Hello Grant, thanks for your reply!
I have tried alot of different light, almost pitch black, some background light, and fully bright light. But the result remains the same. The firmware is up to date and I have no piercings or so 🙂 I will let my brother test the device out to see if it works better on him.
Are you planning to add some feature so manually offset/change the focus area? I read some threads from 2016 where this was also asked by other people.