fiddle with the settings and make it 'less pronounced' ... I've found the default settings for games are pretty extreme to make i look very 3D, and tat's what causes the eye strain, try and set the depth such that most things you are looking at tend to be near the sam field of depth as any menu's or head-up-displays, and decrease the depth till it's comfortable (you will still see the 3D effect and it will still help in judging distance, but it will be easier on the eyes)