Scottish Health Innovations Ltd

Prism Glasses

Prism-Glasses-awardDr. Jonathon Bannister, a Consultant in Anaesthesia and Pain Management in Ninewells Hospital, came to Scottish Health Innovations Ltd (SHIL) for help to develop an idea he had with his colleague Dr. Glyn Walsh, a Senior Lecturer and Registered Optometrist from Glasgow Caledonian University.  Their idea was to produce a device that would help patients suffering from a condition called Phantom Limb Pain (PLP).

What is Phantom Limb Pain?
PLP is a common complication following amputation of a limb. It is considered a dysfunction of the sensory-motor control system. In normal circumstances, the brain sends motor signals to move the limb and receives sensory feedback that indicates that the limb is moving as instructed. In some circumstances the brain still tries to communicate with a severed limb. The discrepancy between the motor signals that the brain sends to move the limb and the sensory feedback that the brain receives results in the sensation of pain where the limb used to be, hence the name PLP.
050324-090804-HC-Hi-res-prism-glasses-3How is it treated?
In addition to pain killers, patients are offered what is known as mirror therapy. The patient places the intact limb in front of the mirror box and the remaining part of the amputated limb in the mirror box behind the mirror. The patient sees a reflection of the intact limb and is ‘tricked’ into believing that they are seeing an intact amputated limb. For example, a right handed amputee would see a reflection of their left arm at the position of the right arm, thus creating the illusion of the presence of the right arm even though the right arm has been amputated.

The Innovation
Mirror therapy is gaining a strong reputation as an effective tool for alleviating PLP and also helping rehabilitation of patients suffering from an inability to move a limb following a stroke.  However, the disadvantage of the mirror box is that it is not easy to use on leg amputations, allows only restricted exercises and is not easily portable. These limitations inspired Dr. Bannister and Dr. Walsh to create the Prism GlassesTM.

The Prism Glasses, by virtue of size, realistic optical illusion and creativity encourage, more frequent therapy and a better chance of a speedy recovery to take place at home. The functions that can be performed are more natural, compared to the mirror box, and the prism glasses have applications in other neurological conditions such as Stroke, Chronic Regional Pain Syndrome, Visual Neglect Syndrome and Potentially Dyslexia.

The versatility of the Prism Glasses means that they will make an ideal research tool to investigate the physiology of PLP and stroke, and can readily be incorporated into studies involving imaging modalities like fMRI.

How did SHIL help?

Step 1 – Establishing the Market and the Clinical Demand
When Dr. Bannister and Dr. Walsh came to SHIL, they had already designed and built a basic prototype however they were still in the early stages of development. SHIL was able to help them build a case for development of the innovation by carrying out independent market research to validate the need for such an innovation and to see if there were any competitors working on anything similar.

Step 2 – Protecting the Idea
SHIL assessed the idea and determined the best way to protect the intellectual property by filing a patent application.

Intellectual property is defined as original creative work such as an invention, piece of music, brand or design that has been developed to such a stage that it can be owned in the same way as physical property. Intellectual property should be protected if it is of commercial value. Protecting IP allows you to manage how it is used and who uses it.

Step 3
SHIL was able to fund the development during the initial stages including the patent costs, and prototype development with Medical Physics at Ninewells Hospital. This novel innovation gained further recognition by winning a Medical Futures Unltd Innovation & Enterprise Award at the Medical Futures Innovation Awards in 2006.

Step 4
Further funding came from SHIL to conduct a clinical trial using the prism glasses as a treatment for phantom limb pain and NHS Tayside Endowment Funds to explore the use of the prism glasses as a treatment for stroke. 

Step 5
SHIL continued to source a manufacturer who will produce a commercial version of the glasses on a large scale for use within a clinical setting. SHIL will be responsible for taking the product to market.  SHIL has recently worked with a web designer to constructed a website ( to raise awareness of the device and make them commercially available.  SHIL is also seeking distributors for overseas markets. 

This is just one example of how SHIL has helped develop an innovation from NHS Scotland. SHIL is working with a wide variety of health care professionals who have come to SHIL with ideas varying from simple innovations to high tech research products.

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