A new app to detect anaemia?

Researchers are using smartphone images of the inner eyelid to test for anaemia
16 July 2021

Interview with 

Selim Suner, Brown University and Rhode Island Hospital




Anaemia is a common condition that makes you feel tired and weak. It’s caused by a lack of iron-rich haemoglobin that’s present in your red blood cells. People who lose a lot of blood, don’t eat a good diet, or have diseases that affect the ability of the body to produce red blood cells can all fall victim. Now anaemia is usually very easy to treat but often greatly underdiagnosed, mainly because, right now, the way you test for it is inconvenient: it involves taking a blood sample and waiting for this to be analysed in a lab. But now, researchers at Brown University have found a faster way to spot it, which can be done in literally the blink of an eye, as Sally Le Page found out by speaking with Selim Suner..

Sally - Okay, I've got my phone on selfie camera mode. I'm holding it as close to my face as possible, until it can no longer focus. I'm pulling down on my lower eyelid. And there we go, a terrifying image of my inner eyelid. Now, as a young millennial, I've probably taken more selfies than the average person, but this is a strange thing to be doing even for me. However, this may become a more normal activity in the future, as a team of researchers at Brown University and Rhode Island Hospital have figured out a way to use photos of people's inner eyelids to test for anaemia, as I heard from lead author Selim Suner.

Selim - There are blood vessels very close to the surface of the inside of the eyelid, and they come together to give the inner eyelid a red hue. And that's primarily what we're extracting from those images is that red hue, and using some fancy math and image processing to extract the redness of the inner eyelid and the less red it is, the more likely that that person has anaemia

Sally - Anaemia is a lack of red blood cells in the blood, and in severe cases can make you seriously ill or even be fatal. And anaemia is incredibly common too.

Selim - It's thought that about a third of the world's population is anemic to a certain extent, and this is more pronounced in developing countries and in countries where there are parasitic diseases such as malaria, and also nutritional deficiencies can cause anaemia as well.

Sally - Right now, the gold standard test for anaemia is a blood test, but Selim's team hopes to be able to develop this eyelid photography test into an app for any smartphone. But what's wrong with a simple blood test?

Selim - Well, you would have to make an appointment with your GP. They would have to order the test. You would have to go to a lab, get your arm or hand stuck with a needle and then wait for the results, which would probably take a few days. Whereas if you had this app, you can take a picture of your lower eyelid and have the results in seconds, it's that fast

Sally - Sounds simple, right? But is it accurate?

Selim- So our test is about 70 to 80% accurate in determining if someone is anaemic, and skin colour does not affect our results. So one use is that we could screen populations with this test and those that come up anaemic on our test would go on to get a blood test and get treated, so that would save resources.

Sally -
Are there any other ways this is more appropriate than a blood test?

Selim - In time-sensitive conditions, for example, after a car accident, this test could be performed with a phone in the ambulance. And if a patient is losing a lot of blood, then we could figure that out very fast.

Sally - I hadn't thought of that. I always think of anaemia as something that comes on gradually because of diet, but I suppose, if you're losing a lot of blood, you're very quickly going to become anaemic.

Selim - Absolutely, and that could occur from traumatic conditions where there's bleeding either internally or externally or from gastrointestinal bleeding, which is a common cause of anaemia.

Sally - You said anaemia is more common in developing countries, and I imagine it's much harder to get a blood test there, but are there enough smartphones with good enough cameras for your app to be useful in those countries?

Selim - Well, we've looked into that, and even though the number of people with access to portable phones with cameras is less in developing countries, this number is growing significantly over time, and it's not as low as people think. For example, in Africa, the penetrance of cell phones with cameras is about 30%.

Sally - It's going to take a bit more research to turn this image analysis into a simple app that works on the majority of phones and doesn't require any training to use accurately. So for now I can thankfully delete all of the photos of my inner eyelid from my phone, but I'll be keeping a close eye on how this develops over the next few years.


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