Posterior vitreous detachment

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

The vitreous is a transparent gel whose posterior surface lies against the retina. Age-related liquefaction and changes in attachment allow this surface to separate, producing a posterior vitreous detachment. The separation may be incomplete or continue to evolve, so the clinical question is not simply whether a PVD exists. The examiner must also determine whether persistent traction has produced a retinal break, haemorrhage or detachment. Explain the difference between vitreous separation and retinal separation early: the similar names can leave a patient either unnecessarily frightened or falsely reassured.

Floaters arise when vitreous opacities cast shadows on the retina. Patients often describe threads, insects, dots or a translucent ring that moves with eye movement and then drifts. Brief arcs of light can occur when traction stimulates the retina, often at the temporal edge of vision and more noticeably against a dark background. Ask the patient to describe what has changed rather than merely confirming the word floater. A longstanding stable thread and a sudden shower of dark dots carry different implications. Persistent central blur or a fixed field defect needs additional explanation.

An uncomplicated PVD is diagnosed after an adequate examination has excluded important associated pathology. Normal acuity is reassuring about central function but does not exclude a peripheral tear. A visible Weiss ring can support posterior vitreous separation near the optic disc, but it neither proves that all vitreoretinal traction has resolved nor certifies an intact peripheral retina. The final explanation should state what was examined, what was found and what future change requires reassessment. This makes reassurance specific and allows another clinician to understand its limits.

Key points

Posterior vitreous detachment is separation of the posterior vitreous surface from the retina, usually as the vitreous changes with age.
Moving spots, cobwebs or a ring-shaped floater and brief peripheral flashes are typical symptoms, but cannot establish a benign diagnosis by history alone.
Retinal traction during separation can tear the retina or disrupt a vessel, producing a sight-threatening complication.
Assessment includes monocular visual function, anterior vitreous examination and a dilated peripheral retinal examination using an indirect viewing technique.
Confirmed uncomplicated PVD generally requires explanation and safety advice rather than medication or a procedure.
Give written instructions about new symptoms and a clear urgent contact route, whether or not a planned follow-up examination is arranged.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Age-related vitreous change

Liquefaction of the vitreous and alteration of its attachments permit the posterior vitreous surface to separate from the retina. The process may evolve rather than occurring uniformly in one instant.

Myopia and ocular history

Myopia, previous ocular surgery and trauma alter the clinical context of vitreoretinal symptoms. These factors increase the importance of assessing for a retinal complication rather than assuming uncomplicated age-related change.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Separation at the retinal interface
The posterior vitreous cortex moves away from the retina as vitreous structure and adhesion change. Residual attachment at particular sites can create traction during this transition.
2
Retinal stimulation
Mechanical traction stimulates retinal tissue and can generate brief perceptions of light without an external light source. More intense or changing photopsia must be interpreted alongside structural findings.
3
Shadows from vitreous material
Condensed vitreous or other suspended material interrupts light reaching the retina, producing mobile perceived opacities. Blood and inflammatory debris can also cause floaters, so the symptom is not specific to uncomplicated PVD.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Mobile vitreous shadows

Floaters drift after gaze changes and may be easier to see against a bright plain background. Ask about onset, number and change, especially a sudden cloud or shower that may represent blood.

Brief traction-related photopsia

Momentary peripheral flashes in one eye are compatible with vitreoretinal traction. Repeated flashes accompanied by a new shadow or visual decline require urgent reassessment even if pain is absent.

Evidence of uncomplicated separation

An examined PVD with unchanged vision, no retinal tear or detachment and no anterior vitreous pigment supports conservative management when reliable advice and access to reassessment are provided.

Features inconsistent with simple reassurance

A fixed curtain, persistent reduction in vision, vitreous haemorrhage, pigment or an inadequately seen peripheral retina increases concern. Do not regard the presence of a PVD as an explanation that excludes these complications.

Red flags requiring action

A dark curtain, missing peripheral vision or newly reduced acuity requires immediate contact with the emergency eye service.
Pigment in the anterior vitreous or a vitreous bleed with acute symptoms warrants emergency referral for a possible retinal break.
An incomplete peripheral retinal examination leaves important uncertainty; arrange examination by a clinician with appropriate equipment and competence.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
History and monocular acuityFirst step
Why
Identify the onset, functional impact and factors increasing retinal risk.
Interpretation and limitations
Document each eye separately with usual correction, previous retinal disease, myopia, trauma and ocular surgery. Central chart acuity may remain good despite a peripheral retinal break.
02
Slit-lamp examination of the vitreous
Why
Look for posterior separation, pigment cells and haemorrhage.
Interpretation and limitations
Pigment in the anterior vitreous is a warning of a retinal break and warrants emergency retinal assessment; its absence does not independently exclude a tear.
03
Dilated retinal examination with indirect viewing
Why
Inspect the retinal periphery for breaks and associated detachment.
Interpretation and limitations
An adequately trained examiner assesses the peripheral retina and uses additional techniques when necessary. A routine undilated direct view or central photograph cannot provide an equivalent exclusion.
04
Specialist ultrasound or macular imaging when needed
Why
Investigate obscured fundal views or unexplained central symptoms.
Interpretation and limitations
B-scan can assess posterior structures when haemorrhage blocks the view, while OCT can clarify a macular interface problem. Neither a negative scan nor a normal central OCT automatically excludes every peripheral break.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Retinal break or detachment

New pigment, haemorrhage, a fixed shadow or visual decline raises concern for a retinal complication. A PVD can coexist with the break that requires urgent treatment.

