Floaters and Light Flashes

” I was sitting around when suddenly I noticed some fireworks like flashes in my side vision. Is this something I should worry about?”

We often get this call from patients who notices light flashes that are often followed by floaters. While this is often not a serious problem it can represent an emergency that if not addressed quickly can lead to blindness.

Floaters and light flashes can be a sign of a retinal detachment and are a common complaint in patients, especially those over the age of 60.  Floaters are most obvious in a light environment with a uniform and/or plain background, and light flashes are observed in either subdued lighting or darkness. They may occur together or independently, and they are most often due to a condition called vitreous degeneration.

What is Vitreous?

Vitreous is a jelly like substance which fills the inside of the eye.  In the normal eye it is very clear and its surface lies right up against the retinal surface.  In various areas within the eye, the vitreous surface is adherent to the retina to different degrees.  In the front of the eye and in areas of retinal degeneration it can  be tightly adherent.  In the macula and around the optic nerve, it can be moderately adherent, and over blood vessels it is mildly adherent.  Everywhere else the adherence is minimal.

What Does the Vitreous Have to Do With Floaters & Light Flashes?

Over time the vitreous begins to degenerate.  Some of the vitreous condenses, forming dense particles within the eye.  These particles will cast a shadow on the retina which appears as a floater, and are often described as “bugs, spots, lines, hair, haze, veil”, etc.  Usually the number of floaters is less than a dozen, and there is no significant loss of central  or peripheral vision.

Further, as the vitreous degenerates, it undergoes a process of liquefaction, “syneresis”, which results in the collapse of the vitreous from its normal position next to the retina.  As this occurs, the vitreous pulls on the retina in those areas where it is more adherent.  This mechanically stimulates the retina, and one then sees a light flash.  Since most of the firmer attachments are in the periphery of the eye, these light flashes will appear in the peripheral visual field as opposed to straight ahead, in the central visual field.

Additionally, as the vitreous collapses, it pulls away from the optic nerve.  In doing so, it also pulls with it a ring of connective tissue which is around the optic nerve.  This can results in a very large floater, which is often described as a “smoke ring” or some variant of a “C”.

These symptoms of floaters and light flashes may initially persist. However, over time, either the patient will get used to the floaters, or more commonly, as the vitreous degeneration progresses, the floaters settle down below the line of sight and are no longer seen.  The light flashes usually subside over a few days to a few weeks, but on occasion may persist for much longer.

Treatment for Floaters and Light Flashes?

Floaters and light flashes, if due solely to vitreous degeneration, are benign.  Therefore, no  treatment is necessary or recommended, and patients are just reassured that the condition is not serious and the symptoms will resolve spontaneously.

Can Floaters and Light Flashes Indicate Anything Serious?

Unfortunately, floaters and light flashes are not always benign.  This is particularly true if the floaters appear as too numerous to count, a large mass and/or a “glob” or “stringy lines”, and sometimes, perceived as colored red.  Under these conditions, a much more serious condition may exist.  These later symptoms may very signal the occurrence of a retinal tear and/or a retinal detachment which are ocular emergencies, generally requiring immediate treatment, usually by a retinal specialist such as Dr. Chen or Dr. Torres.