In the past, infra-red light has been used in many light therapies to heal people after their injuries. Light therapy has also been used for years to affect the mental state of the patient positively and to relieve depression.
Scientific studies on the neurological effects of light therapy are still at an early stage, since there are very few studies investigating the role of light in relieving pain.
Meanwhile, the University of Arizona has explored the effects of LED light and has taken a step toward the potential use of light for some forms of chronic pain, determining the effect of LED’s on the sensory thresholds of visible spectrum light.
Investigators studied the effect of light on experimental neuropathic pain on mice: In the study, mice with neuropathic pain were exposed to green LED light with a wavelength of 525 nm. As a result, they were found to be more tolerant of thermal and tactile stimuli compared to mice not entering the green LED light. This work was also published in the “Pain” magazine.
Visual perception of green wave length
In another study, a group of contact lens-implanted mice were exposed to a white light that allowed the green part of the spectrum to pass through and appeared to release beneficial effects on the mice; Another group of mice that had an opaque lens attached and did not see any light showed no effect.
Mohab Ibrahim from UA’s Banner-University Medical Center Tucson said, “We have tried several wavelengths and reported that the blue light has some analgesic effects, but the effect is most obvious in green illumination” he said and added “whatever happens is through the visual system.”
The project was tried at different light densities and at different day times. The findings showed that the intensity of the ideal light was between 4 lux and 100 lux, while a higher level could cause irritation to the visual system of the mice and cause adverse effects.
The first test to see the effects on humans was performed on patients with chronic pain around the joints, suffering from fibromyalgia treatment in the clinic of Mohab Ibrahim: The first response to treatment was positive on the patients.
Future clinical investigations
“There is a significant reduction in the pain of patients treated with green light,” Abraham said. However, this is not enough data to produce definitive statistical results, but preliminary is promising. We intend to continue with larger clinical trials in this context” he said.
The role of the visual system will be further emphasized while working on the lightening of the aches and pains in the future. However, there is a theory about the increase in induced enkephalin production. This theory involves the regulation of an animal’s response to harmful stimuli. It was also found that enkephalin levels increased in the spinal cord of mice exposed to green light.