Science fiction medicine doesn't get much better than what's offered on board Star Trek's USS Enterprise. Beamed up to the ship with a gaping phaser wound, the patient is sent to sick bay, where "Bones" McCoy directs a handheld device emitting a ray of light onto the injury. It shrinks and vanishes in seconds, leaving not even the trace of a scar.
It may not work so fast or so perfectly, but the technology of light medicine is already with us. Called low-level laser therapy (LLLT), it has been used by some cutting-edge practitioners for decades, and the field is advancing at lightning speed.
The research behind "photobiomodulation" (PBM), as this field is referred to, has grown to a base of thousands of studies, with more published daily: light for wound healing, for muscle and joint recovery, for shingles and nerve pain, for macular degeneration, Parkinson's disease, spinal cord and traumatic brain injury, stroke, depression, and acne, to name a few.
In clinical practice, light therapy still falls largely out of the boundaries of mainstream medicine, but the number of practitioners using the tool is growing with the list of conditions they are using it to treat.
Mainstream medicine does use some forms of light as a tool. Most people will be familiar with lasers used to cut or cauterize
tissue in surgery and 'bili' lights to treat newborn babies with jaundice, for example. But there are many different wavelengths of light, and these, in different intensities, applied for different lengths of time, can encourage or dampen different functions at the cellular level.
Some wavelengths of light at low-power intensities, for example, have been shown to induce photochemical reactions in the body, like photosynthesis in plants. It's these harmless wavelengths of light in the red and near-infrared spectrums that are the tools of LLLT. Because the light doesn't generate heat, it is also sometimes called "cold laser therapy." More recently, researchers have begun investigating high-intensity laser therapy or HILT, also known as laser heat therapy.
Shining a light on pain
One in three Americans experiences chronic pain each year. It's the most common reason that people visit their doctor, and muscle and back pain is the number one reason that people miss work or school.
Mainstream medicine generally responds with steroid injections, nonsteroidal anti-inflammatory drugs (NSAIDs) and other painkillers with cumulative and potentially lethal side-effects.
The use of prescription opiate painkillers has driven the current global opioid addiction crisis. Patients given a 40-day prescription of the drugs have a 45 percent likelihood of still using them a year later, according to the US Centers for Disease Control and Prevention.1
The use of low-level laser therapy for pain control is supported by numerous placebo-controlled studies demonstrating its ability to curb acute pain associated with a long list of conditions—without the use of drugs:
• pain following oral surgery 2
• plantar fasciitis 3
• carpal tunnel syndrome 4
• myofascial pain 5
• pain after coronary artery bypass graft surgery 6
• peripheral somatosensory neuropathy and neuropathic pain 7
• temporal-mandibular joint disorder 8
• knee osteoarthritis 9
• acute low back and neck pain 10
• headache 11
• Bell's palsy 12
• frozen shoulder 13
• a wide variety of musculoskeletal disorders including fibromyalgia.14
One review, published in The Lancet medical journal, reported that "LLLT reduces pain immediately. . . and up to 22 weeks after completion of treatment in patients with chronic neck pain."15
Several studies have reported the benefits of using light to treat oral mucositis or mouth ulcers, which are a common side-effect of chemotherapy and radiation in cancer patients. Earlier this year, the UK's National Institute of Health and Care Excellence (NICE) adopted guidelines promoting the use of LLLT to prevent and treat ulcers.16
Some people are skeptical that one treatment tool can impact such a diverse list of diseases. However, certain wavelengths of light work at a cellular level, common to much disease. It turns out that the mitochondria, the energy producers of the cells, contain molecules that act as photoreceptors (light receptors, like those found in plants) and respond to certain light wavelengths.
In disease and stress, some systems in the mitochondria become overwhelmed, like those that defend them against oxidative stress. Receiving red light in their photoreceptors provides a shot of energy to the system, which allows the mitochondria to reduce oxidation, synthesize new proteins, and complete other maintenance functions that increase their performance as energy producers.
Ultimately, these changes appear to have the capacity to induce long-lasting modulation of the immune system, reduce inflammation, increase circulation, cause cells to multiply, and stimulate the body's own repair mechanisms.17
Ronald Hirschberg, a veterinarian from Brockton, Massachusetts, had chronic pain in his hands from arthritis. After years of performing surgery for several hours at a time, he found he had to cut his schedule.
