot identify the problem underlying your disease they give you multivitamins. Multivitamins, as the name suggests, simply vitalize the body systems thus enabling the body to better diagnose and repair itself. There are innumerable actions which our system takes on its own. Medical science is still learning.

 

So having decided that light therapy is not a hoax, and a having got a feeling of how it works, we now try to build up understanding of why do different colors act differently.  But before that it is useful to have a look at the light spectrum and identify wavelengths representing different colors.

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The Spectrum

 

The violet and blue colors, often referred to as ‘blue’ in technical jargon, cover the bands of 380–450 nm and 450–495 nm respectively. Green, the center color of the spectrum extends from 495 to 570 nm. Yellow light covers the narrow band of wavelengths from 570 to 590 nm. Almost equally narrow is the adjacent orange band from 590nm to 620 nm. The red band and the, the widest and the most employed, extends from 620nm to 750nm. Please see table

 

Table 1: Colors corresponding to different wavelengths in visible light

 

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Do different colors have different effects?

 

There are three important parameters which matter to effectiveness of light in a given situation:

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• Location of Target Cells: How deep in the skin are the target cells located? Certain applications may need superficial irradiance, while others may need the energy to penetrate deeper. A discussion of this parameter will come later wherever needed.

• Penetrating wavelengths: What wavelengths (colors) will penetrate to that depth with sufficient energy, without damaging the superficial flesh with the absorbed energy? We will talk about light penetration and absorption by different types of cells in the skin.

• Wavelength Selection by Cells: Do human cells have any preferences for absorbing different colors of light?

 

For the time being, please note that it is the combination of these three factors that should decide what color will suit what purpose.

 

Penetration

 

The skin is not a uniform layer. It consists of many different types of cells, and their proportion also varies from the surface downwards, and from person to person.  As it is, in normal skin,  near infrared (invisible heat rays) and red light, both having longer wavelengths (lower frequencies) pass through the skin deepest, while blue, indigo, and violet, having the highest frequencies and shortest wavelengths) are attenuated more, getting blocked rather superficially.  Then it becomes logical that cells located deeper in the skin e.g., those in the sabaceous glands should need red or near infrared light to treat. Blue light is not going to reach them. On the other hand, acne needs superficial treatment. Accordingly, blue light in the range 420nm to 450 nm (actually violet region) is a popular choice for treatment of acne.

 

What is a nanometer (nm)? One meter (m) contains 1000 millimeter (mm). One mm contains 1000 micro meter (μm). Thus a μm is a millionth of a meter. A nanometer (nm) is further 1000th of a μm. The wavelength of visible light is measured in nm. For a comparison, the width of a human hair varies from 30 μm to 100 μm. So you can see that light waves have very fine wavelengths.

 

This general trend of gradually decreasing absorption with increasing wavelength is ‘modulated’ by the tendency of certain types of cells to preferentially absorb certain wavelengths.  

 

It would be useful to keep in front of you the scholarly work : Barun V. V;  “Absorption spectra and penetration depth of  normal and pathologically altered  human skin” published in Journal of Applied Spectroscopy, March 2007, and also archived at Researchgate as item 225598882. It appears from diagram 1 of the paper (Similar figures are also available in many papers on the internet. Just search for terms ”skin”, “light”, and “penetration” ) that two peaks of absorption in the skin occur due to hemoglobin components of two types (oxyhemoglobin, and de-oxyhemoglobin)- a narrow one at around 420 nm and a broader one up to about  590 nm of wavelength. Between these two peaks the absorption decreases somewhat at about 470-490 nm (near green end of the blue region of visible spectrum). This creates a minor window of transmission which is sometimes used for blue light therapy. But the region of real utility is beyond 590 nm (orange end of the yellow color region), where there is a sharp fall in attenuation with increasing wavelength. This window of penetration covers the red, and part of the infrared regions with good penetration. Commercial devices normally operate between 630nm and 660nm in the red band, as do most of the research devices. However, researchers keep exploring from about 390nm to 1100 nm avoiding, of course, the two absorption peaks mentioned above. Not shown in the referred diagram is the water absorption curve which starts rising beyond about 1000nm. Thus the window really closes at about 1000 nm, covering mostly the red color in the visible range, and the infrared in the invisible range.

 

So which color to use?

