Flashes and floaters are caused by the degeneration of the transparent vitreous gel that fills the interior of the eye. As aging takes place, the gel breaks down into clumps, which are detected in the visual field as small specks, or floaters. This breakdown can also cause the vitreous to separate from the retina. When this separation occurs, it may pull on the retina, stimulating the photoreceptors, and leading to the perception of flashes of light.
As fluid fills the space of the deteriorating vitreous, the interwoven fibers within the vitreous that attach it to the retina become loose and fall away, also known as posterior vitreous detachment, or PVD.
A consequence of aging, PVD is common in adults over 50, with those who are nearsighted at an increased risk. Symptoms of a vitreous detachment usually include an increase in the amount of floaters in the visual field. While flashes and floaters are not usually treated with surgery, a sudden increase in floaters or flashes may be a sign of a retinal tear, and it is advised that an eye care exam with your doctor be performed as soon as possible to obtain a proper diagnosis.