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.
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.
If you suddenly notice a shower of new floaters, or floaters along with flashes or a dark shadow or a ‘curtain’ in your vision, these symptoms can mean that the retina is tearing.
If you notice any of these symptoms, you need prompt advice and attention. If you cannot contact your optometrist, you should go to A&E or the eye casualty department at your local hospital straight away.
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.
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 have already seen your optometrist and your symptoms have changed, you should go to the eye casualty department at your local hospital or A&E straight away.
Find more information at www.aop.org.uk/patients
Copyright © 2016 Association of Optometrists