The NSAIDs prescribed to him didn't help the pain, but they did give him gastrointestinal problems, so when a client who was a physician trained in LLLT suggested the therapy to him, he says, "I figured I had nothing to lose." In a video testimonial for LLLT therapy, he recounts that "I found that laser for my arthritis condition was very effective to a point that within a matter of a couple of weeks and five or six treatments, I was back to a normal surgery schedule."
Although there are conflicting findings on the benefits of LLLT for arthritis, dozens of studies have confirmed that PBM is an effective painkiller for knee and other arthritic conditions. A recent German study, for example, concluded that low-level laser therapy is a "safe, non-invasive, efﬁcient and efﬁcacious means to reduce pain and swelling and to increase mobility" in hand arthritis.18
Brazilian researchers studying LLLT in a rat model of arthritis showed how this was possible. They examined the light-treated knees of rats using microscopic analyses and found that LLLT-stimulated cells to synthesize collagen in the joint.19
Cold lasers have revolutionized the treatment of sports injuries in the past decade, and handheld light devices are now in routine use among elite athletes. Because PBM reduces short-term inflammation and pain, it is used to help athletes minimize downtime.
Recent studies have found that that LLLT diminishes post-exercise pain, called delayed-onset muscle pain, while speeding up recovery.20 It was also found to improve performance and reduce fatigue among professional cyclists.21
Light therapy was first introduced in attempting to heal smallpox and tuberculosis lesions, and assisting with wound healing is still a major application of the technology.
Researchers at Harvard Medical School and Massachusetts General Hospital concluded in 2007 that "a single exposure to low levels of red or near infrared light significantly stimulates the healing of excisional wounds" based on a variety of experiments in mice.22
Much of the focus of light therapy has been on diabetic wounds. Because of poor circulation, diabetic foot ulcers can be very difficult to heal and can lead to infection, a leading cause of amputation. In the United States, over 100,000 amputations of the lower limbs are performed for diabetes-related complications—mainly ulcers that won't heal—every year,23 and in the UK, about 135 people undergo a diabetes-related amputation every week.24
Several recent studies have found that LLLT can assist in wound healing. A 2017 study from the University of Ljubljana in Slovenia looked at 40 non-diabetic patients and 39 diabetic patients, all referred to the university medical center with non-healing chronic wounds between 2012 and 2014. The patients were randomized into two groups receiving either true or sham phototherapy, three times a week for eight weeks.
The treatment group had increased microcirculation and blood flow in the wound area measured by a laser Doppler, and also had measurably better healing of their wounds compared to the control group, which showed no improvement, leading the researchers to conclude that LED was an effective additional treatment method for chronic wounds in all patients, whether diabetic or non-diabetic.25
A double-blind, randomized, placebo-controlled study from Brazil compared diabetic leg ulcers in two groups of 14 patients—one group treated for 90 days with 1 percent silver sulfadiazine cream (the standard therapy) and "placebo" phototherapy twice per week, and the other group treated with real LLLT.
While placebo-treated ulcers worsened during the initial 30 days, ulcers treated with laser light healed rapidly, achieving 79.2 percent faster healing by day 30 and beyond. By day 90, 58 percent of ulcers in the LLLT group had healed fully, and 75 percent had achieved 90-100 percent healing, while only one placebo-treated ulcer healed fully.26
Wave of the future
Because it reduces oxidative stress and stimulates the body's innate healing responses, light therapy has become a research interest for scientists seeking to repair devastating spinal cord and traumatic brain injuries.
Juanita Anders and fellow researchers at the Uniformed Services University of the Health Sciences in Maryland showed that by shining light wavelengths on the skin in rodent models of spinal cord injury, they could increase the length and number of regrowing nerve extensions, change the immune response and ultimately achieve functional recovery in spinal cord-injured rats.27
Several research teams, including Michael Hamblin's at Harvard Medical School and Massachusetts General Hospital, are also looking at the impact of light on the brain.
Transcranial photobiomodulation, where light is directed at the brain, has been shown to improve cognitive ability in both healthy people and those with dementia. Researchers are testing light-emitting helmets or "brain caps" that patients wear on their heads and intranasal light delivery for use at home.
In a 2018 review of the field, Hamblin says this technique has the potential "to treat a wide range of brain disorders only loosely associated with traumatic brain injury, including Parkinson's disease, depression, anxiety, post-traumatic stress disorder, autism spectrum disorder, and so on."28
There are significant hurdles to overcome before light therapy reaches this hopeful end, but dawn for a promising non-chemical approach to medicine is breaking.
