What are floaters and why do we get them

 

staring eyes 

Have you ever noticed little faint shapes that drift aimlessly around your field of vision? Those are known as floaters. You may grow concerned over them every now and again, or you just might not have ever given them a second thought. Either way, in this article we’re going examine what floaters are, what causes them, and whether or not they pose any threat to our eyes.

 

What exactly are floaters?

Floaters are shapes that drift around in front of your eyes, but they can appear in different ways, notably:

  • Long, squiggly strands
  • Tiny black dots
  • Small, shadowy dots

You can have small floaters meandering around your field of vision at any given time. They are small and usually exit your field of vision quickly.

If you have ever seen a floater, you may have noticed that they always tend to shoot out towards the periphery of your vision when you attempt to focus on them. This is because floaters do not follow your eye movements precisely, and usually drift when your eyes stop moving(1).

 

Why do we get them?

Floaters happen because of changes in the vitreous, the clear, jelly-like substance that fills the inside of your eyeball.  The vitreous jelly shrinks as you get older, and slowly pulls away from the inside surface of the eye.  This shrinking and separation or detachment of the vitreous from the retina is a common phenomenon, particularly in people over 50 years of age(2).  It is also known as Posterior Vitreous Detachment.

 

Who gets them?

Age impacts the risk of developing floaters, as the vitreous tends to shrink and slowly pull away from the retina as a person gets older. Consequently, floaters are most common in those over the age of 60 but can also be found in people younger than age 45.

There are a few other groups who are more susceptible to developing floaters. Notably, floaters are more common in people who suffer from short-sightedness or diabetes or who have had cataract operation

 

Are floaters a problem?

Whilst it can be annoying to see them floating around, they usually don’t pose any threat. However, in some cases, floaters can point towards other issues of various levels of severity.

 

  • Posterior vitreous detachment

Floaters are usually caused by harmless process called of posterior vitreous detachment (PVD), which occurs when the vitreous that contains mainly water and collagen), begins to move away from the retina at the back of the eye towards the centre of the eye. Consequently, collagen can thicken and bits can clump together to form the shadows that we perceive to be floaters.

This is not usually a great cause for concern though, in the vast majority of cases, PVD will not lead to long term changes in your vision. Approximately three quarters of people over the age of 65 experience PVD.

People with PVD may also experience flashing lights. This happens when the vitreous pulls away from the back of your eyes. The movement of the vitreous away from your retina at the back of the eye creates a tug on the retina. The retina reacts by sending a small electrical charge to your brain. You see this as short, small, flashes of light.

 

  • Retinal tear

PVD can cause retinal tear in a few cases. This happens when your vitreous, which is firmly attached to the surface of the retina, tugs quite strongly on the retina as it pulls away.  In a few people this may lead to a retinal tear.

Floaters and flashes don’t usually cause long-term visual impairment. However, anybody who experiences an increase in floaters or associated symptoms is advised to get their eyes examined by an optometrist, as retinal tears can lead to retinal detachment.

 

  • Retinal detachment

Around 10% of patients with PVD develop a retinal tear and around 40% of people with an acute retinal tear will develop a retinal detachment if left untreated. It can occur when the retina pulls away from the blood vessels that supply it with oxygen and nutrients, leading to blindness.

Because the retina transforms light signals into electrical signals, which are fed through the optic nerve to the brain, any signals that the brain receives from a detached retina may be blurry or non-existent. In some cases an increase of floaters can be an indicator of retinal detachment. If your retina is at risk of detaching, you can also experience flashing lights.

 

How can you avoid floaters?

Floaters are often part of the natural ageing process and so can’t necessarily be definitely avoided. You should however speak to your doctor or optician if you have any concerns about your eye health.

 

(1) https://nei.nih.gov/health/floaters/floaters

(2) http://www.moorfields.nhs.uk/condition/flashes-and-floaters

UK/O/0316/0017g

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