Floaters are experienced as grey, blurred shapes that appear to float around in your eyesight. Most people have them, most of the time they are harmless and just a little irritating. But if they trouble you badly, what can you do?

First of all, if your floaters have changed recently or suddenly, if you're seeing white lights, lots of small dots or black shadows or curtain effects, all of those should be investigated promptly. The rest of this article is about everyday floaters that most people experience.

Let's establish what's going on. Anatomically, your pupil is the dark spot in the centre of your eye where the light passes in. Behind that is the lens that focuses the light onto your retina at the back of the eye. What fills the space between your lens and your retina is a clear, jelly-like substance called vitreous humour which is created when we are in the womb and stays there for life. If you have them, floaters are probably there for life too.

As we age, the vitreous humour can change. It can become more liquid, so allowing debris to float around more freely. We experience that 'debris' as floaters, since they float around making shadows on our retina, rather like in a small cinema you can reach up and make hand shadows on the screen. With your eye still, floaters will probably (counter-intuitively) sink to the lowest part of your eye, so if you sleep on your back they may settle on your fovea (the part that sees what you're looking directly at) and trouble you more on waking until they are shaken free by normal eye movement.

Vision is an extremely sophisticated brain process and over time, our brains can learn to ignore some of our floaters by combining what we see from both eyes into one image. It's unlikely that you have a floater in the exact same position in both eyes so the brain chooses what it wants before composing the image for you.

Amazingly, it's because floaters float that they are so difficult for our brain to ignore. By contrast, our retina has permanent blood vessels that are completely 'in the way' of us seeing, but our brain knows where they are and ignores them so completely we are unaware of their existence.

In terms of treatment, there's not a lot that can be done medically. In 2% of cases floater trouble is caused by a detached retina, and only surgery can re-attach it.

If you search the Internet for solutions, you might find a couple (neither are available from Pagan & McQuade). There is an operation in which the vitreous humour is replaced. There is also vitreolysis, a laser treatment that converts the floaters to a gas that is re-absorbed. There are risks associated with such treatment, however, so the advice is usually that floaters present no real health risk and it is better to leave well alone.

Having said that, there are some things you can do yourself. Floaters appear worse when you look at a light, plain area such as the summer sky or a white wall. Consider redecorating with rich colours and patterns. Looking rapidly up, down, left and right might move a particularly annoying floater out of the way for a while. Wearing dark glasses can help too because bright light makes the pupil smaller which brings floaters more into focus, less light opens up your pupil and makes the front-to-back distance that's in focus inside your eye much smaller, so there's a lower probability that any one floater is in focus.