From the past five to six months I have developed a blinking  spot in my vision of right eye that isn't black or grey not coloured. It flickers continuously. Also when I cover my left eye and look at something very tiny as such a small black dot on the wall, it disappears as the spot flickers over it. I have consulted an ophthalmologist recently who performed funduscopy, slit lamp exam and field test and told me that there is nothing wrong. He just gave me cellusoothe eye lubricating drops. Now iam very much tensed ad to what is this and how will it be treated . Please guide me for the same.