High Intensity Laser Therapy vs Low Level Laser Therapy

As the availability of laser therapy grows in the United States, it is important to know that not all lasers are created equal.  Healing lasers utilized in practice have a wide range of specifications which impact how effective the laser is at treating chronic pain.  This article will outline the key differences between High Intensity Laser Therapy and Low Level Laser Therapy so that you can have an informed conversation with your doctor about which is best for your chronic pain.

Classifications of Lasers Used in Therapy and Recovery

The FDA uses four classifications for lasers, including therapeutic lasers, based on their wattage and potential to cause injury if used improperly.

Class 1 lasers are those that are less than 0.39 milliwatts (mW) in power. These are the types of lasers used in laser printers and DVD players.

Class 2 lasers are those emitting less than 1 mW.  These are the types of lasers used in bar code scanners and some laser pointers.

When it comes to therapeutic lasers for pain, we need to move into Class 3 and Class 4 lasers.

Class 3 lasers emit between 1 and 500 mW (or 0.001 – 0.5 watts).  This classification has a broader range of power and includes everything from the lasers used in laser light shows to Low Level Laser Therapy (LLLT) devices used to treat pain.

Class 4  – Any therapeutic laser with a wattage greater than 500 mW (0.5 watts) is considered a Class 4 laser. This class is the broadest range, including medical grade lasers used for therapy and surgery as well as industrial lasers.  Therapeutic lasers for chronic pain treatment, known as High Intensity Lasers or High Powered Lasers, fall into this class.  The therapeutic lasers for pain most commonly seen in clinical practice are 10 watts or less. This is due to their relative affordability.  At InMotion Pain Solutions, we utilize both a 60-watt and 500-watt laser which have a broad range of therapeutic applications for pain relief and injury recovery.

Therapeutic Laser Variables

There are several terms to know when looking at different therapeutic lasers and how effective they are at treating your pain.

Wattage.  Wattage refers to the power emitted by the laser.  One watt (W) is equal to 1000 milliwatts (mW).  Watts and milliwatts are both commonly used to describe the power of a therapeutic laser.

If you think about the common light bulb, you know that a low-wattage bulb gives off less light than a high-wattage bulb.  Depending on where you are using the light, you will choose the wattage, or power, that works best in that situation.  The same is true for therapeutic lasers.

Wavelength.  Light is emitted in the form of waves, with peaks and valleys.  The distance between two peaks is known as the wavelength, and the unit of measurement of a laser wavelength is nanometers (nm).  Wavelength is important because it determines how much of the light is able to penetrate beneath the surface of the skin. Higher nanometers means a higher the percentage of laser light is able to reach the damaged tissue. Lasers that operate at lower nanometer levels are best for surface wounds and skin disorders. Therapeutic lasers that operate at higher wavelengths are better able to treat injuries to deep soft tissues (e.g. muscle, joints, ligaments, etc.).

Continuous, Pulsed, Super Pulsed.  Healing laser light is delivered either in a continuous, pulsed, or super pulsed manner.  If you think of a flashlight, a continuous wave would be the light being switched to “on”.  A pulsed wave can be compared to turning the light off and on in a repetitive fashion. When it comes to pulsing therapeutic lasers, the pulsing is done so quickly and at such a high frequency it is not visible to the naked eye.

The benefit to pulsing laser light is that the time during which the light is switched off allows both the laser and the treatment area to cool.  In super pulsed lasers, very high levels of light energy are delivered in factions of a second.  This enables the laser to deliver more energy deeper into the tissues without causing the tissues to overheat.  This is just one of the many safety features incorporated into High Intensity Laser Therapy. As a comparison, the energy from a 905 nm continuous wave laser penetrates to approximately 2.5 cm. However, a 905 nm super-pulsed laser can deliver energy to a depth of 10 cm¹.

Some lasers operate in a dual-channel mode that benefits both superficial and deep tissue.

Dosage.  The amount of energy or dosage that is delivered to a unit of area of the body is measured in joules.  Joules is calculated by multiplying watts by time in seconds:  Joules = Watts (Seconds).  The unit measurement is Joules/cm^2.  High Intensity Lasers are able to deliver more joules to the body in less time than Low Level Lasers.