[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Ophthalmology](https://durgical.com/en/ophthalmology/) › [Approach by symptom](https://durgical.com/en/ophthalmology/areas/approach/) › Floaters and flashes

# Floaters and flashes

- Clinical approach

New floaters and flashes are usually the vitreous gel peeling off the retina. It can tear the retina, so each new episode needs a dilated exam soon.

Updated Nov 5, 2026

**See it in 3D:** [Vitreous](https://durgical.com/en/anatomy/vitreous-body/) · [Retina](https://durgical.com/en/anatomy/retina/)

## Key points

- New floaters and flashes = posterior vitreous detachment until a tear is excluded.
- Shadow or curtain = retinal detachment, same day.
- Only a dilated peripheral exam excludes a retinal tear.
- Bilateral zigzag lights for 20 minutes = migraine aura.

## What it is

Floaters are shadows cast on the retina by opacities in the vitreous; flashes (photopsia) are the retina being pulled. Their sudden onset in an adult is usually a posterior vitreous detachment, which becomes common after 50 and earlier in short-sighted people. Its danger is a retinal tear, found in a minority of acute cases, which can progress to a retinal detachment. Long-standing, unchanged floaters are usually harmless.

## Red flags

- A shower of new floaters or a sudden large increase.
- A shadow or curtain in the peripheral vision: retinal detachment.
- Reduced visual acuity.
- High myopia, previous detachment in the other eye, recent eye surgery or trauma.
- Pigment cells or blood in the vitreous on slit lamp exam: high chance of a retinal tear.

## Step-by-step approach

- Ask when it started, whether the floaters are new or a change, and whether there are flashes or a shadow.
- Distinguish migraine aura: zigzag lights in both eyes spreading over about 20 minutes, often followed by headache.
- Measure visual acuity and test the peripheral field of each eye.
- Check the red reflex: vitreous haemorrhage dulls it.
- Refer for a dilated exam of the peripheral retina; the direct ophthalmoscope cannot exclude a peripheral tear.

## Floaters and flashes: what they mean

| Picture | Likely cause | Urgency |
| --- | --- | --- |
| New floaters and flashes, no shadow | Posterior vitreous detachment | Dilated exam within about a day if red flags, otherwise within days |
| Shower of floaters, dark haze | Vitreous haemorrhage, possible retinal tear | Same day |
| [Curtain or shadow, reduced vision](https://durgical.com/en/conditions/retinal-detachment/) | Retinal detachment | Same day; emergency if central vision is still normal |
| [Zigzag lights in both eyes, then headache](https://durgical.com/en/conditions/migraine/) | Migraine aura | Not urgent if typical |
| Old floaters unchanged for years | Vitreous condensations | Routine |

## Keys to the differential

- A posterior vitreous detachment is a normal ageing event, but a symptomatic one needs a peripheral retina exam because a tear may be silent.
- A retinal tear found before detachment is treated with laser or cryotherapy in the clinic.
- Flashes that persist in one eye are retinal; flashes seen with either eye closed are cortical (migraine).

## Next step / Initial management

- New floaters or flashes: dilated retinal exam by ophthalmology, the same day if there is a shadow, reduced vision or a shower of floaters, otherwise within a few days.
- Retinal tear: laser retinopexy or cryotherapy promptly to prevent detachment.
- Retinal detachment: same-day referral for surgery.
- Uncomplicated posterior vitreous detachment: explain the warning symptoms (more floaters, flashes, a shadow) and to return at once if they appear; a follow-up exam is often arranged in the following weeks.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main risk of an acute posterior vitreous detachment?

A retinal tear, which can progress to a retinal detachment.

## Which symptom with floaters means a same-day referral?

A shadow or curtain in the vision, reduced acuity, or a sudden shower of floaters.

## Why is the direct ophthalmoscope not enough to exclude a retinal tear?

Because tears are usually in the peripheral retina, which needs a dilated exam with indirect ophthalmoscopy or a slit lamp lens.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/ophthalmology/floaters-and-flashes/)

## Connections

## See it in 3D 2

The structures of Durgical's 3D anatomy where it is found.

- [Vitreous](https://durgical.com/en/anatomy/vitreous-body/)
- [Retina](https://durgical.com/en/anatomy/retina/)

## Related 4

- [Retinal detachment: how fast to refer](https://durgical.com/en/ophthalmology/retinal-detachment-how-fast-to-refer/)
- [Dilated fundus examination: when and how](https://durgical.com/en/ophthalmology/dilated-fundus-examination-when-and-how/)
- [Ocular ultrasound and point-of-care scanning](https://durgical.com/en/ophthalmology/ocular-ultrasound-and-point-of-care-scanning/)
- [Sudden painless visual loss](https://durgical.com/en/ophthalmology/sudden-painless-visual-loss/)

## Related conditions 4

- [Retinal detachment](https://durgical.com/en/conditions/retinal-detachment/)
- [Migraine](https://durgical.com/en/conditions/migraine/)
- [Diabetic retinopathy](https://durgical.com/en/conditions/diabetic-retinopathy/)
- [Refractive errors and presbyopia](https://durgical.com/en/conditions/refractive-errors-and-presbyopia/)

[← All of ophthalmology](https://durgical.com/en/ophthalmology/)

Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.

Sources: [Posterior Vitreous Detachment](https://www.ncbi.nlm.nih.gov/books/NBK563273/) (StatPearls Publishing (NCBI Bookshelf), 2026); [Retinal Detachment](https://www.ncbi.nlm.nih.gov/books/NBK551502/) (StatPearls Publishing (NCBI Bookshelf), 2024); [Vitreous Hemorrhage](https://www.ncbi.nlm.nih.gov/books/NBK559131/) (StatPearls Publishing (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/ophthalmology/floaters-and-flashes/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/ophthalmology/floaters-and-flashes/