About Flashes and Floaters.

What are Flashes?

Flashes of light lasting a few seconds may appear in your vision when the vitreous gel pulls or tugs on the retina. This may happen as a natural result of aging or it may occur temporarily if you receive a blow to the head or eye. Usually these flashes, which are often described as lightning streaks, are noticed at night.

Light flashes appearing as wavy lines in both eyes and lasting from a few minutes to half-an-hour, are usually a sign of an ocular migraine headache. Migraine-related flashes are often noticed in a lighted environment. Flashes of this nature are not a symptom of eye problems. The onset of new light flashes of short duration at night, especially when accompanied by the appearance of many new floaters or a blackening out of part of your field of vision, may indicate a retinal tear or detachment.

Retinal detachment requires immediate medical attention, as it can easily cause blindness. Both the appearance of flashes and the sudden onset of numerous small floaters warrant an ophthalmological investigation.

What are Floaters?

Floaters are deposits of various size, shape, and consistency floating within the normally transparent fluid (vitreous) inside the eye, appearing as spots, threads, or fragments of cobwebs singly or together with several others in one's field of vision — especially when looking at a blank surface or an open monochromal space, such as blue sky.

Despite the name "floaters", many of these specks have a tendency to sink toward the bottom of the eyeball, in whichever way the eyeball is oriented; looking up or lying back tends to concentrate them near the the center of one's gaze, while the textureless and evenly lit sky forms an ideal background against which to view them .

Sometimes fine dark lines in amorphous mass - like small branching twigs - are seen. These floaters move around and are called 'muscae volitantes' (Latin for 'flying flies'), because they seem to dart about like flies as the eye is moved. Over time, you will become less aware of these floaters as the brain learns to ignore these retinal images. Therefore, while some floaters may remain in your vision, many of them will fade over time and become less bothersome.

The Location of Floaters

The vitreous is a normally clear, gel-like substance that fills the center of the eye. It makes up approximately 2/3 of the eye's volume, giving it form and shape before birth.

Floaters, when present, are suspended in the vitreous. Thus, they generally follow the rapid motions of the eye, while drifting slowly within the fluid. When they are first noticed, the natural reaction is to attempt to look directly at them. However, attempting to shift one's gaze toward them can be difficult since floaters follow the motion of the eye, remaining to the side of the direction of gaze. Floaters are, in fact, visible only because they do not remain perfectly fixed within the eye. Although the blood vessels of the eye also obstruct light, they are invisible under normal circumstances because they are fixed in location relative to the retina, and the brain "tunes out" stabilized images due to neural adaptation. This does not occur with floaters and they remain visible.

The shapes are shadows projected onto the retina by tiny structures of protein or other cell debris discarded over the years and trapped in the vitreous humour. Floaters can even be seen when the eyes are closed on especially bright days, when sufficient light penetrates the eyelids to cast the shadows.

The Occurrence of Floaters

Floaters are common and do not cause problems for most people. In fact, people usually learn to ignore them, given some time. However, to those with severe cases, floaters are definitely a distraction — especially if the spots seem to constantly drift through the field of vision.

Floaters have been known to catch and refract light in ways that somewhat blur vision temporarily until the floater moves to a different area. Many times they trick the sufferer into thinking they see something out of the corner of their eye that really is not there. For people with severe floaters, it is nearly impossible to completely ignore the large masses that constantly stay within almost direct view. Some sufferers have noted a decrease in ability to concentrate while reading, watching television, walking outdoors, and driving, especially when tired.

Although more common in elderly people, floaters can certainly become a problem to younger people, especially if they are myopic. Floaters are also more common after cataract operations or after trauma. In some cases, floaters are congenital.

Tear Film Debris

Sometimes the appearance of floaters has to be attributed to dark specks in the tear film of the eye. Technically, these are not floaters, but they do look the same from the viewpoint of the patient. People with blepharitis or a dysfunctional meibomian gland are especially prone to this cause, but ocular allergies or even the wearing of contact lenses can cause the problem. To differentiate between material in the vitreous humour of the eye and debris in the tear film, one can look at the effect of blinking: debris in the tear film will move quickly with a blink, while floaters are largely unresponsive to it. Tear film debris is diagnosed by eliminating the possibility of floaters and macular degeneration.

Causes of Floaters

There are other causes for the appearance of floaters, of which the most common are described here. Basically, any way by which material enters the vitreous humour is a cause for floaters.

Vitreous syneresis

The most common cause of floaters is vitreous syneresis, shrinkage of the vitreous humour.

In the young eye, the vitreous gel is solid and the posterior vitreous surface is well attached to the retinal surface.		In the aging eye, small pockets of liquidfied vitreous (lacunae) can develop within the gel.
Lacunae may form pockets and lead to separation from the retinal surface.		Contraction of the vitreous can produce light flashes or can cause physical tears.

