The Effect of Light Therapy on Chronic Pain
Phase: NA
Conditions: Chronic Pain
Sponsor: University of Arizona

Official Title: 
The Effect of Light Therapy on Chronic Pain 
NCT number: 
03677206 
Document Type: 
Study Protocol and Statistical Analysis Plan 
Date of the 
Document: 
04/14/2016 

The Effect of Light therapy on Chronic Pain 
Chronic pain is a major health problem.  In the United States alone, more than 100 
million patients have been identified with chronic pain [1].  On average, 261-300 
billion US dollars are spent every year to manage pain and 297-336 billions US 
dollars are lost to work productivity [1].  Aside from the financial burden chronic 
pain places on our society and health care system, the emotional tax produced by 
chronic pain has resulted in severe life altering events that ranges from shattering 
family unites [2] to suicide attempts [3-5]. 
Opioids have been the gold standard to treat chronic pain [4].  Sadly, there are many 
side effects associated with chronic opioid use [5].  Other classes of medications 
have also been utilized to control chronic pain such as NSAIDs, antidepressants, 
anticonvulsants, gabapentoids, and recently cannabinoids.   
 
Regardless of the class of medications employed, patients always run the risk of 
developing side effects.  Some of these side effects may be fatal.   Given the long 
lasting nature of chronic pain, the odds of developing side effects, whether social or 
medical, will increase with time.   
 
An ideal approach would be to develop agents or techniques that are safe, effective, 
and affordable for long-term use to control chronic pain. 
 
Light therapy for managing pain remains underutilized.  This may be mainly due to 
insufficient basic science data regarding the mechanisms.  In an attempt to 
investigate the mechanism of controlling pain using light therapy, Hwang at el 
investigated the role of three wavelengths (405, 532, and 650 nanometer) on 
inflammatory mediators released by human annulus fibrosus cells treated with 
macrophage-like cells conditioned media containing pro-inflammatory cytokines 
and chemokines.  The 405-nanometer light significantly reduced the release of IL-6 
in a time dependent manner.  The levels of IL-8 was reduced significantly with all 
wavelengths used, thus providing a possible mechanism for light therapy pain 
control [6]. 
 
Our pilot studies have shown behavioral responses in naïve and chronic pain model 
rats when exposed to certain light emitting diodes (LED) wavelengths.  When naïve 
rats were exposed to green or blue LED light for 8 hours a day over five days it 
produced significant antinociception (analgesia) manifested by prolonged paw 
withdrawal latency from a heat source.  This antinociception lasted for four days 
after green LED light was terminated.  White LED light had no effect of rats. The 
antinociception effect of green LED was reversed when naloxone or CB1cannabinoid 
receptor antagonist was on board.  The peripheral CB2 cannabinoid receptor 
antagonism failed to reverse the antinociception effect of green LED light.  
Therefore, there seems to be a significant role for the endogenous endorphin and 
cannabinoids system. Similar effects were achieved in rats of chronic pain model.   
 
Given the safety of using light and the relative affordability of LED light, our 
hypothesis is that exposing chronic pain patients to green or blue LED light will 
control their pain or at least lower their pain medication requirement. This grant 

The Effect of Light therapy on Chronic Pain 
will enable us to conduct a small clinical trial that may provide us with initial data to 
apply for more significant federal grant for a larger clinical trial with greater 
number and variety of chronic pain patients. 
 
Specific Aim : Investigate the effect of green and blue LED light on patients 
with chronic pain.    
Patient with chronic pain will be recruited from the pain clinic.  The patients will be 
randomized into three groups.  Each group will contain 10 patients. The first group 
will be control group exposed to white LED light.  The second group will be exposed 
to green LED light.  The third group will be exposed to blue LED light.  Patients will 
be given the LED light and asked to conduct the experiment at home and keep pain 
intensity and pain medications diaries. Each patient will be asked to set in a dark 
room for two hours a day and activate the light provided to him or her for 7 days.  A 
success will be defined as improved daily activities and functionality, better sleep, 
decreased pain intensity, or decreased pain medicine use by the end of day 7.  
 
Significance:  
 
A. 
We open the door for the use of LED of a safe wavelength, with virtually 
no side effects, to offer a novel way of managing chronic pain 
B. 
There is practically no counter indication for the use of green or blue LED 
therapy. 
C. 
Potential for lowering opioids, and other pain medication, and lowering 
the associated side effects, misuse, dependence, legal and social 
consequences of chronic use.  
D. 
Very affordable cost associated with using green or blue LED therapy. 
 
 
1. 
Institute of Medicine (U.S.). Committee on Advancing Pain Research Care and 
Education., Relieving pain in America : a blueprint for transforming prevention, 
care, education, and research. 2011, Washington, D.C.: National Academies 
Press. xvii, 364 p. 
2. 
Smith, A.A. and M.L. Friedemann, Perceived family dynamics of persons with 
chronic pain. J Adv Nurs, 1999. 30(3): p. 543-51. 
3. 
Hooley, J.M., J.C. Franklin, and M.K. Nock, Chronic pain and suicide: 
understanding the association. Curr Pain Headache Rep, 2014. 18(8): p. 435. 
4. 
Hassett, A.L., J.K. Aquino, and M.A. Ilgen, The risk of suicide mortality in 
chronic pain patients. Curr Pain Headache Rep, 2014. 18(8): p. 436. 
5. 
Gray, D., et al., Comparative analysis of suicide, accidental, and undetermined 
cause of death classification. Suicide Life Threat Behav, 2014. 44(3): p. 304-
16. 
6. 
Hwang, M.H., et al., Low Level Light Therapy Modulates Inflammatory 
Mediators Secreted by Human Annulus Fibrosus Cells during Intervertebral 
Disc Degeneration In Vitro. Photochem Photobiol, 2015. 91(2): p. 403-10.