Flashes and Floaters
Black spots that drift about within your field of vision are called vitreous floaters. The vitreous gel is a clear jellylike material that fills up the inside of the eye. Normally, it is crystal clear, but occasionally little clumps of condensed proteins or pigment from the iris start floating about within this jelly. If they come near your line of vision, then the shadows they cast on the back of the eye appear to you as dark spots.
Vitreous floaters can occur at any time, but are more common with age. Almost everyone has seen some floaters at some time or other.
A complete eye exam with dilation of the pupils will ensure that there is nothing seriously wrong with the eyes. With advancing age, the vitreous becomes less of a jelly and more of a liquid. This in itself is not harmful, but once the vitreous is liquid, it pulls away from the retina. The retina is a delicate structure, like wet Kleenex, that lines the inside of the eye and is critical to vision. Like the film within a camera, it is where vision is focused and processed. Being delicate, it is vulnerable to being torn by movements of the vitreous gel, especially if there is any adherence between the two.
The retina does not feel pain. Any tugging on the retina by movements of the vitreous gel are perceived as flashes of light (usually very brief and startling). The flashes of light do not necessarily hurt the retina, but are a warning that the vitreous gel is pulling away from the retina, and that damage to the retina may occur.
To put things in perspective, almost everyone eventually experiences the signs of vitreous gel liquefaction, but very, very few (less than 1%) develop a retinal detachment. Nevertheless, at the first sign of vitreous floaters or flashes, you should have a complete eye examination. If that reveals that the vitreous is undergoing this expected liquefaction and separation from the retina, then you should restrict all vigorous physical activity for about one month to allow the gel to separate from the retina as gently as possible.
Assuming that the symptoms do not worsen in any way, then a dilated exam of the retinas is repeated after one month. Once the gel is completely separated from the retina, you are"home-free"— the flashes stop, the retina is out of danger, and the floaters eventually dissolve, or are absorbed. Eye exams are then performed on an annual basis. It is important to be aware that with a retinal detachment, there appears to be a dark curtain being drawn across your vision. With separation of the vitreous gel, there is slight haziness of vision temporarily for a couple weeks, because the back surface of the gel has a"skim" on its surface much like cream that has been sitting out awhile. This"skim" dissolves very quickly, however, and the haze which it causes is much different than the dark curtain of detachment.
In summary, vitreous floaters are very common and usually do not indicate a serious problem. Floaters plus flashes indicate liquefaction of the vitreous gel. This eventually occurs to everyone and once it occurs in one eye, it usually follows in the other within a year. The incidence of serious complications is less than 1%. An eye exam immediately and again in one month, will help ensure that there has been no damage to the retina.