Most of us have seen strange shapes in front of our eyes - from tiny dots, to long, shadowy strands in our field of vision.
But do you need to worry?
If you see something such as a large ‘blank’ spot, or flashing lights at the edge of your vision, the answer is definitely, ‘Yes’.
Spots in front of our eyes are a normal part of vision, for the most part - known as ‘floaters’, they’re usually the shadows of debris inside our eyes.
‘Floaters’ are particularly common among older people - they’re seen particularly often in people in their 60s and 70s, and tend to occur more often after the age of 40.
They’re a normal part of the ageing process, experienced by 70% of us - but changes in the way they appear could be a cause for concern.
The NHS says, ‘Floaters are small pieces of debris that float in the eye’s vitreous humour. Vitreous humour is a clear, jelly-like substance that fills the space in the middle of the eyeball.
‘The debris casts shadows onto the retina (the light-sensitive tissue lining the back of the eye). If you have floaters, it’s these shadows you’ll see.’
But if your ‘floaters’ start to change - for instance, if you notice an increase in the number of floaters you can see, or if you see white flashes, you should visit an optician immediately.
In rare cases, an increase in the number of floaters can be the first sign of a retinal tear, or retinal detachment - which could require surgery.
Visit your optician immediately if you notice an increase or sudden change in your floaters, particularly if you notice white flashes and some loss of vision.
Eye expert Dr Susan Blakeney says that a large ‘blank’ area could be a warning sign.
Dr Blakeney says, ‘The main symptom of detachment is a large blank area in your vision that won’t go away, which may be associated with flashing lights or a general fuzziness.
'If this happens, go to A&E straight away as it can lead to permanent blindness - but if caught early enough, a torn or detached retina can be put back into place.’
If you do have floaters, don’t bother treating them with eye drops - they won’t make a difference.
Instead, ensure that you book in to see an optician regularly - the NHS recommends making an appointment every two years.
In many cases, your brain will simply adapt to the floater and begin to ‘edit it out’ from your vision - so that you won’t notice it so often.
A very small number of people report a strange visual distortion where it looks like there is television static in front of their eyes - like ‘visual snow’.
Sufferers report that using screens can aggravate the symptoms - but there is at present no cure, according to Peter Goadsby of University College London, speaking to the Daily Mail.
Professor Goadsby says that a brain area responsible for processing visual information may be behind the disorder.
He says, ‘This area is overactive in people with visual snow and it seems to be a disorder of the way in which this part of the brain responds to the information it receives from the eyes.
‘For those affected it can be extremely disabling and affect their work and personal lives.’
Goadsby recommends seeing an optician to rule out other possible causes first.
Most of us have experienced kaleidoscopic coloured lights in front of our eyes - it’s a natural response to looking at bright things.
But if you experience colourful flashes which last longer than a few seconds, it could be the sign of a migraine.
But if the flashing lights are at the edges of your vision, and persist longer than 30 minutes, it could be a sign of a detached retina - and you should go directly to A and E.
The Royal National Institute for the Blind says, ‘If you develop any of the symptoms associated with retinal detachment you should see an eye health professional as soon as possible.
‘A retinal detachment happens when the retina separates from the back of the inside of your eye. If a retinal detachment isn’t detected or treated quickly it may result in a loss of some or all the vision in your eye.’