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Floaters, flashing lights and PVD


  • 77% of the US general population report seeing floaters
  • 33% of the US general population in a survey say floaters impair vision
  • Between 8% and 26% of patients with acute PVD symptoms have a retinal tear at the time of the initial examination
  • 25% of floaters are due to degeneration of the vitreous and no other cause is found

As you age, your eyes experience natural changes, for example in the consistency of the jelly known as vitreous humour, the fluid that fills the inner cavity of the eye. Sometimes you adapt easily to the changes but sometimes they interfere with your vision and medical help is needed.

The Harley Street Eye Clinic is here to offer an examination of your eye and either reassure you that the changes are normal and nothing to worry about, or offer treatment as appropriate. One way or another, our aim is to help you obtain the best vision possible in your situation.

As the vitreous humour ages, it can pull away from the retina at the back of the eye causing a condition known as posterior vitreous detachment (PVD), a common and often benign condition. Features typically associated with PVD are floaters and flashing lights.

Floaters in your eye can appear like specks or flecks in your vision. They zip off when you try to look at them, then drift back when you stop. Most often they do not interfere with your vision, but very occasionally your eye might require examination and treatment by your eye specialist.

Flashing lights are short-lived, and most commonly occur together with floaters, with most patients experiencing the flashing lights initially and floaters later on.

Sometimes flashing lights do not occur with floaters. They are also less common than floaters, and usually last for hours or a couple of days at most. If you experience flashing lights in your vision then this could indicate a serious problem with your eye and you should contact your ophthalmologist.

Here, at The Harley Street Eye Clinic, we can help with PVD and the floaters and flashing lights that might accompany it, to help restore the clarity of your vision.

What causes floaters, flashing lights and PVD?

The eye is like a camera with two aspects to its anatomy: focusing (a lens system), and a film at the back of the eye called the retina. In between the two lies a transparent jelly known as the vitreous humour.

In youth, the jelly mainly consists of water and collagen and has a stiff, jelly-like consistency sticking to the retina like glue. However, with age the vitreous jelly becomes more watery, less jelly-like and loses its usual shape, pulling away from the retina surface. This condition is called posterior vitreous detachment (PVD) or vitreous syneresis.

Once the separation between vitreous jelly and retina, and the degenerative process or liquification of the jelly has begun, collagen fibres contained within the jelly, change from being transparent to globular. These globules or particles are perceived as floaters.

Aging, dehydration, and genetics can all contribute to this process. By the age of 70 years, 70-80% of the population has vitreous separation or detachment in one or both eyes.

Having floaters in your eye is like having debris floating in and out of your vision. They often appear like tiny dark-coloured spots, specks, flecks, thread-like strands, squiggly lines, and ‘cobwebs’. They are very distracting and usually most visible when you look at bright light. If you have floaters then you may have stopped reading as much, and no longer enjoy television, or avoid sunlight.

Should you be concerned about floaters in your eye?

Sometimes your brain simply adjusts to their presence and floaters are harmless. Floaters are an extremely common part of ageing and over time the brain learns to ignore them. Unless a direct cause for the floaters is found, floaters may simply be due to degeneration and liquification of the vitreous jelly, where collagen fibres become thickened and visible. This condition is known as vitreous syneresis.

However, if they are impeding your vision or you are worried about them, it is important to have your eye examined by your ophthalmologist. The Harley Street Eye Clinic is happy to help you.

Occasionally, floaters can be a symptom of a more serious condition, including:

Flashing lights

As the vitreous jelly separates from the retina, it can create the effect of flashing lights in your vision. This is a one-off event due to irritation caused by the pull of the vitreous jelly from the live retina. Because the retina transmits electrical signals to the optic nerve, the retina is effectively an electronic board, hence the flashing lights, when the retina is being pulled.

What do flashing lights and floaters mean in terms of eye health?

In many patients, flashing lights and floaters are simply symptomatic of posterior vitreous detachment (PVD) without complications. But in some patients the separation of the vitreous jelly can indicate more serious problems, and this is referred to as PVD with complications. These complications might include: retinal tear, retinal detachment or vitreous haemorrhage. The cause of your flashing lights and/or floaters depends on your individual risk factors, which are often determined by the anatomy of your eye.

Find out more

To discuss the cause and treatment of your condition, please call us on the number below.
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0207 060 0086

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