Reasoning GP · Algorithm · 1-page summary
Flashes and floaters — PVD, retinal tear and detachment
For: adults and children with new flashes and/or floaters, face to face or remote. Not for: a red eye without floaters, or visual loss without flashes or floaters (use the red eye or vision loss algorithm). Children go straight to block 2.
Core rule: symptoms alone cannot exclude a retinal tear. Every new flash or floater needs a dilated peripheral retinal examination, usually within 24 hours; normal acuity, fields, red reflex or direct fundoscopy exclude nothing.
0Stop — act now — screen every patient by name for these
- Shadow, curtain or new field defect; reduced vision or new persistent blur; sudden shower of floaters or red haze; poor or absent red reflex; RAPD; significant eye trauma → Same-day eye casualty.
- Pain, photophobia or redness with floaters; recent eye surgery or intravitreal injection with pain, reduced vision or new floaters → Same-day, contacting the treating eye unit directly.
- Visual loss with persistent neurological deficit → 999. Do not delay referral for BP, glucose or INR; do not stop anticoagulants; the patient does not drive.
1Triage — the history sets the speed
| Presentation | Route |
|---|---|
| New, no red flag | Dilated exam, usually ≤24 h: eye casualty, urgent eye service, optometrist able to dilate (local pathway). Not a routine sight test. |
| Transient loss | Monocular or homonymous → TIA pathway, specialist ≤24 h (NG128) |
| Central distortion | Urgent ophthalmology; wet AMD → macular service ≤1 working day; sudden or reduced vision → Same-day |
2Screen — lower the threshold
- Higher-risk eye: high myopia, previous tear or detachment, recent eye surgery, trauma, family history, Stickler, Marfan → ≤24 h, never routine.
- Known proliferative diabetic retinopathy + new floaters → ≤24 h; shower, red haze or reduced vision → Same-day
- Child, new floaters → ophthalmology ≤24 h; with visual loss, trauma or inflammation → Same-day
- Child, absent or white red reflex → consider urgent retinoblastoma referral ≤2 weeks (NG12); plus new squint → Immediately (NG127)
- First or atypical aura, persistent deficit, weakness, speech change, or older with no migraine history → consider urgent stroke or neurology assessment.
3Assess — triage only
☐ Acuity each eye, glasses or pinhole ☐ Confrontation fields each eye ☐ Pupils (RAPD) ☐ Red reflex ☐ Direct fundoscopy if competent ☐ Anterior segment ☐ Do symptoms stay in one eye when the other is covered?
BP, glucose, INR only if bleeding or retinopathy is suspected. Eye service: dilated exam, B-scan, OCT.
4Classify — the eye service confirms
- PVD — one new ring or cobweb floater, brief peripheral flashes in one eye → still dilated exam ≤24 h; "uncomplicated" only after it.
- Tear or detachment — many new dots, spreading shadow or curtain, reduced vision → same-day.
- Vitreous haemorrhage — red haze, many dark floaters, poor red reflex → same-day, even if anticoagulated or diabetic.
- Migraine aura — zig-zag in both eyes' fields, develops over ≥5 min, lasts 5–60 min, fully reversible → reassure only if typical.
- Benign floaters — long-standing, unchanged, no flashes, normal acuity and fields. Any change → reassess.
- Uncertain — treat as new flashes and floaters: dilated exam ≤24 h.
5Treat today — no drug treatment in primary care
- Tear or detachment: laser, cryotherapy or surgery by the eye service only. The GP's job is speed and advice.
- Anticoagulants and antiplatelets: do not stop for floaters or vitreous haemorrhage; the eye team and prescriber decide.
- Gas in the eye after surgery: no flying and no nitrous oxide until the gas has gone; carry the wristband.
- Uncomplicated PVD after dilated exam: flashes settle over weeks, floaters fade over weeks to months; give written warning symptoms.
6Refer routinely
- Long-standing unchanged floaters, normal acuity and fields, no flashes or risk factors → routine optometrist.
- Follow-up after PVD is set by the examining eye service.
- Diabetes aged 12+ → NHS Diabetic Eye Screening. Migraine with aura → CG150; check contraception (UKMEC).
7Never reassure by
- Normal acuity, confrontation fields or direct fundoscopy.
- A normal red reflex or central fundus view.
- Calling it "just a PVD" before a dilated examination.
- One negative eye exam: a tear can develop in the following weeks.
- Transient monocular loss treated as "just my eye": it is a TIA route.
- A routine optometry slot in place of a prompt dilated exam.
8Safety-net — in writing, then document it
Same day “A shadow or curtain, a sudden shower of new floaters, more flashes, or blurred vision — go to eye casualty or call NHS 111 straight away, even at night or at the weekend. Don't wait for a GP appointment.” Same-day contact: symptoms in the other eye, floaters that change, or new distortion of straight lines → urgent eye assessment, usually ≤24 h.
Every patient: written warning signs and out-of-hours contacts; they apply to both eyes; no driving while vision or field is affected (DVLA). 999 for visual loss with a persisting neurological deficit.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Acuity and fields recorded for each eye
Dilated exam booked ≤24 h, or done by the eye service
Anticoagulants unchanged; driving advice given
Written safety-net with out-of-hours route
Summary of the full Reasoning GP flashes and floaters algorithm, which holds the detail, examination, treatments and evidence. Sources: College of Optometrists guidance on flashes and floaters; Royal College of Ophthalmologists emergency eye care (2024); NICE NG128, NG82, NG127, NG12 (updated April 2026), CG150; DVLA; local urgent eye-care pathway. Clinical reference — follow local eye-care pathways.