What is light therapy? Under the umbrella term of either “light therapy” or “phototherapy,” there are many modalities using the properties of light (as both a wave and particle, known as a photon) to influence physiological processes. Some examples include LASER, infrared, red light, and blue light. Light is a form of energy that is measured in wavelength. Therapeutic wavelengths for physical therapy purposes are between 600nm-1000nm.
What is it supposed to do? Light therapy, as it will be referred to in the remainder of this article, proposes to affect tissue repair and pain control. By adding energy to the body in the form of light, cells absorb this energy and increase their activity.
Chukuka Enwemeka wrote an article in 2004 stating: “Evidence indicates that cells absorb photons and transform their energy into adenosine triphosphate (ATP), the form of energy that cells utilize. The resulting ATP is then used to power metabolic processes; synthesize DNA, RNA, proteins, enzymes, and other products needed to repair or regenerate cell components; foster mitosis or cell proliferation; and restore homeostasis.”
Thus, by using light therapy inflammation is accelerated to resolution, blood flow is increased, which allows for improved availability of nutrients to tissues, fibroblasts are encouraged to proliferate (to aid in healing damaged tissues), collagen fibers are synthesized more quickly and alignment of these fibers improves, nerve cells can be stimulated to initiate healing and repair of axonal damage, enzymatic activity is increased to reduce pain, and nerve conduction is modulated to reduce pain.
What are the risks? Before undergoing a session of light therapy, it is important to consider the following contraindications for this type of treatment:
Cancer, direct treatment over the eyes, direct treatment over a fetus or uterus during pregnancy, direct treatment of the thyroid gland, patients with high sensitivity to light (idiopathic photophobia), and patients undergoing other treatments of taking other medications that significantly increase light sensitivity. The following is a list of medication classes that increase photosensitivity.
Antibiotics, nonsteroidal Anti-inflammatories (NSAIDs), diuretics (hydrochlorothiazide, furosemide, etc), retinoids, HMG-CoA (statins), neuroleptic drugs (phenothiazines), tricyclic antidepressants (amitriptyline, etc), oral contraceptives, anti-hypertensives (atenolol, captopril), corticosteroids, antifungals, sildenafil, and barbituates
Enwemeka, C. (2012). Light Therapy: A Handbook For Practitioners. Milwaukee: University of Wisconsin-Milwaukee.
Enwemeka, C. (2004). Therapeutic Light. Disciplinary Journal of Rehabilitation, 17(1), 1-10.
Smith, K. (1991). The Photobiological Basis Of Low Level Laser Radiation Therapy. 19-24. Retrieved January 27, 2015.
Blog post written by Jessica Manley, DPT