Posterior Vitreous Detachment: Floaters, Flashes and Retinal Tear Risk

Table of Contents

1. The Vitreous Gel and How It Ages
2. What a Posterior Vitreous Detachment Is
3. Who Gets It and When
4. Floaters and Flashes and Why They Happen
5. How Often a Retinal Tear Comes With It
6. How Eye Doctors Examine the Eye
7. What Happens Afterwards
8. Signs Eye Services Treat as Urgent
9. Treatments Studied for Lasting Floaters
10. What Is Not Known
11. Key Research Papers
12. Connections
13. Featured Videos

The Vitreous Gel and How It Ages

The space between the lens at the front of the eye and the retina at the back is filled with the vitreous, a clear gel. It is mostly water. A review by the vitreous researcher Jerry Sebag notes that large molecules make up only about 2% of the vitreous, yet they are what keep it a gel and keep it transparent. The two main ones are collagen, which forms a fine scaffold of fibres, and hyaluronan, a water-holding molecule that sits between the fibres and keeps them apart.

In a young eye the gel is even and clear, and its back surface (the posterior vitreous cortex) is stuck firmly to the retina. With age, and in nearsighted eyes, that arrangement breaks down. A 2016 review by Milston, Madigan and Sebag describes how collagen separates from hyaluronan and the freed collagen fibrils clump together into thicker fibres. Two things happen at once:

• Liquefaction (synchysis): pockets of watery fluid form inside the gel where the scaffold has collapsed.
• Syneresis: the remaining gel shrinks and condenses, a little like a set jelly that weeps water and pulls in on itself.

The clumped fibres scatter light and cast shadows on the retina. That is the origin of many everyday floaters, and these reviews describe them as especially common in nearsighted eyes. At the same time the glue between the back of the gel and the retina weakens. Liquefied gel plus weaker adhesion is the set-up for a posterior vitreous detachment. An early review of vitreous ageing in 1987 already described these changes as rheologic (how the gel flows), biochemical and structural.

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What a Posterior Vitreous Detachment Is

In a posterior vitreous detachment, the back surface of the vitreous gel lifts off the retina and the shrunken gel moves forward into the middle of the eye. Fluid from the liquefied pockets fills the space left behind. Nothing is lost from the eye. The gel has simply separated from the wall it used to be stuck to.

Scans show that this is usually a slow process with a sudden ending. In a 2001 study, Uchino and colleagues imaged 209 healthy eyes (volunteers with a mean age of 52.3 years) with optical coherence tomography, a light-based scan that shows the layers at the back of the eye in cross-section. They sorted the eyes into five stages:

• Stage 0, no detachment: 29.2% of eyes.
• Stage 1, a partial detachment around the centre of vision in up to three quarters of the circle: 47.8%.
• Stage 2, partial detachment all around the centre, still attached at the centre of vision (the fovea) and the optic nerve: 12.4%.
• Stage 3, detached over the back of the eye except at the optic nerve: 1.9%.
• Stage 4, complete detachment: 8.6%.

The partial stages caused no symptoms and could not be seen with a standard lens examination. The researchers found partial detachment beginning as early as people's thirties and forties, usually starting in the upper part of the eye, and extending slowly over years. The detachment became complete when the gel finally let go of the optic nerve head, the spot where the nerve leaves the eye. That final release is the moment many people notice a sudden new floater.

Where the gel was stuck most firmly, the retina can be pulled hard as the gel separates. If the retina gives way instead of the gel, the result is a retinal tear. Fluid can then pass through the tear and lift the retina off, which is a retinal detachment. A thin film of gel left behind on the centre of the retina can also become the base for an epiretinal membrane.

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Who Gets It and When

Age is the main driver. The Uchino scan study found a significant step-by-step progression of the stages with age. A 2026 study from Argentina that staged 1,984 eyes with wide-field optical coherence tomography found that complete detachment increased with age and was more frequent in women aged 60 and over.

Nearsightedness (myopia). A nearsighted eye is usually longer from front to back. In a South Indian cohort of 615 people with type 2 diabetes, followed with ultrasound scans, myopia (odds ratio 2.14) and a longer eye (odds ratio 1.35 for longer axial length) were independent risk factors for progressing to a complete detachment, alongside age. The European multicentre MYOPRED study, which followed nearsighted eyes 25.0 mm or longer having lens surgery, found that each extra millimetre of eye length raised the rate of progression to complete detachment (hazard ratio 1.25), as did each decade of age (hazard ratio 1.37).