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Now consider for a moment. Yellow, orange and red are three neighboring colors in the same sequence. Skin absorption has a peak at the yellow color, but the absorption decreases at a very fast rate as we move from the peak absorption at yellow towards higher wavelengths (orange and red). Here is how we interpret it:

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• Lower wavelengths of yellow light energy are absorbed, mostly by the hemoglobin. This energy has limited use for treating underlying tissue.

• Surface absorption is less at the orange end of the yellow band, reducing very fast (light traveling deeper) as we increase the wavelength through orange and red colors. Red light travels the deepest of all among the visible colors. Edge of the yellow band, and the orange band, open a window of penetration in the visible spectrum.

• The window extends through the red color into the infrared (invisible, heat, wavelength >750 nm) till about 1000 nm. Beyond that absorption by water molecules starts increasing.  That is the upper end of the window.

 

Why a heat wave is called infrared (below red) when its wavelength is larger than that of red? The reason is that higher wavelength means lower frequency. Heat waves have a frequency lower than visible red. The infra- and ultra- prefixes are with reference to the radiation frequency. Ultraviolet energy has a frequency higher than the visible violet color.

 

Hence, the real color for light therapy is red (and infrared as an extension) for deeper effects, and blue and violet for superficial treatments.

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Location of Cells- Depth Profile of Skin

 

Do you know that your skin is the largest organ your body? Most diseases, some fatal, relate to skin. Fortunately, while light therapy cannot affect deeper malaise directly, it can certainly affect skin diseases. The skin has multiple known functions: sensation of touch, heat and cold; regulation of body temperature through perspiration; and protection to all other organs from non-oral infection and the elements. The skin is normally divided into three main layers:

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• The Epidermis: (epi- for surface, and dermia for skin). Epidermis is the uppermost layer of skin. It consists mainly of keratinocytes (about 90 to 95 %,), and melanocytes, which form the balance 5 to 10 % along with some Merkel cells, and Langerharn cells. It provides the following functions:

  • It is a waterproof barrier. 

  • It has the ability to repair itself.

  • It protects against invasion by external organisms; and conserves body water, except through controlled sweating.

  • It creation of our skin tone. Skin color is created by the melanocytes.

  • Melanocytes produce the pigment (color) melanin which is responsible for protecting you against the ultraviolet radiation from the sun. Absorption by melanin is highest at the ultraviolet end, and lowest at the red end in the visible bands.

  • It maintains body temperature by controlled sweating.

 

The epidermis is a layered structure. (Experts define seven layers in the epidermis itself). The basal (bottom-most) layer is always creating new cells by cell division. Most of the new cells are pushed up to the surface. On the way up they keep producing a material called keratin and keep gradually dying at the same time. This process is very gradual and may take one to two months. By the time they reach the surface they are virtually flat sacs of keratin, and are called keratinocytes. At the surface they are like a border security force, protecting the body against external invasion. They do this by producing pro inflammatory mediators to attract leukocytes to the site who are the real fighters.  Keratinocytes gradually shed off to get replaced by new cells. The keratinocytes also help in wound repair by filling up the gap.

 

• The Dermis: It is the middle layer and lies immediately beneath the epidermis. It contains the following:

  • Connective tissue -which binds together the other stuff in the skin.

  • Elastic fibers – they provide the skin its stretch and resilience.

  • Capillaries – or tiny blood vessels for blood supply.

  • Hair erector muscles - control the position of hairs.

  • Sensory cells – to sense heat and cold; pain, touch, and pressure.

  • Nerve fibers – control the muscles and glands, and sensory messages.

  • Pigment cells- which are source of melanin.

  • Sweat glands-whose upper ends form the pores for sweat.

  • Hair follicles – holes in epidermis which grow hairs.

  • Sebaceous glands – they produce oil to keep hair follicles free of dust and bacteria. Together with keratinocytes they make the skin waterproof.

 

• The Hypodermis or the Subcutaneous tissue:  This is the deepest layer of skin and comprises mostly of connective tissue and fat. The fatty layer can provide insulation to the body, and is a source of energy when deficiency of nutrition occurs.

 

Wavelength Selectivity

 

Why the Windows of Transmission and Absorption?

