Sudden floaters and flashes in a parent: when it means an eye doctor today
Dad sees cobwebs, Mum sees a flash at the edge of her sight. Most floaters are the eye's jelly ageing, but one pattern means a retinal tear. Here is which pattern, who is at higher risk and what the examination involves.
Go to an eye doctor the same day if…
I see parents and grandparents for squint, cataract and everyday eye problems, so one family can keep one eye doctor. Family eye care Where I practise
- Floaters are shadows of tiny clumps in the vitreous, the jelly inside the eye. With age the jelly can peel away from the retina, called a posterior vitreous detachment (PVD), and that pull can cause flashes.
- Go to an eye doctor the same day for a lot of new floaters, flashes of light, a shadow at the side of the vision, a grey curtain over part of the sight, or sudden blurring.
- Old floaters that have not changed, with no flashes and no shadow, can wait for a routine eye check. If you cannot tell whether a floater is new, treat it as new.
- Being short-sighted, having had cataract or other eye surgery, an eye injury, and a tear or detachment in the other eye or in the family raise the risk of a retinal tear.
- The examination is painless: dilating drops, then a look at the retina through a special lens. A tear found early can be treated with laser or freezing.
Your father looks up at the ceiling fan and says there are cobwebs in front of his eye. Your mother mentions a flash of light at the edge of her sight, like a camera going off, and then a shower of dark dots. Both say it is probably age, and both may be right. Both also need to know that one particular pattern of floaters and flashes is a sign of a retinal tear, and that is a problem measured in hours and days.
This page sets out what these symptoms usually are, the pattern that means an eye doctor today, who is at higher risk, and what the examination involves. It is written for adults and for the grown-up children who get the phone call.
Why is my parent suddenly seeing floaters and flashes?
Most often the jelly inside the eye is ageing. The American Academy of Ophthalmology explains that as we get older "the vitreous starts to thicken or shrink", which can lead to a posterior vitreous detachment, or PVD: the vitreous peeling away from the retina, the light-sensing layer at the back of the eye. Floaters are the shadows of clumps in that jelly. Flashes happen "when the vitreous rubs or pulls on your retina".
Floaters look like specks, dots, circles, lines or cobwebs, and they show up most against something plain such as a blank wall or a blue sky. If your parent has had the same few for years, that is one thing. A sudden new set, or flashes, is another.
The same jelly pulling on the retina that causes the flash can also pull a hole in it. The action: ask when it started, which eye, and whether it is a few new specks or a lot at once, then read the next section.
Which floaters and flashes mean going to an eye doctor today?
Go the same day for any of these. They are the Academy's list for when to call an ophthalmologist, and the NHS gives the same advice for floaters that "suddenly appear" or "suddenly increase in number".
- A lot of new floaters, or a sudden increase in the number.
- Flashes of light, especially with new floaters, or many flashes.
- A shadow in the peripheral (side) vision.
- A grey curtain covering part of the sight. The Academy's words are "a gray curtain covers part of your vision".
- Sudden blurring of the vision.
These can mean a torn or detached retina, which the Academy calls "a serious condition that needs to be treated". It adds that an untreated detached retina can mean you "quickly and permanently lose your sight". That is the reason for "today" rather than "this week". It is not a reason to panic, only to move. The action: do not wait to see whether it settles overnight, and do not book the next free slot in a fortnight.
When can floaters wait for a normal appointment?
When they are old, familiar and unchanged. The Academy says most floaters and flashes "are not a problem" and tend to "fade and become less noticeable over time". A few specks your parent has noticed for years, with no flashes, no shadow and no change in number, can be mentioned at the next routine eye check.
What cannot wait is the word "new" or "more". Nobody can tell by looking at a parent whether a new floater is harmless jelly or a tear, and nobody can tell from a description over the phone either. Only an examination of the back of the eye separates them. The action: if you are unsure whether a floater is new, treat it as new until an eye doctor has looked.
A shimmering zigzag line that spreads and clears in both eyes is a different pattern, usually a migraine aura, and it is covered in flashing lights and zigzag lines: when it is migraine. Flashes in one eye, or flashes with floaters, are the pattern on this page.
Who is at higher risk of a retinal tear or detachment?
The Academy lists being short-sighted, having had eye surgery such as cataract or glaucoma surgery, a serious eye injury, a tear or detachment in the other eye, and family members who had a retinal detachment. The NHS lists the same groups. For a parent who is very short-sighted, the eye is longer than usual, which is why the warning signs matter more. High myopia: what changes once the number gets high goes through the eye-health checks that come with a high prescription.