Cataract surgery. In the same South Indian cohort, people who had cataract surgery were 2.32 times more likely to progress to a complete detachment. In the MYOPRED study, four out of ten nearsighted eyes that had no detachment or only a partial one before surgery progressed to a complete detachment within a year of the operation (40.2% by 12 months). The Argentine study, in eyes of ordinary length operated on with a low-pressure fluid system, reported a different picture: progression followed age, sex and starting stage rather than a general speeding-up from surgery, with an excess of complete detachment only in operated women aged 70 to 79. The effect of surgery may therefore depend on the eye and on how the operation is done.

Eye injury. A blow to the eye is also described in the clinical literature as a trigger of an earlier detachment, but the studies cited on this page did not measure how much it adds.

Diabetes. In people with diabetes the gel can matter more than usual, because in diabetic retinopathy new blood vessels grow along the back surface of the gel. The South Indian cohort found that 80.8% of eyes with no detachment at the start went on to a partial or complete detachment during follow-up.

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Floaters and Flashes and Why They Happen

Floaters are shadows. When the gel separates, its dense back surface, now floating in the middle of the eye, casts shadows onto the retina. People describe dots, threads, cobwebs or a ring. The ring is often the old attachment around the optic nerve, which eye doctors call a Weiss ring. Floaters drift when the eye moves and are easiest to see against a bright sky or a white wall. The Milston review describes the dense collagen of the back surface of the gel as the most common source of new floaters, and posterior vitreous detachment as the most common cause of them.

Flashes (photopsia) are brief streaks or arcs of light, often at the edge of vision and most noticeable in the dark. They happen because the retina reacts to pulling the same way it reacts to light. Each time the gel tugs on the retina, the retina sends a signal the brain reads as a flash.

A cloud or a shower of dots can mean blood. If the separating gel tears a small blood vessel, or tears the retina where a vessel crosses it, blood spills into the gel. Red blood cells show up as many tiny dark specks or a haze. Eye doctors examining the eye may also see pigment cells floating in the front part of the gel (sometimes called "tobacco dust"), a finding linked to a tear.

Symptoms usually affect one eye. The second eye often follows months or years later.

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How Often a Retinal Tear Comes With It

Two systematic reviews give the clearest numbers. A 2009 review in JAMA by Hollands and colleagues pooled 17 studies of people with sudden floaters, flashes or both and a posterior vitreous detachment who were seen by an eye specialist. It found a retinal tear in 14% of them (95% confidence interval 12% to 16%).

A 2019 systematic review by Gishti and colleagues from the Rotterdam Eye Hospital pooled 13 studies and broke the risk down by symptom:

The same review found that people reporting more than 10 floaters, or a cloud in their vision, had a much higher risk of a tear (odds ratio 19.8). The risk was greater when both symptoms were present, and greater still with more than 10 floaters, a curtain or a cloud, or bleeding seen on examination.

The Hollands review reported the same pattern from the doctor's side. A person's own sense that their vision had got worse was the symptom most strongly linked to a tear (likelihood ratio 5.0). Blood in the gel seen through the slit-lamp microscope was the best-studied finding pointing towards a tear (likelihood ratio 10). The absence of pigment cells in the gel was the best-studied finding pointing away from one (likelihood ratio 0.23).

Put plainly: most people with a new posterior vitreous detachment do not have a tear, but roughly one in seven of those who reach an eye specialist do, and the chance rises with the number of new floaters, with a cloud or curtain, and with bleeding.

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How Eye Doctors Examine the Eye

A posterior vitreous detachment cannot be confirmed, nor a tear ruled out, from symptoms alone. The examination is what decides it. The American Academy of Ophthalmology covers this examination in its Preferred Practice Pattern on posterior vitreous detachment, retinal breaks and lattice degeneration, last updated in 2025.