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Suppose you are visiting a beach. An advertising team of a dressmaking company comes by and offers dresses as free gifts. Would you accept a dress of any size offered by them? Or would you rather check if they have a dress of your size? Obviously, you can only utilize a dress of your own size. That is more or less like what happens when light energy is provided to the skin.  Cells in the epidermis, the dermis, and the subcutaneous layer, all can either absorb light or pass it. The absorption coefficient (fraction absorbed), and transmission coefficient (fraction transmitted) depend on the wavelength and nature of component particles. That is why you see absorption peaks for hemoglobin at wavelengths below about 600 nm.

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But the example ends here. It is not that the size of the wave must fit the size of the absorbing particle. Rather, the particles are selective about what ‘quanta’ of energy (amount of energy) they will accept. The amount of energy possessed by a photon of a wave depends on the wavelength. Hence, the particles are selective in absorbing energy of a given color (or wavelength). Why are they selective at all? That is because of the available energy levels in the atoms of the material. Hemoglobin absorbs energy in wavelengths extending from 400 nm to about 590 nm. The absorption decreases sharply beyond 590 nm. That is the reason for the transmission windows. You can see that blue light (actually in the range of violet light) is used for treatment of disorders which have a surface nature, like acne vulgaris. For ailments associated with cells deeper below, and for general stimulation, ant-aging, etc., the deeper penetrating wavelengths of yellow, orange, red, and infrared, within the transmission window are preferred, the last two (red and infrared) being most popular.

 

Multiple Wavelength Treatment

 

In exploring the potential of light therapy for various disorders, of the skin and elsewhere, researchers have often resorted to combination of multiple wavelengths. In all successful experiments, the red light (and near infrared) is most often present. The other light is often, blue. The red light is more effective because of deeper penetration, and the blue will often be added for its antibacterial and antifungal effect in skin diseases.

 

The Yellow Light

 

The yellow light sits on the orange end of the penetration window. Part of the yellow spectrum is absorbed superficially by the skin and part is transmitted with relatively high attenuation. Thus, it has properties and hence, uses which resemble both the red, and the blue colors, that is, it has some utility for superficial applications and some for deeper effects. It is an in between color. Instead of using yellow light to obtain doubtful dual effects, medical personnel prefer to use a two, or even, three color treatment, mostly, a combination of red/infrared and blue (technically violet).

 

Dosage

 

Before discussing dosage, it is useful to explain a few related terms.

 

Irradiance or Power Density

 

Having discussed the color choices we come to the all-important matter of dosage. The source, eg, LED lamp, emits power in watts (more often, in milli watt) at the design frequency (wavelength). That is the power of the source. The emitted light has a beam pattern which spreads (very little for collimated laser light), but more for non-coherent, non-focused light. Power illuminating the target skin spreads over a surface area. The power incident per unit area is called Power (surface) Density, or Power Density. The standard unit for power density is w/m2, (watt per sq. meter), but power levels used in light therapy are often described more meaningfully in mw/cm2. Physicists tend to call it irradiance.

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Fluence or Dose

 

Now irradiance has a cumulative effect over time. When irradiance of this level falls on a target area for a given time, the target receives a dose of energy. One watt/ m2 falling for one second makes one Joule/m2. Fluence or Dose is measured in Joules/m2, or J/cm2.

 

Fluence (Dose) = Irradiance x Time

                       

J/m2                 =   W/m2       x    sec     (Watt= Joule / sec)

 

 

A power of  100 mw / cm2 for 2 min (120 s) gives a dose of 100 x 120 = 12000 mJ/cm2, or12J/cm2.

 

 

Arndt-Schulz Rule

 

This is a rather commonsense rule. It was basically stated for harmful drugs. What it says is that very small quantities of harmful drugs will have a positive effect. More will have more beneficial effect, but beyond a certain limit it will do harm. Why should a poison benefit you (albeit in small quantities)? That is understandable. Human system reacts to external influences, and puts up a very intelligent defense thus curing itself of disease that would be caused by the poison. Incidentally, that is the principle of homeopathic medicine.  It was stated in 19th century by Hugo Schulz and Rudolf Arndt. According to them, weak stimuli accelerate physiologic activity, medium stimuli inhibit physiologic activity, and strong stimuli halt physiologic activity. The rule is now said to be out of favor with medical profession, reportedly because it does not specify what is weak, medium, and strong. But thinking open-mindedly, this does not detract from the general truth of the rule. The only thing to remember is that the “weak”, “medium”, and “strong”, varies from person to person. Do you recall that a medicine doze is often specified in milligram per body weight? As medical professionals admit themselves, one’s defensive strength changes even from moment to moment depending on the circumstances.

