For the many seniors who have day time hours to play enlarge or create a more visible circle which indicates your turn.
You know you can make the table bigger by stretching the sides? Maybe that helps too a bit.
With our new poker client using html5 instead of flash the notice of turn is definitely more apparent, this should go live in the next 2 or 3 months. In the meantime as happiness suggests, you can change the size of the window to make the game table bigger.