Flashes and Floaters

Floaters look like small, often dark spots or hair-like strands that appear to float in front of your eyes. They are very common and often harmless. Occasionally an increase in floaters can be a sign of problems inside the eye. Because they “float” in the jelly at the back of your eye, you will find that as you move your eye the floater will also move in that direction. Often people only see floaters whilst staring at a light coloured surface or at the sky during the day.

It is common for floaters to increase as you age. The vitreous humour (gel at the back of the eye), naturally shrinks and separates into a watery fluid and wavy collagen fibrils, both of which we classify as floaters. Sometimes the gel shrinks enough to collapse away from the retina (light sensitive lining at the back of the eye).
The collapse of the vitreous gel can pull on your retina and in turn can cause you to see “flashes”.

They are more common if you are short-sighted or as you get older. They may also increase if you have had an eye operation such as cataract surgery.

Occasionally a sudden increase in floaters may be a sign of a more serious eye condition such as a retinal detachment. This is when your retina pulls away (detaches) from the back of your eye. This often leads to a sudden increase in floaters, onset of flashes, a blank spot in your vision or a shadowing within your visual field which does not cease. This needs immediate attention and hence you should contact us immediately. If this is not possible you should seek urgent attention from an eye casualty department at the hospital.

These are small bright sparkles, lightning or fireworks, which usually occur in the extreme corners of your vision. These flashes do not last for a defined length of time, and you may notice them more if you go from a light to dark environment.

Flashes occur when there is a pull on your retina. This might happen as the vitreous gel inside your eye collapses. They can also occur if you are hit in the eye. Sometimes flashes simply indicate a tug on your retina and nothing more. However constant flashes may be a sign of a retinal detachment.

Often people notice a shimmering of light or zig-zag lines that may be associated with migraines. These often appear on one side of your vision, which then expands to the outside of your vision with a sort of jagged pattern. This may obscure at least a part of your vision. The shimmers usually cease after 10-20 mins and may be followed by a headache, although some people do get migraine shimmers even if they do not get the headache afterwards.