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Dry Eye

What Can Cause Flashes & Floaters?

Flashes and Floaters

To suddenly get flashing lights or things floating in front of your eyes can be quite alarming if you've never experienced it before. Unfortunately a quick search on Google often leaves you fearing the worst, but often it's something minor that causes similar symptoms.


These are a specific type of visual disturbance, not always including flashing lights. Sometimes they just cause your vision to flicker or look like rippling water. What they have in common is that they tend to last a while - anything up to an hour. An intense, pulsing headache may follow, but sometimes there is just the visual disturbance - this is a visual migraine. Migraines are caused by unusual blood flow to the brain, hence the pulsing headache often experienced.

Posterior Vitreous Detachment (PVD)

Your eyeball is filled with a jelly called Vitreous Humour. This gel can sometimes have little bits caught in it which we see as Floaters, drifting across our vision as little dots or wispy strands.

Over time the jelly shrinks and becomes more liquid, and as it does so it peels off the retina, which lines the back of the eye. Often it peels off slowly, but sometimes it sticks and tugs at the retina which responds and you see a little flash of light. The peeling process is normal and happens in all eyes, often completely unnoticed. If however you suddenly develop floaters or flashing lights come in for a check as soon as possible. We'll have a good look at your eyes and check that all is well. We want to make sure that the retina is not being peeled off too.

Retinal Detachment

This is a serious eye condition, but if caught early there is a good chance your sight can be saved. Lots of things can cause detachment, but any recent bumps to the head or eye, or if you are short sighted, can increase your risk. Symptoms can include a film or 'grey curtain' across your vision along with flashing lights. If you have these symptoms contact us as soon as possible. The sooner it is picked up, the better the treatment outcome.

With all concerns over flashes and floaters we may have to put drops into the eye to dilate your pupils, allowing us to have a good look at the back of the eye. We can also take photographs and 3D scans of the retina to allow us to keep detailed records and to detect any minor changes.

If you are screened as part of the hospital diabetic program please be aware that it provides an in depth examination of the eye with regard to diabetes. Unfortunately it is possible to have more than one condition affecting your eyes, so our screening looks at all aspects of your eye health.

If you have any sudden symptoms, or you experience the onset of flashes or floaters, call us immediately - we want to check your eyes and put your mind at rest.

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