I think it depends on the situation... A retinal detachment can take days before it completely detaches or it can happen in a day. Either way if it's starting to detach it's something you should get to the doctor about asap so they can fix it surgically. My grandfather had it a few years ago and I also had a friend have it happen in hs. My understanding with the flashing lights is that it's like bright white lights that suddenly appear in your vision. They may appear to flash on and off and in different parts of your vision (similar to seeing white spots).

It was found out that I had a small retinal detachment two weeks ago, by that blood leaked inside the cornea so I had a sudden blurred eye. I had the surgery last week to remove the blood and corrected the retina by laser and they put gas(N2O) inside the eye to give pressure until the retina cured! Now almost one week my visions is coming back slowly, stll I fell bubble in that eye!!Anybody have a comment on this!!