Brain Sciences


Meet the expert: Professor Omar Mahroo

Omar Mahroo is Professor of Retinal Neuroscience at UCL, and Consultant Ophthalmologist at Moorfields Eye Hospital and St Thomas’ Hospital in London.

Omar Mahroo

What attracted you to the area of retinal function and why is it important?

As an undergraduate medical student at Cambridge, I was fascinated by visual neuroscience. I was taught by the late Roger Carpenter, an eminent neurophysiologist. In my third year, lectures by Trevor Lamb, a world authority on photoreceptors, inspired me further – I proceeded to a research project, then a PhD, and then post-doctoral work under his supervision. In my clinical training, I gravitated towards ophthalmology and in particular retinal diseases, given I had established a research interest in this area.

Light detection and visual processing in the retina can shape our view of the world more than any other sensory system. Retinal diseases are a leading cause of blindness. Inherited retinal diseases, which are mostly diseases of the photoreceptors, are the leading cause of blindness certification in working age individuals.

Unfortunately, the majority of these are untreatable. Better understanding of retinal function, in health and disease, could give us greater insight into these conditions and help inform the development of future therapies. Also, we know that a very common condition, myopia, is driven somehow by retinal signalling; identifying the pathways involved could help in prevention of myopia and its complications. Finally, the retina has similarities with the neuronal circuitry of the brain, and it is possible that explorations of retinal function can shed light on brain function and some of the impairments in specific neurological or neuropsychiatric disorders.

Can you tell us about your current research and the focus of your lab?

Broadly, we investigate human retinal function in health and disease using retinal electrophysiology and several complementary approaches in collaboration with other investigators, which include multimodal retinal imaging, genetic sequencing and machine-learning techniques.

The electrical response of retinal neuronal populations can be recorded non-invasively from the living human eye as the electroretinogram (ERG). It’s a bit like an ECG, but coming from the retina rather than the heart. Our team investigates the range of responses in healthy individuals and also how the retina adapts to different light levels.

We are developing and deploying novel testing protocols to better understand rare retinal diseases. We are trialling the use of portable devices to improve accessibility to testing. We are also investigating associations between the electrical responses of the retina and genetic variants that have been associated with myopia to try to understand the mechanism by which they might confer myopia risk (we published some of our first results from this study last year).

What aspect of your work most excites you and why?

Many aspects of my work excite me! Scientifically, making new discoveries is always exciting, and I am more excited by the possibility that one day these might help make a difference to future patients with conditions that are currently poorly understood and sadly still not treatable.

It is also very rewarding to see junior members of the research team develop and progress. I have the honour of supervising students who have won awards for the research they conducted in my lab, and I’m as thrilled as they are.

Clinically, making a difference to patients, getting difficult diagnoses right, and improving their quality of life is always fulfilling. I am consulted on difficult cases from home and abroad, and often can’t really add much to what the clinicians have already thought of, but, now and again, I’m able to make a suggestion that reveals the diagnosis. It’s great to see the trainees and fellows in my clinics develop, and the teaching dimensions of my work are also rewarding. Being in an environment where we are all constantly learning from each other (and from our patients) is tremendously stimulating. 

What would you say to someone who is considering whether to study ophthalmology at UCL?

Ophthalmology is a post-graduate medical specialty, so I’ll answer with reference to Moorfields, which is closely connected with the UCL Institute of Ophthalmology. Moorfields Eye Hospital is one of the largest eye centres in the world in terms of numbers of patients seen. I would recommend that anyone training in ophthalmology should consider spending at least some time at Moorfields. There are many rare conditions that are seldom encountered in other centres. The range of clinical expertise is extensive and there is a strong focus on teaching and sharing learning points. Much of the teaching is online and therefore easily accessible. One particular weekly session, which is close to my heart, is “Prof Bird Teaching”. This is a clinical retinal case discussion that I chair with Pearse Keane, and that has been running for many years. It now runs online on Zoom, and attracts an international audience, which means you may well get the chance to hear opinions from experts from different continents!

The Institute of Ophthalmology is an epicentre of global vision research, and many seminal discoveries in vision science have been made there. Numerous global leaders in ophthalmology and eye research have spent time at Moorfields and/or the Institute. 

What’s the best advice you would give your younger self?

I don’t know what the best advice would be, and I don’t know if young me would have listened to old me anyway. In terms of clinical practice, one piece of advice that I received early on, and that stuck with me, was during a period at Yale, from a physician called Vincent Quagliarello, who told us, “Be your patient’s advocate.”  I took this to mean going the extra mile for patients.

A bit of advice in research would be that when your results (sometimes frustratingly and depressingly) don’t seem to add up, that can be the time when, if you persist (possibly looking at everything from another angle), you can make a real breakthrough that can upturn conventional wisdom. That’s a little dramatic; a more general way of expressing it would be that things that puzzle you (clinically and scientifically – even little things) can be turned into testable hypotheses and make for some interesting and meaningful research, with wider ramifications. Another bit of lifestyle advice would be to remember to find time for the kids in their early years as that time doesn’t come back (nor does any time!).