14/08/2026
Class of laser vs pbm research
https://www.facebook.com/share/p/1HkHQ9urDP/?mibextid=wwXIfr
Class IV Lasers and Photobiomodulation (PBM)
Understanding the Differences, Potential Benefits, and Limitations
Photobiomodulation (PBM), often referred to as low-level light therapy, has become increasingly popular in both human and veterinary medicine. At the same time, high-powered Class IV therapeutic lasers are widely marketed as providing superior tissue pe*******on and faster results.
The reality is more nuanced.
Although both technologies use light to influence biological tissues, they differ substantially in how that light is produced, delivered, and interacts with the body. Neither is inherently “better.” Each has advantages, limitations, and appropriate clinical applications.
Understanding these differences begins with one important fact:
Laser classification is a safety classification—not a measure of therapeutic effectiveness.
What is a Class IV laser?
Lasers are classified according to their power output and the hazards they present.
A Class IV laser produces more than 500 milliwatts (0.5 W) of optical power. Because of this high output, these devices can cause permanent retinal injury from direct or reflected beams and, depending on power and exposure time, may also produce skin burns.
Class IV simply means:
* higher optical power
* greater safety precautions required
* greater potential for tissue heating
It does not mean the laser penetrates deeper.
It does not mean it is more effective.
It does not mean it produces better clinical outcomes.
What is photobiomodulation?
Photobiomodulation refers to the use of visible or near-infrared light to influence cellular function without producing significant tissue heating.
Rather than relying on thermal effects, PBM aims to stimulate normal biological processes.
Laboratory research suggests PBM may influence:
* mitochondrial activity
* ATP production
* nitric oxide release
* reactive oxygen species signalling
* inflammatory pathways
* gene expression
* tissue repair
These effects are often described as photochemical rather than thermal.
Power versus pe*******on
One of the biggest misconceptions in rehabilitation is that a more powerful laser automatically penetrates deeper.
Unfortunately, tissue optics are far more complicated.
Light entering tissue may be:
* reflected
* scattered
* absorbed
* transmitted
How much reaches deeper structures depends on many factors, including:
* wavelength
* beam divergence
* spot size
* pulse characteristics
* tissue hydration
* pigmentation
* hair coat
* contact pressure
* treatment duration
Increasing power alone does not guarantee greater pe*******on.
In fact, increasing power may simply increase heat production within superficial tissues.
What does the research show?
A frequently cited study by Luna et al. (2020) compared a portable photobiomodulation device with a Class IV therapeutic laser on living horses.
The investigators measured how much light passed through folds of both light and dark equine skin.
They reported:
* significantly greater light transmission with the PBM device
* approximately 17-fold greater transmission through light skin
* approximately 8-fold greater transmission through dark skin
* more than tenfold greater transmission overall
These findings challenged the common assumption that higher-powered Class IV lasers necessarily achieve deeper pe*******on.
However, the study should be interpreted carefully.
It compared one PBM device with one Class IV laser.
It does not demonstrate that all PBM devices outperform all therapeutic lasers.
Nor does it prove superior clinical outcomes.
It simply demonstrates that, under the conditions tested, considerably more light passed through equine skin using the PBM device.
Potential benefits of Class IV lasers
When used appropriately, Class IV lasers may offer several advantages.
Shorter treatment times
Higher power allows a therapeutic dose to be delivered more quickly.
Thermal effects
Controlled tissue warming may:
* increase local blood flow
* reduce muscle guarding
* improve tissue extensibility before stretching
These thermal effects may be desirable in some situations.
Large treatment areas
Higher output can make treating larger muscle groups faster.
Potential disadvantages of Class IV lasers
Higher power also introduces potential drawbacks.
Increased heat
Surface tissues absorb much of the energy.
Excessive heating may:
* reduce patient comfort
* require constant movement of the applicator
* limit treatment time over one location
* increase the risk of burns if used incorrectly
Greater safety requirements
Because of retinal injury risk:
* protective eyewear is essential
* reflective surfaces should be avoided
* accidental beam exposure must be prevented
Dose becomes more critical
Photobiomodulation follows a biphasic dose response.
Too little light may have little effect.
Too much may reduce the desired biological response.
Higher-powered devices require careful dosing.
Potential benefits of photobiomodulation devices
PBM devices generally emphasize non-thermal cellular stimulation.
Potential advantages include:
Minimal heating
This allows treatment of:
* acute injuries
* inflamed tissues
* areas where additional heat would be undesirable
Lower safety risk
Most PBM devices do not pose the same burn hazards as high-powered lasers, although eye protection may still be recommended depending on the device.
Comfortable treatments
Most horses tolerate PBM well because treatments produce little or no sensation.
Larger treatment fields
Many PBM devices illuminate relatively broad areas, potentially improving dose uniformity.
Potential disadvantages of PBM
Longer treatment times
Lower power often means treatments take longer.
Variable devices
PBM encompasses a huge range of products.
Not all are created equally.
Wavelength, irradiance, pulse characteristics, and total energy vary considerably between manufacturers.
Evidence continues to evolve
Although laboratory evidence is extensive, clinical studies in horses remain variable in quality.
Many promising findings still require larger, well-controlled trials.
Which is better?
There is unlikely to be a single answer.
Different tissues, injuries, treatment goals, and clinical situations may favour different approaches.
The quality of the treatment protocol is probably more important than the label on the machine.
Successful photobiomodulation depends on:
* selecting an appropriate wavelength
* delivering an appropriate dose
* treating at the correct frequency
* targeting the correct tissues
* integrating light therapy with sound veterinary care, rehabilitation, exercise, and management
No device can compensate for poor diagnosis or inappropriate rehabilitation.
Practical take-home message
Class IV lasers and photobiomodulation devices both use light as therapy, but they are not interchangeable technologies.
A Class IV laser is defined by its power and safety classification, not by therapeutic superiority.
Likewise, photobiomodulation should be viewed as a distinct therapeutic approach that seeks to harness the biological effects of light while minimizing thermal effects.
Current evidence suggests that more power does not necessarily mean greater tissue pe*******on, and the effectiveness of any light-based therapy depends on much more than output alone.
As with most tools, success lies not in owning the most powerful device, but in understanding the science behind how it is used.
https://koperequine.com/how-inflammation-in-muscles-and-fascia-affects-energy-restoration/
