Floaters

What are floaters?

Floaters are shapes that people can see drifting across their vision. Floaters are small bits of debris floating in the vitreous jelly inside the eye. They can come in a variety of forms such as small black dots, short squiggly lines or even large cobweb shapes. Shortsighted people tend to suffer from them more and they increase, as we get older.

What causes Floaters?

The eye is filled with a jelly like substance called vitreous. The vitreous sits behind the pupil and lens. The jelly is made mainly of water with a meshwork holding it together. As we get older, a process known as vitreous syneresis occurs; the meshwork breaks down and lakes form. The solid portion of the gel forms debris. The debris casts shadows onto the retina, which we see as floaters.

In 70% of people, by the age of 70, the liquefied vitreous gel can loose its support framework causing it to collapse. This process is known as a posterior vitreous detachment (PVD). As the vitreous gel peels away from the retina, it can cause people to see intermittent flashes of light. The flashing light will usually subside over 4 to 12 weeks, but in some patients it may take a little longer. When a posterior vitreous detachment occurs people often become aware of a cobweb or net curtain-like floater that can be quite intrusive at first.

Inflammation in the eye is a rare cause of floaters.

What complications could occur?

In the vast majority of cases floaters are harmless and represent the normal, natural (although occasionally annoying) aging change of the eye. They usually become much less obvious with time as the brain adjusts to the change and eventually filters them out.

Very rarely during the development of a posterior vitreous detachment, the vitreous gel can be stuck to a patch of retina and cause a tear. If the seal of the retina against the back of the eye is broken, fluid can start to track in behind the retina causing it to detach from the back of the eye a little like wallpaper peeling of a wall. This uncommon event occurs in approximately 1 in 10,000 of the population in general. Usually, if a tear develops in the retina people experience a very marked shower of floaters associated with flashes of light in their peripheral vision. The light is usually persistent and occurs in daylight. Some people notice a curtain effect coming in from their peripheral visual field. This requires urgent attention by an eye doctor.

Treatment options

Since floaters do not harm the eye, and in the vast majority of people, they do not cause a significant problem, we generally do not recommend any form of treatment for them. It is possible to carry out an operation to the eye to remove the vitreous gel (vitrectomy), which will also remove the floaters. Very occasionally, this course of treatment is useful in people with very severe floaters or in those who are cannot adapt to them.

What are the risks of surgery?

Vitrectomy surgery carries with it the risk of various complications and it is for this reason that we generally do not recommend it for the treatment of floaters. The most common side effect of the vitrectomy surgery is the development of cataract at an earlier stage than it would have done otherwise. Rarely this can be immediately after the surgery but more commonly; this may come on 2-3 years after the operation. This is one of the reasons we try to avoid this approach in younger patients.

The most severe complication from this kind of surgery is blindness in the eye, usually because of a severe bleed during surgery or an infection in the eye after the operation. This is an extremely rare occurrence (approximately 1 in every 800 cases) but it is important that patients are aware that there is a chance, albeit very small, that it could happen.

About 4% of patients develop a retinal detachment after the surgery. In this situation, further surgery is required to reattach the retina, which can sometimes lead to reduced vision in the eye afterwards.

Where can I find more information?

Further information can be found at the following websites:

http://www.nei.nih.gov/health/floaters/index.asp

http://www.moorfields.nhs.uk/Eyehealth/Commoneyeconditions/Floaters

http://www.nhs.uk/conditions/Floaters/Pages/Introduction.aspx

http://en.wikipedia.org/wiki/Floaters

Scientific Evidence

The advice in this booklet is based on a variety of sources, including latest research published in peer-reviewed scientific journals. It has also been scrutinized by a panel of experts from the Britain & Eire Association of Vitreoretinal Surgeons (“BEAVRS”). If you require further information about this, please ask your surgeon.

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