Neeraj Dhaun, MD, PhD, says advances in OCT tech may positively impact patients with chronic kidney disease

Neeraj (Bean) Dhaun, MD, PhD. Image courtesy of Heidelberg Engineering.

The 21st International SPECTRALIS Symposium (ISS) is underway in Heidelberg, Germany. Organised by Heidelberg Engineering, the scientific programme on 13 and 14 June includes a lineup of leaders in ophthalmology, as well as experts from adjacent fields sharing their knowledge.

Neeraj Dhaun, MD, PhD, better known to his patients and colleagues as Bean, is a professor of nephrology at the University of Edinburgh; an honorary consultant nephrologist at the Royal Infirmary of Edinburgh; and director of the Edinburgh Clinical Research Facility. He is also a senior fellow, INSERM and Université Paris-Descartes and the PARis Cardiovascular Centre, France.

Prof Dhaun shared his insights with Ophthalmology Times Europe ahead of the meeting. Here, he answers questions about the new ocular imaging tools that are opening doors for patients with kidney disease. Read on to learn how much power ophthalmologists wield in detecting and even preventing kidney disease.

Ophthalmology Times Europe: We know that the kidneys are a prime “subject” for ocular biomarkers/metabolomic indicators. How do ocular biomarkers change with progression of chronic kidney disease?

Neeraj Dhaun (Bean), MD, PhD: The eye and the kidney are structurally and functionally similar and so there is huge potential for ocular biomarkers to be used to track kidney injury. We know that progression of retinopathy (diabetic, hypertensive or otherwise) that we can identify on retinal fundus photography tracks with decline in kidney function. These processes happen slowly and consequently there aren’t any major changes or big steps that require urgent action from a kidney perspective. However, it would be sensible for ophthalmologists who identify vascular changes at the back of the eye to highlight these to patients and clinicians and encourage them to have their kidney function checked, as we know early identification and treatment of kidney disease improves outcomes.

OTE: Let's learn more about your presentation title. Please, walk us through the “old concepts” that you mention. Are there misconceptions or outdated protocols that persist within ophthalmology and nephrology?

BD: Since 1836, we have known that the eye and the kidney are linked. Conditions like diabetes mellitus result in damage to the small blood vessels in the eye which we see as diabetic retinopathy which is reflected in the kidney as diabetic nephropathy. Unfortunately, by the time this is identified patients have often already lost >50% of their kidney function. Therefore, new technologies that allow us to identify patients at risk of kidney disease at an early stage before significant damage occurs are critical.

OTE: Focusing on those “better tools” and “new horizons,” what are some of the technological developments that have had a major impact in recent years?

BD: The development of optical coherence tomography (OCT) has transformed clinical ophthalmology and provides unique insights into ocular and systemic health. The high resolution imaging afforded by OCT allows identification and segmentation of the retinal layers, including of the choroidal circulation. This is a purely vascular layer at the back of the eye and changes here may reflect systemic microvascular function. This is particularly relevant in kidney disease and cardiovascular disease. Using this technology, our group has shown that patients with kidney disease have thinning of the retina and choroid and that the degree of thinning can identify individuals at highest risk of future decline in kidney function. Most interestingly, we showed that these changes are reversible if a patient's kidney function improves (for example, following kidney transplantation).

OTE: And looking ahead, what technologies or techniques do you predict will have a major impact on oculomics, going forward?

BD: OCT angiography has emerged in recent years and may provide additional information to evaluate a patient's vascular health and predict future kidney and cardiovascular disease. This technology provides a detailed angiogram of the capillary circulation allowing retinal perfusion to be assessed. Additionally, there is now a wealth of ocular imaging data including from OCT scans as these are now readily available in opticians worldwide. By combining deep machine learning with retinal images, researchers have shown the eye can accurately predict an individual's risk of developing a number of systemic diseases, including heart attack, heart failure and stroke. In terms of ’new horizons’, I would be very keen to see how newer ultrahigh resolution OCT imaging devices can help us define systemic disease even earlier in their trajectory.

OTE: Why is it so important for ophthalmologists to understand kidney disease and its relation to the eye?

BD: The eye, unlike other organs, allows clinicians to directly assess its structure and function without the need for invasive biopsies. With advances in technology, the data provided by eye imaging can now be used to detect a range of diseases. Ophthalmologists can be at the forefront of this revolution in healthcare by identifying at-risk individuals and encouraging them and their clinicians to screen them for disease. This may result in earlier diagnosis and improved outcomes for patients.

OTE: What do you hope are the key takeaways from your talk at ISS?

BD: I would like the ophthalmology community to appreciate that they are in an excellent position to provide insights not only into ocular diseases but also diseases affecting other parts of the body, for example, the brain, heart and kidney. Going forward, it would be ideal if retinal imaging were able to identify systemic diseases before they are clinically apparent at a time when we might modify their trajectory for the better, or even prevent them developing altogether.