Phil Harrington, of Franklin, Tennessee, a physics teacher before becoming a chiropractor, started using LLLT in his practice in 2005, mostly in patients who had pain associated with joint replacements.
"Even if their surgery was 'successful,' " he says, "people would have residual pain and lots of scar tissue. Laser is great because you can use it directly over metal implants." Patients of his reporting pain of eight or nine on a scale of one to 10 say their pain went down to a two after a single LLLT treatment.
Harrington was so impressed with the technology, he sold his practice in 2007 to focus solely on spreading the word about light therapy through the company K-Laser. "In my role now, I communicate with doctors all around the world who are using therapeutic lasers," he says. "They are treating literally everything from head to toe—headaches, Bell's palsy, neck pain, carpal tunnel, sports injuries, arthritic knees, plantar fasciitis and much more.
"A treatment that is increasing in popularity in the last few years is laser for the symptoms associated with neuropathy [nerve pain]. Modern medicine really has no answer for those patients, but with the laser we can restore their sensation and function."
A light history
Light in medicine traces back to at least 1903, when the Nobel Prize in medicine was awarded to Danish doctor Niels Finsen for treating smallpox and tuberculosis lesions effectively with "concentrated light radiation." Finsen was celebrated for having "opened a new avenue for medical science."
Finsen was a big champion of sunbathing, too, and his Swedish compatriot Auguste Rollier launched some of the first 'sanatoriums,' where the chronically ill were treated with exposure to high-altitude sunlight and fresh air.
These hospital/spas were copied around the globe until the end of World War II, but then the use of light as a vital and powerful healing therapy fell out of fashion as the pharmaceutical revolution in medicine dawned.
Light research continued, however. In 1967, Hungarian Endre Mester was trying to kill cancer in mice with a low-level laser when he noticed that the laser helped heal the mice's wounds and caused their shaved hair to grow back more quickly where the tumors had been surgically implanted.1 He began to research this phenomenon of what he called "laser bio stimulation."
The next big break in light therapy came in 2001, when NASA, which developed light-emitting diodes (LEDs) to grow plants in space, reported they also had tremendous medical potential.
LEDs increased cell growth by 140 to 200 percent in Petri dishes, and when used with hyperbaric oxygen, they decreased wound size up to 36 percent in rats.
"LED produced improvement of greater than 40 percent in musculoskeletal training injuries in Navy SEAL team members and decreased wound healing time in crew members aboard a US Naval submarine," the NASA researchers reported.
They also found that LEDs produced a 47 percent reduction in the pain of children suffering from oral mucositis, a side-effect of cancer treatment.2
Since then, more than 400 double-blind, placebo-controlled trials and 4,000 laboratory studies of LLLT have been published.3
The US Food and Drug Administration approved the use of LLLT and LED therapy in 2001, soon after the NASA study, but the swift uptake of use was primarily outside of pharmaceutical-based mainstream medicine.
Seeing the light
A study from the University of Heidelberg, Germany, a decade ago described 203 patients (90 men and 113 women) with beginning ("dry") or advanced ("wet") forms of age-related macular degeneration. A total of 193 of them were treated using LLLT four times over two weeks. Ten patients received mock treatment and served as controls.
LLLT significantly improved vision in 95 percent of eyes with cataracts and 97 percent of eyes without cataracts.
Vision and color distortion and spots were reduced, and patients with advanced degeneration showed less swelling and bleeding. Improved vision was maintained for three to 36 months after treatment, while the eyesight of the control group was unchanged.
The researchers concluded that "LLLT significantly improved visual acuity without adverse side-effects and may thus help to prevent loss of vision."
Since then, a number of studies in animals and humans have explored the use of LLLT for eye disease. A 2016 review of the literature concluded that the therapy's low risk and low cost, along with promising clinical and preclinical studies in animal models, make light therapy "well-poised to become an important player in the treatment of a wide range of retinal disorders" including age-related macular degeneration and diabetic retinopathy, both leading causes of blindness globally.1
After LLLT relieved his arthritis pain, veterinarian Ronald Hirschberg (see main story) saw the potential of light therapy for his own patients.
He uses his Thor Laser from the UK on a daily basis to treat dogs with osteoarthritis, before and after surgery to promote healing, for fractures, soft tissue trauma, corneal ulcers, earaches and non-healing wounds, and he typically sees 90 to 95 percent success with the treatment.
"I think that laser therapy is one of the two most important changes in [veterinary] practice," along with the introduction of diagnostic ultrasound. "I think I could no longer practice without it. "