What are floaters?

Floaters appear as spots, lines, circles, clouds, cobwebs and various other shapes in your vision. They can appear black or grey in colour and may often be see through. Floaters may also appear to stay in one place or move around.

What are flashes?

Flashes appear as sparks or strands of white light that flicker across your vision.

Why do they appear?

Floaters occur when the vitreous (the jelly-like substance filling the eyeball) becomes separated from the nerve layer at the back of the eye (retina). 

Floaters are seen when clumps of this vitreous jelly produce shadows on the retina.

Flashes occur when the vitreous bumps, rubs or tugs against the retina.

What does this mean?

For most people, floaters and flashes are caused by Posterior Vitreous Detachment (PVD), a natural change that occurs in the eye.

Over 75% of those aged over 65 will develop PVD. It is not a sign of disease, as most PVD happens naturally as you get older. No treatment is needed for PVD.

A few patients with PVD may also develop a tear or hole in the retina. A detailed examination will check for this and treatment with laser may be needed to prevent a retinal detachment.

Other causes of floaters and flashes


Coloured flashes, enlarging zig zag lines or kaleidoscope images commonly affecting both eyes, usually indicates a migraine. Older people frequently experience the visual symptoms of migraine but no headache.

Retinal Detachment

This occurs when the retina separates from the back of the eye. Most often it happens because of a tear or a hole in the retina, which allows fluid to leak between the retinal layers, causing the retina to detach. Usually on operation is needed to repair the hole and preserve sight.

Common signs of retinal detachment

  1. The development of a veil like obstruction to your peripheral vision (to the side)
  2. Rapid deterioration of your vision
  3. An increase in the number of floaters and / or flashing lights in your vision