U of T researchers accurately measure blood pressure using phone camera (opens in new tab)

This is really interesting. I love the idea.

> The researchers found they were able to measure three types of blood pressure with 95 to 96 per cent accuracy.

First question, what is the third type of blood pressure? I just know the two numbers, systolic and diastolic.

Second, what it the accuracy of current devices? (Which also have gone automated, and seem pretty nifty) It seems like being 5% off could push someone over the newly lowered border of worrying blood pressure at systolic > 120.

How is this measuring pressure? Changes in brightness could just be more flexible veins or some other attribute being measured than pressure. Without more info, this seems too good to be true.