Posterior segment inflammation

Inflammatory cells within the vitreous can create floaters, sometimes with blurred vision or other ocular inflammatory signs. Examination is needed to distinguish inflammation from ordinary vitreous condensation.

Migraine-related visual phenomena

A gradually evolving visual pattern perceived in both eyes can suggest cortical aura. A patient's description of one-sided symptoms needs clarification, and new monocular retinal warning features require eye assessment.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01New symptomsArrange an adequate examination promptlyFirst stepA patient develops new flashes or floaters without an established assessment of the current episode.

1Identify visual decline, a field shadow, trauma and previous retinal problems, and arrange the appropriate urgent eye assessment.
2Seek same-day emergency retinal review for a curtain, a sudden shower, haemorrhage or other signs of a possible break or detachment.
3If examination equipment or competence is insufficient, refer to a service able to assess the peripheral retina rather than recording a presumed benign PVD.

02Uncomplicated findingsExplain the result and support adaptationDilated examination confirms PVD with preserved vision and no retinal complication.

1Describe the change in the vitreous and explain that ordinary uncomplicated separation does not require eye drops to reattach the gel.
2Discuss the impact of floaters on reading and daily tasks, acknowledging that symptoms may persist while becoming less intrusive.
3Provide written warning symptoms and the exact route to urgent reassessment; arrange any planned review according to examination findings and the local retinal pathway.

03Subsequent changeReassess a potentially evolving retinal eventSymptoms change after a PVD diagnosis or the initial retinal examination was incomplete.

1Treat a new curtain, a substantial increase in floaters or reduced vision as a new clinical event requiring urgent review.
2Tell the receiving clinician what was previously examined, whether haemorrhage or pigment was present and when the symptoms changed.
3Avoid promising that a previous normal examination or a particular number of symptom-free days makes a delayed retinal break impossible.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Retinal tearing

Vitreous traction can exceed the strength of a focal retinal attachment and create a break. Symptoms may change as the tear develops, including after the first examination.

Bleeding into the vitreous

A disrupted retinal vessel can release blood into the vitreous and obscure vision or examination. The associated possibility of a retinal break needs urgent specialist assessment.

Rhegmatogenous retinal detachment

Fluid can pass through a retinal break and separate the retina from its underlying support. A progressive field shadow or central loss indicates a potentially sight-threatening consequence.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Record whether the peripheral retinal examination was complete and whether any area could not be visualised, with a plan to resolve that limitation.
A planned follow-up interval depends on risk, ongoing traction, haemorrhage and examination quality; it does not replace immediate review for new warning symptoms.
Ask patients to seek urgent help for a new field shadow, a sudden shower of floaters or diminished vision in either eye, including after routine discharge.
Review persistent disabling symptoms in context, including reading, work and mental distress, without assuming that all continuing floaters require intervention.
Explain that symptoms in the fellow eye represent a separate episode needing its own assessment rather than an automatic repeat of the previous benign diagnosis.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

PVD and retinal detachment differ

The vitreous can separate while the retina remains attached and functional. A retinal detachment disrupts the relationship between the neurosensory retina and its supporting layers and needs a different treatment pathway.

Normal acuity has a limited reach

A patient may read the smallest available line while a peripheral tear is present. The combination of symptoms, vitreous findings and peripheral examination is more informative than chart acuity alone.

Persistent floaters need proportionate discussion

When floaters remain functionally troublesome after retinal disease has been excluded, a specialist can discuss the burden and procedural risks. NICE restricts YAG laser vitreolysis for symptomatic floaters to research because evidence remains insufficient.

Activities follow individual findings

Avoid imposing indefinite restrictions on every patient with uncomplicated PVD. Ask about high-impact activities and follow any individual retinal-team advice, particularly if a tear, haemorrhage or recent treatment changes the situation.

11Common pitfallsFrequent interpretation and management errors.

01
Calling a PVD harmless before the peripheral retina has been adequately examined for an associated break.
02
Using the lack of pain or normal central acuity to dismiss a new curtain or a sudden shower of floaters.
03
Treating an observed Weiss ring as proof that the entire vitreous has separated safely.
04
Telling patients to wait for their next appointment when new symptoms develop after an initially normal retinal examination.