I was thinking today that you have too much of a visibility advantage when using high-zoom scopes because in real life while aiming with a scope you can see like in Survarium, close and far, but your eyes aren't in focus.
Here is how it looks in Survarium: https://i.imgur.com/0FV06S8.png
Here is what I'm suggesting: https://i.ytimg.com/vi/AI2xXrQpTGs/maxresdefault.jpg
In some games it's done like this (This is Red Orchestra 2, running Unreal Engine 3), and the scope doesn't zoom outside of its area, but for what I've read that solution would be pretty demanding on the PC because the game would have to be rendered twice.
I hope what I propose isn't too demanding or hard to implement.