Understanding Eye Floaters
Understanding Eye Floaters

Understanding Eye Floaters

Eye floaters are shapes that appear to hover in your line of sight. This eye condition can be caused by a number of reasons, from eye injuries through to just growing older.

Eye floaters are shapes that appear to hover in your line of sight. They can come in different forms - you might see a lot of smaller floaters or just a few large ones. 

Signs and symptoms

diagram explaining Eye floaters

Floaters generally appear most clearly against a light background such as a pale wall. If you have eye floaters, you may start seeing these shapes:

  • Long thin strands
  • Small dark dots
  • Shadowy dots
  • Cloudy patches

Complications of Eye Floaters

Eye floaters shouldn’t normally have an impact on your vision, however relatively big floaters may be distracting and can affect your ability to concentrate, making tasks such as driving or reading harder.

What causes Eye Floaters?

Floaters occur as a result of debris floating in the substance in your eyeball between your lens and retina – this is known as the vitreous humour, and it is made almost completely from water. The debris can appear due to the following:

Ageing process

Eye floaters generally start to appear as you reach 40, becoming more common at 60 and 70. However, they can also occur in younger people. The ageing process causes strands of collagen to show up in your vitreous humour, forming swirling shapes as your eyes move. These strands cast shadows on your retina.

Posterior Vitreous Detachment

A condition known as posterior vitreous detachment (PVD) can also cause floaters to develop. PVD is found in three-quarters of people over 65, and maybe a result of age-related changes in the vitreous humour. The vitreous humour’s centre becomes more liquid as you get older, causing the outer layer (known as the cortex) to come away from the retina. The collagen in the cortex thickens and forms clumps, leading to the development of floaters.

PVD can also cause you to see flashing lights as a result of the cortex tugging on the retina. This stimulates the retina, causing a signal to be sent to your brain where it is interpreted as light.

Retinal Tears

The retina and vitreous humour become separated in about 50% of all people by the time you reach your 50s, but this rarely causes complications and in most cases, you might not even notice it happen. Sometimes when the vitreous humour detaches, blood vessels in the retina can burst and leak into it – floaters are caused by the red blood cells, which can look like smoke or small dots.

These floaters generally last for a few months before being absorbed into the retina. 

The vitreous humour may not fully separate from the retina and therefore when it pulls away it causes the retina to tear and blood to leak into the vitreous humour. This results in a number of floaters and possibly bright flashes of light. The floaters and flashing lights shouldn’t have any long-term effects, and they may be an indicator of another condition such as a migraine, however, if you experience them you should see an eye care specialist.

Retinal Detachment

Retinal tearing may lead to the retina becoming detached from the back of the eye, which can result in damage to your vision. However, the condition is rare and only affects 1 in 10,000 people, although it can be more common in people who have myopia (short-sightedness).

Damage to the retina can cause the images your brain receives to become patchy or lost entirely, while retinal detachment can also cause floaters, flashing lights, and vision loss.

Other causes

Floaters may also be as a result of:

  • Cataract Surgery – which can cause PVC, retinal tearing, and retinal detachment.
  • Infection
  • Uveitis 
  • Eye Injuries

Floaters are generally more common in people who suffer from short-sightedness or diabetes. 

How are Eye Floaters diagnosed?

If you believe you have floaters you should tell your optician or eye care specialist. They may ask how long you’ve been experiencing floaters and any other symptoms you’ve had, and they might also ask for a medical history including previous eye surgeries and injuries. If you suddenly start seeing a high number of floaters, you should see your eye care specialist. 

doctor holding up a lens while preforming an eye test for eye floaters

Retinal exam

Your retinas may be examined by an eye care specialist, who will do this by looking through your pupil. They might dilate the pupil using eye drops if they need a better view of your retina.

Your eye care specialist may also use a slit lamp to examine your eyes, which can leave your vision slightly blurred and can also cause temporary photophobia.

Other tests 

You could also be given other tests in order for your eye care specialist to understand your symptoms. They might take a better look at your retina using a light, ask you to move your eye in different directions, or use a special instrument to press on your eye.

Another test the specialist may use is an eye pressure test, also known as tonometry. This involves anaesthetic and dye being applied to your cornea before a blue light is held to your eye to measure the pressure inside it.

How do you treat Eye Floaters? 

Eye floaters rarely cause major issues with vision, therefore they don’t usually need to be treated – medications such as eye drops have no effect. Your brain may even start ignoring them, which means you won’t notice the floaters.

Your eye care specialist might ask you to return for check-up appointments afterward in order to check on the condition of your retina.


If your vision is seriously affected by the floaters, or they don’t get better over time, you may be offered a vitrectomy. This is a procedure for the removal of the vitreous humour from your eye – any debris causing you to see floaters is removed as well, and it is all replaced with a saline solution.

However, this is a rare course of action as eye surgery carries a number of risks, and vitrectomies aren’t always offered by the NHS. Side effects may include retinal tearing or detachment, and the procedure could also result in cataracts.

Laser treatment

Floaters may also be treated by laser surgery, where the laser is used to break them up or move them. While some think that this method is safer than vitrectomies, the treatment is rare and normally not available on the NHS, and there hasn’t been a lot of in-depth study into its effects.