Acute onset flashers and floaters

Background

Eye anatomy.

• Photopsia is defined as a visual phenomenon characterized by the perception of flashes of light or flickering in the visual field
• Acute onset flashers and floaters is a common ED complaint, especially in older adults
• The critical EM concern is ruling out retinal detachment and vitreous hemorrhage, which are sight-threatening
• Most common cause is posterior vitreous detachment (PVD), which is benign but has ~10-15% risk of associated retinal tear
• Risk factors for retinal detachment: myopia (nearsightedness), prior cataract surgery, prior retinal detachment in other eye, trauma, family history, increasing age

Clinical Features

Floaters

• A sensation of gray or dark spots, cobwebs, or strands moving in the visual field
• Caused either by light bending at the interface of fluid pockets in the vitreous jelly or cells/blood located within the vitreous
• May persist for months to years
• New onset of many floaters ("shower of floaters") or sudden increase in existing floaters is more concerning than a single new floater

Flashes (Photopsia)

• Monocular, repeated, brief flashes of white light in the peripheral visual field
• Related to traction on the peripheral retina from areas of tightly adherent vitreous jelly
• Flashes occurring with movement or position change suggest mechanical traction (vitreous on retina)
• Distinguish from migraine aura: migraine visual symptoms are typically binocular, with scintillating scotoma lasting 15-30 minutes, and often followed by headache

Red Flags for Retinal Detachment

• "Curtain" or "shadow" coming across visual field (indicates retinal detachment in progress)
• Dense new floaters or shower of floaters (may indicate vitreous hemorrhage from retinal tear)
• Decreased visual acuity (suggests macular involvement)
• Visual field deficit
• Loss of red reflex on fundoscopy
• Pigmented cells ("tobacco dust" / Shafer's sign) in anterior vitreous on slit lamp

Differential Diagnosis

Acute onset flashers and floaters

• Ocular causes
  • Floaters and/or flashes
    • Posterior vitreous detachment
    • Retinal tear or retinal detachment
    • Posterior uveitis
  • Predominantly floaters
    • Vitreous hemorrhage secondary to proliferative retinopathy
    • Sympathetic ophthalmia
  • Predominantly flashes
    • Oculodigital stimulation
    • Rapid eye movements
    • Neovascular age-related macular degeneration
• Non-ocular causes
  • Intraocular foreign body
  • Migraine aura (classic)
  • Migraine aura (acephalgicmigraine)
  • Occipital lobe disorders
  • Postural hypotension

Posterior Vitreous Detachment (Most Common)

• Age-related separation of vitreous from retina
• Benign but 10-15% risk of associated retinal tear

Sight-Threatening

• Retinal detachment: flashes, floaters, visual field curtain, decreased acuity
• Vitreous hemorrhage: sudden dense floaters, decreased acuity, absent or diminished red reflex
• Retinal tear (without detachment): may progress to detachment if untreated

Other

• Migraine with visual aura (binocular, scintillating, lasts 15-30 min)
• Ocular migraine (monocular, but transient)
• Posterior uveitis (cells in vitreous, pain, redness)
• Endophthalmitis (post-surgical, painful, decreased vision)

Evaluation

Bedside Exam

• Visual acuity (each eye separately) — decreased acuity suggests macular involvement
• Visual field confrontation test — detect curtain or field defect
• Pupillary exam: RAPD suggests significant retinal pathology
• Direct ophthalmoscopy: look for blood in vitreous (obscured view = vitreous hemorrhage), retinal tears, detached retina
• Slit lamp exam: look for pigmented cells ("tobacco dust") in anterior vitreous — highly suspicious for retinal tear
• Intraocular pressure: may be low with retinal detachment

Bedside Ultrasound (POCUS)

• Ocular ultrasound is highly sensitive for detecting retinal detachment and vitreous hemorrhage
• Retinal detachment appears as a bright membrane tethered to the optic disc
• Vitreous hemorrhage appears as swirling echogenic material in posterior chamber
• Can be performed at bedside when direct fundoscopy is limited (e.g., by vitreous hemorrhage obscuring view)

Retinal Images

• 

  Central Retinal Vein Occlusion (CRVO)

• 

  Retinal detachment

• 

  CMV retinitis

• 

  Open-angle glaucoma (cupping)

• 

  Roth spots due to retinal vein occlusion (retinal hemorrhage)

• 

  Central retinal artery occlusion: cherry-red spot, retinal edema and narrowing of the vessels.

Management

Retinal Detachment

• Macula-on detachment (macula still attached): ophthalmologic emergency — same-day or next-day repair for best visual outcomes
• Macula-off detachment: urgent but not emergent (macula already detached); repair within 24-72 hours
• Position patient with detachment side down (gravity helps keep retina in place)
• Emergent ophthalmology consultation

Vitreous Hemorrhage

• Ophthalmology consultation within 24 hours
• Head-of-bed elevation (allows blood to settle inferiorly, clearing visual axis)
• Identify and treat underlying cause (diabetic retinopathy, retinal tear)

Posterior Vitreous Detachment (No Tear or Detachment)

• Reassurance that floaters typically improve over time
• Ophthalmology follow-up within 1-2 weeks (retinal tear can develop days to weeks after PVD)
• Strict return precautions

Disposition

Referral of patients with presumed posterior vitreous detachment

Clinical Assessment	Disposition
Floaters and/or flashes with “red flag” sign of acute Retinal Detachment Monocular visual field loss (“curtain of darkness”)	Same-day (immediate) referral to retinal surgeon (minutes may matter) High risk of Retinal Detachment
New-onset floaters and/or flashes with high-risk features: Subjective or objective visual reduction examination Vitreous hemorrhage or vitreous pigment on slitlamp examination	Same-day referral to ophthalmologist or retinal surgeon
New-onset floaters and/or flashes without high-risk features	Referral to ophthalmologist within 1 to 2 weeks Counsel patient regarding high-risk features
Recently diagnosed uncomplicated posterior vitreous detachment with New shower of floaters New subjective visual reduction	Rereferral to ophthalmologist to rule out new retinal tear or detachment Contact ophtho to help determine urgency
Stable symptoms of floaters and/or flashes for several weeks to months, not particularly bothersome to the patient and without high-risk features	Elective referral to ophthalmologist Counsel patient regarding high-risk features that should prompt urgent reassessment

Emergent Ophthalmology Consultation

• Macula-on retinal detachment
• Retinal tear identified on exam
• Vitreous hemorrhage with suspected retinal detachment

Urgent Ophthalmology Referral (24-48 Hours)

• Vitreous hemorrhage without retinal detachment
• Macula-off retinal detachment
• High-risk features (many new floaters, visual field changes, decreased acuity)

Routine Ophthalmology Follow-Up (1-2 Weeks)

• Isolated posterior vitreous detachment with normal exam and acuity
• Single new floater without associated flashes, visual field changes, or decreased acuity

Return Precautions (All Patients)

• New or worsening floaters
• New flashes of light
• "Curtain" or shadow in peripheral vision
• Decreased vision

See Also

Eye Algorithms

• Red eye
  • Bilateral red eyes
  • Unilateral red eye
  • Red eye (by symptoms)
  • Red eye (peds)
    • Neonatal conjunctivitis
• Periorbital swelling
• Acute vision loss (noninflamed)
• Acute onset flashers and floaters
• Painful eyes with normal exam
• Neonatal eye problems
• Retinal detachment
• Acute vision loss (noninflamed)
• Eye Exam

References

1. 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):2243-2249.