ConditionEyes & vision
Eye Floaters and Flashes of Light
Floaters are small specks, threads or cobwebs that drift across your vision, and flashes are brief streaks or arcs of light, usually at the edge of vision. Both most often come from age-related changes in the vitreous, the gel that fills the eye, especially when it pulls away from the retina (posterior vitreous detachment). Long-standing floaters are harmless. A sudden increase in floaters, new flashes, or a shadow over your vision can mean a retinal tear or detachment and needs an eye exam the same day.
Also called: Eye floaters, vitreous floaters, flashes of light, photopsia, posterior vitreous detachment symptoms
At a glance
- Floaters
- Dots, threads, rings or cobwebs that move with eye movement, most visible against bright backgrounds.
- Flashes
- Brief flickers or arcs of light, often at the side of vision, more noticeable in the dark.
- Most common cause
- Posterior vitreous detachment, usually after age 50 or earlier in nearsighted people.
- Serious causes
- Retinal tear or detachment, bleeding or inflammation inside the eye.
- What to do
- New or sudden symptoms need a dilated eye exam within 24 hours.
- Treatment
- Usually none; laser for tears, surgery for detachment; rarely surgery for severe floaters.
When to get help
Call 911 or go to the ER
- A dark shadow, curtain or veil spreading over part of your vision: go to an eye emergency service or ER today
- A sudden shower of many new floaters, especially with flashes, or loss of vision
- Floaters or flashes after an eye injury
See a doctor within a day or two
- A new floater or new flashes, even a single one, especially if you are nearsighted or had cataract surgery: see an eye doctor within 24 hours
- Floaters with eye pain, redness and light sensitivity (possible inflammation)
- New floaters in someone with diabetes, which can signal bleeding
Book a routine appointment
- A few long-standing floaters that have not changed
- Floaters that bother you when reading or using screens
- A follow-up exam 4 to 6 weeks after a new posterior vitreous detachment, or as advised
What causes floaters and flashes
The vitreous is a clear gel that fills the back of the eye and is attached to the retina, the light-sensing layer. With age, the gel becomes more liquid and its collagen fibers clump together. These clumps cast shadows on the retina, which you see as floaters.
Eventually the vitreous shrinks and separates from the retina. This is posterior vitreous detachment (PVD). It is a normal aging change that most people experience by their 60s or 70s. As the gel tugs on the retina during separation, the retina is mechanically stimulated and sends signals the brain interprets as flashes of light.
Who is at higher risk of PVD and complications
- age over 50
- nearsightedness (myopia), which brings PVD earlier
- cataract or other eye surgery
- eye injury
- inflammation inside the eye
- previous retinal tear or detachment, or a family history of detachment
When floaters and flashes are serious
In about 1 in 10 to 1 in 7 people with a symptomatic PVD, the pulling gel tears the retina. A retinal tear can let fluid pass under the retina, lifting it off and causing a retinal detachment, which can lead to permanent vision loss if not repaired quickly.
| Symptom pattern | Likely meaning |
|---|---|
| A few old floaters, unchanged for months | Normal vitreous changes |
| One new larger floater (often a ring) with occasional flashes | Posterior vitreous detachment |
| Many new floaters ("a swarm of flies" or "pepper"), flashes | Possible retinal tear with bleeding |
| Shadow or curtain spreading from the edge of vision | Retinal detachment |
| Red haze or sudden cloud of floaters in diabetes | Vitreous hemorrhage |
| Floaters with pain, redness, light sensitivity | Uveitis (inflammation) |
Because you cannot tell a simple PVD from a tear by symptoms alone, every new episode needs a dilated eye exam.
Flashes that are not from the retina
- Migraine aura: shimmering zigzag lines that spread over 5 to 60 minutes, usually in both eyes' field of vision, often followed by headache. They are not caused by retinal pulling. See migraine.
- Head injury: "seeing stars" after a blow.
- Low blood pressure on standing can cause brief sparkles.
- Occipital lobe problems such as stroke or seizures (rare).
Diagnosis
An optometrist or ophthalmologist will:
- Check vision and eye pressure.
- Dilate the pupils with drops.
- Examine the whole retina, including the far edges, with a slit lamp and an indirect ophthalmoscope, sometimes pressing gently on the eyelid to view the periphery.
- Use ultrasound if bleeding blocks the view.
Your vision will be blurry and light-sensitive for a few hours after dilation, so arrange not to drive.
Treatment
Floaters and uncomplicated PVD
No treatment is needed. Floaters usually become less noticeable over weeks to months as they settle out of the line of sight and the brain learns to ignore them. Flashes typically fade within a few weeks to months. A follow-up exam is often scheduled, because a tear can still develop in the first weeks.
Retinal tear
A tear without detachment is sealed with laser photocoagulation or cryotherapy (freezing) in the clinic. This creates a scar that welds the retina down and greatly reduces the risk of detachment.
Retinal detachment
Requires surgery, usually within days or hours depending on whether central vision is affected: pneumatic retinopexy (gas bubble), scleral buckle, or vitrectomy.
Persistent, disabling floaters
For a small number of people, dense floaters seriously affect vision years after onset. Options include vitrectomy (removing the vitreous gel), which is effective but carries risks such as cataract and retinal detachment, and YAG laser vitreolysis for certain floaters, which has limited evidence. These are reserved for severe cases.
Living with floaters
- Move your eyes up and down to shift a floater out of the line of sight.
- Reduce glare with sunglasses and adjust screen backgrounds.
- Know the warning signs and act quickly if they change.
Frequently asked questions
When should I worry about eye floaters?
Worry if floaters appear suddenly, increase in number, come with flashes of light, or are followed by a shadow or curtain over your vision. These can signal a retinal tear or detachment. See an eye doctor the same day. Old, unchanged floaters are usually harmless.
Can floaters and flashes go away?
Flashes from a posterior vitreous detachment usually fade over weeks to a few months. Floaters often become less noticeable as they settle and the brain adapts, but they may never disappear completely. Treatment is rarely needed.
What causes flashes of light in the corner of my eye?
The most common cause is the vitreous gel pulling on the retina during posterior vitreous detachment. A retinal tear can cause similar flashes. Migraine aura causes zigzag flashing patterns. New flashes always need an eye examination to check the retina.
Are floaters normal after cataract surgery?
Some people notice floaters after cataract surgery, because vision becomes clearer or a vitreous detachment occurs. However, the risk of retinal tear and detachment is higher after cataract surgery, so new floaters or flashes should be checked promptly.
Can stress cause floaters?
Stress does not cause floaters, which come from physical changes in the vitreous gel. Stress and tiredness may make you more aware of existing floaters. Any new floaters or flashes should be examined rather than put down to stress.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Ophthalmology: Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern
- National Eye Institute: Floaters; Retinal detachment
- MedlinePlus: Floaters
- NHS: Floaters and flashes in the eyes
- American Society of Retina Specialists: Floaters and flashes