Could a point-of-care test diagnose a dangerous fungal eye infection?

Most people in the UK will be familiar with an at-home pregnancy test or a Covid-19 test. Both are common lateral flow devices (LFDs), which are increasingly used to diagnose many different health conditions.

Thanks to Sight Research UK funding, microbiologist Dr Beth Mills is developing an LFD to rapidly diagnose a sight-threatening eye infection called microbial keratitis, which could ensure patients receive effective treatment straight away.

Patients with microbial keratitis are usually given antibiotic eyedrops. These usually work well if the infection is bacterial. But for fungal infections, which are less common in the UK, antibiotics don’t work. It takes up to two weeks to get a fungal diagnosis, and even then, around half of lab tests fail to identify the pathogen causing the infection. Any delay in treatment increases the risk of surgery and often leads to vision impairment.

Beth’s two-year project is both multidisciplinary and international. At the University of Edinburgh’s Centre for Inflammation Research, her team is identifying suitable antibodies that can be put into an LFD. Prototype devices are manufactured by a commercial company and then returned to the lab for validation. The most promising devices are then sent to a clinical partner in India – where half of all cases of keratitis are fungal – to be tested on patient samples. Meanwhile, back in Edinburgh, computing students are building a smartphone app to help accurately determine whether the LFD result is positive or negative.

“Working across disciplines and with partners means that we can prototype and develop really rapidly. We say that we want to ‘fail fast,’ iterate, and move on.”

If the project is successful, a cost-effective, point-of-care LFD for fungal keratitis will be ready for clinical trial and regulatory approval – crucial steps to undertake to bring this product to market.

“It’s exciting that funding is available for these really innovative, translational projects that have a potential to transform the landscape for diagnostics. Small charities such as Sight Research UK have to be really careful about where they put their resources, so I definitely feel a sense of responsibility to make sure that we deliver results.”