Posterior vitreous detachments and retinal detachments

Over time, as we age, the vitreous loses support and its framework contracts. This may lead to vitreous detachment, in which the vitreous body is released from the retina. During this detachment, the shrinking vitreous can stimulate the retina mechanically, causing the patient to see random flashes across the visual field, sometimes referred to as "flashers." The ultimate release of the vitreous sometimes makes a large floater appear, usually in the shape of a ring ("Weiss ring"). As a complication, part of the retina might be torn off by the departing vitreous body, in a process known as retinal detachment. This will often leak blood into the vitreous, which is seen by the patient as a sudden appearance of numerous small dots, moving across the whole field of vision.

Regression of the hyaloid artery during pregnancy

The hyaloid artery, an artery running through the vitreous humour during the fetal stage of development, regresses in the third trimester of pregnancy. Its disintegration can sometimes leave cell matter.

Other common causes

Patients with retinal tears may experience floaters if red blood cells are released from leaky blood vessels, and those with a posterior uveitis or vitritis, as in toxoplasmosis, may experience multiple floaters and decreased vision due to the accumulation of white blood cells in the vitreous humour.

Other causes for floaters include cystoid macular edema and asteroid hyalosis. The latter is an anomaly of the vitreous humour, where by calcium clumps attach themselves to the collagen network. The bodies that are formed in this way move slightly with eye movement, but then return to their fixed position.

Diagnosis of Floaters

Usually the appearance of new floaters or light flashes does not indicate any serious eye problem. However, the only way to ensure that the floaters or flashes are not symptomatic of a more serious problem, is to have your retina examined. If, following the exam, you develop large numbers of new floaters that seem to get worse over time, we recommend that you have your eyes re-examined.

Standard vision tests like the Snellen visual acuity measurement, which measures your vision as 20/20, etc., are unable to quantify floaters and how the disability interferes with day-to-day functioning and overall quality of life. Floaters are often readily observed with the use of an ophthalmoscope or slit lamp. However, if the floater is a small piece of debris and near the retina, your eye doctor may not be able to observe it even if it appears large and obvious to you.

Increasing background illumination or using a pinhole to effectively decrease pupil diameter may allow a person to obtain a better view of his or her own floaters. The head may be tilted in such a way that one of the floaters drifts towards the central axis of the eye. In the sharpened image the fibrous elements are more conspicuous. (If the pinhole is kept moving slowly in small circles, the same technique evokes an interesting entoptic effect known as the vascular figure, which is a view of the blood vessels within one's own eye.)

Treatment of Floaters

When floaters appear in your line of vision, move your eye around — up and down as well as from side to side. This movement creates a swirling in the vitreous fluid and may cause the floater to move out of your field of vision.

Regular Check-Ups

To safeguard your vision, individuals over age 40 should undergo a comprehensive eye exam annually. If you are under age 40 and have risk factors such as high blood pressure, diabetes or a family history of glaucoma or macular degeneration, a yearly exam is also recommended. Individuals under age 40 who are in good health, with no known risk factors should have their eyes examined every two years.

In some patients floaters can cause persistent, distracting and disabling symptoms. In these patients, visual tasks such as reading or driving become laborious, and productivity and overall quality of life may suffer. It is advisable to wait at least one year to allow enough time for the floaters to become less prominent naturally. If they do not, then one may consider vitrectomy surgery or laser surgery. We must caution at the very outset of this discussion that laser or surgical treatment of floaters is not considered a standard management strategy and is recommended by a minority of physicians, even then under exceptional circumstances. We are not aware of any vitamins or drugs that can reduce floaters.

Pars Plana Vitrectomy (PPV)

Pars plana vitrectomy is a procedure usually reserved for complicated posterior segment disease. It has a well-known risk profile, and justifiably there is reluctance to offer this surgery to treat floaters. However, the post-operative complication rate following PPV has been assessed in the setting of retinal detachment surgery or in the presence of complicated vitreo-retinal disease. It may be argued that pars plana vitrectomy for floaters, in eyes that have an established posterior vitreous detachment, may be associated with a lower incidence of both intraoperative and post-operative complications.

The three main postoperative complications that one must consider in vitrectomy are: development or progression of nuclear sclerosis cataract, retinal detachment and choroidal or vitreous hemorrhage (bleeding) in the eye.

Laser Vitreolysis

Another treatment is laser vitreolysis. In this procedure a YAG laser is focused onto the floater and in a quick burst vaporizes the structure into, presumably, a less dense and not as noticeable consistency. This procedure can be time-consuming and there is no consensus as to how completely effective it is. One study found laser vitreolysis "to be a safe but only moderately effective primary treatment conferring clinical benefit in one third of patients".

(856) 667-3937

Kindermann Eye Associates
3001 Chapel Avenue, Suite 200
Cherry Hill, New Jersey 08002