Eye floaters: should I be worried about them?

Eye floaters are spots in your vision, and can appear as specks, thin string-like shapes, or as cobwebs floating across and drifting around when you move your eyes (hence the name ‘floaters’). Eye floaters are pretty common, and are in fact a natural, harmless part of ageing. However, in some cases, floaters need to be treated when they become problematic. Leading Moorfields ophthalmologist Mr Sui-Chien Wong explains everything you need to know about eye floaters, including their causes, how serious they are, and what happens if they need treatment.  

What are eye floaters?

In the eye there is a gel-like structure called the vitreous, and over time, it can liquefy, which causes ‘clumps’ to appear in the vitreous. These clumps cast a shadow on the retina, and this is what we perceive as floaters.

Eye floaters are actually very common. A lot of us have them, and our brain tends to adapt to them over time and learns to ignore them. However, on occasion, floaters that develop suddenly or those which are associated with loss of vision can be due to a more worrying cause like a retinal tear or retinal detachment. Therefore it’s important that if you notice a sudden change in the appearance of your floaters, get it checked out by a vitreoretinal surgeon.

What causes eye floaters?

The commonest cause for eye floaters is development of clumps in the gel in our eyes called the vitreous. Over time, this gel liquefies and clumps form and these manifest themselves as floaters. This is the commonest cause and it is also the least worrying cause.

There are other reasons floaters can develop. For example, if there is a tear in the retina, then retinal detachment can occur, where the retina is pulled from its usual position at the back of the eye. Floaters can also be caused by inflammation or blood in the eye. For example, in patients that have diabetes there can be some bleeding, and they can develop an inflammation in the eye that can also cause floaters to appear. Floaters should always be assessed by a vitreoretinal surgeon, as depending on the cause, treatment may be required.

Are eye floaters dangerous?

This really depends on the reason you've developed eye floaters. The commonest cause of eye floaters is the liquefaction of the normal vitreous gel. Therefore, in that scenario, floaters are not dangerous.

However, there some other causes that can lead to potential loss of sight, and sometimes that can happen very rapidly. When there's a sudden onset of many floaters with associated loss of central or peripheral vision, then you really need to get your eyes checked all to ensure that there isn't a retinal detachment, which could lead to blindness if it is not treated. Sometimes in some conditions such as diabetes, bleeding can also develop.

Floaters can also be a sign of progressive retinal disease of the eye that, again, needs more attention. Whether floaters are dangerous or not depends on the cause. Usually they are not dangerous but sometimes treatment is required to prevent loss of vision.

How are eye floaters treated?

The treatment of floaters depends on the cause. For floaters which are caused by clumps forming in the vitreous gel, treatment means to manage them conservatively.  These eye floaters don't cause any problems in terms of threats to sight; in fact the brain learns to adapt to them and a lot of us have this kind of floater.

However, in some individual, floaters can end up being very troublesome. They can affect  daily quality of life, and in these cases, we may use treatment to remove floaters. In order to treat this kind of floater, we may perform an operation called vitrectomy, where we remove the gel from inside the eye and clear the floaters. Interestingly, the vitreous doesn't actually have any function after we're born. It is only there to help the eye when we are in our mother's womb, meaning the vitreous can be safely removed. The risk of complication is low and the space that is occupied by the vitreous is replaced by fluid that the eye normally produces anyway, so this maintains the normal eye pressure.

When there are other causes for floaters such as a retinal detachment or bleeding in the eye, vitrectomy surgery can be done to treat the underlying retinal problem, also meaning that the floaters would also be removed.

Can eye floaters cause blindness?

Floaters can occasionally cause blindness depending on the underlying reason. If there is a sudden onset of new floaters, particularly if associated with curtains coming across one’s peripheral vision, then this could be a sign of a retinal detachment or retinal tear that, if left untreated, can lead to blindness.

The chance of a retinal detachment developing in the general population is about one in 10,000. This means that retinal detachment, especially when compared to the frequency of floaters, is uncommon, but statistically means that some people will experience it.

However, it is important to note that in cases where the cause for eye floaters is the clumping of the normal vitreous or gel in the eye due to ageing changes do not cause blindness.

If you have experienced a change in your eye floaters, or are experiencing them for the first time, make an appointment to see an ophthalmologist.