Flashes and floaters most often indicate a Posterior Vitreous Detachment (PVD) which is a normal part of the aging process of the human eye. Vitreous is the jelly-like material that fills the large central cavity of the eye. It is 98% water and 2% proteins, which give the vitreous a stiff consistency similar to a thick gelatin. The vitreous loosely connects to the retina, the light sensitive layer in the back of the eye.
As we age, the watery elements in the vitreous separate from the fibrous components. As this occurs, the vitreous may condense and contract and pull away from the retina, resulting in a PVD. The resulting contracted vitreous is more mobile and frequently bumps gently against the retina, causing the characteristic "flashes" that often accompany a PVD. The "floaters" that are usually reported are from the condensed fibrous elements of the vitreous and sometimes can be from tiny pieces of retina that may have been pulled loose into the vitreous cavity by this vitreous separation. Contributing factors include age, severe nearsightedness (myopia) and injuries to the eye.
All patients who experience a recent onset of flashes and floaters should be examined by an ophthalmologist or optometrist. Most of the time nothing unusual is found, and simple reassurance is all that is needed. The flashes eventually go away, and the floaters diminish and become less bothersome with time.
However, a tear in the retina is found in about 5% of eyes with a PVD. If left untreated, these tears can lead to a retinal detachment, which is a very serious sight threatening condition that requires surgery to repair. When symptoms appear, it is important to examine the eye soon after the onset. Because retinal damage can worsen very quickly, the sooner the retinal detachment is detected, the better chance for a good outcome.