The app requires an ARCore-compatible device. Please check whether your device is supported:
The user is shown static text. He should then move as far from the phone screen as possible until the text becomes little blurry. After that, the user either presses a camera button or quickly covers his nose with a palm which triggers the measurement action. The app measures the distance from the phone screen to the user's face (more precisely, to the tip of user's nose) using augmented reality and uses this information to give the user approximate amount of optic correction in diopters which the user would need to see clearly.
The user's progress is tracked within the app, and can be viewed using in-app charts.
The progress can be imported / exported.
Source code: https://github.com/denisk20/diopter-calc
This app only gives approximate results and should not be considered the primary source of information when choosing glasses. Please consult with a certified optometrist.