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Glossary of Terms

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Print this definitionOptometric Phototherapy (Syntonics)

Optometric Phototherapy (or Syntonics) is one component of Vision Therapy offered at Vision West.

Syntonics is the use of specific frequencies (colours) of visible light projected into the eyes, to enhance visual efficiency (focus/eye movements) and visual information processing (interpreting what is being seen).

It is used within a program of Vision Therapy, the word Syntonics is defined as ‘balance', which implies this procedure is a form of vision therapy being utilised to enhance the balance within the visual system.

Assessment involves measuring the visual fields. This is measured prior to Syntonics using a specialised instrument called a Stereo Campimeter, which allows measurement of the ability to perceive the expanse of visual space within which someone can detect not only movement but also different colours.

In cases of visual fatigue and visually related learning difficulties, an individual's perceptual visual fields may become temporarily constricted. For example if there exists difficulty maintaining focus or binocular vision for reading it is possible that a person may only see a few letters at a time on the page, rather than being able to scan across the lines of words in the text being read.

If visual stress is influencing the volume of visual information that can be processed per eye movement then Syntonics may be beneficial in improving the visual information processing.

Common situations where this can be an issue include the visual skills required for reading and in the classroom environment, with words often moving, merging or ghosting on the page and children possibly skipping lines or words as they find it difficult to locate their eyes accurately.

Constricted perceptual visual fields can also affect visual-spatial awareness, the ability to perceive and judge where objects are in one's visual space, an important skill for organising work on the page when writing and also for balance and co-ordination such as in movement and sport.

Syntonics usually involves home based therapy which is reviewed in-office. In most case, the therapy would involve hiring a Syntoniser (light unit) along with the specific and individually prescribed coloured filters required. The filter is placed in the Syntoniser and the prescribed coloured light viewed in a dark room, usually for twenty minutes per day for an average period of four weeks.

There are most commonly one or two differently coloured filters required.

Common visual conditions where Optometric Phototherapy may be beneficial include:

  • Visually Related Learning Problems
  • Focus and eye movement difficulties
  • Binocular Vision difficulties
  • Headaches
  • Photophobia (glare sensitivity)
  • Acquired Brain Injury
  • Sports Vision
Print this definitionOrthokeratology

Orthokeratology more commonly referred to as ‘Ortho-K', the use of contact lenses to reshape the cornea (front surface of the eyes) in order to reduce levels of myopia and astigmatism. The lenses are worn in the evening whilst sleeping and allow clear vision for the next day once removed upon waking.


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Word of the Moment

Presbyopia (age related near vision loss)
Where the flexibility and elasticity of the crystalline lens in the eye reduces with age, in so doing the near focus ability of the eye reduces. This requires near vision spectacles to compensate for the loss of focus ability with age. more