New smartphone app uses selfie to measure blood pressure

SANTA MONICA, Calif. (KABC) -- In the U.S., 122 million people have high blood pressure and doctors say about two-thirds are unaware.

Part of the reason is that many people don't visit their doctors, nor do they have access to home blood pressure monitors. But the launch of a new smartphone app could make knowing your status as easy as taking a selfie.

Sleight of hand is a big part of magician Joe Selph's act, but when it came to his blood pressure, he was under an illusion.

"My blood pressure was apparently high for me," he said.

Selph suffered a heart attack in 2015. Now he keeps a close eye on his blood pressure. But even with a home device, it's no easy trick.

"I have to pull this thing out of a drawer, have to get it set up, put it on. You got to sit there. You got to rest," Selph said.

"We recommend taking blood pressure measurements at different times of the day, several days a week," said cardiologist Dr. Raed Bargout, with Dignity Health Care Glendale Memorial Hospital.

He admits that could get cumbersome. But what if reading levels could be as easy as taking a 55 second selfie? A new app called Together by Renee has a feature that aims to do just that.

"The way that that works is the camera is looking at the changes in the blood vessels in the whites of my eyes, right, and along this part of my face," said Nick Desai, co-founder of Together by Renee.

After detecting blood movement, the app uses artificial intelligence and algorithms to measure blood pressure, heart rate and even blood oxygen levels. But how accurate is it?

Bargout, who does not have a relationship with the app, says a University of Toronto study shows the technology hits close to the mark.

"They're accurate in the range of 95%, which is, which is extremely good," he said.

App developer Dr. Renee Dua says hypertension patients can use the feature to track if their therapies are working.

"You're taking all these medicines for your blood pressure, but how do you know that you're actually controlling your blood pressure and this is a simple and easy way to do it," she said.

Most Americans should aim for no more than 120 over 80. A recent USC Dornsife Center study found only about 40% of respondents knew what a healthy blood pressure reading was.

This, combined with not knowing your own readings gives you a false confidence that can have deadly consequences.

"We call blood pressure in textbooks 'the silent killer' for a reason. The majority of patients who are hypertensive are asymptomatic," Bargout said.

He said the app should not replace regular doctor visits, and he's not ready to tell people to throw out their home devices. But using a selfie video to measure blood pressure is yet another tool he thinks his patients will welcome.

"I'm all about any kind of app that will help me make my life easier and more importantly help me maintain my health," Selph said.

Together by Renee is a free app. Developers said it works with all skin colors, but is not very accurate if you have a lot of facial hair.