 

The Safe Doze

 

The Arndt-Schulz rule applies to light therapy dose also. Here, it is called Biphasic Dose response, or more Hormesis. Low doses will stimulate, and too high a doze, may do harm if not burn the skin outright. This understanding has resulted in practitioners going for low powers, calling it Low Level Light Therapy (LLLT), or going even lower, Ultra Low Level Therapy (ULLLT). Experimental radiation levels as low as of 100 μW/ cm2 have been quoted in the literature to produce noticeable results. Dose levels of a few joules / cm2 are popular. Note, however, that every individual, in a given state of health, has his or her own levels of “low”, “medium”, or “strong”.

 

The World Association of Laser Therapy (WALT) had made some recommendations for minimum and maximum doses of laser therapy for certain ailments. A glance at those shows that they discourage irradiance (power density) of more than 100 mW / m2. Most often, they have specified a minimum dose which comes out to be 1 to 2 J/cm2, whether pulsed or continuous. (More on this later). Their recommendations are specific to near infrared (NIR) wavelengths 860 and 904 nm. But it can be taken as a guide line for visible light therapy also if we operate in the window of transmission discussed above.

 

The actual dosage will depend somewhat on:

  

• The type of disease you are treating,

• The color of light you are using,

• Whether it is pulsed or continuous, and also on

• The duty ratio of a pulsed system.

• To complicate things further, skin over some parts of the body may be more sensitive than in others.

 

Duty ratio in a pulsed system is the fraction of time the source is transmitting. For example, if a source is ON for 4 ms and then OFF for 6 ms, (and the cycle repeats), the source is transmitting for 4ms out of every 4+6, or 10ms. The duty ratio is 4 out of 10, or 0.4, or 40%. (As if the source is on duty for 40% of the time!). The average power of a pulsed source is the transmitted power during the ON period multiplied by the duty ratio.

 

It is always best to seek expert advice. However, as a general guideline:

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• Follow the instructions of the equipment supplier but subject to medical advice.

• If you feel uncomfortable immediately stop the exposure and give things time to settle.

• Reduce the irradiance level before resuming

• The red light and IR light will normally exhibit a self-warning capability. They can cause a local feeling of discomfort or burning when things become excessive. Below that level, red light will generally stimulate.

 

The Lower Limit

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The Arndt-Schulz rule is stated variously. The above statement did not mention a lower threshold for effectiveness. The fact is that a stimulus below a threshold level may not produce any observable effect.

 

The threshold phenomenon is built into humans. Imagine a person calling you and approaching you. If the person is far away you do not notice him. Although the sound energy reaching you is increasing all the time as he is approaching you, you do not notice it. Then suddenly you notice it and may also feel it growing louder. The change comes when his sound energy just exceeds your hearing threshold. One of the reasons people feel healthy from “this morning” is that at some time during the previous night they crossed the threshold of well-being, but noticed it only “this morning”. The threshold phenomenon enters human relations also. You may except misbehavior by a colleague up to an extent, and then show your indignation. That is your “tolerance threshold”.  

 

Limitation on Power Density

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The upper limit on power density (eg,100 mW/cm2) is understandable. Human tissue will not absorb and spread the power evenly in quick time. If you pump too much power the area under irradiance may be overloaded, and even damaged. Laser treatments use this phenomenon for destroying target structures in the skin.

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Pulsed Operation and Intense Pulse Light Therapy

 

Various irradiation regimes are being studied with good results. Although World Association of Light Therapy does not differentiate between pulsed and continuous operation (they simply specify the total dose) researchers have studied pulsed operation in many different ways. The main consideration here is that the subject flesh has a ‘relaxation time’, i.e., the time interval in which it can absorb and utilize most of the energy pulse it has received. The pulse interval must respect that. Further, if the strength and the length of the pulse are high too much energy may be concentrated in the irradiated tissue during the pulse, and damage may result even if the average is within acceptable limits. It is something like feeding a person three doses of medicine at once, and then, may be, skipping the next two doses. That may be overdose. An extra long pulse will be like an overdose, particularly if the pulse strength is also high.

