Recently, researchers at the University of Toronto figured out a way with a quick video selfie to accurately measure blood pressure with your smartphone's camera by developing a technology known as transdermal optical imaging (TOI) (透皮光学成像)．
Cameras on smartphones can catch red light reflected from hemoglobin (血红素) under our skin, which permits TOI to visualize and measure blood flow changes. Researchers measured the blood pressure of 1,328 Canadian and Chinese adults by getting twominute videos of their faces on an iPhone. “From the video got by the technology, you can see how the blood flows in different parts of the face and through this flow, you can get a lot of information，” said Kang Lee, lead author of the study.
Lee also helped create an app called Anura, which allows people to try out the TOI software for themselves, giving them the ability to record a 30second video of their face and receive measurements for stress levels and resting heart rate. Lee said more research was needed to make sure that the measurements were as accurate as possible, explaining that the study didn't test people with very dark or very fair skin.
“In order to improve our app to make it usable, particularly for people with hypertension (高血压)，we need to collect a lot of data from them, which is very hard because a lot of them are already taking medicine，” Lee explained. “We cannot tell them not to take medicine, but from time to time, we get participants who don't take medicine so we can get hypertensive people this way. ”
The scientists said there were many potential applications of the technology, including providing health services for those who lived in remote areas.
