What are flashes?
Sometimes the jelly inside your eye shrinks a little and tugs on the retina (the light-sensitive layer) at the back of your eye. This can cause flashes of light at the edge of your vision. This is different from the disturbance of vision that can happen with a migraine.
What are floaters?Often, people who have healthy eyes see floaters. They appear as spots, lines or cobweb effects, usually when you look at a plain surface such as a white wall, screen or a clear blue sky. They are usually caused by cells clumping together in the clear jelly in the main part of your eye and casting shadows on your retina – the light-sensitive layer of the eye. The sudden appearance of new floaters is different and may be caused by the jelly shrinking and can sometimes mean there is a tear in the retina.
When should I be concerned?
If you suddenly notice a shower of new floaters, or floaters along with flashes or a dark shadow or a ‘curtain’ in your vision, you should take urgent action. Follow the advice at the bottom of this page. These symptoms can mean that the retina is tearing.
What will happen if the retina tears?The retina is the light-sensitive layer at the back of your eye which receives images and sends them to your brain. If the retina tears, it may come away from the back of the eye and can lead to a retinal detachment which can result in you losing part or all of your vision.
How is retinal detachment treated?A tear may be treated by using a laser. If treated quickly you may have a better chance of full recovery. However, if your retina has become detached, you will need surgery. The operation may restore most of your vision but may come too late for a full recovery.
What to do if your symptoms change
Look out for the following:
Flashes or floaters getting worse
A black shadow in your vision
A sudden cloud of spots
A curtain or veil over your vision
Any change in vision
If you notice any of these symptoms, go to an Accident and Emergency department immediately.
Resources for your practice
Download the Flashes and floaters leaflet and share it in your practice.
If you're a practitioner, we recommend that you use this information, following a suitable examination, to reinforce advice given to the patient who has presented with symptoms of flashing lights or floaters.
Visit our For patients section for more info on eye health.