Flashes of light — white or silvery flashes that appear in the peripheral visual field, often triggered by eye movements — can be a sign of retinal traction or a retinal tear. When these flashes of light are sudden, new or recurrent, they require an urgent ophthalmological consultation to rule out a serious retinal complication.
Flashes of light in the eyes: what you need to know
Flashes of light, also known as photopsia or phosphenes, are visual perceptions of light without any external source. They appear as white or silvery flashes, luminous arcs or sparkles, most often in the peripheral field of vision — sometimes even with the eyes closed or in darkness.
They occur when the retina is mechanically stimulated: when the vitreous body exerts traction on it, the retina interprets this stimulation as light. Flashes of light of retinal origin are typically brief (fractions of a second), unilateral, and triggered or worsened by eye movements.
Sudden flashes of light: which warning signs require an urgent consultation?
Seek immediate medical attention if you experience:
- new, sudden and repeated flashes of light in one eye;
- flashes of light associated with a sudden increase in floaters;
- the appearance of a dark shadow or curtain across the visual field;
- decreased vision or distorted vision;
- flashes of light following eye or head trauma.
These signs, whether isolated or combined, may indicate a retinal tear or the onset of a retinal detachment — an emergency that must not be delayed.
Why can flashes of light signal a retinal emergency?
The most common cause of flashes of light is posterior vitreous detachment (PVD): the vitreous gel shrinks and pulls on the retina as it separates. In 10 to 15% of PVD cases, this traction causes a retinal tear in the periphery.
If fluid seeps beneath the retina through the tear, a retinal detachment can develop within hours to days — with a risk of permanent vision loss if the macula is affected. Flashes of light can also indicate a vitreous haemorrhage caused by the rupture of a retinal blood vessel.
Flashes of light or ocular migraine: how to tell them apart?
Flashes of light of retinal origin and the scintillating scotomas of ocular migraine can appear similar, but they have distinctly different characteristics:
- Retinal flashes of light: brief (fractions of a second), unilateral, triggered by eye movements, persisting over several days or weeks during an active PVD;
- Migrainous scintillating scotomas: last 15 to 30 minutes, progress as a luminous arc from the centre towards the periphery, may be bilateral and often precede a headache — they are neurological rather than retinal in origin.
When in doubt, only an ophthalmological examination with a dilated fundus examination can confirm or rule out a retinal origin for the flashes of light.
Risk profiles associated with flashes of light
Certain patients are more susceptible to retinal complications associated with flashes of light and should seek consultation even more promptly:
- high myopes (myopia > –6 dioptres): prematurely aged vitreous, more fragile peripheral retina;
- individuals with a history of retinal tear or detachment in the fellow eye;
- diabetic patients (risk of vitreous haemorrhage from retinopathy);
- following ocular trauma or head injury;
- after recent eye surgery (cataract surgery, intravitreal injection).
What does the emergency examination involve?
When a patient presents with flashes of light, the ophthalmologist performs a dilated fundus examination, which allows visualisation of the entire peripheral retina and detection of:
- a retinal tear (round hole or horseshoe tear);
- early retinal detachment;
- a vitreous haemorrhage;
- signs of a recent PVD (Weiss ring, peripheral traction).
If the fundus is difficult to visualise due to vitreous opacity, an ocular ultrasound is used to complete the assessment.
What treatment is available for flashes of light?
Treatment depends on the cause identified during the examination:
- if a retinal tear is discovered, it is treated urgently with laser photocoagulation to seal it and prevent progression to detachment;
- if a retinal detachment is confirmed, urgent surgical intervention is required (vitrectomy or scleral buckle);
- if the assessment reveals an uncomplicated PVD, close follow-up at 4–6 weeks is recommended, as secondary tears may develop subsequently.
Flashes of light associated with an uncomplicated PVD generally subside over several weeks as the vitreous stabilises.
FAQ: flashes of light and retinal emergencies
Are flashes of light always serious?
No, not always. An uncomplicated PVD causes transient flashes of light without immediate danger. However, since 10 to 15% of PVD cases are accompanied by a retinal tear, any episode of sudden flashes of light warrants a fundus examination to rule out a complication.
Flashes of light and floaters: which combination is dangerous?
The combination of flashes of light and a sudden increase in sudden floaters is the classic presentation of PVD with a risk of retinal tear. If a dark shadow or decreased vision is also present, the likelihood of a retinal detachment is high: this constitutes an absolute emergency.
Can flashes of light occur after physical exertion or trauma?
Yes. An eye or head injury, intense physical effort or sudden hypotension can trigger flashes of light. Direct trauma can cause a retinal tear. In this context, a prompt ophthalmological consultation is essential.
Can flashes of light recur despite an initially normal examination?
Yes. If flashes of light persist, intensify or reappear after a reassuring initial examination, a further consultation is necessary. An active PVD can cause secondary tears in the first few weeks following symptom onset.
When to consult Dr Julien Gozlan for flashes of light
Dr Julien Gozlan, an ophthalmic surgeon specialising in vitreoretinal conditions in Paris 16, sees patients on an urgent basis for fundus examinations. If you experience sudden flashes of light — especially combined with new floaters or a dark shadow — do not wait: a retinal tear treated promptly means a retinal detachment prevented.
📍 Consultation at Cabinet Ophtalmologique Paris – Auteuil
Dr Julien Gozlan welcomes you at the Cabinet Ophtalmologique Paris – Auteuil for an urgent fundus examination and the management of retinal conditions.
Book an Appointment on DoctolibFurther reading
- Sudden floaters: another warning sign frequently associated with flashes of light.
- Retinal tear: diagnosis and preventive laser treatment.
- Retinal detachment: urgent surgical management.
- Posterior vitreous detachment: the most common cause of flashes of light and eye floaters.