• Vision check and history. The Hollands review reports that a drop in vision noticed by the person is the strongest symptom linked to a tear, which is why the reviewers call measuring visual acuity a constant part of the assessment.
• Dilated examination. Drops widen the pupil so the doctor can see the whole retina, out to the far edges where most tears form. A slit-lamp microscope is used to look into the front part of the gel for blood or pigment cells.
• Scleral depression. During the dilated examination, the doctor gently presses on the outside of the eyelid over the white of the eye. This pushes the far edge of the retina into view and helps show small tears that would otherwise be hidden.
• Optical coherence tomography. This light scan shows whether the gel is still attached at the centre of vision and the optic nerve. As the Uchino study showed, it can detect partial detachments that a lens examination misses. It also shows a membrane or a hole at the centre of vision. It cannot see the far edges of the retina well.
• B-scan ultrasound. When blood in the gel, a dense cataract or another cloudy view blocks the doctor's sight, an ultrasound probe placed on the closed eyelid maps the gel and the retina by sound. Studies such as the South Indian diabetes cohort used ultrasound to stage detachments, and the MYOPRED study used it alongside optical coherence tomography. Sebag's 2020 review also uses ultrasound images of the gel to judge how dense floaters are.

Retinal photographs and scans are covered in more depth on the retinal imaging page.

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What Happens Afterwards

Floaters often become less noticeable. Sebag's 2020 review notes that many people adapt to floaters, and in practice the brain often learns to ignore what remains. Flashes usually stop once the gel has fully let go, because there is nothing left to pull.

A tear found at the first visit is usually sealed with a laser or a freezing treatment around the tear, to stop fluid getting underneath. Those treatments are described on the retinal detachment page.

A tear that appears later. A clear first examination does not rule out a later tear completely, because the gel can keep pulling for a while. The Hollands review found that people first diagnosed with an uncomplicated posterior vitreous detachment had a 3.4% chance of a retinal tear within six weeks. That risk was higher with new onset of at least 10 floaters or a person's own sense of worse vision during that time.

Later studies of routine follow-up report low numbers:

• A US urgent-care clinic study (Patel and colleagues, 2022) followed 491 eyes for a mean of 147 days. It found delayed retinal breaks in 2.0% and delayed retinal detachments in 0.6%. People who developed a late break or detachment were more likely to have lattice degeneration (thin patches at the edge of the retina) or a history of a retinal break in the other eye.
• A Canadian study (Nassrallah and colleagues, 2019) notes that people are typically seen again 4 to 6 weeks after the first visit. Of 105 people with an uncomplicated detachment and no new symptoms who came back (median six weeks), none had a new tear or other new finding. The authors suggested routine follow-up of people without new symptoms may have limited benefit.

The Gishti review concluded that a follow-up examination "might be prudent in a subgroup" of people, which in the studies above are those with bleeding, many floaters, lattice degeneration or an earlier tear. Follow-up timing differs between eye services, and the published studies do not settle on one interval for everyone.

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Signs Eye Services Treat as Urgent

The studies above point to a short list of signs that hospitals and eye services treat as reasons for a same-day eye examination. They are signs, not a diagnosis. Any of them can come from a harmless detachment or from a tear.

• A sudden shower of new floaters, many dots at once, or more than about ten new floaters.
• New flashes of light, especially together with new floaters.
• A cloud or haze over part of the vision, which can mean bleeding into the gel.
• A curtain, shadow or grey area spreading across part of the vision, from the side, top or bottom. This is the classic sign of the retina lifting off.
• A noticeable drop in sharpness of vision in the affected eye.
• A new burst of floaters or flashes in an eye already known to have a posterior vitreous detachment.

The Gishti review's authors wrote that their findings support "the necessity of an immediate examination" of people with symptoms of a posterior vitreous detachment. The Hollands review concluded that people at higher risk be sent for urgent eye assessment. Other causes of a sudden change in vision are listed on the blurred vision page.

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Treatments Studied for Lasting Floaters

For most people floaters fade into the background. For some they do not. Sebag's 2020 review describes floaters that measurably lower contrast sensitivity (the ability to see faint shades of grey) and reduce quality of life, and calls this vision degrading myodesopsia. Two procedures have been studied.

Laser vitreolysis

Neodymium-doped yttrium-aluminium-garnet (YAG) laser vitreolysis uses short laser pulses, aimed through the pupil, to break up or vaporise a floater. It is done in the clinic, without opening the eye.

