This is the next article in our ‘Light and health’ series, where we look at how light affects our physical and mental health in sometimes surprising ways. Read other articles in the series.

You’re not feeling well. You’ve had a pounding headache all week, dizzy spells and have vomited up your past few meals.

You visit your GP to get some answers and sit while they shine a light in your eyes, order a blood test and request some medical imaging.

Everything your GP just did relies on light. These are just some of the optical technologies that have had an enormous impact in how we diagnose disease.

1. On-the-spot tests

Point-of-care diagnostics allow doctors to test patients on the spot and get answers in minutes, rather than sending samples to a lab for analysis.

The “flashlight” your GP uses to view the inside of your eye (known as an ophthalmoscope) is a great example. This allows doctors to detect abnormal blood flow in the eye, deformations of the cornea (the outermost clear layer of the eye), or swollen optical discs (a round section at the back of the eye where the nerve link to the brain begins). Swollen discs are a sign of elevated pressure inside your head (or in the worst case, a brain tumour) that could be causing your headaches.

The invention of lasers and LEDs has enabled many other miniaturised technologies to be provided at the bedside or clinic rather than in the lab.

Pulse oximetry is a famous example, where a clip attached to your finger reports how well your blood is oxygenated. It does this by measuring the different responses of oxygenated and de-oxygenated blood to different colours of light.

Pulse oximetry is used at hospitals (and sometimes at home) to monitor your respiratory and heart health. In hospitals, it is also a valuable tool for detecting heart defects in babies.

2. Looking at molecules

Now, back to that blood test. Analysing a small amount of your blood can diagnose many different diseases.

A machine called an automated “full blood count analyser” tests for general markers of your health. This machine directs focused beams of light through blood samples held in small glass tubes. It counts the number of blood cells, determines their specific type, and reports the level of haemoglobin (the protein in red blood cells that distributes oxygen around your body). In minutes, this machine can provide a snapshot of your overall health.

For more specific disease markers, blood serum is separated from the heavier cells by spinning in a rotating instrument called a centrifuge. The serum is then exposed to special chemical stains and enzyme assays that change colour depending on whether specific molecules, which may be the sign of a disease, are present.

These colour changes can’t be detected with the naked eye. However, a light beam from an instrument called a spectrometer can detect tiny amounts of these substances in the blood and determine if the biomarkers for diseases are present, and at what levels.

3. Medical imaging

Let’s re-visit those medical images your GP ordered. The development of fibre-optic technology, made famous for transforming high-speed digital communications (such as the NBN), allows light to get inside the body. The result? High-resolution optical imaging.

A common example is an endoscope, where fibres with a tiny camera on the end are inserted into the body’s natural openings (such as your mouth or anus) to examine your gut or respiratory tracts.

Surgeons can insert the same technology through tiny cuts to view the inside of the body on a video screen during laparoscopic surgery (also known as keyhole surgery) to diagnose and treat disease.

How about the future?

Progress in nanotechnology and a better understanding of the interactions of light with our tissues are leading to new light-based tools to help diagnose disease. These include:

• nanomaterials (materials on an extremely small scale, many thousands of times smaller than the width of a human hair). These are being used in next-generation sensors and new diagnostic tests
• wearable optical biosensors the size of your fingernail can be included in devices such as watches, contact lenses or finger wraps. These devices allow non-invasive measurements of sweat, tears and saliva, in real time
• AI tools to analyse how blood serum scatters infrared light. This has allowed researchers to build a comprehensive database of scatter patterns to detect any cancer
• a type of non-invasive imaging called optical coherence tomography for more detailed imaging of the eye, heart and skin
• fibre optic technology to deliver a tiny microscope into the body on the tip of a needle.

So the next time you’re at the GP and they perform (or order) some tests, chances are that at least one of those tests depend on light to help diagnose disease.

