Meet the Researcher: Dr Mervyn Thomas

19 December 23

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Press Office

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Dr Mervyn Thomas, PhD, FRCOphth, is a Clinical Associate Professor/Honorary Consultant Ophthalmologist and Clinical Lead of the Ulverscroft Eye Unit. Based at the University of Leicester Ulverscroft Eye Unit, Dr Thomas has received the Wolfson Prize (Royal College of Physicians), the Alcon research prize, the PhD prize for the best thesis across the College of Life Sciences, and the European Paediatric Ophthalmology Society Prize. Research kick-started by Fight for Sight and Nystagmus Network sparked Dr Thomas’ passion for Ophthalmology and has led to a greater understanding of infantile nystagmus and the Leicester grading system for foveal hypoplasia.

We have awarded four grants to Dr Mervyn Thomas since 2016. Three of these were in partnership with the Nystagmus Network. He works as a clinician scientist, splitting his time 50/50 in the NHS, seeing patients with vision problems and the remaining 50 percent of the time conducting research at the University of Leicester.

Support from Fight for Sight and Nystagmus Network has been instrumental in impacting patient care for individuals with sight loss and shaping Dr Thomas’ clinical academic career. His career has focussed on infantile nystagmus, a condition where a baby's eyes move rhythmically from side to side on their own.

“As one might imagine, this to and fro movement of the eyes in an infant can be quite an alarming sign, both for the parents and clinicians”, explained Dr Thomas. He added: “Unfortunately, since there are many causes for infantile nystagmus, it is not uncommon for them to undergo a diagnostic odyssey; repeated appointments, lots of tests, seeing different specialists until eventually coming to a diagnosis. This [process] could take years.”


Genetic causes of infantile nystagmus

Work funded by us and conducted by Dr Thomas has led to easier diagnosis and prognosis enabled by better genomic sequencing techniques.

Dr Thomas explained: “At the start of my clinical academic career, we could only test one gene at a time in the NHS. However, next-generation sequencing technologies were on the horizon (where you could test multiple genes in one go). Utilising this new technology, I recognised the need for a more efficient diagnostic process for infantile nystagmus.”

The realisation prompted his first grant application: “This is when I applied for Fight for Sight funding for a small grant of approximately £15,000 in 2016. I was very fortunate to receive this grant, it was a game-changing event for our work.”

““I was very fortunate to receive this grant, and it was the very first grant I had ever proposed, which was a game-changing event for our work.””

The funding, he said: “allowed us to embark on a pioneering journey.” That journey led to the formation of the first ever genetic panel specifically for infantile nystagmus. The team was able to analyse multiple genes simultaneously. “This was not just a step forward. It was a leap into a new era of diagnosis,” said Dr Thomas.


Increasing diagnostic accuracy

The genetic panel meant the ability to offer patients and their families a more accurate diagnosis, which can significantly improve outcomes.

“Our genetic panel demonstrated exceptional sensitivity and specificity, meaning we could trust the results. Not only were we able to diagnose 80 percent of cases directly from the panel results, but we also found that in just over 10 percent of cases, the results from the genetic panel revised the original clinical diagnosis,” said Dr Thomas.

““This was not just a step forward. It was a leap into a new era of diagnosis."”

Since publishing his findings, other groups have also shown the value of such a genetic testing strategy and this has led to establishing multi-centre collaborations. “We subsequently championed infantile nystagmus to be included within the 100,000 Genomes Project through Genomics England, and once again, devised virtual genetic panels based on our underpinning research funded by Fight for Sight,” Dr Thomas said.

The work led to whole genome sequencing for people with nystagmus and has facilitated better genetic counselling, helping families understand the risks and implications of the condition, “providing clarity in a situation that was once shrouded in uncertainty,” said Dr Thomas.


Improving the prognosis for people with nystagmus

Dr Thomas’ second Fight for Sight Grant, co-funded with Nystagmus Network, focussed on prognosis by harnessing handheld optical coherence tomography. As Dr Thomas explained: “This is where you use what looks like a hairdryer to image the eyes of children and obtain high resolution images of the retina, the light sensing organ at the back of the eye.”

Using these scans, Dr Thomas and his team developed a grading system to grade how well-developed the retina is, which can provide information on the visual potential in children with nystagmus or underdevelopment of the retina. The aim was to see if they could use an early scan in their first couple of years of life to predict their future vision. It led to a grading system which Dr Thomas developed in Leicester called the Leicester grading system for foveal hypoplasia.

“It was a proud moment for us,” said Dr Thomas. “And we're very thankful for Fight for Sight for funding, again, a small grant that allowed us to do this work. We showed that the initial scan can predict the future vision in these children with underdevelopment of the fovea or foveal hypoplasia. So, we were able to show both diagnostics from a genetic point of view and prognostics in relation to infantile nystagmus using handheld optical coherence tomography.”

The development led to awards, collaborations and publications.
More recently, using this collaborative network, Dr Thomas has helped establish the foveal development investigator group consisting of around 20 centres across 12 different countries that get together and look at cases of nystagmus or foveal hyperplasia and see how the retinal features linked to the genetics. This resulted in a press release and publication in the journal Ophthalmology.


Career-defining research

Early funding from Fight for Sight has helped Dr Thomas leverage additional funding for larger grants. “So, in addition to these international awards and the follow-up on funding, we've also attracted bright young clinicians to undertake research in this field,’ said Dr Thomas.

Funding from Fight for Sight has also helped Dr Thomas progress in his career. “This has shaped my career by allowing me to obtain an NIHR clinical lecturer post successfully, and more recently, the clinical associate professor post in Leicester,” he said.

He added, “None of this would have been possible without the support of Fight for Sight, especially the early funding. The funding was not just financial assistance. At that time, as an early career researcher and a trainee ophthalmologist, it was a vote of confidence in our vision, a belief in the potential of our research to change lives.

“The journey from receiving the Fight for Sight grant to making significant advancement in treatment and care of infantile nystagmus has been incredibly rewarding. It is a testament to what can be achieved with dedicated research, backed by visionary support.”