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These days there are so many words flowing around that involve light therapy that people get confused! What do they all mean and what is the difference between them?

Photonics in the simplest form means the use of light to generate energy, detect or transmit information!  So photonics therapy is generally used to describe light therapy.  Any light.

Photobiomodulation or PBM is a flashy name to describe the form of light therapy that utilises non-ionizing light sources, including lasers, light emitting diodes, and/or broadband light, in the visible (400 – 700 nm) and near-infrared (700 – 1100 nm) spectrum.

  • Photo” means light.
  • “Bio” means life.
  • “Modulation” means a change in something.

So photobiomodulation is the use of light to cause a change in man or animal life.

One way that light travels is in waves, like sound. The wavelengths of light are measured in nanometers (nm). A nanometer is one billionth of a meter!  The wavelength of the light will determine what colour it is.

Violet Light – 380-450 nm
Blue Light – 450-495 nm
Green Light – 495-570 nm
Yellow Light – 570-590 nm
Orange Light – 590-620 nm
Red Light – 620-750 nm
(non visible) Infrared energy – 750 nm – 1200 nm

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Laser therapy is a specific form of PBM that utilises laser light to modulate biological processes. What makes laser light different is 3 unique properties:

  1. Monochramacity – one single wavelength
  2. Coherency – where all the waves are in one beam as opposed to scattered
  3. Together these provide targeted stimulated emissions 

The more monochromatic a light beam the longer the coherency and the deeper the penetration. Lasers are classified from level 1-4 with most red lights being equivalent to level 1 and level 4 being hazardous. Levels 2, 3B and 3R are commonly used by vets and therapists and we distribute the Spectravet lasers of these classifications.

Laser Therapy is not a thermal modality; in most applications, local tissue temperature will not rise more than 1-2°C. At its primary level, laser therapy depends upon the actual interaction between light and tissue, such as the absorption of photons by photoreceptive molecules (chromophores) at a sub-cellular level. These primary interactions create photochemical and photophysical reactions that lead to a cascade of biological processes.

By controlling for photon energy (wavelength), and the rate (power), quantity (time) and distribution (intensity) of that energy as it is delivered to the tissue, we can influence various photochemical and photophysical processes and the biological activities they support, and thereby tailor the resulting higher-level effects to produce desired clinical outcomes (

Equestricare is very excited to be able to offer our clients treatment with and/or purchase of the Spectravet Red which is a combination of laser diodes and red light diodes in one machine, delivering what we believe to be the utmost in pain relief and benefit to your horse.

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Red light is a specific wavelength (620nm – 700nm) that just happens to be red (as shown above). The most common wavelengths you will see are 630 nm (orange-red) and 660 nm (deep red) which roughly coincide with the absorption peaks of cytochrome c oxidase (the target of light therapy), plus they are cheaply available and efficient.

Red light is so popular because it is affordable, easy to use and effective.  Red light torches range from $90 – $1000 and vary more in their specs then you might think.  The most common lights on the market are the Aculight, Photonic Health Light, AAH Light and Advanced Photonic Therapy Torch.

We use and recommend the AAH light because it gives you the option of three settings. 100mw, 250mw and 500mw and you can also change the head colour to green or blue.

Photo source: eye

A lot of photobiomodulation therapy (PBMT) uses near near infrared light, which comes just after red on the spectrum, but it is invisible. Most common near infrared wavelengths used are 810, 830 and 850 nm. The key difference between red and infrared is that red wavelengths of light are absorbed and used in the first 25mm of skin tissue, whereas infrared light can penetrate much deeper into the body.  The AAH light PBM torch we sell has 660nm diodes and 810nm diodes (

The biggest difference between lasers vs light emitting diodes (LED’s) is that LEDs are of a visible wavelength and they are neither coherent or monochromatic resulting in spontaneous emission of light energy. 

But how does light affect biological processes? To put it simply, in the words of Heidi Richardson, the amplified light enters the tissues at the skin  and the photoreceptive cells (chromophores) there absorb the light and create a photochemical reaction in the tissue which creates a cascade of biological processes all aimed at restoring homeostasis to the body.

Strangely enough these photoreceptors are found to be more concentrated in areas of tissue that are traumatised, inflamed or diseased!! Cool hey

These processes include but are not limited to:

  • Increased ATP (Adenodine triphosphate)
  • Release of Nitric Oxide
  • Vasodilation
  • Phagocytosis 
  • Intercellular signalling

All of which together have been proven through scientific research to stimulate healing, reduce inflammation, provide pain relief, reduce oedma, increase collagen alignment, decrease oxidative stress, regenerate neural tissue, promote would healing and tissue repair.

When used on the acupoints, certain wavelengths of light have been proven to trigger the response of that acupoint.

If you are more interested in reading the research behind light therapy check out these articles here;

Author Jessica Blackwell

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