Matthew Griffith, Associate Professor and ARC Future Fellow and Director, UniSA Microscopy and Microanalysis Facilities, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This week’s ABC Four Corners episode Pain Factory highlighted that our health system is failing Australians with chronic pain. Patients are receiving costly, ineffective and risky care instead of effective, low-risk treatments for chronic pain.

The challenge is considering how we might reimagine health-care delivery so the effective and safe treatments for chronic pain are available to millions of Australians who suffer from chronic pain.

One in five Australians aged 45 and over have chronic pain (pain lasting three or more months). This costs an estimated A$139 billion a year, including $12 billion in direct health-care costs.

The most common complaint among people with chronic pain is low back pain. So what treatments do – and don’t – work?

Opioids and invasive procedures

Treatments offered to people with chronic pain include strong pain medicines such as opioids and invasive procedures such as spinal cord stimulators or spinal fusion surgery. Unfortunately, these treatments have little if any benefit and are associated with a risk of significant harm.

Spinal fusion surgery and spinal cord stimulators are also extremely costly procedures, costing tens of thousands of dollars each to the health system as well as incurring costs to the individual.

Addressing the contributors to pain

Recommendations from the latest Australian and World Health Organization clinical guidelines for low back pain focus on alternatives to drug and surgical treatments such as:

• education
• advice
• structured exercise programs
• physical, psychological or multidisciplinary interventions that address the physical or psychological contributors to ongoing pain.

Two recent Australian trials support these recommendations and have found that interventions that address each person’s physical and psychological contributors to pain produce large and sustained improvements in pain and function in people with chronic low back pain.

The interventions have minimal side effects and are cost-effective.

In the RESOLVE trial, the intervention consists of pain education and graded sensory and movement “retraining” aimed to help people understand that it’s safe to move.

In the RESTORE trial, the intervention (cognitive functional therapy) involves assisting the person to understand the range of physical and psychological contributing factors related to their condition. It guides patients to relearn how to move and to build confidence in their back, without over-protecting it.

Why isn’t everyone with chronic pain getting this care?

While these trials provide new hope for people with chronic low back pain, and effective alternatives to spinal surgery and opioids, a barrier for implementation is the out-of-pocket costs. The interventions take up to 12 sessions, lasting up to 26 weeks. One physiotherapy session can cost $90–$150.

In contrast, Medicare provides rebates for just five allied health visits (such as physiotherapists or exercise physiologists) for eligible patients per year, to be used for all chronic conditions.

Private health insurers also limit access to reimbursement for these services by typically only covering a proportion of the cost and providing a cap on annual benefits. So even those with private health insurance would usually have substantial out-of-pocket costs.

Access to trained clinicians is another barrier. This problem is particularly evident in regional and rural Australia, where access to allied health services, pain specialists and multidisciplinary pain clinics is limited.

Higher costs and lack of access are associated with the increased use of available and subsidised treatments, such as pain medicines, even if they are ineffective and harmful. The rate of opioid use, for example, is higher in regional Australia and in areas of socioeconomic disadvantage than metropolitan centres and affluent areas.

So what can we do about it?

We need to reform Australia’s health system, private and public, to improve access to effective treatments for chronic pain, while removing access to ineffective, costly and high-risk treatments.

Better training of the clinical workforce, and using technology such as telehealth and artificial intelligence to train clinicians or deliver treatment may also improve access to effective treatments. A recent Australian trial, for example, found telehealth delivered via video conferencing was as effective as in-person physiotherapy consultations for improving pain and function in people with chronic knee pain.

Advocacy and improving the public’s understanding of effective treatments for chronic pain may also be helpful. Our hope is that coordinated efforts will promote the uptake of effective treatments and improve the care of patients with chronic pain.

Christine Lin, Professor, University of Sydney; Christopher Maher, Professor, Sydney School of Public Health, University of Sydney; Fiona Blyth, Professor, University of Sydney; James Mcauley, Professor of Psychology, UNSW Sydney, and Mark Hancock, Professor of Physiotherapy, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.