Sarah Houston

Sarah Houston is a final year PhD student working with Dr Adam Dubis and Professor John Greenwood. Her project which is jointly funded by the NIHR and the MS Society, involves studying small blood vessels at the back of the eye.

What was your journey into ophthalmology?

Biology was always my favourite subject at school, I particularly enjoyed learning all about the Human Body! So I found studying for an undergraduate degree in Human Biology at Queen’s University in Belfast really interesting. It was during my final year project that I became fascinated by the structure and function of the eye. I worked on a project with a great supervisor; Dr Tom Gardiner a vision and vascular specialist, this involved studying photoreceptors; the cells at the back of the eye that respond to light. It made me realise that studying the eye is particularly useful as it allows you to study a range of different diseases and because we can see all the blood vessels in the living eye without touching it, we can track any changes over time. This could be useful in finding out more about conditions such as diabetic retinopathy, hypertension and many others.

In this image Sarah Houston is leaning into a black box. There are lots of electronic parts in the box.

During my degree I also spent a year in the laboratory, but decided being solely a lab-based researcher wasn’t the career for me. Having found my interest in the eye, I was lucky to hear about a NHS Scientist Training Programme and got a place on the Ophthalmology and Vision Science stream in Liverpool. This was a three year work-based and academic training course which involved studying visual assessment, imaging and visual electrophysiology. I learnt about lots of different ways of monitoring and diagnosing different eye conditions. At the end of the programme I had a Master’s degree and a clinical scientist qualification, but was really keen to learn more and carry out my own research. Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology together are a centre for research excellence and I am very pleased to have been offered a place here to carry out a PhD.

In this image Sarah Houston is looking at the computer screen and looking at images from the AO

Can you tell us about your current research?

My PhD project is looking at the blood vessels in the retina, the light sensitive region at the back of the eye in Multiple Sclerosis (MS). MS is a condition that affects the brain and spinal cord. In MS, the coating that protects nerves (myelin) is damaged. This causes a range of symptoms like blurred vision and problems with how we move think and feel. The blood vessels at the back of the eye haven’t really been studied in much detail before in this condition. This is because MS has been considered an inflammatory disease, but in the later stages of MS the anti-inflammatory drugs don’t work. So we think something else may be happening and we really want to investigate this further.

Previously in 2014, a trial of 140 patients led by Professor Jeremy Chataway treated half the patients with a high daily dose of statins and the other half placebo. The team believed that the statins would work by reducing inflammation. The statins did work reducing brain volume loss compared to the placebo, but they found that it wasn’t because they reduced inflammation, as the markers for inflammation were still high. We therefore think that it might be to do with blood flow. The statins might work to improve blood flow in MS patients.

We’ll be using high resolution none invasive imaging to find out what is happening in the living eye. I’m using imaging techniques that are currently used in the clinic such as OCT and OCTA. As part of the trial we’ll also use oximetry, this technique enables us to monitor the percentage of oxygen in the blood. I am also using a very advanced technique called Adaptive Optics Scanning Laser Ophthalmoscopy (AO). It was originally developed to look at stars in astronomy. The technique can correct in real-time the aberrations of the eye; when light rays enter the eye they depart from the normal course and AO can correct for this which is the reason imaging is limited with other techniques. AO allows us to image the vessels at the back of the eye in a lot of detail, we’ll even be able to image the blood flowing through the smallest vessels of the eye. What is great about these techniques is we’ll be able to see any changes over time in patients.

So far we are getting the baseline data, we’ve been measuring the blood flow in patients and in healthy individuals – my PhD will be based on the results from this. The clinical trial will then run for two years and hopefully we will be able to see if the statins have made a difference to the vessels and if they have in what way.

This is an example of the imaging that is possible with the Adaptive Optics Scanning Laser Ophthalmoloscopy (AO)

How has your work been supported by the NIHR Moorfields Biomedical Research Centre (BRC)?

My PhD is half funded by NIHR Moorfields BRC – so thank you! There is also lots of additional courses and training that is available to me, to help in my development. The research is also supported by all the infrastructure that BRC has put in place; such as the clinical research facility where the clinical trial takes place.

What does the future of ophthalmology look like?

The future for ophthalmology looks very exciting. There are constantly new developments in high resolution imaging, this could be used to study retinal blood flow in other brain diseases, such as dementia and stroke. We have an excellent team of physicists and programmers who work tirelessly to improve analysis techniques and the software that we use. The potential for using A.I. along with advanced imaging techniques could lead to faster diagnosis and a better understanding of what is happening in a number of different conditions.