Product design
Glucose pump application ● Eversense
I redesigned a mobile app for Eversense’s first permanently-implanted glucose sensor. The app quickly received FDA approval.
In use, the app first had to assist the user in first positioning an external transmitter over the implanted sensor.
Then the app had to provide blood sugar status and recommendations to patients with little technical or scientific background.
Linear vs. logarithmic scale?
A big issue was how to plot data over time. A person with diabetes ideally maintains a glucose level between 70 mg/dl and 180 mg/dl. A critical low is around 40 mg/dl, but readings can be as high as 400 mg/dl. A purely linear numeric scale topping out at 400 mg/dl would have looked very bottom-heavy since most readings would be clustered in the bottom 50% of the scale. I solved the problem by using a logarithmic scale. The ideal target range was vertically centered on the scale and the upper and lower ranges were approximately the same size.
Here are the two scales displayed side-by-side.
Note that both scales “0” and “250” points align, but it’s not possible to display “400” on the linear scale in this view.