A clear jelly-like substance called the vitreous humour (or gel) fills the inside of the eye. It allows light to reach the retina (and macula) at the back of the eye. With age, the gel changes, becomes weaker, and shrinks. When this happens, bits called floaters can break loose. They can be seen as specks, flecks or cobwebs that drift around in your field of vision.
What causes floaters in your field of vision?
Floaters are not usually a sign of anything serious, and not everyone who develops floaters will notice any symptoms. The brain can adapt to changes in vision over time and often ignores floaters. If you notice a floater in your direct field of vision, moving your eye may help move it. Most people who develop floaters will notice something, although they tend not to permanently affect vision. However, in some patients floaters persist, obscuring central vision and causing difficulties with activities such as reading or driving.
How are they treated?
Floaters can be removed with an operation called a vitrectomy. A vitrectomy is an extremely rare event and the decision to perform one is not taken lightly.
Floaters are most noticeable when looking at plain backgrounds, such as the sky, white walls or computer screens. You will not see the floaters, but will see shadows they cast on the retina. They never seem to stay still, as they move when your eye moves.
There is no link between floaters and macular disease. Macular disease affects the tissues lying under the retina, while floaters occur when there is damage within the eye. It is impossible to predict or prevent floaters. Floaters may occur due to inflammation in the eye (uveitis); eye infection; short-sightedness (myopia); cataract surgery; diabetes or ageing.
What else should I look out for?
The symptoms of floaters are similar to serious conditions such as a detached retina which is sight-threatening. The sudden appearance of floaters could mean that the vitreous gel is pulling on the retina, which could cause a retinal tear and lead to a detached retina. If aqueous fluid fills the hole left by the tear, sight can also blur. A retinal tear or detachment requires immediate medical attention.
Floaters may also indicate posterior vitreous detachment (PVD), which is more common than retinal detachment, but not as serious.
You should seek help from your ophthalmologist promptly if:
- you have never had floaters before, or flashing lights suddenly appear
- you experience floaters already and they increase or change
- you have any sudden change in, or loss of, vision – or if a dark shadow or curtain appears in your vision.
The best way to identify floaters and their causes is to have an eye test at least every two years. If you experience floaters, let your optometrist know. Tell them how long you have had them, and whether you have had eye surgery or an eye injury.
If you still have questions about floaters, call our Advice and Information Service on 0300 3030 111.