Cataract surgery is worth a line for the household: after Ah Ma's cataract operation: how the family can help covers the first weeks. A study of 8,305 adults with acute symptomatic PVD in a large health system found that prior cataract surgery and prior laser vision surgery were each linked to a higher chance of a retinal tear or detachment, as were blurred vision and age under 60.
Risk is a reason to know the signs, not a reason to expect trouble. The action: tell any eye doctor about previous surgery, injury and a family history of detachment.
How often is a retinal tear found when floaters start suddenly?
Not in most people, but often enough to examine everyone who has the symptoms. In the same health-system study, of 8,305 adults who presented with the symptoms of an acute PVD, about 5 in 100 (5.4%) were found to have a retinal tear and about 4 in 100 (4.0%) a retinal detachment. The other nine in ten or so had a PVD without either. The authors note that this is lower than earlier reports from specialist retina practices.
Those numbers are the reason for the advice. You cannot know which group your parent belongs to without the examination, and the cost of checking is a few hours. The cost of missing a tear that goes on to detach the retina can be permanent loss of sight. The action: use these figures to steady yourself on the way, not to decide the visit is optional.
What does the eye examination involve?
It is painless. The eye doctor puts in dilating drops to widen the pupil, then looks through a special lens at the retina, checking it for any changes. That is how a tear, a detachment or bleeding into the jelly is found or ruled out. The Academy describes this as the way a retinal problem is diagnosed. Your parent will also have the vision tested.
If the retina is healthy and the result is a PVD, the usual plan is reassurance and a clear warning to come back at once if the symptoms change.
That matters, because a study of 7,999 eyes with acute PVD found new retinal breaks in 2.6% and new detachments in 1.0% after the first examination, and its authors concluded that repeat examination may be prudent. So the follow-up visit, if one is advised, is part of the care and not a formality. The action: keep it, and know the warning signs by heart.
What happens if there is a tear or a detachment?
A tear caught early can be sealed. The NHS describes laser or freezing treatment on tears to stop them progressing. A detached retina needs hospital surgery. The Academy describes three approaches: a gas bubble to push the retina back, removal of the vitreous with air, gas or oil, and a band sewn to the outside of the eye. The NHS notes most procedures use local anaesthetic and recovery takes about two to six weeks, when vision may stay blurred.
The floaters themselves are a separate matter. The Academy says severe floaters can be removed by surgery, but "this has risks and is seldom necessary or recommended". Most people get used to them, and they tend to settle. The action: what matters is finding a tear, not removing the specks.
What should I do tonight if my parent has these symptoms?
If any sign in the same-day list applies, go to an eye doctor or to a hospital with an eye service today, and take your parent's glasses and a list of their medicines. Do not wait for the clinic that opens next week. Note when it started, which eye, whether there were flashes, and whether anything hit the eye or there has been eye surgery.
If none applies and the floaters are old and unchanged, book an eye check for the coming weeks. If it is a child rather than a parent who sees spots, spots floating in my child's vision has the version for children, where the cause is less likely to be age. The action: when something new appears in a parent's eye, going today and finding nothing costs an afternoon, and that is a fair price.
- A lot of new floaters appear at once, or the number suddenly rises.
- There are flashes of light, especially together with new floaters.
- A shadow appears at the side of the vision.
- A grey curtain covers part of what you can see.
- The sight suddenly blurs, or any of this follows a knock to the eye or eye surgery.
Common questions
Why am I suddenly seeing floaters in one eye?
Are flashes of light in the eye an emergency?
What does a retinal detachment look like?
Can floaters go away on their own?
Who is more likely to get a retinal tear or detachment?
What happens at the eye examination for floaters and flashes?
If the doctor finds only a vitreous detachment, can I forget about it?
Is it safe to wait until my usual clinic opens?
- American Academy of Ophthalmology · What are floaters and flashes? · www.aao.org
- American Academy of Ophthalmology · What is a detached retina? · www.aao.org
- NHS · Retinal detachment · www.nhs.uk
- Ophthalmology 2022 · Complications of acute posterior vitreous detachment (Kaiser Permanente Northern California cohort) · pubmed.ncbi.nlm.nih.gov
- Ophthalmology 2020 · Delayed retinal breaks and detachments after acute posterior vitreous detachment · pubmed.ncbi.nlm.nih.gov