Properly designed roundabouts have 2 lanes in and out for each road so the right lane turns into the right lane of the road to the right without much need to slow or stop. The left (inner lane) acts as a yield and moves to the center of the roundabout when traffic is clear and turns out of the roundabout into a left lane further around the circle. Assuming the inner green area is of a large enough radius, why do you need to see across? If you're in the right lane, it shouldn't matter (though training drivers in the inner lane of the roundabout that they can only turn out into left lanes and not right lanes can be a challenge), and if you're in the left lane as long as the sight lines aren't obstructed enough that you can see say 90degrees around the circle you should have enough room to know when traffic is clear to pull into the inner lane. What's going on on the opposite side of the roundabout shouldn't affect you in the slightest.