Floaters and Flashes
If you see black spots or spider webs that seem to float in a cluster or singly in your vision, or if you see spots that move or remain suspended in one place, or flickering or flashing lights that are most prominent when you look at a bright background, then you have experienced floaters and flashes.

A common cause of floaters and flashes is a condition called posterior vitreous detachment (PVD). The space between the lens and the retina of the eye is filled with a clear, jelly-like substance called vitreous. At birth, the vitreous has an egg-white consistency and is firmly attached to the retina. With age, the vitreous thins and may separate from the back of the eye. As the vitreous pulls free from the retina, it may be accompanied by light floaters and/or flashes. Floaters can be caused by tiny bits of vitreous gel or cells that cast shadows on the retina or from blood seeping into the vitreous. Flashes occur when the vitreous tugs on the sensitive retinal tissue.

In some cases, floaters and flashes may be symptoms of more serious problems, such as retinal tears or retinal detachment. Symptoms of a retinal detachment include sudden vision loss along with floaters and flashes, a veil or curtain that obstructs part or all vision, or a sudden increase in the number of floaters. All patients who notice floaters or flashes should seek immediate medical attention.