When Dr Kristin Larson first heard about syntonics – a form of light therapy – she was intrigued enough to start investigating further.
I first heard about syntonics several years ago from other optometrists in the online behavioural optometry community and it piqued my interest. It seemed like a really good tool that would help people in cases where nothing else could. I’m drawn to niche areas of optometry, and I quickly identified this as an area in which I could add value and differentiate myself within the profession.
Syntonics has had a wealth of support in the scientific literature, including recent exciting research out of Spain
Syntonics is a treatment with coloured light that brings about balance to the autonomic nervous system. It was developed in the 1930s and has been in use since then. It has been used in treatment of strabismus, amblyopia, post head injury, and in learning-related visual disorders.
Having disovered syntonics, and with a love for learning, I started watching recordings of old conferences and consulting with a syntonics ‘guru’ in the United Kingdom. I really fell down the rabbit hole of learning, so to speak.
That was just before the pandemic, and once the world went into lockdown everything went online. In a way, that made it much easier to learn about this field as many of the conferences that were once in person and mainly in the US became accessible.
While it is impossible to know how many optometrists provide syntonics, the United States-based College of Syntonic Optometry (CSO) has a worldwide membership of 260, and the Australian College of Syntonics currently has 30 members.
I set up my practice to bring the best in optometry to the community, providing primary care, dry eye treatment, plus vision therapy. Syntonics has been a great addition to my practice – I have been able to incorporate it in cases of visual dysfunction where I use a combination of therapeutic prescription lenses and vision therapy. Some patients travel across town to see me as I am the only syntonics provider in Western Australia.
The main things we evaluate in syntonics are colour fields, or functional fields, and pupil responses. We plot where a person can perceive a series of different colours in their periphery. Narrowed colour fields correlate with a variety of visual symptoms including eye strain, difficulty reading, photophobia, etc.
We look at the pupil as a barometer of the balance of the sympathetic and parasympathetic systems. For example, we measure how long the pupil holds its constriction when the light source is held on it. When the pupil constricts as usual, but then is not able to maintain the constriction, this is known as an ‘alpha omega pupil’. This is distinct from pathology known to affect visual fields and pupil responses, and these features are amenable to change.
The usual treatment involves daily exposure of 20 minutes to two combinations of light filters, with 20 exposures over four weeks and regular re-evaluations. Changes in the colour fields, along with changes in pupil responses, indicate that the combination of colours is producing the intended effect.
A classic case would be a patient with convergence insufficiency from a general eye exam. I would find the alpha omega pupil and reduced colour fields. Viewing the patient holistically, the sympathetic nervous system would be overstimulated with other ‘fight or flight’ response symptoms of feeling anxious and difficulty sleeping. Sometimes, treatment with syntonics alone helps to improve convergence because the brain can better fuse the view of the two eyes together. While I don’t treat for systemic issues, it is a beneficial side effect when other issues a patient has been experiencing improve as a result.
Still on the Learning Journey
I feel like I’m just at the beginning of my journey with this field of behavioural optometry. There’s a core group of practitioners around the world who have been working in syntonics for a good few decades and many of them are active in passing on their knowledge and experience to practitioners who are newer to the field. It has been a very supportive professional community to be part of.
What about the science behind this? It can be difficult for practitioners to accept something that was not taught in their basic training. Syntonics has had a wealth of support in the scientific literature, including recent exciting research out of Spain where changes in functional magnetic resonance imaging scans were demonstrated after one minute of exposure to certain wavelengths of light.
Syntonics has provided me with a great deal of personal satisfaction, I’ve learnt new things, and I’m providing a therapy that is making a real difference. I very much enjoy providing what can be a life-changing treatment to patients with something ‘off the beaten path’.
Dr Kristin Larson OD is a US-trained optometrist and the owner of Eyecare Plus Glen Forrest in Perth, Western Australia.
1. Argilés, M., Sunyer-Grau, B., Arteche-Fernandez, S., et al., Functional connectivity of brain networks with three monochromatic wavelengths: a pilot study using resting functional magnetic resonance imaging, Sci Rep 12, 16197 (2022). doi.org/10.1038/s41598-022-20668-9.