Floaters - Diagnosing floaters

Although floaters are usually harmless and don't significantly affect your vision, you should have your eyes checked by an optician on a regular basis (at least once every two years).

You can use the post code search facility to find opticians in your local area.

Tell your optician if you have symptoms of floaters. They may ask about your:

• symptoms – including how long you've had floaters
• medical history – for example, whether you've previously injured your eye or had eye surgery

Visit your optician immediately if a new floater suddenly appears or if there's a rapid increase in the number of floaters you can see. They may refer you to an ophthalmologist (a specialist in diagnosing and treating eye conditions).

In rare cases, floaters may be a sign of retinal tears or retinal detachment. The ophthalmologist will check for this by examining your retina (the light-sensitive layer of cells lining the back of the eye).

Examining the retina

By looking through your pupil, the ophthalmologist will be able to see a small part of your retina. The pupil is the hole at the front of your eye that increases and decreases in size depending on the light conditions.

If the ophthalmologist needs a clearer view of your retina, a procedure known as dilation may be used. This is where eye drops are used to widen your pupil so the whole of your retina can be examined.

The ophthalmologist may use an instrument called a slit lamp to examine your eyes. A slit lamp has a lens and a bright light to enable the inside of your eye to be examined. After the examination, your vision may be a little blurry and your eyes will be sensitive to light for a few hours. You should avoid driving while your eyes remain dilated.

Other tests

To get a better understanding of your eye symptoms, the ophthalmologist may also carry out other tests. For example, they may:

• ask you to look in different directions
• push on your eye using a special instrument
• examine your retina more closely using a bright light

Eye pressure test (tonometry)

An eye pressure test (tonometry) uses an instrument called a tonometer to measure the pressure inside your eye (intraocular pressure).

During the test, a small amount of anaesthetic and dye will be placed onto your cornea (the transparent layer of tissue that covers the front of the eye).

A blue light from the head of the tonometer will be held against your eye to measure the intraocular pressure.