You know when you look at the light for too long, and it kinda leaves an imprint on your vision.

Well the past few weeks this has ben happening to me loads, but without looking at light, a similar kinda thing will appear like in the middle of my vision and then it'll get bigger and eventually disappear. It only affects my vision slightly, but I'm scared it might get worse. It happens like once every two weeks.

Is this anything to worry about?