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Low-Level Light Therapy/LLLT, Indications, Contraindication

Low-Level Light Therapy/LLLT/Infrared Radiation Therapy (IR) sometimes called infrared light is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye, although IR at wavelengths up to 1050 nanometers (nm)s from especially pulsed lasers can be seen by humans under certain conditions.^[rx]^[rx] IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz).^[rx] Most of the thermal radiation emitted by objects near room temperature is infrared. As with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon.

Infrared (IR) radiation is electromagnetic radiation with wavelengths between 760 nm and 100,000 nm. Low-level light therapy (LLLT) or photobiomodulation (PBM) therapy generally employs light at red and near-infrared wavelengths (600–100 nm) to modulate biological activity. Many factors, conditions, and parameters influence the therapeutic effects of IR, including fluency, irradiance, treatment timing and repetition, pulsing, and wavelength. Increasing evidence suggests that IR can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment. Nerve cells respond particularly well to IR, which has been proposed for a range of neurostimulation and neuromodulation applications, and recent progress in neural stimulation and regeneration are discussed in this review.

Another Name

You may have heard of red light therapy (RLT) by its other names, which include:

Photobiomodulation (PBM)
Low-level light therapy (LLLT)
Soft laser therapy
Cold laser therapy
Biostimulation
Photonic stimulation
Low-power laser therapy (LPLT)

Types of Low-Power Laser Therapy/LPLT

IR is divided into different bands: Near-Infrared (NIR, 0.78~3.0 μm), Mid-Infrared (MIR, 3.0~50.0 μm) and Far-Infrared (FIR, 50.0~1000.0 μm) as defined in standard ISO 20473:2007 Optics and photonics — Spectral bands [rx]

Infrared light immediately follows red light on the electromagnetic spectrum. Infrared (IR) light energy is broken down into three groups:

Near-Infrared – also called infrared-A (IR-A). Near IR spans wavelengths 760 to 1,400 nm. Most home therapy devices use these wavelengths.
Mid Infrared – also called infrared B (IR-B) – These wavelengths are used in many household electronic devices such as remote controls.
Far Infrared – or IR-C– also known as longwave infrared, thermal infrared (thermal-IR). This is the largest part of the IR spectrum, used in infrared saunas.

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Most studies showing benefits of red/NIR light therapy used light outputs of 20-200mW/cm². This is basically a measurement of power density – how much power the light is emitting (in watts) over how big of an area. To put that in different terms, if you shine the light on your torso (let’s say, for the sake of ease of calculation, that it’s an area of 50cm x 40cm, which equals 2,000cm²). And the light you’re using is 200 watts (which is 200,000mW), then you have 200,000mW/2,000cm² = 100mW/cm²

A third scheme divides up the band based on the response of various detectors:^[rx]

Near-infrared – from 0.7 to 1.0 µm (from the approximate end of the response of the human eye to that of silicon).
Short-wave infrared – 1.0 to 3 µm (from the cut-off of silicon to that of the MWIR atmospheric window). InGaAs covers to about 1.8 µm; the less sensitive lead salts cover this region.
Mid-wave infrared – 3 to 5 µm (defined by the atmospheric window and covered by indium antimonide [InSb] and mercury cadmium telluride [HgCdTe] and partially by lead selenide [PbSe]).
Long-wave infrared – 8 to 12, or 7 to 14 µm (this is the atmospheric window covered by HgCdTe and microbolometers).
Very-long wave infrared (VLWIR) – (12 to about 30 µm, covered by doped silicon).

Indications of Low-Power Laser Therapy/LPLT

Additional clinical research is needed to prove that RLT is effective. At the moment, however, there’s some evidence to suggest that RLT may have the following benefits:

Promotes wound healing and tissue repair
Improves hair growth in people with androgenic alopecia
Help for the short-term treatment of carpal tunnel syndrome
Stimulates healing of slow-healing wounds, like diabetic foot ulcers
Skin Wounds
Photo prevention
Relieve pain
Stiffness
Fatigue of rheumatoid arthritis
Ankylosing spondylitis
Potentiate photodynamic therapy
Treat ophthalmic, neurological, and psychiatric disorders, and
Stimulate the proliferation of mesenchymal and cardiac stem cells
Reduces psoriasis lesions
Aids with short-term relief of pain and morning stiffness in people with rheumatoid arthritis
reduces some of the side effects of cancer treatments, including oral mucositis
Improves skin complexion and builds collagen to diminish wrinkles
Helps to mend sun damage
Prevents recurring cold sores from herpes simplex virus infections
Improves the health of joints in people with degenerative osteoarthritis of the knee
Helps diminish scars
Relieves pain and inflammation in people with pain in the Achilles’ tendons
Reduce the signs of damage, DNA damage,^[rx] and aging from UV rays^[rx]
Reduce wrinkles^[rx]
Reduce color patches, hyperpigmentation, and skin discoloration^[rx]
Enhance collagen synthesis and collagen density (research has shown it can enhance the production of collagen by 31%)^[rx]^,^[rx]
Accelerate repair in the epithelial layer of skin
Combat other skin conditions like acne, keloids, vitiligo, burns, herpes virus sores, and psoriasis
Speed wound healing by enhancing skin tissue repair and growth of skin cells
Chronic neck ^pain[rx]
Knee pain^[rx]
Fibromyalgia
Low back pain
Chronic pain in the elbow, wrist, and fingers
Chronic joint disorders
Sacroiliac joint pain
Chronic tooth pain
Osteoarthritis pain
Tendinitis and myofascial pain^[rx]
Benefit cognitive performance and memory
The improved mitochondrial function of brain cells
Have a protective effect on neurons
Improve cellular repair of neurons
Increase brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF)
Decrease brain inflammation (decreased pro-inflammatory cytokines and increased anti-inflammatory cytokines)

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Contraindication of Infrared Radiation Therapy

Treatment Contraindications for Light Therapy

Open wounds
Metastatic Lesions
Areas of decreased sensation
parts of the body with metal implants, like in a total knee replacement of lumbar fusion
Near or over a pacemaker
the uterus during pregnancy
Over the gonads
Malignancies and precancerous lesions
On patients with vascular abnormalities, i.e. deep vein thrombosis, emboli, severe atherosclerosis
The eye directly
Over the stellate ganglion
For hemophiliacs not covered by factor replacement
The spinal cord after laminectomy
Directly over metal implants
Over an electronic device
Tissues previously treated with deep Xray or radiation
Tuberculosis (local)
Damaged or at-risk skin, i.e. skin rash, eczema
Anesthetic areas
Excitable tissue,
With pregnant women
Around the eyes, breasts, or sexual organs
Over fractured bones
Near or over an implanted electrical stimulation device
Women who are pregnant should consult their physician before beginning IRR light therapy treatments.
Clients with epilepsy should consult their physicians before beginning IRR light therapy treatments.
You must wait five days after Botox or cosmetic fillers.
Some thyroid conditions.
People with a history of skin cancer
Systemic Lupus erythematosus should also avoid this kind of treatment.
The use of photosensitizing medications (i.e. lithium, melatonin, phenothiazine antipsychotics, and certain antibiotics).
Diseases that involve the retina of the eye