I am having a flickering in right eye I.mean it starts feeling as if it's upper lid is shaking and it does not stop when I place my hand to stop .it does not appear outside but I feel it inside as if upper lid is flickering but I was working on my system for four continue hrs and then it started flickering I don't know what other word I use for it but I felt it for quite few minutes it was not stopping and not visible to others to get noticed but it was irritating what could be the reason for it I wear specs of .50 power in right eye .left is ok.