Also the shrunken gel can bump the retina if it is too close to the retina. In some cases it can cause a detachment of the retina itself. When the detached gel slightly bumps the retina by looking quickly to the side, one can can see the result, usually in the dark, as a flash of light. A retinal detachment however would look like a persistent jagged lighting bolt or a peculiar dark area. . Some strenous occupations like police work in the field would call for a precautionary laser welding of the retina even though the retina are not yet detached.
So far the flashing bump of the retina in my eyes have become rare and the retina are intact. That means the gel has receded to a point that that it usually clears the retina with bumping.