• Sham-controlled trial, 2017. Shah and Heier randomly assigned 52 people with a Weiss ring floater from a posterior vitreous detachment to the laser or a sham laser. At six months, the laser group reported 54% symptom improvement against 9% with the sham. 53% of the laser group described their symptoms as significantly or completely improved, against none in the sham group. Sharpness of vision did not change, and no difference in side effects was found. The trial was small, from a single private practice, and the authors called for larger and longer studies.
• Second randomized trial, 2021. Ludwig and colleagues in Brazil analysed 21 eyes. Subjective improvement was 77% with the laser against 25% in the control group. Contrast sensitivity did not differ between the groups.
• Meta-analysis, 2026. Alnajres and colleagues pooled 15 studies with 718 treated eyes (2 randomized trials and 13 observational studies). They found a 15.0-point gain on a 100-point vision quality-of-life questionnaire and better contrast sensitivity, with no change in sharpness of vision. Side effects were infrequent and short-lived, most often blurred vision and bleeding on the retina, with no permanent vision loss. The authors rated the certainty of the evidence as limited, because most studies were not randomized.

Reviews by Sebag's group are more cautious. The 2016 review found reported success rates ranging from 0% to 100% and concluded that only vitrectomy had proven value at that time. The 2020 review describes the laser as "occasionally slightly effective".

Vitrectomy for floaters

A vitrectomy is an operation in which a surgeon uses fine instruments through tiny openings in the white of the eye to remove the gel, replacing it with clear fluid. It is the same operation used for retinal detachment and epiretinal membrane.

• Benefits reported. In a survey of 48 surgeons from 16 countries by the European VitreoRetinal Society, covering 581 eyes operated on for floaters, 92% of patients were satisfied and 86.3% reported complete resolution of daily-life symptoms. Satisfaction was lower in people whose floaters were smaller to begin with.
• Risks reported. A retinal break caused during surgery occurred in 5% of eyes (29 eyes). A retinal detachment developed in 2.4% (14 eyes), at a median of three months. A cataract developed in 84 eyes (48.6% of those reported), at a median of 16 months after surgery. Removing only the central gel (core vitrectomy) and faster cutting speeds were linked to fewer retinal breaks.
• The survey was retrospective, and its authors named careful patient selection and informed consent as the most important parts of the operation.

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What Is Not Known

• Prevention. No treatment has been shown to prevent or slow the ageing of the vitreous gel. Sebag's 2020 review names prevention as a goal for future research, not something available now.
• Who will tear. Symptoms and examination findings shift the odds, but no test predicts which eye will develop a late tear. The follow-up studies were small and retrospective, and the Patel study's authors noted it lacked the power to detect differences between groups.
• The best follow-up interval. Studies report 4 to 6 weeks as typical, and some found few or no late tears in people without new symptoms. No large trial has compared follow-up schedules.
• Cataract surgery's share. Studies of nearsighted eyes report a faster detachment after lens surgery, while a study of normal-length eyes operated on under low pressure did not find a general acceleration. How much surgery itself adds is unsettled.
• Floater treatments. The laser trials were small and short, and the vitrectomy data come from a retrospective survey. No large randomized trial has compared the laser with vitrectomy, and the 2026 meta-analysis called for one.
• Drug treatments. The reviews mention drugs that might dissolve or loosen the gel (pharmacologic vitreolysis) and optical corrections as ideas under study, not proven treatments for floaters.

Decisions about examinations and procedures belong with an eye specialist.

