Not all Light is Equal - Laser vs. LED

Laser Therapy Surpasses LED Therapy

Not all light is the same, and not all monochromatic light can provide the same medicinal benefit. Substantial controversy exists in the field of low level power laser therapy over the values of true laser light when contrasted with lesser proven therapeutic values of LED’s (Light Emitting Diodes).
The two forms of light, laser light and light from LED’s, should be scientifically compared to show the completely different biological effects of each, particularly where a number of medical devices are available with LED’s and super luminescent LED’s (SLLED’s) as light emitting components. LED’s and SLLED’s are frequently falsely advertised and promoted as lasers when they are not lasers. A meaningful comparison of benefits requires clarification.
Literally hundreds of reported clinical and scientific studies and papers on the subject of light therapy are available. Almost all these studies involved laser light, exclusively, as the light source that provided the reported medically benefit. However, the clinical and scientific sources and references listed on the web sites for leading LED light devices are not from the use of LED therapy, they are from the use of laser therapy. Manufacturers of LED devices such as Bioflex, Anodyne and the Dynatron Solaris units (clearly all LED therapy devices), primarily use laser light studies to justify their advertised claims of LED medical efficacy.

A number of independent studies compare the effectiveness of laser light to LED light. The majority of those studies prove that laser light is far more effective than LED light, particularly when treating tissue at any significant depth. Although LED light therapy has some undeniable beneficial effect, that effect is actually rather limited to certain superficial tissue treatment.

Authors of most leading and widely used laser therapy textbooks unanimously opine that there are significant differences between laser light and LED light, differences that prove the biostimulative effects of each of the devices are far from equal. The clear consensus is that laser light (LLLT) achieves greater and deeper stimulative and therapeutically beneficial results. For example, the following quotation is from a highly respected laser therapy textbook used today, “Laser Therapy”, by Turner and Hode:

“Many producers of therapeutic instruments claim that LED treatment is as effective as laser treatment. However, in light of the clear lack of peer-reviewed studies to support these claims, LED producers make references to laser research in their marketing materials. A significant effect was observed with lasers, which was not achieved with the other, less narrow-band light sources (LED). Conclusion: Either all the investigators who conducted the research cheated, or the effects are specific to laser light.

In the literature there is good support for the hypothesis that at least some of the biostimulative effects in-vivo are laser specific. In fact, we have not yet found one single study indicating that non-coherent light (LED) is as efficient as coherent light. This does not mean non-coherent light (LED) is not useful, only that it (LED) is less efficient and probably only efficient on superficial structures.” emphasis added

Other international laser experts and researchers agree that in comparison, laser light therapy is far superior to LED therapy, all as indicated by the studies of these researchers’ published work. Here are a few of those other studies:

Bihari – LED’s, when compared to lasers, demonstrate a much lower efficacy.

Kubota – no difference between control and LED 840 nm groups.

Berki – the positive effects from laser therapy were not seen when irradiating the cell cultures with normal monochromatic (LED) light of the same wavelength and doses.

Muldiyarov – Analyzed cases where the rats were treated with ordinary red light and found there was no essential differences from the control group.

Haina – compared to the 22% increase in positive laser effects, the increase in the incoherent (LED) group was less than 10%.

Laakso – ACTH and B-endorphin levels were significantly elevated in the LLLT groups but not in the LED group.

Pöntinen – 670nm laser induced a temporary vasodilation and increased blood flow; however, LED at 635nm with doses between 0.68 and 1.36 J/cm2 decreased blood flow at least for 30 minutes after irradiation.

Lederer – found that incoherent light of the same wavelength and power density showed no influence.

Rosner – found that non coherent infrared light was ineffective or had adverse effect.

Nicola – Non-coherent light of the same wavelength and dose was less favourable.

Onac – The therapeutic window appears to be narrower for monochromatic non-coherent light.

Zhou – laser showed the best effect while the non-coherent LED light showed the poorest. Coherency does not influence the transmission; rather, because of interference in the scattered light field, coherency influences the microscopic light distribution into tissue. While it is easier to achieve higher power density with lasers than with LED’s, this is not the general reason for the better results with lasers; the coherency of the laser light source is the most important factor behind the superior results of laser light.