A snap shot taken of a patient’s retina could in the future become a lifesaver in the fight against a pandemic that is emerging as a leading killer in both low and middle income countries.
This pandemic is cardiovascular disease and its victims for the most part feel no symptoms or pain and have little inclination to see a doctor. When the symptoms do finally present often it is too late.
According to the World Health Organization in 2019 an estimated 17,9 million people died from cardiovascular disease. This presented a third of all global deaths and of this total 85% were due to heart attacks and strokes. And it is set to get worse with a policy statement from the American Heart Association warning that by 2030 40,5% of the US population is projected to have some form of cardiovascular disease.
Another disturbing statistic is that sub-Saharan Africa is one of the only geographic regions globally where mortality due to cardiovascular disease is on the increase.
The rise has been balmed on lifestyle choices that include unhealthy eating, physical inactivity and harmful use of tobacco and alcohol.
But besides heart attacks and strokes, (also known as cerebrovascular disease) cardiovascular disease include other illnesses such as hypertension, coronary heart disease, heart failure and deep vein thrombosis.
Diagnosing these illnesses is difficult as doctors only see the patients when the disease is at an advanced stage. Even though patients at risk of developing cardiovascular disease most often aren’t flagged by doctors.
Now a machine that is often a centerpiece of many an optometrist and ophthalmologist practice could provide the much needed early warning system for cardiovascular disease.
A recent research study looked, among other things, at the use of retinal imaging to examine the health of the small blood vessel in the eye.
Retinal imaging takes a digital photo of the back of the eye (known as the retina) which is traditionally used to assess the health of the optic nerve and the eye itself. However Professor Hans Strijdom of the Centre of Cardiometabolic Research in the Division of Medical Physiology, at Stellenbosch University, is using the technology to measure the width of the retina blood vessels and with that take a peek into their health.
“It gives you an amazing view of what’s going on inside of that person’s body in terms of the cardiovascular system. And that is really the big advantage of this technology,” explains Strijdom.
One of those tell tale signs could be for example dilated blood venules (small blood vessels draining blood from the retina) that point to developing high blood pressure.
The research project was called the EndoAfrica study and was developed to examine whether HIV infection and antiretroviral therapy (ART) are associated with cardiovascular risks and changes.
The study was run at three field sites in three provinces with two cameras used.
Besides the University of Stellenbosch, the North-West University and Walter Sisulu University also took part in the study.
“So what we found in that study were differences between the HIV control groups,” says Strijdom. “One of the interesting findings, we could show, was that people with HIV who were on treatment had an overall retinal profile that was more healthy than those that were not on treatment, and even to a certain extent compared to those that didn’t have HIV at all.”
The study did show how easily the system could be set up and rolled out in a rural setting. Technicians could learn to use the camera in a handful of weeks and the procedure to image a patient only took a couple of minutes. There was no need for eye drops to dilate pupils and the only temporary discomfort is the flash of the camera.
“It opens itself for telemedicine, where you can capture an image without a specialist. You can then easily send that image via WhatsApp,” says Strijdom. Software, which is still in development, will also provide a diagnosis of the image. “This software will give a strong indication that something is wrong,” says Strijdom. If something is noted a specialist would then examine the image.
There is still however a lot of work to be done before retinal imaging becomes part of the arsenal fight against cardiovascular disease. The team is ironing out and the nuts and bolts. And the production of smaller and cheaper retinal cameras is currently being developed. They are still looking at HIV and its relationship with cardiovascular disease.
“You need to understand the mechanism between these retinal changes, if you can figure out this mechanism you will immediately open up avenues.”