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Key Research Papers

1. Gishti O, van den Nieuwenhof R, Verhoekx J, van Overdam K. Symptoms related to posterior vitreous detachment and the risk of developing retinal tears: a systematic review. Acta Ophthalmol. 2019;97(4):347-352. PubMed PMID: 30632695
2. Hollands H, Johnson D, Brox AC, Almeida D, Simel DL, Sharma S. Acute-onset floaters and flashes: is this patient at risk for retinal detachment? JAMA. 2009;302(20):2243-9. PubMed PMID: 19934426
3. Kim SJ, Bailey ST, Kovach JL, Lim JI, Vemulakonda GA, Ying GS, Flaxel CJ; American Academy of Ophthalmology Preferred Practice Pattern Retina/Vitreous Committee. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern. Ophthalmology. 2025;132(4):P163-P196. PubMed PMID: 39918519
4. Uchino E, Uemura A, Ohba N. Initial stages of posterior vitreous detachment in healthy eyes of older persons evaluated by optical coherence tomography. Arch Ophthalmol. 2001;119(10):1475-9. PubMed PMID: 11594947
5. Milston R, Madigan MC, Sebag J. Vitreous floaters: Etiology, diagnostics, and management. Surv Ophthalmol. 2016;61(2):211-27. PubMed PMID: 26679984
6. Sebag J. Vitreous and Vision Degrading Myodesopsia. Prog Retin Eye Res. 2020;79:100847. PubMed PMID: 32151758
7. Sebag J. Ageing of the vitreous. Eye (Lond). 1987;1(Pt 2):254-62. PubMed PMID: 3308528
8. Gella L, Raman R, Pal SS, Ganesan S, Sharma T. Incidence, Progression, and Associated Risk Factors of Posterior Vitreous Detachment in Type 2 Diabetes Mellitus: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Study (SN-DREAMS II, Report No. 7). Semin Ophthalmol. 2017;32(2):191-197. PubMed PMID: 26146895
9. Ullrich M, Ivellio-Vellin H, Ivastinovic D, Palkovits S, Fernández-Vega Sanz Á, Tassignon MJ, Poyales F, Gundersen KG, Amon M, Güell JL, Vryghem JC, Nuijts RMMA, Pilwachs C, Gleiss A, Findl O; MYOPRED study group. Development of posterior vitreous detachment after lens surgery in myopic eyes - Results from the MYOPRED study. J Cataract Refract Surg. 2026 (online ahead of print). PubMed PMID: 42922391
10. Scarfone H, Rodríguez EC, Feijoo TC, Corrales L, Lotito PA, Del Carmen Romero M. Posterior vitreous detachment following phacoemulsification under low intraocular pressure: a population-based OCT study. Graefes Arch Clin Exp Ophthalmol. 2026;264(6):1813-1821. PubMed PMID: 41642306
11. Patel SN, Lee C, Cui D, Wingert AM, Zhou S, Scott IU. Association of staffing with Incidence of delayed retinal break or detachment after posterior vitreous detachment in a resident urgent care clinic. Graefes Arch Clin Exp Ophthalmol. 2022;260(3):791-798. PubMed PMID: 34661735
12. Nassrallah G, Kondoff M, Ross M, Deschenes J. Posterior vitreous detachment and incidence of delayed retinal breaks: a retrospective, 2-year study at an academic centre. Can J Ophthalmol. 2019;54(4):509-512. PubMed PMID: 31358152
13. Shah CP, Heier JS. YAG Laser Vitreolysis vs Sham YAG Vitreolysis for Symptomatic Vitreous Floaters: A Randomized Clinical Trial. JAMA Ophthalmol. 2017;135(9):918-923. PubMed PMID: 28727887
14. Ludwig GD, Gemelli H, Nunes GM, Serracarbassa PD, Zanotele M. Efficacy and safety of Nd:YAG laser vitreolysis for symptomatic vitreous floaters: A randomized controlled trial. Eur J Ophthalmol. 2021;31(3):909-914. PubMed PMID: 33148023
15. Alnajres A, Alsenani S, Almajhadi M, Alzahrani R, Alruwaily H, Almaiman N, Al-Fakhri AS, Albloushi AF, Alkatan HM. Neodymium-Doped Yttrium-Aluminum-Garnet Laser Vitreolysis for Primary Symptomatic Vitreous Floaters: A Systematic Review and Meta-Analysis. Ophthalmol Retina. 2026 (online ahead of print). PubMed PMID: 42537719
16. Zeydanli EO, Parolini B, Ozdek S, Bopp S, Adelman RA, Kuhn F, Gini G, Sallam AB, Aksakal N; EVRS Floaters Study Group. Management of vitreous floaters: an international survey the European VitreoRetinal Society Floaters study report. Eye (Lond). 2020;34(5):825-834. PubMed PMID: 32313173

PubMed Topic Searches

1. Posterior vitreous detachment, symptoms and retinal tears
2. Delayed retinal breaks and follow-up after posterior vitreous detachment
3. Laser vitreolysis for floaters
4. Vitrectomy for floaters

Connections

• Ophthalmology
• Retinal Detachment
• Epiretinal Membrane
• Diabetic Retinopathy
• Cataracts
• Blurred Vision
• Retinal Imaging

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