Flashes and floaters are caused by changes in the consistency of the gel-like fluid that fills the back section of the eye. This fluid is called vitreous humor, or simply, vitreous. The vitreous is firmly attached to several components in the posterior section of the eye: the optic nerve, large retinal vessels, the central retina (macula) and importantly for our discussion here, the front section of the retina and along the edges of retinal thinning (lattice). Visualization of sight of flashes and floaters may herald a retinal tear or retinal detachment. These ocular emergencies of the retina are treatable here in Atlanta and beyond. Most retinal tears or detachments result from traction of the vitreous upon the retina. This vitreous pulling is usually caused by a posterior vitreous detachment, or PVD. The initial event of a PVD is syneresis (a collapsing) of the central vitreous. Syneresis leads to movement of the entire vitreous fluid, and pulling on the retina ensues. The vitreous is mostly water and also contains strands of collagen. These collagen strands can cast shadows on the retina, thus causing floaters. The movement of the vitreous causes the visual sensation of flashing light.
Most floaters are harmless and do not indicate a dangerous retinal condition. However, floaters may be associated with pathological changes in the posterior segment of the eye. Retinal detachments and tears generally cause a marked increase in the amount and density of floaters, and are usually accompanied by the sight of flashing lights. An urgently scheduled, dilated eye exam is in order if one notices the onset of flashes and floaters.
The symptom of a”flashing light”; is caused by the vitreous gel pulling upon the retina. Flashes may be elicited with movement of the head or eyes, especially if in a dark environment. Like floaters, seeing flashing lights may be harmless, but these phenomena may be associated with a serious problem.
Anyone with symptoms of flashes of light or new floaters should be examined by an ophthalmologist as soon as possible. If the retina is determined to be healthy and without problems, no treatment of floaters is necessary. With time, the flashes fade and the floaters become less noticeable. The brain learns to ignore the floaters, and the floaters also become more difficult to see as they shift position over time. Flashes and floaters themselves are frustrating but not dangerous. However, if a retinal problem is found, the ophthalmologist will suggest immediate treatment.