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There are equipment on the market which supply high irradiation initially, and then settle down to a lower level. The logic here is that an initial ‘shock’ will jolt the system into reaction, and the subsequent irradiation will be well utilized.

 

Light Therapy- What it will do?

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What will light therapy treat? It will treat virtually anything, and treat it non-invasively. However, it is more specialized in skin diseases for reasons explained earlier. In a nutshell, light therapy, especially low level light therapy stimulates the irradiated flesh. Hence, it will be beneficial in almost all ailments, especially those relating to skin. Light therapy is widely used in treating acne vulgaris, eczema, neonatal jaundice, and psoriasis, in addition to many others. While blue (being near to the bactericidal ultraviolet light) is used for certain skin infections, red light therapy has a very wide and general accelerating effect on health processes.

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Bright light therapy (affecting mainly through the eyes), is used for treatment of Circadian Rhythm Disorders such as delayed sleep disorder.  It is also a popular treatment for  Seasonal Affective Disorder (SAD), and has been recommended for non-seasonal psychiatric disorders also. It is useful in mitigating effects of jetlag also.

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The use of Low level light therapy for wound healing has been well documented with a plausible explanation for the role in the healing mechanism. High power lasers can also be used to close cuts instead of stitching.

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Neonatal jaundice is a very common disorder for newborns. Blue-green light in the range 460-490 nm is useful for this disorder.

 

The list of disorders treated by red light therapy is very long and still growing. Understandably, light therapy, of which red light therapy is most effective, will be more effective against disorders of the skin, even skin cancer.

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Chronic Skin Conditions

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Chronic skin conditions are not considered curable by mainstream medicine. They only try to manage these problems through drugs and hygiene. However, light therapy has been shown to help in these disorders.

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• Acne- Most effectively treated with blue or violet light for its high energy. Red light is also useful.

• Eczema- Popular treatment is Ultraviolet A, or blue light.  Red light will also add a healthy effect

• Psoriasis, and Rosacea can be treated with intense pulse light therapy, or low level red light therapy.

• Vitiligo is loss of pigment in patches of the skin probably due to an auto immune process destroying pigment. Narrowband UVB light therapy can help re-pigmentation. However, extended treatment is required.

 

Final note:

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Light therapy is real and useful. Most beneficial range is the red light because of its general stimulatory action and deeper penetration. Blue light, with less of penetration, but shorter wavelength has properties similar to ultraviolet, that is, it is useful against microbes causing skin infections.  If single color is to be used, it is red light, more or less like a panacea. The alternative could be infrared, but that may have its distinctive problems.

 

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Alex Hankey and Elena Ewing,

New Light on Chromotherapy: Grakov's ‘Virtual Scanning’ System of Medical Assessment and Treatment, Evid Based Complement Alternat Med. 2007 Jun; 4(2): 139–144, Published online 2006 Oct 5. doi:  10.1093/ecam/nel060

PMCID: PMC1876617

Pinar Avci, MD, et. al. ; Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring;  Semin Cutan Med Surg. 2013 Mar; 32(1): 41–52; PMCID: PMC4126803

Weiss RA1, Weiss MA, Geronemus RG, McDaniel DH.

A novel non-thermal non-ablative full panel LED photomodulation device for reversal of photoaging: digital microscopic and clinical results in various skin types; J Drugs Dermatol. 2004 Nov-Dec;3(6):605-10; PMID: 15624743

 

Daniel barolet, MD; Light emitting Diodes (LEDs) in Dermatology, Semin Cutan Med Surg.

American Academy of Dermatology, Colored light sources lighting the way for new office- and home-based skin devices,  News item dated 15 march 2011

Hoon Chung,,et al; The Nuts and Bolts of Low-level Laser (Light) Therapy; Ann Biomed Eng. 2012 Feb; 40(2): 516–533;  Published online 2011 Nov 2. doi:  10.1007/s10439-011-0454-7;  PMC3288797

Bartos A1, Grondin Y1, Bortoni ME1, Ghelfi E1, Sepulveda R1, Carroll J2, Rogers RA3. Pre-conditioning with near infrared photobiomodulation reduces inflammatory cytokines and markers of oxidative stress in cochlear hair cells, J Biophotonics. 2016 Jan 21.