Area of expertise: Digital Health and Diagnostics
Important conditions of the central nervous system, with wide societal impact, have distinctive symptoms that affect vision. Importantly, a patient may have sight-threatening disease with near-normal visual acuity, yet have profound derailment of colour vision, or of contrast sensitivity, not detected by a simple eye test. Consequently, such diseases are often detected late, when opportunities for effective treatment have lapsed.
This is particularly true of a common neurodevelopmental disorder, amblyopia, commonly known as “lazy eye”, the leading cause of poor vision in children. It affects 2 to 4% of children below 7 years of age. Ideally, in order to be effective, treatment needs to start in early infancy. Yet, infants do not respond to the complex instructions needed to perform a vision test. Children are normally screened for amblyopia as late as 4-5 years, when they can follow instructions and, yet, when treatment becomes less effective.
An example more typical of a young working adult population, is optic neuritis, acute inflammation of the optic nerve that causes loss of vision in one eye. It is highly associated with multiple sclerosis, being the first sign of the disease in 15-20% of cases. The most typical visual sign is a decreased perception of colour in the affected eye. No clinical standards are available to measure this and, typically, antiquated tests designed for colour blindness, are inconsistently used, with poorly repeatable and subjective results.
The contribution of the EPSRC CDT in Medical Devices and Health Technologies
The diagnosis of these conditions entails important common elements. They can, in principle, be diagnosed by asking the patient to detect or identify, a target over a background. For example, they can be asked to look at a dot, or to read a letter. In young infants, or in patients with profound cognitive disabilities, rather than asking for a response, the target can be shown, and the instinctive curiosity-driven movement of the head and eyes towards the target can be detected, registered and interpreted to determine vision without instruction or a need for shared language.
In recent years, digital displays, ranging from computer monitors and phones to more sophisticated virtual reality (VR) headsets, have reached performance levels that allow delivering solid and reliable eye tests. Also, these devices are often paired with cameras and sensors, that can be used to look at the patients and detect their responses.
The EPSRC CDT in Medical Devices and Health Technologies, at the University of Strathclyde, also supported by funding from the Teresa Rosenbaum Bolden Charitable Trust (Rosetrees Trust) and RS Macdonald Trust and receiving clinical support from NHS Forth Valley and NHS Greater Glasgow & Clyde, is developing new technologies that, leveraging screens, VR headsets, cameras, and sensors, allow testing for those vision markers that are related to visual brain disorders, such as colour vision, or contrast vision.
These tests are being designed to be deliverable manually, automatically, or even remotely, via teleconference. Through this activity, the EPSRC CDT in Medical Devices and Health Technologies is:
- Creating new ideas, methods and technologies for vision testing.
- Forming new partnerships, currently with NHS and, through ongoing intellectual property protection and transfer, soon with industry.
- Attracting funding, currently from two charities and, prospectively, with industry, that is currently negotiating with the University of Strathclyde an appropriate framework.
- Ultimately, benefitting patients. The study has highlighted important pitfalls in current child testing, and the technologies under development are now undergoing trial within the NHS, in view of making them available in the near future.
Success of the project would lay the ground for a radical advancement in screening and diagnostics of optic nerve and visual brain dysfunction, ultimately enabling a step change in improving outcomes. Given the low capital costs and the ease of use, the proposed technologies are suitable for resource-limited settings, and hence applicable in low- and middle-income countries, in addition to high-income environments such as the UK.