What are floaters?
Floaters are shapes that you might sometimes see drifting across your vision. These shapes 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. Short-sighted 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 the vitreous which sits behind the pupil and the lens. The vitreous is mainly made up of water with a meshwork holding it together. As we get older, a process known as vitreous syneresis occurs, whereby the meshwork breaks down, causing pockets of fluid to form and creating debris within the disrupted meshwork. This debris then casts shadows onto the retina, which we see as floaters.
By the age of 70, approximately 70% of people experience the liquefied vitreous gel losing its support framework, which causes it to collapse; in a process known as a posterior vitreous detachment (PVD). As the vitreous gel peels away from the retina, patients can see intermittent flashes of light. The flashing light will usually subside over 4 to 12 weeks but in some patients it can take longer. When a posterior vitreous detachment occurs, patients often become aware of a cobweb or net curtain-like floater that can be quite intrusive at first. Inflammation in the eye can also be a rare cause of floaters.
Should I be worried about Floaters?
In the vast majority of cases, floaters are harmless and represent the normal changes eyes experience as we age. Although occasionally annoying, floaters 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 become stuck to a patch of retina, causing a tear. If the seal of the retina is broken, fluid can start to track in behind the retina causing it to detach from the back of the eye; similar to wallpaper peeling off a wall. This event is very uncommon and appears in approximately 1 in 10,000 of the population. Usually if a tear develops in the retina, patients experience a very marked shower of floaters accompanied by flashes of light in their peripheral vision. This light is usually persistent and occurs in daylight. Some patients notice a curtain effect coming in from their peripheral vision, which requires urgent attention by a consultant ophthalmologist. It is important to have your eyes examined as soon as possible in the event of any new floaters or flashes in order to identify and treat any possible retinal tears.
Since floaters do not harm the eye and in most people do not cause a significant problem, we generally do not recommend any form of treatment.
It is possible to carry out surgery on the eye to remove the vitreous gel (vitrectomy), which would also remove the floaters.
Occasionally, this course of treatment is useful for patients with very severe floaters or for those who are unable to adapt to them.
What are the risks of surgery?
Vitrectomy surgery carries a risk of various complications, and for this reason we do not generally recommend surgery to treat floaters. The most common side effect of a vitrectomy surgery is the development of cataracts at an earlier stage than it would have naturally. Rarely this can be immediately after the surgery, but more commonly may develop 2-3 years after the surgery. This is also one of the reasons why this approach is avoided wherever possible with younger patients.
The most severe complication from this kind of surgery is blindness in the eye, usually caused by a severe bleed during surgery or an infection in the eye following surgery. Whilst this is an extremely rare occurrence, it is important that patients are aware of any potential risks.
Approximately 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 following surgery.
Where can I find more information?
Further information can be found by visiting the following websites: www.nei.nih.gov/health/floaters/index.asp
The advice in this booklet is based on a variety of sources, including the latest research published in peer-reviewed scientifi c journals. It has also been scrutinised by a panel of experts from the Britain & Eire Association of Vitreoretinal Surgeons (“BEAVRS”). If you require further information about this, please speak to your surgeon.