David is a chartered scientist and has a doctorate in human post fracture bone healing from the University of Salford. He has a degree is physics, chemisty and education and also has avionic and electronic engineering qualifactions from the Royal Air Force. He is internationally recognised for his involvement in electrotherapy and has lectured at conferences around the world and on the University of Nottingham School of Veterinary Medicine and Science Veterinary Physiotherapy course. He has to-date now published three books on related subjects.
What is Light Therapy?
Light therapy, better known as phototherapy, uses LEDs singularly or in a cluster or sometimes in a cluster surrounding a small Laser emitter. LEDs can be made to produce light at any colour by doping the silicon used in their construction. The colours produced are very pure.
What does red light do?
Red light at around 630nm has, from research, been shown to cause a cyclooxygenase reaction within tissue cells exposed to it. This reaction produces nitrous oxide to be released locally causing the opening up of small blood vessels increasing blood flow to the area. Another reaction is to inhibit the release of prostenoids such as prostaglandin that stimulates pain receptors, again locally reducing pain perception.
What does blue light do?
Blue light emitters produce higher energy wavelengths that are antibacterial and ideal for use around open wounds and lesions.
How deep does the light penetrate?
The depth to which the light reaches in tissue is very superficial and dependant upon colour. Blue light has a higher frequency and very poor tissue penetration. It is scattered very superficially at the surface hence its higher energy is absorbed by surface borne bacteria killing them. Red light penetrates through the dermis to the sub dermal layers stimulating epithelial tissue to help reduce scar tissue. Infrared wavelengths carry the lowest energy but penetrate the deepest but is still relatively superficial to between 1 cm and 2 cm to 1% intensities to that applied at the surface. Pulsing is believed to increase efficacy in both stimulation and in reducing tissue turbidity.
How long should the LED be applied for?
Power levels affect timing of application. Around 3 joules per square cm is an accepted level under ideal conditions.
What are ‘ideal conditions’?
Ideal conditions are where access to skin is unimpeded by hair.
What is the difference between true lasers and LEDs?
LEDs in the form of true lasers share the same characteristics as straight forward emitters. They provide a greater spot density but over a very small area. the laser beam scatters the instant it enters tissue and so does not really have any advantages over LEDs at the same frequencies.
CAM Georgie White has previously discussed the evidence for the success of LED therapy and her conversation on this can be found here: https://www.caninearthritis.co.uk/cam-conversation-with-cam-georgie-white-about-light-emitting-diode-therapy/